WO2015042621A2

WO2015042621A2 - Methods for production of fertile putative intergeneric hybrid plants from sorghum and maize and/or maize and sorghum crosses

Info

Publication number: WO2015042621A2
Application number: PCT/AP2013/000002
Authority: WO
Inventors: Alexander BOMBOM Jr.; Emilio OVUGA
Original assignee: Bombom Alexander Jr; Ovuga Emilio
Priority date: 2013-09-27
Filing date: 2013-09-27
Publication date: 2015-04-02
Also published as: WO2015042621A3; WO2015042621A9

Abstract

The present invention relates to methods of obtaining fertile putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants and plants produced thereby. In certain aspects, fertile putative sorghum x maize intergeneric hybrid plants are produced by crossing a sorghum parent plant NOT comprising a sorghum recessive mutant iap allele with pollen from a maize parent plants comprising a recessive mutant endosperm allele such as waxy1 (wx1) and/or opaque-2 (o2). In further aspects, the invention provides methods for the production of fertile putative maize x sorghum intergeneric hybrid plants and plants produced thereby. Specifically, fertile putative maize x sorghum intergeneric hybrid plants are produced by crossing a maize parent plant as female and comprising a recessive mutant endosperm allele such as waxy1 (wx) and/or opaque-2 (o2), wherein the mutant alleles maybe expressed in the homozygous single or double recessive state with pollen from a sorghum parent plant. The invention also provides methods for the development of subsequent filial generations of the putative F₁ sorghum x maize and/or maize x sorghum intergeneric hybrid plant and plants thereof. Methods of utilising sorghum x maize and/or maize x sorghum intergeneric hybrid plants, progeny and products obtained therefrom are also provided.

Description

Title of Invention: Methods for Production of Fertile Putative Intergeneric Hybrid Plants from Sorghum and Maize and/or Maize and Sorghum Crosses

Background of the invention

The present invention was initiated in 2009 and developed out of curiosity and desire by the inventors to contribute to agricultural development through the sorghum x maize and/or maize x sorghum technology. The work and observations presented in this invention were carried out using personal and/or family resources of the inventors. Additional work and effort is required to conclusively provide proof of concept and validate the existence and true identity of hybrid plants derived from the sorghum x maize and/or maize x sorghum crosses. This is an extensive research venture that requires the additional efforts and collaboration of other research groups and/or business partners. This work is dedicated to the memory of Dr. Justus Imanywoha whose simplicity and mentorship has been an inspiration to the first inventor (Alexander Bombom). "Always think outside the box, you might find something interesting", he said. Alexander Bombom is also grateful to Dr. Phinehas Tukamuhabwa and Professor Emilio Ovuga for encouraging him with suggestions, questions and challenges to explore this important piece of work further.

Field of the invention

The present invention relates generally to the field of agriculture with respect to the discipline of plant breeding and genetics. Specifically, it relates to putative fertile sorghum x maize and/or maize x sorghum intergeneric hybrid plants and methods for production thereof including methods for producing hybrid plants beyond the Fi intergeneric hybrid generation. This invention also provides for the use of putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants, progeny and parts thereof including products obtained therefrom.

Description of related art

Maize and sorghum are important staple cereals in Uganda and most of sub-Saharan Africa and contribute to a large portion of the caloric intake among the population in region. However, a constant rise in population growth rates implies that demand for more food is projected to rise to over 52 million tonnes annually by the year 2020 (Pingali, 2001). Furthermore, trends in climate change, a diminishing genetic resource base, an expanding need for livestock feed and a growing demand for maize and sorghum in food industry as well as for non-food uses such as industrial starch and biofuels, implies that resilient and more specialized crop plants and/or varieties need to be developed. Maize and sorghum belong to the grass family (Poaceae) and each species possesses unique grain and/or crop attributes better suited to different end-user needs. Improvement for crop characteristics such as grain quality (protein, starch, Beta carotene etc.), drought and heat tolerance, increased grain and/or biomass yield, pest and disease resistance, resistance to weeds, for example striga, acid and/or alkaline soil tolerance can be harnessed if genetic material from maize and sorghum were to be combined in a single plant.

Wide crosses provide opportunity to generate novel sources of genetic variation among important crop plants with the benefit of gene transfer, induction of haploids and/or creation of new species (Nitzsche and Zenkteler, 1984). Reports of successful interspecific and intergeneric hybridizations among cereals have been documented (Nitzsche and Zenkteler, 1984). The most notable cereal intergeneric hybrid and new species currently under production being Triticale derived from a cross between wheat and rye (Nitzsche and Zenkteler, 1984). Efforts to hybridize maize and sorghum to obtain true fertile hybrid plants have been unsuccessful (Laurie and B.ennet, 1989; Mock and Loescher, 1973) and may be attributed to a multiple of factors that include both genetic and/or physical barriers. A recessive allele referred to as inhibition of alien pollen (iap) that allows for alien pollen tubes to grow into sorghum styles has been identified (Laurie and Bennett, 1989). Successful development of interspecific hybrids between sorghum and johnsongrass [Sorghum halepense (L.) Pers.] have been reported (Dweikat, 2005). More recently, development of the sorghum line Tx3361 possessing the iap allele has also facilitated successful intergeneric hybridization between sorghum (Sorghum bicolor) and sugar cane (Saccharum spp) producing viable hybrid seed (Hodnett et al., 2010).

The present invention documents for the first time observation of fertile putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants derived from a cross between maize and sorghum (Bombom, unpublished data). The precise molecular and/or genetic factors leading to this success are yet to be elucidated although personal intuition of the inventors points to genotype specific factors inherent within plants of the Zea and Sorghum genera used. The technology derived from this invention is expected to impact significantly on agricultural development in Africa and beyond more specifically with regard to improvement of either one of the two crop species for different agronomic traits.

Summary of the invention The present invention provides a sorghum x maize intergeneric hybrid plant derived from the crossing of sorghum as the female parent plant and maize as the male parent plant (pollen donor) to obtain a progeny plant therefrom. The sorghum parent plant does not comprise a genetic compatibility system such as the recessive sorghum iap allele reported earlier and may be male fertile or carry the male sterility trait. In other aspects, for example, the maize parent plant is derived from the genus Zea and family Poaceae. In certain specific embodiments, the maize parent plant may be a Zea mays subspecies including Zea mays var. amylacea (Flour corn), Zea mays var. everta (Popcorn), Zea mays var. indentata (Dent corn), Zea mays var. indurate (Flint corn), Zea mays var. saccharata and Zea mays var. rugosa, Zea mays (Amylomaize), Zea mays var. tunicata (Pod corn) or Zea mays var. japonica (Striped maize). In more specific aspects, the sorghum and/or maize parent plant comprises one or more transgenes.

In more specific embodiments, the present invention also provides a maize x sorghum intergeneric hybrid plant derived from the crossing of maize as the female parent plant and sorghum as the male parent plant (pollen donor) to obtain a progeny plant therefrom. The maize parent plant may comprise a homozygous recessive mutant endosperm allele such as waxyl (wxl) or opaque-2 (o2) and may be expressed in the homozygous single or double recessive state. The maize parent plant may be a Zea mays subspecies including Zea mays var. amylacea (Flour corn), Zea mays var. everta (Popcorn), Zea mays var. indentata (Dent corn), Zea mays var. indurate (Flint corn), Zea mays var. saccharata and Zea mays var. rugosa, Zea mays (Amylomaize), Zea mays var. tunicata (Pod corn) or Zea mays var. japonica (Striped maize). In more particular aspects, the Zea mays plant may comprise one or a combination of homozygous recessive mutant endosperm alleles including but not limited to amylose extender (ae), dull (du), waxy (w ), sugary-1 (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken-1 (sh), shrunken-2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2 (fl2). In other aspects, for example, the sorghum parent plant is derived from the genus Sorghum and family Poaceae. In certain specific embodiments, the sorghum parent plant may be a Sorghum bicolor plant or a hybrid between Sorghum bicolor cultivars/varieties or a wild sorghum variety. In more specific aspects, the sorghum and/or maize parent plant comprises one or more transgenes.

In one embodiment, the invention provides sorghum x maize intergeneric hybrid plants produced from a cross wherein the sorghum parent plant is used as the female. In specific aspects, the sorghum parent plant is a Sorghum bicolor plant or a hybrid between Sorghum bicolor cultivars/varieties or a wild sorghum variety. In more specific aspects, the sorghum parent plant does not comprise a homozygous recessive sorghum iap allele. In further embodiments, the sorghum parent plant may be male fertile or comprise a male sterility trait, such as a cytoplasmic or genetic male sterility allele (e.g., sorghum ms3). In a specific embodiment, the sorghum parent plant may be defined as an agronomically elite sorghum plant, wherein, agronomically elite refers to a culmination of distinguishable traits contributing to a beneficial phenotype, which allows a producer to harvest a product of commercial value (Rooney et al, 2010) (PCT US2009/051706). Such traits may include yield, disease resistance, pest resistance, environmental stress tolerance, starch yield and quality and important nutritional components. In yet further embodiments, the sorghum parent plant may be a plant of sorghum line ATx630, ATx623, BTx630, Epuripur.

In yet another embodiment, the invention provides maize x sorghum intergeneric hybrid plants produced from a cross wherein, the maize parent plant is used as the female. In specific aspects, the maize parent plant is an inbred line (IL), open pollinated variety (OP V), hybrid, isogenic or near isogenic line or synthetic cultivar. In more specific aspects, the maize parent plants comprise a homozygous recessive mutant endosperm allele such as wxl or o2 and may be expressed in a homozygous single or double recessive state in the endosperm. In yet further embodiments, the maize parent plant may be a plant of maize line w /Hi27, CML182, 1 15-28 or Longe-5 (OPV).

In another aspect, the invention provides a part of sorghum x maize and/or maize x sorghum intergeneric hybrid plant disclosed herein. A part of the sorghum x maize and/or maize x sorghum intergeneric hybrid plant includes, but is not limited to, a protoplast, cell, gamete, meristem, leaf, root, anther, pistil, flower, seed, embryo, stalk, petiole or grain. In other aspects, a sorghum x maize and/or maize x sorghum intergeneric hybrid seed is provided and may be defined as comprising a functional endosperm. In further aspects, a plant seed may comprise an artificial seed coat comprising but not limited to a pesticide, a fungicide (see for example, U.S. Pat. No. 3,849,934) or other coating agents. It is worth noting that seed coat agents are important in increasing viability (e.g. percent of seeds that germinates) or improve the storability of plant seeds over long periods of time. In still further aspects, a sorghum x maize and/or maize x sorghum intergeneric hybrid plant part is provided of a plant comprising a doubled number of chromosomes, such as plant gamete comprising 2n chromosomes. Such gametes may, in certain aspects, be produced by treating a sorghum x maize and/or maize x sorghum intergeneric hybrid plant with a microtubule inhibiting agent or chromosome doubling agent, such as a chemical chromosome doubling agent (e.g., Colchicine).

In other aspects, the sorghum x maize and/or maize x sorghum intergeneric hybrid plant provided herein may be defined as comprising one or more transgenes. For instance, the sorghum x maize and/or maize x sorghum intergeneric hybrid plant can comprise a transgene, which confers enhanced starch content and/or quality, protein quality, aflatoxin resistance, disease resistance, insect and/or pest resistance, herbicide resistance, drought tolerance, acidic soil tolerance, salt tolerance, water logging, male sterility, Beta carotene improvement, grain yield or increased biomass. In specific embodiments, the transgene can be directly introduced into the sorghum x maize and/or maize x sorghum intergeneric hybrid plant. In yet further embodiments, a transgene may be inherited from a parent plant. The parent plant may have been directly transformed or may have inherited the transgene from a progenitor thereof. Furthermore, the present invention provides a method involving crossing a sorghum parent plant with a second plant wherein the sorghum parent plant and/or second plant comprise a transgene and selecting a progeny plant that comprises the transgene. In other specific aspects, the invention also provides a method involving crossing a maize parent plant with a second plant wherein the maize parent plant and/or second plant comprise a transgene and selecting a progeny plant that comprises the transgene. In other aspects, a method involving breeding a transgenic plant of the invention may comprise selecting a progeny plant by marker assisted selection (e.g., by detection of a transgene or product thereof) (Rooney et al., 2010).

In further embodiments, there is provided a progeny plant of a sorghum x maize and/or maize x sorghum intergeneric hybrid plant described herein. In some aspects, a progeny plant may be grown from a seed. In still further embodiments, there is provided a tissue culture of regenerable cells of sorghum x maize and/or maize x sorghum intergeneric hybrid plants described herein. The regenerable cells could be from embryos, meristematic cells, pollen, ovules, leaves, roots, root tips, anther, pistil, flower, seed, boll or stem of a sorghum x maize and/or maize x sorghum intergeneric hybrid plant. Thus, in some aspects there is provided a sorghum x maize and/or maize x sorghum intergeneric hybrid plant regenerated from tissue culture regenerable cells. In still further embodiments, there is provided a method for producing a commercial product comprising obtaining a sorghum x maize and/or maize x sorghum intergeneric hybrid plant or a part thereof, and producing a commercial product therefrom. The commercial product could be food (grain or grain flour commonly used in making bread), animal feed, silage, malt beverages, alcoholic or non-alcoholic beverages. In some aspects, the sorghum x maize and/or maize x sorghum intergeneric hybrid plant may be combined with plants from other gena such as Saccharum to produce a commercial product such as ethanol, molasses, bagasse, biodiesel, bioplastic or fermentable biofuel feed stock. Thus, a commercial product involving the use of a sorghum x maize and/or maize x sorghum intergeneric hybrid plant or part thereof, to produce a commercial product form part of this invention.

In further specific embodiments, a "Sormaize" intergeneric hybrid plant is provided, developed by crossing a sorghum parent plant as female with a maize (Zea) parent plant as male. The sorghum parent plant could be an inbred line, hybrid between sorghum and its wild sorghum relatives, cultivar or land race. In more specific aspects, the sorghum line does NOT comprise a recessive sorghum iap allele. In other specific aspects, the maize parent plant used in the cross comprises pollen of genotype homozygous recessive mutant waxy (wx) allele and may be an inbred line, near isogenic line, hybrid, open pollinated variety or cultivar. Further still, the development of <="sormaize" intergeneric hybrid plants may include Zea plants comprising homozygous single or double recessive mutant alleles including but not limited to amylose extender (ae), dull (du), waxy (wx), sugary- 1 (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken-1 (sh), shrunken-2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2 (fl2). In yet other specific aspects, the Zea plants used as male may include but not limited to Zea mays var. Ceratina, Zea mays var. amylacea (Flour corn), Zea mays var. everta (Pop corn), Zea mays var. indentata (Dent corn), Zea mays var. indurate (Flint corn), Zea mays var. saccharata (Sweet corn) and Zea mays var. rugosa, Zea mays (Amylomaize), Zea mays var. tunicata (Pod corn) or Zea mays var. japonica (Striped maize). In certain specific aspects, a "sormaize" plant may be produced by crossing a sorghum parent plant and a wxlHiH, CML182, 1 15-28 or Longe-5 lines of Zea mays plant.

In a further aspect, the invention provides a sorghum plant or part thereof, comprising a male sterility trait wherein the plant is not homozygous for a recessive sorghum iap allele. The male sterility trait may be characterised as cytoplasmic or genetic male sterility. In some aspects, the sorghum plant comprises Al type cytoplasmic sterility. In certain specific aspects, the sorghum plant may be a plant of line ATx630. In still further aspects of the invention, a sorghum plant or part thereof is male fertile and does not comprise homozygous recessive sorghum iap allele. In certain specific aspects, the sorghum plant may be a plant of line BTx630, Epuripur.

In other specific embodiments, a "Maisorghum" intergeneric hybrid plant is provided, developed by crossing a maize parent plant as female with a sorghum parent plant as male. The maize parent plant could be an inbred line, hybrid, open pollinated variety or synthetic cultivar. In more specific aspects, the maize parent plant and/or line comprises a recessive endosperm mutant allele such as waxy (wx). In some aspects, development of "maisorghum" intergeneric hybrid plants may include use of Zea plants comprising homozygous single or double recessive mutant alleles in different combinations including but not limited to amylose extender (ae), dull (du), waxy (wx), sugary-1 (su), sugary-2 (su2), brittle-l (btl), brittle-2 (bt2), shrunken- 1 (sh), shrunken- 2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2 ( 12). In some specific aspects, "maisorghum" plants may be produced by crossing a maize parent plant with a BTx630, BTx623, Seredo or Epuripur sorghum line. In a further aspect, the invention provides a maize plant or part thereof, comprising homozygous recessive wx, o2 and/or wx-o2 allele. In certain specific aspects, the maize plant may be a plant of line /Hi27, Longe-5 or 1 15-28 respectively.

In a further aspect, the invention provides a method for producing sorghum x maize intergeneric hybrid embryos, the method comprising the steps of: a) crossing a sorghum parent plant not homozygous for the sorghum iap allele and is used as the female with maize pollen of genotype comprising homozygous recessive mutant endosperm allele; b) obtaining a sorghum x maize intergeneric hybrid embryo resulting from the crossing; c) growing the hybrid embryo to produce a sorghum x maize intergeneric hybrid plant to maturity (herein referred to as Fl progeny). In certain specific aspects, methods for producing an intergeneric sorghum x maize embryo as described herein may be further defined as producing a hybrid seed, wherein the hybrid seed comprises an embryo and functional endosperm. In other aspects of the invention, embryos (e.g. embryos associated with a non-functional endosperm for example due to post-zygotic incompatibility, may be rescued using tissue culture methods to produce sorghum x maize intergeneric hybrid plants. In a further aspect, the sorghum parent plant for use in methods described herein comprises male sterility, such as comprises genetic male sterility or cytoplasmic male sterility. In still further aspects of the invention, the sorghum parent plant for use in methods described herein comprises male fertility, wherein pollination of sorghum parent plant florets requires emasculation prior to hybridisation with maize pollen. In some embodiments, the method further comprises d) harvesting seed comprising embryo and functional endosperm of mature sorghum x maize intergeneric hybrid plants (Fl progeny).

In still a further aspect, a method of the invention may comprise producing a plurality of sorghum x maize intergeneric hybrid plants and selecting hybrid plants comprising characteristics similar to or different from either parent plant. In some embodiments, the method further comprises, e) backcrossing the sorghum x maize intergeneric hybrid plant to obtain a monocot plant. In a further embodiment, the method comprises further backcrossing the plant to produce an introgressed progeny plant homozygous for at least one introgressed trait or gene. In more specific embodiments, the backcrossing may be carried out between a sorghum x maize intergeneric hybrid, or progeny thereof and a sorghum parent plant or a maize parent plant. The backcrossing could be serial backcrossing such as backcrossing for at least 2 to 10 times. In still further embodiments, the method comprises, f) crossing first generation (Fl) sorghum x maize intergeneric hybrid progeny plants with itself to obtain second generation (F2) hybrid plants expressing plant characteristics similar to or different from either parent plant. In still further aspects, the invention provides for crossing two putative sorghum x maize intergeneric hybrid plants that are genetically distinct from each other to obtain a monocot plant.

In a further embodiment, the invention also provides a method for producing maize x sorghum intergeneric hybrid embryos, the method comprising the steps of: a) crossing a maize parent plant homozygous for a recessive mutant waxy (wx) or opaque-2 (o2) allele and is used as female with sorghum as the male parent plant; b) obtaining a maize x sorghum intergeneric hybrid embryo resulting from the crossing; c) growing the hybrid embryo to produce a maize x sorghum intergeneric hybrid plant to maturity (herein referred to as Fl progeny). In certain specific aspects, methods for producing an intergeneric maize x sorghum embryo as described herein may be further defined as producing a hybrid seed, wherein the hybrid seed comprises an embryo and functional endosperm. In other aspects of the invention, embryos (e.g. embryos associated with a non-functional endosperm, may be rescued using tissue culture methods to produce maize x sorghum intergeneric hybrid plants. In some embodiments, the method further comprises; d) harvesting seed comprising embryo and functional endosperm of mature maize x sorghum intergeneric hybrid plants (Fl progeny). In still further aspects, a method of the invention may comprise producing a plurality of maize x sorghum intergeneric hybrid plants and selecting hybrid plants comprising characteristics similar to or different from either parent plant. In some embodiments, the method further comprises, e) backcrossing the maize x sorghum intergeneric hybrid plant to obtain a monocot plant. In a further embodiment, the method comprises further backcrossing the plant to produce an introgressed progeny plant homozygous for at least one introgressed trait or gene. In more specific embodiments, the backcrossing may be carried out between a maize x sorghum intergeneric hybrid, or progeny thereof and a maize parent plant or a sorghum parent plant. The backcrossing could be serial backcrossing such as backcrossing for at least 2 to 10 times. In still further embodiments, the method comprises, f) crossing first generation (Fl) maize x sorghum intergeneric hybrid progeny plants with itself to obtain second generation (F2) hybrid plants expressing plant characteristics similar to or different from either parent plant. In still further aspects, the invention provides for crossing two maize x sorghum intergeneric hybrid plants that are genetically distinct from each other to obtain a monocot plant.

In certain aspects, a second parent plant crossed to a sorghum or maize plant in accordance with the intervention is a plant in the Poaceae family. The second plant may be a Zea, Saccharum, Panicum, Miscanthus, Erianthus, Sorghastrum Sorghum or Pennisetum. In certain specific embodiments, the second monocot plant is a Zea mays mays, Zea mays huehuetenangensis, Zea mays mexicana, Zea mays parviglumis, Zea nicaraguensis, Zea perennis, Zea diploperennis, Zea luxurians, Zea diploperennis, Saccharum officinarum, Saccharum spontaneum, Saccharum officinarum x Saccharum spontaneum hybrid plant, Pennisetum purpureum, Pennisetum ciliare, Pennisetum glaucum, Panicum virgatum, Sorghastrum nutans, Andropogon gerardii, Andropogon hallii, Arundo donax, Tripsicum dactyloides, Sporobolus airoides, Schizachyrium scoparium, Miscanthus floridulus, Sorghum bicolor or it wild relatives or Miscanthus sinensis plant. In some aspects, backcrossing may be carried out between the sorghum x maize and/or maize x sorghum intergeneric hybrid plant or progeny thereof and a non-sorghum or non-maize parent plant within the Poaceae family.

In still further aspects, characteristics for expression in sorghum x maize and/or maize x sorghum intergeneric hybrid plants may include improved agronomic characteristics of agricultural and industrial significance as influenced by heterosis resulting from specific parental lines used in the crossing. Specific characteristics may include but not limited to, enhanced starch yield, content and/or quality, protein quality, aflatoxin resistance, disease resistance, insect and/or pest resistance, herbicide resistance, drought tolerance, acidic soil tolerance, alkaline soil tolerance, water logging, fertility, photoperiod insensitivity, seed size, seed color, Beta carotene improvement, germination, increased biomass, vegetative propagation, seed viability after storage, height, stem diameter, grain yield, cyanide content or any other characteristics of interest.

In certain aspects, non-fertile sorghum x maize and/or maize x sorghum intergeneric hybrid plants or seed or Fl progeny may be treated with a chromosome-doubling agent to increase fertility, such as a chemical chromosome-doubling agent (e.g. Colchicine or functional equivalent). Treatment of sorghum x maize and/or maize x sorghum intergeneric hybrid plants with a chromosome-doubling agent may be used to generate fertile or partially fertile allopolyploid plants that are capable of self-reproduction. After treatment, the sorghum x maize and/or maize x sorghum intergeneric hybrid plant or seed or Fl progeny may be assessed and selected for fertility as a male and/or female plant. In a further aspect, the sorghum x maize and/or maize x sorghum intergeneric hybrid produced from previous methods may be in form of a seed or a plant.

Definition of terms

As used herein, the term "Sormaize" refers to a fertile putative intergeneric hybrid between a plant from the genus Sorghum as the female parent plant and a plant from the genus Zea (or a hybrid thereof) as the pollen donor or male parent plant. A Sormaize plant or plant part may be defined as comprising at least one chromosome or chromosomal segement from the genus Sorghum and at least one chromosome or chromosomal segement from the genus Zea.

As used herein, the term "Maisorghum" refers to a fertile putative intergeneric hybrid between a plant from the genus Zea as the female parent plant and a plant from the genus Sorghum as the male parent (or a hybrid thereof). In certain aspects, a Maisorghum plant or plant part may be defined as comprising at least one chromosome or chromosomal segement from the genus Sorghum and at least one chromosome or chromosomal segement from the genus Zea. As used herein the specification, "a" or "an" may mean one or more. In conjunction with word "comprising" as used herein in the claim(s) the words "a" or "an", may mean one or more than one.

The use of the term "or" in the claims is used to mean "and/or" unless explicitly indicated to refer to alternatives only or the alternative are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and "and/or". As used herein "another" may mean at least a second or more.

The term "about" is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine value, or the variation that exists among the study subjects.

The term "plant" is intended to encompass plants at any stage of development or maturity, including a plant that has been detasseled or from which seed or grain have been removed. A seed or embryo that will produce the plant is also included within the term plant.

As used herein, the term "plant part" includes but is not limited to pollen, tassels, seeds, branches, fruit, kernels, ears, cobs, husks, stalks, root tips, anthers, stems, roots, flowers, ovules, stamens, leaves, embryos, meristematic regions, callus tissue, anther cultures, gametophytes, sporophytes, microspores, protoplasts, and the like. Tissue culture of various tissues of plants and regeneration of plants therefrom is well known in the art. Plant cell as used herein includes plant cells that are intact in plants and/or parts of plants, plant protoplasts, plant tissues, plant cell tissue cultures, plant calli, plant clumps, and the like. Further, as used herein, "plant cell" refers to a structural and physiological unit of the plant, which comprises a cell wall and also may refer to a protoplast. A plant cell of the present invention can be in the form of an isolated single cell or can be a cultured cell or can be a part of a higher-organized unit such as, for example, a plant tissue or a plant organ. Thus, as used herein, a "plant cell" includes, but is not limited to, a protoplast, a gamete producing cell, and a cell that regenerates into a whole plant.

Allele refers to any of one or more alternative forms of a gene or genetic locus. Alleles are associated with specific observable traits or characteristics in organisms. Seasons A and B as described herein, refers to the first and second rain seasons respectively. Uganda is characterised by a bimodal rainfall pattern with the first rain season running from March to July and the second rains from September to December each year.

Backcrossing refers to the crossing of a hybrid progeny such as an F 1 progeny with one of its parents in order to achieve offspring with genetic identity closer to that of the parent. Backcrossing can be used to introduce one or more single locus conversions from one genetic background into another.

Phenotype refers to an organism's observable traits or characteristics including but not limited to its morphology, development, biochemical or physiological properties, phenology. Phenotypes are a manifestation of gene expression in an organism and may be influenced by environment or the interaction between the organism's genotype and the environment.

As used herein, the terms "resistance" or "tolerance" are used interchangeable to describe plants that show no symptoms to a specified biotic pest, pathogen, abiotic influence or environmental condition. The terms are used to describe plants showing some symptoms but are still able to produce marketable product with acceptable yield and quality.

A transgene refers to a gene or genetic locus that has been introduced or transferred into a given genetic background from another through natural means or by any of a number of transformation or genetic engineering techniques. The introduction of a transgene has the potential to change the phenotype of an organism.

Embryo rescue refers to an in-vitro culture technique involving the excision and culture of immature or weak embryos onto media culture providing opportunity for the isolated embryo to survive and develop into a viable plant. Plant embryos are multicellular structures that have the potential to develop into a new plant. Embryo rescue is important in wide hybridization and development of interspecific and intergeneric crosses that would normally produce seeds, which are aborted.

Brief description of the illustrations

Description of the preferred embodiments may be best understood by reference to one or more of the accompanying photographs or illustrations. The figures provided in this patent or application file are illustrative and/or photographs executed in color. Copies of this patent or patent application publication and Use or Reproduction of the illustrations or photographs herein will be provided by the Office upon request and payment of the necessary fee. Figure 1A. Schematic illustration of the unsuccessful cross between maize and sorghum using either crop species as the female parent plant in reciprocal crosses. Success appears to rely on the presence of homozygous recessive mutant alleles in the maize parent plant.

Figure IB. Schematic illustration for the success observed in the sorghum x maize cross wherein sorghum is the female parent plant. Maize pollen genotype comprising homozygous recessive mutant alleles appears to be the underlying factor observed to lead to success of the sorghum x maize cross.

Figure 1C. Schematic illustration for the success observed in the maize x sorghum cross wherein maize is the female parent plant. Maize parent genotypes comprising homozygous single or double recessive mutant alleles in endosperm were observed to result in to a successful maize x sorghum cross; thus homozygous recessive mutant alleles might be a prerequisite in circumventing the hybridisation barriers between maize and sorghum.

Figure 2A-D. Photographs of plants of the maize line wx/Hi27 and sorghum line BTx630. The very first sorghum x maize cross was performed using a plant from maize line wx7Hi27 and sorghum line ATx630 wherein, the sorghum plant was the female parent plant and maize the male parent plant or pollen donor. Figure 2A. Photograph of a plant from the maize line wx/Hi27. The maize parent line wx/Hi27 is a near isogenic line (NIL) comprising homozygous recessive waxy (wx) in endosperm. Figure 2B. Photograph of a plant from the sorghum line BTx630. The male sterile sorghum line ATx630 and maintainer BTx630 both comprise homozygous recessive waxy allele in endosperm. Figure 2C. Photograph shows the tip of a tassel that was shedding pollen (Left plate) and a cob (Right plate) of a plant of maize line wx7Hi27. Figure 2D. (Left plate): Photograph of a panicle from the sorghum maintainer line BTx630; Figure 2D. (Right plate): Photograph of a panicle showing the male sterile phenotype from the sorghum line ATx630 used as female in the original cross.

Figure 3A-C. Photographs showing seed of the sorghum parent plant, maize parent plant, and the putative sorghum x maize Fl hybrid. Figure 3 A - Plate showing seed of sorghum maintainer line BTx630. Figure 3B - plate showing seed of putative sorghum x maize hybrid. Figure 3C - Plate showing seed of maize line wx7Hi27.

Figure 4. Photograph showing the maize parent plant wx/Hi27 (Blue bucket to extreme left), sorghum line BTx630 (Blue bucket to extreme right) and 5 putative sorghum x maize Fl plants derived from seed in Figure 3B of the original sorghum x maize cross. Note: The sorghum x maize hybrid plants were not uniform as expected of ideal hybrid plants from within crop species. In addition to variation in growth rate, plants differed in booting time (flowering) and panicle size and shape among others. All seeds from which the maize parent plant, sorghum parent plant and putative Fl sorghum x maize hybrid plants germinated were planted on the same date.

Figure 5A-B. Photographs of panicles of putative sorghum x maize Fl hybrid plants varying in shape and size. Figure 5 A. Panicles derived from the putative sorghum x maize Fl hybrid plants shown in Figure 4.

Figure 6A-D. Samples of putative F2 sorghum x maize hybrid seed harvested from individual panicles of putative Fl hybrid plants shown in Figure 5 A.

Figure 7. Photograph of sorghum parent line BTx630, maize parent line wx7Hi27, Fl putative sorghum x maize hybrid plant ATx630/wx7Hi27 and F2 putative sorghum x maize hybrid plants F2A and F2B. The F2 putative sorghum x maize hybrid plants exhibited more vigour compared with the Fl putative sorghum x maize hybrid plant as shown in this photograph. Leaf orientation of F2 putative sorghum x maize hybrid plants that segregated to resemble that of the maize or sorghum parent plant; plant F2B had droopy leaves similar to the maize parent plant while plant F2A had erect leaves similar to the sorghum parent plant.

Figure 8A and 8C. Photographs showing phenotypes of maize parent plant (blue bucket(s), extreme left), sorghum parent plant (blue bucket(s), extreme right) and putative F2 sorghum x maize intergeneric hybrid plants (light green bucket(s) in middle) segregating for plant 'architecture' to resemble either the maize or sorghum parent plant. The seed that was planted in the pots giving rise to the F2 putative sorghum x maize hybrid plants was derived from the same Fl panicle. Figure 8B. The inventor Bombom Alexander with one F2 plant that segregated to resemble the sorghum parent plant in plant stature.

Figure 9A-H. Selected panicles from F2 putative sorghum x maize hybrid plants showing variation due to segregation for fertility, seed color, seed set and panicle shape and size. All panicles were bagged and self-pollinated to maintain purity of individual plants. Figure 9A shows a panicle that likely under went complete post-zygotic incompatibility leading to embryo lethality and/or endosperm abortion. Figure 9B shows a panicle with small brown shriveled seeds similarly resulting from post-zygotic incompatibility. Figure 9C, 9D and 9E show panicles with at least 90% seed set derived from putative F2 sorghum x maize hybrid plants that segregated to phenotypically resemble the sorghum parent plant in stature. Figure 9F, 9G, and 9H show panicles with seed set ranging approximately 50-70% derived from putative F2 sorghum x maize hybrid plants that segregated to resemble the maize parent plant in stature. This observation might be a result of partial male and/or female fertility as revealed by the poor seed set and many undeveloped florets.

Figure lOA-C. Photographs showing plant stalks of the sorghum parent plant, maize parent plant, and putative F2 sorghum x maize hybrid plants. Figure 10A. Plant stalks of maize line wx/Hi27. Figure 10B. Plant stalks of sorghum maintainer line BTx630. Figure IOC. Plant stalks of putative F2 sorghum x maize hybrid plants.

Figure 11A-E. Selected samples of putative F3 sorghum x maize hybrid seed harvested from individual panicles of putative F2 sorghum x maize hybrid plants some of which are shown in Figure 8 indicating segregation for seed color.

Figure 12A-F. Selected samples of putative F4 sorghum x maize hybrid seed harvested from individual panicles of putative F3 sorghum x maize hybrid plants. Figure 12A-B shows samples of F4 putative sorghum x maize hybrid seed harvested from plants that were observed to segregate and resemble the sorghum parent plant in terms of plant stature. Figure 12C-F shows samples of F4 putative sorghum x maize hybrid seed harvested from plants observed to segregate phenotypically to resemble the maize parent plant in stature.

Figure 13. Photograph showing putative F4 sorghum x maize hybrid plants resembling the maize parent plants (F4 plants on the right) and the sorghum parent plants (F4 plants on the left) in stature. The sorghum-like plants were derived from the seed sample 2057 while the maize-like plants were derived from the seed sample 2069. The most notable feature in terms of plant stature is the plant height.

Figure 14A-C. Putative sorghum x maize hybrid panicles showing shriveled seed with collapsed endosperm that likely under went post-zygotic incompatibility. Figure 14A. An Fl putative sorghum x maize hybrid panicle showing some shriveled seed (turned brown in color. Seeds that appear white in color are those that developed with normal endosperm) circled in white from the mid-section to the top of the panicle. Figure 14B-C. Panicles derived from F4 putative sorghum x maize hybrid plants showing shriveled seed circled in black as a result of post-zygotic incompatibility.

Figure 15A. Panicle of sorghum line ATx630 showing male sterile phenotype (Left plate) and seed from sorghum maintainer line BTx630 (Right plate). The male sterile sorghum line ATx630 and maintainer BTx630 both comprise homozygous recessive waxy allele in endosperm. Figure 15B. Seed of maize inbred line CML182 (Left plate) and plants of the maize inbred line CML182 (Right plate). Maize inbred line CML182 comprises homozygous recessive opaque-2 (o2) allele in the endosperm. This second cross BTx630/CML182 was carried out to unambiguously determine repeatability of the original sorghum x maize cross wherein sorghum line BTx630 was used as the female parent plant and maize inbred line CML182 as the male parent plant.

Figure 16A-D. Figure 16A-B shows variation in seed set resulting from the crossing of sorghum line ATx630 as female with pollen from maize inbred line CML182. Fl putative sorghum x maize hybrid seed harvested from the sorghum panicles following successful hybridization and development was observed to exhibit at least two phenotypes as maize-like or sorghum-like. Figure 16C. Fl putative sorghum x maize hybrid seed sorted and characterized as having an appearance to maize seed. Figure 16D. Fl putative sorghum x maize hybrid seed sorted and characterized as having an appearance to sorghum seed.

Figure 17A-C. Pots planted with Fl putative sorghum x maize hybrid seed to test for viability of the two seed phenotypes shown in Figure 16C and 16D. Figure 17A shows delayed germination of Fl putative sorghum x maize hybrid seed characterized as maize-like compared with the sorghum-like seed phenotype. Figure 17B shows a low germination percentage of Fl putative sorghum x maize hybrid seed characterized as maize-like compared with the sorghum-like phenotype. Figure 17C. Maize parent plant CML182, sorghum parent plant BTx630 and putative Fl sorghum x maize hybrid plants compared for plant vigour; putative sorghum x maize hybrid plants that germinated from the maize-like seeds were observed to be less vigorous compared with the hybrid plants that germinated from the sorghum-like seeds. All seeds including parents and progeny were planted on the same date.

Figure 18A-C. Putative Fl sorghum x maize hybrid plants from the cross ATx630 (sorghum)/CML182 (maize). Figure 18A-B. Putative Fl sorghum x maize hybrid plants germinated from a planted seed characterized as maize-like by the inventor(s). Figure 18C. Putative Fl sorghum x maize hybrid plants germinated from a planted seed characterized as sorghum-like by the inventor(s).

Figure 19. Photograph of sorghum parent line BTx630, maize parent line CML182 and Fl putative sorghum x maize hybrid plants ATx630/CML182 showing 2 panicles per plant. Both panicle on the Fl putative sorghum x maize hybrid plants resulting from this cross emerged and matured at the same time. The second sorghum panicle in the putative hybrid plant emerging at about the same leaf position as the ear on the maize parent plant.

Figure 20. Amylose quantification in starch sample using the potassium iodide/iodine test. The brown color of the starch solution is indicative of less amylose in a given starch sample while the deep blue color is indicative of higher amylose content in a given starch sample.

Figure 21A-G. Photographs of maize parent line CML078 and sorghum line RTx2907 wherein, the maize line was used as female in the cross. Figure 21 A. A plant and ear of maize inbred line CML078. The maize inbred line CML078 has normal endosperm and does not comprise a homozygous recessive mutant allele. Figure 2 IB. Photograph of a panicle, potted and field plants of sorghum line RTx2907. Sorghum line RTx2907 comprises recessive mutant waxy allele in its background. Figure 21C and 2 ID. Ears of maize line CML078 following pollination with viable pollen from sorghum line RTx2907 showing seed development to the blister stage about 3-4 days post-pollination. Figure 21E and 21F. Ears of maize line CML078 following pollination with viable pollen from sorghum line RTx2907 showing disintegrated kernels 7- 10 days post-pollination as result of post-zygotic incompatibility and/or other physical factors of environment. Figure 21G. An ear of maize inbred line CML078 showing well filled kernels following self-pollination using viable pollen from the same plant. This cross was repeated twice, first in 2010 and the second time in 2013 using the same maize parent line CML078 and sorghum lines RTx2907 and BTx623 and obtained the same results.

Figure 22A-I. Photographs of the cross, involving maize line wx7Hi27 and sorghum maintainer line BTx630 wherein the maize line wx/Hi27 was used as female and sorghum maintainer line BTx630 as the male parent plant. Figure 22A. Potted plant of maize line wxlHUT. Figure 22B. A receptive ear of maize line wx7Hi27 covered with a transparent polyethylene shoot bag showing silks ready for pollination. Figure 22C. A full size ear of maize line v xiHi27 showing well filled kernels. Kernels of maize line wx/Hi27 comprise homozygous recessive waxy allele in endosperm. Figure 22D. A panicle of sorghum maintainer line showing well filled sorghum kernels. Kernels of the sorghum maintainer BTx630 comprise homozygous recessive waxy allele in endosperm. Figure 22E. Potted plant of sorghum maintainer line BTx630. Figure 22F-H. Ears of maize line wxiHi27 showing differences in seed set of fully developed putative Fl maize x sorghum hybrid kernels resulting from the cross¹ wx/Hi27 X BTx630. Figure 221. Harvested ears showing fully developed putative first generation backcross (BC1F1) kernels with varying seed set wherein, the maize parent line wx/F£i27 was used as the female parent plant and the putative Fl sorghum x maize hybrid progeny as the male parent plant or pollen donor.

Figure 23. Fl putative maize x sorghum hybrid plants resulting from the cross wx7Hi27 X BTx630 at the 3-leaf vegetative stage of plant growth exhibiting the phenotype of Chlorophyll mutants (circled in black) characterized as Albina green (Kolar et at, 2011). At least 3 putative Fl maize x sorghum hybrid plants from this cross out of the 10 that germinated were observed to manifest this trait on the third leaf and partly the fourth leaf. The chlorophyll mutant phenotype disappeared, as the seedlings grew older.

Figure 24A-E. Photographs of the cross, involving maize line wxiHi27 and sorghum maintainer line BTx623 wherein the maize line wx7Hi27 was used as female and sorghum maintainer line BTx623 as the male parent plant. This cross using the maize line Wx/Hi27 as female with a different sorghum line other than BTx630 as the male parent plant or pollen donor was carried out to unambiguously determine repeatability of the maize x sorghum cross. Other sorghums used in crosses with maize line wx7Hi27 and successfully obtained well developed putative Fl maize x sorghum hybrid seed include improved local sorghum lines 'Epuripur' and 'Seredo'. Kernels from all the sorghum lines mentioned including BTx623, 'Epuripur', and 'Seredo' are white in color, comprise normal endosperm and are not homozygous recessive for any mutant endosperm alleles.

Figure 24A. Potted plants and receptive ear of maize line wx Hi27. Figure 24B. A panicle that was shedding pollen and plants of sorghum maintainer line BTx623. Figure 24C-E. Ears of maize line wx7Hi27 showing differences in seed set of fully developed putative Fl maize x sorghum hybrid kernels resulting from the cross wx7Hi27 X BTx623. Figure 25A-G. Photographs showing emergence and growth of putative Fl sorghum x maize and maize x sorghum hybrid plants. Figure 25A. Emergence of maize line wxiHi27 seedling. Figure 25B. Emergence of putative Fl sorghum x maize hybrid seedling from the cross ATx630 X wx7Hi27. Figure 25C. Emergence of maintainer sorghum line seedlings. Figure 25D-E. Emergence of putative Fl maize x sorghum hybrid seedlings from the cross wx7Hi27 X BTx630. Figure 25F-G. Putative Fl maize x sorghum hybrid plants from the cross wx7Hi27 X BTx630 (Figure 25D and 25E) at the 5-6 leaf vegetative growth stage.

Figure 26A-D. Plants of maize line wx7Hi27, putative Fl sorghum x maize hybrid plants and putative Fl maize x sorghum hybrid plants showing reaction to Turcicum leaf blight (TLB) disease. Figure 26A. Maize parent plants, wx7Hi27 at anthesis showing susceptibility to Turicum leaf blight disease. Figure 26B. Seedlings of putative Fl sorghum x maize hybrid plants showing early characteristic lesions symptomatic of turcicum leaf blight circled in black. The turcicum leaf blight symptoms disappeared as putative sorghum x maize hybrid plants grew older. Figure 26C. Plants of putative Fl maize x sorghum cross u>x7Hi27 X BTx630 showing symptoms of susceptibility to turcicum leaf blight. Figure 26D. Plants of putative Fl maize x sorghum cross wxlUxll X BTx623 showing a lesion characteristic of turcicum leaf blight disease. Most plants from this particular cross wx7Hi27 X BTx623 displayed tolerance to turcicum leaf blight disease (See Figure 27).

The observations made on the putative Fl sorghum x maize hybrid plants shown in Figure 26B and the low turcicum leaf blight severity among putative Fl maize x sorghum hybrid plants in Figure 26D appears to suggest some level of introgression from the maize and sorghum parent plants with respect to disease resistance loci. If confirmed, this finding will contribute significantly to disease resistance breeding in maize and sorghum.

Figure 27. Putative Fl maize x sorghum hybrid plants from the cross, wx7Hi27 X BTx623 at reproductive stage. All Fl maize x sorghum hybrid plants were self-pollinated. Notice the low severity and/or absence of turcicum leaf blight lesions on some of the Fl maize x sorghum hybrid plants.

Figure 28. Putative F2 maize x sorghum hybrid ears of the cross wxlWxll X BTx623 harvested from putative F l maize x sorghum hybrid plants shown in Figure 27. The area circled in black shows some would be kernels in which fertilization likely occurred leading to embryo formation but endosperm development failed. Figure 29A-C. Photograph showing variation in the morphology of tassels of the maize parent plant and the respective F l putative maize x sorghum hybrid plants. Figure 29A; Tassel of the maize parent plant wxlHilT. Figure 29B. Tassel of putative Fl maize x sorghum hybrid, wxlHUl X BTx623. Figure 29C. Tassel of putative Fl maize x sorghum hybrid, wxlHiH X BTx630.

Figure 30A-B. Figure 30A. Photograph of an ear of a double recessive hybrid maize line 1 15- 28 and sorghum line 'Epuripur'. In this cross, the hybrid maize line was used as the female parent plant and the sorghum plant 'Epuripur' as the male parent plant. The hybrid maize line 1 15-28 was derived from a cross between waxy, near isogenic maize line x7Hi27 and high lysine maize inbred line CML182 and comprises homozygous double recessive wx-o2 mutant alleles in endosperm. Kernels of sorghum line 'Epuripur' comprise normal endosperm and are not homozygous recessive for any mutant endosperm alleles.

Figure 30B. Ears of maize line 1 15-28 showing differences in seed set of fully developed putative F l maize x sorghum hybrid kernels resulting from the cross 1 15-28 X Tg (Epuripur).

Detailed description of the preferred embodiment

Sorghum and maize are important cereal crops in most of sub-Saharan Africa and East Asia used mainly for food, feed and production of traditional beverages including beer and malt. In developed economies, both crops are used mainly for feed and potential for other nonfood/feed uses have also been explored in industry including for starch production, paper, and bio-ethanol among others. To meet these diverse demands, improvement of both crops is imperative following an increase in the amount of genetic diversity present within germplasm of both crop species. The low and/or ever shrinking genetic diversity observed in germplasm within breeding programmes may be attributed in part to stringent selection over time among other factors. By carrying out wide hybridisation, the genetic diversity among crop plants can be enhanced. Moreover, to date there are no documented reports of successful fertile, self- reproducing putative hybrid plants obtained from a cross between maize and sorghum. The present invention discloses for the first time development of fertile, self-reproducing putative intergeneric hybrid plants created by crossing sorghum with maize in one direction using sorghum as the female parent plant and maize with sorghum in the other direction (reciprocal cross) using maize as the female parent plant. In certain aspects, the present invention may allow for the combination of agronomically important traits from sorghum and maize into a single putative hybrid plant, and provides opportunity for improvement of either one of the two important crops. Using methods described herein, agronomically important traits that can be harnessed from the present invention include but are not limited to increased crop yield, increased biomass, improved crop quality aspects such as reduced cyanide levels in sorghum, improved protein and starch grain quality, β-carotene introgression into sorghum from high carotene maize sources, resistance to anatoxin and pest and disease tolerance in maize and sorghum. Stay green in sorghum, a trait that allows the sorghum plant withstand prolonged periods of water stress can be introgressed into maize as a non-transgenic approach to drought and heat tolerance in maize.

The failure to successfully cross maize with sorghum and/or sorghum with maize may be attributed to a number of physical, genetic or even environmental factors. Earlier reports cite pre-zygotic and/or post-zygotic incompatibility mechanisms as one of the causes for failure to obtain hybrids involving wide crosses (Bartek, 2010). Studies by Laurie and Bennet (1989) identified a recessive allele designated inhibition of alien pollen (iap) that allows for alien pollen tubes to grow into sorghum styles. Furthermore, development of the sorghum line Tx3361 disclosed in Patent application number 20100064382 possessing the iap allele has facilitated successful intergeneric hybridization between sorghum {Sorghum bicolor) and sugarcane {Saccharum spp.) producing viable hybrid seed (Hodnett et al, 2010). Methods for the production of intergeneric hybrid plants between sorghum and saccharum using the iap allele in the sorghum line Tx3361 as female parent plant are disclosed in patent application number PCT/US2009/051706 (Rooney et al., 2010).

Experiments presented herein demonstrate that sorghum parent plants not homozygous for the recessive iap allele and used as female when pollinated with maize pollen comprising mutant genotype waxy (wx) or opaque-2 (o2) successfully hybridised producing viable sorghum x maize hybrid seed. Furthermore, the experiments demonstrated that maize plants used as female and comprising homozygous endosperm mutant alleles wx or o2 in the single or double recessive state successfully hybridised with sorghum producing viable maize x sorghum hybrid seed. The putative hybrid plants obtained from the crossing of sorghum with maize were observed to segregate for plant stature in the second filial generation as either maize or sorghum. Other phenotypic traits for which segregation was observed included for example, plant height, fertility, plant senescence pattern, panicle size and shape, seed size, color and shape, and stalk type. In one embodiment, the present invention discloses fertile putative intergeneric hybrid plants of a cross between sorghum and maize and parts thereof wherein the sorghum plant was used as the female parent plant and maize as male parent plant. In specific embodiments, the sorghum parent plant does not comprise homozygous sorghum recessive iap allele and may be male sterile or male fertile (with emasculation). In one embodiment, the sorghum parent plant is a white seeded line possessing Al cytoplasmic male sterility trait. In certain aspects of the invention, the male sterile sorghum parent plant is a plant of line ATx630. In other specific embodiments, the male fertile sorghum parent plant is a plant of sorghum line BTx630 or Epuripur (Tegemeo). In other specific embodiments, the maize parent plant used as male is a near isogenic line (NIL) with yellow endosperm and comprising homozygous recessive waxy (wx) allele in endosperm. In other specific aspects, the maize parent plant is a plant of line wxlHill. Other experiments revealed herein disclose that mutant recessive endosperm allele opaque-2 (o2) also hybridised with sorghum. In more specific aspects, the maize parent plant comrprising homozygous recessive o2 genotype is an elite maize inbred line CML182. In further embodiments, the maize parent plant may be homozygous single or double recessive for a combination of mutant recessive endosperm alleles.

In yet a further embodiment, the present invention also discloses fertile putative intergeneric hybrid plants of a cross between maize and sorghum and parts thereof wherein the maize plant was used as the female parent plant and sorghum as male parent plant. In specific embodiments, the maize parent plant comprises homozygous recessive waxy (wx) allele in endosperm. In some aspects, the maize parent plant is a near isogenic line comprising yellow endosperm and is a plant of line wxlHUT. In certain aspects, the maize parent plant is an inbred line or open pollinated variety with white endosperm and comprising the mutant recessive endosperm allele opaque-2 (p2). In more specific aspects, the o2 maize inbred line and/or open pollinated variety is a plant of line CML182 and Longe-5 respectively. In a more specific embodiment, the maize parent plant may be a hybrid plant comprising double recessive mutant endosperm alleles wx-o2 wherein, the hybrid plant is a plant of line 115-28. In further embodiments, the sorghum parent plants used as male in the crosses with maize comprise white endosperm and are plants of line BTx630, BTx623, Epuripur (Tegemeo) or Seredo. In more specific aspects, plants of sorghum line BTx630 comprise the waxy allele in endosperm.

The present invention thus contemplates successful hybridisation of sorghum with maize can be achieved using pollen obtained from maize plants produced from seed with endosperm homozygous single or double recessive for specific endosperm mutant alleles. In another aspect, the present invention further contemplates that successful hybridisation of maize, as female with sorghum as the male parent plant shall involve the use of mutant endosperm alleles in the maize parent plant. It should be understood that using maize plants to obtain pollen or as female in the crosses comprising homozygous mutant endosperm alleles other than wx and/or o2 in the single recessive or double recessive state (in different combinations with each other) to produce successful crosses with sorghum are also contemplated within the scope of the claims in the present invention.

In one embodiment, F l putative intergeneric hybrid seed recovered from the original sorghum x maize cross disclosed in the present invention exhibited different sheds of brown color and were viable on planting (Figure 3B. In specific aspects of the present invention, Fl putative hybrid seed and plants derived therefrom were obtained without the need for embryo rescue. Putative sorghum x maize intergeneric hybrid plants produced from Fl seed were phenotypically variable and most resembled the sorghum parent (Figure 4). For example, Fl putative sorghum x maize hybrid plants comprised traits including variable growth rate, plant height, panicle size and shape, seed size, shape, and seed color (Figure 5A-B and Figure 6A- D). In other specific aspects, Fl putative sorghum x maize hybrid plants comprised unique traits including the production of two strong panicles that emerged and matured at the same time (Figure 19). Putative F2 sorghum x maize intergeneric hybrid plants demonstrated increased plant vigor compared with putative Fl hybrid plants (Figure 7). In still further embodiments of the invention, putative F2 sorghum x maize hybrid plants were demonstrated to segregate for traits including but not limited to panicle size and shape, seed size, color and morphology, seed set, plant height, stem type, fertility, plant architecture or stature with plants resembling either maize or sorghum (Figure 8A-C, Figure 9A-H, Figure lOA-C, and Figure 1 1A-E). In other specific aspects, biochemical studies presented herein demonstrate that putative Fl sorghum x maize hybrid plants were superior for some starch physicochemical properties and skewed to either parent for others (Table 4). In particular aspects of the present invention, self-pollination of putative F2 sorghum x maize intergeneric hybrid plants and selecting individual plants from this generation (F2) based on plant stature as resembling the maize or sorghum parent plant, demonstrated that subsequent generations of F3 and F4 plants had their phenotype fixed as 'maize-like' or 'sorghum-like' (Figure 12A- F and Figure 13). In still further embodiments, seed derived from 'maize-like' plants were often observed to produce some seed with shrivelled or collapsed endosperm likely due to post-zygotic incompatibility and/or other unknown factors (Figure 14B-C).

The present invention also directs to the procedures for.producing a putative "sormaize" plant comprising; a) Collecting pollen from a maize parent plant produced from seed comprising a mutant endosperm allele in the homozygous single recessive or double recessive state; b) Pollinating flowers on a panicle of the sorghum parent plant with the said pollen ensuring proper observation of all crossing procedures to avoid contamination from extraneous pollen; c) growing the putative Fl seed derived from the crossing to obtain a putative Fl sorghum x maize intergeneric hybrid plant. Furthermore, any procedures using the putative sorghum x maize intergeneric hybrid plant in any breeding proceedure for development of pure lines including haploid and double haploid breeding, improvement of sorghum and/or maize or plants from other genera within the Poaceae family for any agronomically or industrially important traits are considered part of this invention: selfmg, crossing with other putative "sormaize" plants, backcross breeding, hybrid breeding and crosses to maize and sorghum populations or plants from other genera within the Poaceae. Any plants produced using putative sorghum x maize intergeneric hybrid plants as a parent are within the scope of this invention.

It should be understood that "sormaize" plants or progeny derived therefrom can through routine manipulation of cytoplasmic or other factors, be produced in a male-sterile form. Such embodiments are also contemplated within the scope of the present invention.

In a further embodiment, the present invention discloses methods for producing putative maize x sorghum intergeneric hybrid plants and parts thereof wherein the maize plant is used as the female parent plant and sorghum as the pollen donor or male parent plant. In specific embodiments, the maize parent plant comprises mutant endosperm homozygous single recessive for the waxy (wx) allele. Experiments carried out and presented herein demonstrate that maize parent plants comprising mutant endosperm, homozygous single recessive for the o2 allele similarly resulted in a successful cross with Fl seed having functional endosperm and embryo. In still further embodiments, maize plants comprising double recessive mutant endosperm alleles wx-o2 also resulted in successful putative maize x sorghum Fl seed with functional endosperm and developed embryo (Figure 30A-B). In specific aspects of the invention, the maize plant is a near isogenic line or inbred line, wx7Hi27 and/or CML182 comprising yellow endosperm and white endosperm respectively. In still further aspects of the invention, the maize plant is an open pollinated variety (OPV) comprising o2 allele in the endosperm. In specific aspects of the invention, the OPV maize plant is a plant of line Longe- 5 (locally referred to by farmers as "Nalongo" because of its tendency to produce two harvestable ears). In certain aspects of the invention, the sorghum parent plant used as male in the cross is a plant of line BTx630, BTx623, Epuripur (Tegemeo) or Seredo. In particular aspects, Fl putative maize x sorghum hybrid plants from the cross wx/Hi27 x BTx630 were weak and exhibited a phenotype characteristic of chlorophyll mutants at the 3 leaf stage of plant growth (Figure 23).

In more specific embodiments, crosses carried out and disclosed herein the present invention demonstrate that normal or wild type endosperm maize when crossed with sorghum did not result in successful Fl progeny seed with functional endosperm. Observations from experiments presented herein reveal fertilisation occurred with seed developing to the blister stage before degenerating about 7-10 days post-pollination due to endosperm breakdown (Figure 21A-F). In specific aspects of the invention, the maize plant is a plant of inbred line CML078. It should be understood that maize plants produced from seed comprising homozygous mutant endosperm alleles in the single or double recessive state including but not limited to wx, o2, du, su, fl, to obtain successful crosses of maize with sorghum are contemplated within the scope of the claims in the present invention.

In one embodiment, Fl putative maize x sorghum intergeneric hybrid seed produced plants that phenotypically resembled maize than sorghum. In specific aspects of the invention, no embryo rescue was carried out in crosses involving mutant endosperm maize lines despite the low seed set observed. However, in crosses involving normal or wild type maize endosperm lines, embryo rescue might be a requisite in order to obtain putative maize x sorghum intergeneric hybrid plants.

The present invention also directs to procedures for producing a putative "Maisorghum" plant comprising; a) Collecting pollen from a sorghum parent plant that may or may not comprise a homozygous recessive mutant endosperm allele; b) Pollinating a receptive ear of a maize parent plant with genotype comprising homozygous single recessive or double recessive for mutant endosperm alleles with the said pollen ensuring proper observation of all crossing proceedures to avoid contamination from extraneous pollen; c) growing the putative Fl seed derived from the crossing to maturity to obtain a putative Fl maize x sorghum intergeneric hybrid plant. In specific aspects, any procedures using the putative maize x sorghum intergeneric hybrid plants in any breeding proceedure for development of pure lines including haploid and double haploid breeding, improvement of sorghum and/or maize or plants from other genera within the Poaceae family for any agronomically or industrially important traits are considered part of this invention: selfing, crossing with other putative "maisorghum" plants, backcross breeding, hybrid breeding and crosses to maize and sorghum populations or plants from other genera within the Poaceae. Any plants produced using putative maize x sorghum intergeneric hybrid plants as a parent, are within the scope of this invention.

It should be understood that "maisorghum" plants or progeny derived therefrom can through routine manipulation of cytoplasmic or other factors, be produced in a male-sterile form. Such embodiments are also contemplated within the scope of the present invention.

The present invention provides potential for improvement of maize and/or sorghum for one or more agronomically important traits including as a new cereal for food, feed or other industrial purposes as a result of speciation events. This observation is supported by literature which suggests that occurrence of wide hybridization could contribute to plant evolution as even a single hybrid plant may serve as the progenitor of a new species, provided it is fertile (Ellstrand et ah, 1996; Matthew and Simon, 2004). To achieve this goal, the potential value of sorghum and/or maize germplasm for improvement of either one of the two crops or plants from other genera within the Poaceae family requires production of large numbers of hybrids of wide genetic diversity.

Parent plants for producing fertile putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants

Sorghum

The genus sorghum comprises at least 25 distinct species that are classified into five taxonomic subgenera or sections, Eu-sorghum, Chaetosorghum, Heterosorghum, Parasorghum, and Stiposorghum (Price et al, 2006). Sorghum belongs to the Eu-sorghum section and is a member of the family Poaceae, subfamily Panicoideae, and the tribe of Andropogoneae. Plants within the genus sorghum are known to possess important plant attributes that if harnessed from the wild can enhance agronomic traits of agricultural importance in crop plants. Among these attributes include but not limited to drought and heat tolerance, disease resistance, weed and pest resistance, cold tolerance, acid and saline soil tolerance and water logging. Cultivated sorghum, Sorghum bicolor is a tropical species important in drought prone areas of the world as a food and feed crop. Sorghum is also used for making sorghum syrup or sorghum molasses and alcoholic beverages. In Africa, sorghum has been used for brewing and more recently, efforts to breed and utilise varieties suited to this purpose on large scale have been embarked on by breeding programmes. With potential for utilisation in non-food applications especially in industry, varieties and hybrids of sorghum have been bred to possess unique traits or characteristics to meet these demands including high grain yields, high starch yield, and sugar.

Species of sorghum contemplated in this invention include but are not limited to, Sorghum bicolor, Sorghum almum, Sorghum amplum, Sorghum angustum, Sorghum arundinaceum, Sorghum bicolor subsp. drummodii (Sudan grass), Sorghum brachypodum, Sorghum bulbosum, Sorghum burmahicum, Sorghum ecarinatum, Sorghum exstans, Sorghum grande, Sorghum halepense (Johnson grass), Sorghum interjectum, Sorghum intrans, Sorghum laxiflorum, Sorghum leiocladum. Sorghum macrospermum, Sorghum matarankense, Sorghum nitidum, Sorghum plumosum, Sorghum propinquum, Sorghum purpureosericeum, Sorghum stipoideum, Sorghum timorense, Sorghum trichocladum, Sorghum versicolor, Sorghum verticiliflorum, Sorghum vulgare var. technicum (broomcorn).

The sorghum species used in the present invention is Sorghum bicolor. Previous attempts in crossing sorghum with maize using a sorghum line comprising homozygous recessive mutant iap/iap allele demonstrated pollen tube growth in sorghum styles but were not successful in producing hybrid plants (Laurie and Bennett, 1989; Bartek, 2010). In particular embodiments, the sorghum parent plant used in the present invention does NOT comprise an iap/iap mutant allele. In specific aspects of the invention, the sorghum line may be male sterile or male fertile and/or may or may not comprise a homozygous recessive endosperm mutant allele. In a specific aspect, a male sterile sorghum plant comprising homozygous recessive waxy (wx) mutant allele in endosperm is a plant of line ATx630. In another aspect, a male fertile sorghum plant comprising homozygous recessive wx mutant allele in endosperm is a plant of line BTx630. In another aspect, a male sterile sorghum plant comprising normal endosperm is a plant of line ATx623. In a further aspect, a male fertile sorghum plant comprising normal endosperm is a plant of line BTx623, Epuripur (Tegemeo) or Seredo. In certain aspects, sorghum plants described herein may comprise one or more agronomically advantageous traits. Such traits may be bred into a parent sorghum line and then passed on to an intergeneric hybrid plant or may be bred directly into an intergeneric hybrid line. In certain aspects, agronomically advantageous traits may be introduced by introduction of one or more transgenes into a sorghum plant or an intergeneric hybrid plant. In one aspect, a transgene may be introduced into an endosperm mutant sorghum line such as ATx630 or BTx630 by directly transforming cells from such a sorghum plant. In a further aspect, a transgene may be introduced into a normal endosperm sorghum line such as ATx623, BTx623, Epuripur, or Seredo by directly transforming cells from such a sorghum plant. In one aspect, a transgene may be introduced into an endosperm mutant sorghum plant by crossing a sorghum plant comprising the transgene with an endosperm mutant sorghum line such as ATx630 or BTx630. In another aspect, a transgene may be introduced into a normal endosperm sorghum plant by crossing a sorghum plant comprising the transgene with a normal or wild type endosperm sorghum line such as ATx623, BTx623, Epuripur, or Seredo. Fl progeny from such a cross can then be backcrossed to a mutant endosperm sorghum line or self crossed (with itself or other Fl progeny) and the products of the second cross screened for the presence of the transgene and inheritance of the homozygous recessive mutant endosperm allele where such mutant sorghum lines are used. Thus, transgenic sorghum plants homo2ygous for a recessive endosperm mutant allele including but not limited to wx are included as part of the present invention and may be used in methods for the development and/or production of fertile putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants as described herein.

Maize

The plant maize of the genus Zea and species mays is an important cereal in the third world where its grain is consumed mainly as food. However, within the species Zea mays, at least 8 subspecies have been identified. The genus Zea is contained within the family Poaceae, subfamily Panicoideae, and the tribe of Andropogoneae. Other uses of maize include as a feed for livestock and poultry. Non-food or feed uses of maize are mainly as biofuels and starch. In industry, maize contributes about 83% of the total starch were its unique attributes are important in food products, textile, adhesives, corrugating and paper making (Ceballos et ah, 2007; Singh and Singh, 2007). Maize is grown worldwide but is constrained by a number of biotic and abiotic factors. Biotic factors include but are not limited to foliar diseases such as gray leaf spot disease, turcicum leaf blight, ear rots, and virus diseases including maize streak virus disease, insect pests and parasitic weeds such as striga. Abiotic factors include but are not limited to water stress conditions, susceptibility to cold stress in temperate regions, heat stress and intolerance to acid and/or alkaline soils.

The species of maize used in the present invention is Zea mays var. Ceratina. In particular embodiments, the maize plant disclosed herein is a Zea mays subspecies comprising homozygous single recessive mutant waxy (wx) endosperm allele. In certain aspects of the invention, the maize plant disclosed comprises homozygous single recessive opaque-2 (o2) mutant allele in endosperm. In still further aspects, it has been demonstrated that maize plants homozygous double recessive for mutant endosperm alleles wx-o2 result in successful production of fertile putative intergeneric maize x sorghum and/or sorghum x maize hybrid plants. Thus mutant endosperm alleles either in the homozygous single recessive state or double recessive state contemplated in the present invention include but are not limited to amylose extender (ae), dull (du), waxy (wx), sugary-1 (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken- 1 (sh), shrunken- 2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2 ( 12). In still further embodiments, sub species of maize comprising one or more of the above mentioned homozygous recessive mutant endosperm alleles and contemplated within the present invention include but are not limited to Zea mays var. amylacea (Flour corn), Zea mays var. everta (Popcorn), Zea mays var. indentata (Dent corn), Zea mays var. indurate (Flint corn), Zea mays var. saccharata (Sweet corn) and Zea mays var. rugosa (Sweet corn), Zea mays (Amylomaize), Zea mays var. tunicata (Pod corn) or Zea mays var. japonica (Striped maize). In other embodiments, species within the genera Zea comprising homozygous recessive single, double or other combination of homozygous recessive endosperm alleles contemplated within the present invention include but are not limited to Zea mays mays, Zea may huehuetenangensis, Zea mays Mexicana, Zea mays parviglumis, Zea nicaraguensis, Zea perennis, Zea diploperennis or Zea luxurians. Some Zea mays varieties contemplated for use according to the disclosure include but are not limited to tropically adapted maize lines Hi25, Hi26, Hi27, Hi28, Hi29, Hi30, Hi31, Hi32, Hi33, Hi34, Hi35, Hi36, Hi37, Hi38, Hi39, Hi40, Hi41, Hi42, Hi43, Hi44, Hi45, Hi47, Hi48, Hi49, Hi50, Hi51, Hi52, Hi53, Hi54, Hi55, Hi56, Hi57, Hi58, Hi59, Hi60, Hi61, Hi62, Hi63, Hi64, Hi65, Hi66, Hi67, Hi68 under registration number PL-181 to PL-193, PI 593007 to PI 593019 and PL-327 to PL-353, PI 641224 to PI 641250; near isogenic line wx7Hi27, CML182, Longe-5, 115-35 or 115-28. In particular embodiments, the maize parent plant disclosed in the present invention is a Zea mays var. Ceratina plant comprising homozygous single recessive waxy (wx) endosperm allele. In specific aspects of the invention, the maize plant is a plant of line w.xJHi27. In further embodiments, a maize plant disclosed herein comprises homozygous single recessive opaque-2 (o2) endosperm allele. In specific aspects of the invention, the maize plant(s) is a plant of line CML182 and/or Longe-5. In still further embodiments, the maize parent plant disclosed herein comprising homozygous double recessive waxy-opaque-2 (wx-o2) mutant endosperm allele is a hybrid plant derived from a cross between maize line wxlHi27 as male and CML182 as female. In specific aspects, the homozygous double recessive endosperm maize hybrid plant in the present invention is herein designated 115-28. In one embodiment, the maize parent plant disclosed herein comprising normal or wild type endosperm and demonstrated not to produce successful putative hybrid seed is a plant of line CML078.

In certain aspects, maize plants described herein may comprise one or more agronomically advantageous traits. These traits may be bred into a parent maize line and then passed on to an intergeneric hybrid plant or may be bred directly into an intergeneric hybrid line. In certain aspects, agronomically advantageous traits may be introduced by introduction of one or more transgenes into a maize plant or an intergeneric hybrid plant. In one aspect, a transgene may be introduced into a single recessive endosperm mutant maize line such as wxlHin, Longe-5 or CML182 or double recessive endosperm mutant maize line such as 115-28 by directly transforming cells from such a maize plant. In one aspect, a transgene may be introduced into an endosperm mutant maize plant by crossing a maize plant comprising the transgene with an endosperm mutant maize line such as w 7Hi27, .CML182, Longe-5 or 1 15-28. The Fl progeny from such a cross can then be backcrossed to a mutant endosperm maize line or self crossed (with itself or other Fl progeny) and the products of the second cross screened for the presence of the transgene and inheritance of the homozygous recessive mutant endosperm allele. In certain aspects, putative maize x sorghum intergeneric Fl hybrid plants exhibited mutant chlorophyll phenotype characterised as albina green at the 3 leaf stage of plant growth (Figure 23) (Kolar et ah, 2011).

In certain aspects, maize, sorghum and putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants of the present disclosure may comprise one or more agronomically advantageous traits including but not limited to increased grain yield, increased starch content and quality, enhanced protein quality, improved digestibility, increased biomass, increased sugar content, enhanced drought and heat tolerance, reduced lodging, senescence time, acid or alkaline soil tolerance, weed and pest resistance, Beta-carotene improvement, aflatoxin resistance, foliar disease resistance including anthracnose resistance, downy mildew resistance, head smut resistance, gray leaf spot resistance, turcicum leaf blight resistance, zonate resistance and virus disease resistance such as maize streak virus disease resistance among others. For example, putative sorghum x maize intergeneric hybrid plants described herein and observed as segregating phenotypically to resemble maize senescence in a similar way to maize while those segregating phenotypically to resemble sorghum stay green for longer and senescence in a similar way to sorghum.

Other monocots

In certain aspects, intergeneric crosses may be developed using methods described herein utilising the first plants derived from seed comprising single or double recessive endosperm mutant alleles as female such as maize and the second plant being a member of the Poaceae. In still further aspects, intergeneric crosses may be developed wherein the first plant used as male produces pollen with genotype homozygous recessive for any one mutant endosperm alleles and the second monocot used as female is a plant of the Poaceae family such as sorghum. Monocots contemplated within the present invention include but are not limited to plants within the genera and species Zea mays mays, Zea mays x Zea mays hybrid plant, Zea mays huehuetenangensis, Zea mays mays x Zea mays Mexicana hybrid plant, Zea mays Mexicana, Zea mays parviglumis, Zea nicaraguensis, Zea perennis, Zea diploperennis, Zea luxurians, Saccharum officinarum, Saccharum spontaneum, Saccharum officinarum x Saccharum spontaneum hybrid plant, Pennisetum purpureum, Pennisetum ciliare, Pennisetum glaucum, Panicum virgatum, Sorghastrum nutans, Andropogon gerardii, Andropogon hallii, Arundo donax, Tripsicum dactyloides, Sporobolus airoides, Schizachyrium scoparium, Miscanthus floridulus, Sorghum bicolor hybrid plants or Miscanthus sinensis plant.

In certain aspects, a monocot plant used for the crosses described herein may itself be a 'sormaize' or 'maisorghum' plant crossed with maize or sorghum or any other member of the Poaceae family.

Incompatibility and compatibility systems in maize and sorghum The success or failure of wide hybridisations may be hinged on a number of factors underlying the genetic systems, mode of pollination (cross pollinating or self pollinating), genetic distance/relatedness and/or the physical reproductive structures of the plant species involved. In compatible situations however, wide hybridization is considered a vital tool in plant breeding providing opportunity for increased genetic variation, gene transfer of important traits and the creation of new species (Nitzsche and Zenkteler, 1984). Breeding for improved agronomic and/or industrial characteristics in crop plants for various uses is constrained by a shrinking natural genetic variability withi crop species. Examples of such traits include but are not limited to high grain yield and grain quality characteristics that includes protein, starch quality and digestibility, tolerance to biotic and abiotic stress and improvement for industrial purposes such as biofuels. To meet these increasing demands for food, fibre and other agricultural and/or industrial needs, it is imperative that efforts are directed towards hybridizing widely diverse plant materials to develop unique plant genotypes and/or entirely new plant species. Nonetheless, viable wide interspecific and/or intergeneric hybrid plants have been observed rarely both in nature and/or with controlled hybridisation, largely because of reproductive barriers which may be a result of self- incompatibility or cross incompatibility. Reproductive barriers may be pre-zygotic barriers or post-zygotic barriers. Pre-zygotic barriers are characterised by gametic incompatibility that may be described as gametophytic incompatibility or sporophytic incompatibility, which occur prior to fertilisation and are dependant on the inhibiting action of incompatibility genes. Self-incompatibility serves to discourage prospects for high inbreeding within species. The principles pertaining to the biology of self-incompatibility in plants is well studied and based on the solanaceae where one locus, designated 'S', is involved (Newbigin et al, 1993). Basically, the gametophytic form of self-incompatibility comprises a mechanism in which incompatibility of foreign pollen is determined by its own (haploid) 'S' genotype. Upon landing on the stigma, incompatible pollen germinates and grows into style of recipient plant and at some point within the stylous tissue towards the ovary gets "arrested". In the sporophytic form of self-incompatibility, the behaviour of incompatible pollen is determined by the diploid 'S' genotype of the pollen producing plant. In other words, with the sporophytic incompatibility system, incompatible pollen tube growth is "arrested" on the surface of the stigma.

Studies among the gramineae (grasses) reveal two loci 'S' and 'Z', independent of each other in determining self-incompatibility (Newbigin et al, 1993). The implication is that it leads to more breeding efficiency as more genotype combinations are possible. Thus, with this self- incompatibility system, one allele different at either locus from that present in the female parent is a prerequisite. For example, if the maternal parent plant genotype is S 1 S2 Z1Z2 and paternal parent plant is S1 S2 Z1Z3, pollen of genotype SlZl S2Z1 will be incompatible while pollen of genotype S1Z3 S2Z3 will be compatible. A detailed understanding of the molecular aspects and functions of the S- and Z- genes can be obtained from various sources in the literature.

Post-zygotic barriers manifest after fertilisation has taken place and are characterised by hybrid breakdown often observed in the form of embryo lethality and/or endosperm abortion or death of the hybrid plant prior to maturity.

Various factors might play a role in cross compatibility or incompatibility mechanisms observed in plants including but not limited to environmental factors, genome size, genetic factors and/or possibly physical factors present in the inflorescence of either crop plants. Cross incompatibility in plants may be due to incompatibility and/or incongruity. Cross incompatibility mechanisms function as described with self-incompatibility above resulting from the inhibiting action of incompatibility genes. Incongruity the other hand is attributed to the lack of genetic information between either one of two plants disrupting the pollen-pistil relationship and leading to failure of fertilization. It is also likely that genes that function specifically to recognize foreignness could block an otherwise compatible reaction in a similar manner as reported for cross-incompatibility and/or self-incompatibility. In Sorghum bicolor, the challenge of incompatibility with its wild relatives has been overcome following identification of a homozygous recessive gene designated inhibition of alien pollen (iap) (Laurie and Bennett, 1989). In intergeneric crosses with maize, Laurie and Bennette (1989) demonstrated that maize pollen tubes grew into a limited number of styles of one accession Sorghum nervosum but were not successful in obtaining a viable hybrid plant. Through a backcross breeding strategy, the iap allele has been introgressed into an elite sorghum line with better agronomic attributes designated Tx3361 and intergeneric hybrid plants developed with Sorghum halepense and Saccharum (Dweikat, 2005; Bartek, 2010; Rooney et al., 2010).

Incompatible reactions often manifest as absence of seed set despite the use of viable pollen on receptive stigmas in which case, the barrier to crossing is complete. There is a possibility that some pollen genotypes may be incapable of germinating and/or growing on particular pistils or are excluded by competition with pollen of other genotypes. In cases were partial or full seed set is observed, the reaction is referred to as partial compatibility. In the present invention with sorghum as the female parent plant, the tap allele or embryo rescue was not utilized to obtain putative hybrid seed with functional endosperm and subsequently, fertile putative sorghum x maize intergeneric hybrid plants therefrom. Rather, maize pollen comprising mutant homozygous recessive waxy and/or opaque-2 genotypes was observed to result in partial seed set in sorghum compared to when maize pollen of wild type (non-waxy and/or non-opaque-2) genotype was used (Bombom unpublished data). Complete and partial incompatibility reactions have also been reported in maize. In the genus Zea, incompatibility is attributed to an allele gal in pollen in which silks with Gals Gals genotype are non- receptive to pollen of gal gal genotype (Kermicle and Evans, 2010). Despite increased insights into the genetic basis for compatibility and/or incompatibility reactions among cereals, little success has been achieved in developing intergeneric hybrid plants between maize and sorghum. In the present disclosure, the inventors observed successful partial compatibility in crosses involving maize and sorghum wherein, the maize parent plant was used as female in the cross. In all successful crosses, maize genotypes possessing mutant alleles waxy and/or opaque-2 in endosperm in a homozygous single or double recessive state resulted in partial seed set that gave rise to fertile putative intergeneric maize x sorghum hybrid plants. It follows therefrom that using maize genotypes possessing mutant endosperm alleles in the homozygous single or double recessive state including but not limited to the waxy (wx) and opaque-2 (o2) alleles are within the scope of the present invention. Homozygous recessive mutant endosperm alleles are reported to have pleiotriopic effects on other loci. For example, the waxy allele in addition to influencing the end products of the starch metabolic pathway also has an effect on lysine metabolism and hence lysine levels in maize endosperm. The o2 mutation is associated with increased non-zein proteins and subsequently elevated lysine and tryptophan levels in maize endosperm. The mechanism by which o2 achieves this is by interfering with synthesis of prolamins in endosperm particularly the 19 kDa and 22 kDa alpha zein proteins (Vivek et al., 2008). Other studies have also demonstrated a positive correlation between increased concentration of eEFIA (a translation elongation factor) and lysine content in the endosperm (Habben et al, 1995). Central to lysine enhancement in maize endosperm is the presence of o2 in the homozygous recessive (o2o2) (Micic-Ignjatovic et al, 2008). Nonetheless, o2 exhibits pleiotropic effects including a soft chalky endosperm that likely results from its effect on the starch metabolic pathway. It is therefore logical to envisage that mutant endosperm alleles might have similar pleiotropic effects on loci that govern other plant attributes including compatibility and/or incompatibility reactions in specific sorghum and maize genotypes.

Development of fertile putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants

Reports of successful intergeneric hybridization involving sorghum are limited. Moreover, there are no reports of successful hybridization between sorghum and maize to date. Following the discovery of sorghum iap allele and subsequent development of sorghum germplasm Tx3361, intergeneric hybridization with Saccharum and Miscanthus have been reported (Rooney et al, 2010). In the present invention, the inventors observed that mutant endosperm maize lines when used as female with sorghum pollen resulted in seed set of putative maize x sorghum intergeneric hybrid seed with functional endosperm and developed embryo. Furthermore, when sorghum was used as the female parent plant and pollinated with maize pollen comprising mutant genotype wx putative sorghum x maize intergeneric hybrid seed was obtained. This observation demonstrates that barriers to hybridization between sorghum and maize may be circumvented through the use of endosperm mutant alleles. In addition, it is likely that combining the use of mutant endosperm alleles with sorghum iap allele may contribute in part to enhancing the efficiency of sorghum iap allele in generating successful wide crosses where sorghum is involved. This may be important given the limited range of the sorghum iap allele that may not have wide application across genera among the gramineae.

The present invention provides methods for development of fertile putative Fl sorghum x maize and/or maize x sorghum intergeneric hybrid plants and their subsequent filial generations and seed derived therefrom. In one aspect, such a method for development of sorghum x maize hybrid plants comprises the steps of: a) obtaining a sorghum plant NOT homozygous for the recessive iap allele and may or may not comprise homozygous recessive mutant endosperm alleles and is used as female in the cross; b) crossing the sorghum plant with maize pollen comprising a mutant recessive genotype and obtaining an Fl progeny, wherein the maize parent plant is used as the male parent; c) obtaining putative Fl sorghum x maize intergeneric progeny seed and growing them to maturity to obtain F2 seed; d) obtaining putative F2 sorghum x maize intergeneric progeny seed and growing them to maturity to obtain F3 seed; e) selecting putative F2 sorghum x maize intergeneric hybrid plants segregating for plant stature to resemble either the maize parent plant or the sorghum parent plant. Other characteristics observed and selected for at the F2 generation include but are not limited to seed size, color and shape, fertility, panicle size and shape, seed set among others; F) growing F3 putative intergeneric sorghum x maize hybrid seed derived from plants selected at the F2 generation for plant stature and obtaining uniform progeny stands resembling either the sorghum parent or maize parent plants (Figure 13).

In another aspect, such a method for development of maize x sorghum hybrid plants comprises the steps of: a) obtaining a maize plant homozygous single or double recessive for mutant endosperm alleles wx and/or o2 and is used as female in the cross; b) crossing the maize plant with sorghum pollen and obtaining an Fl progeny, wherein the sorghum parent plant is used as the male parent; c) obtaining putative Fl maize x sorghum intergeneric progeny seed and growing them to maturity to obtain F2 seed; d) growing F2 seed to obtain putative F2 maize x sorghum intergeneric hybrid plants; e) selecting putative F2 maize x sorghum intergeneric hybrid plants segregating for unique plant attributes of agricultural importance to crop improvement such as disease resistances (Figure 26A-D and Figure 27).

In still further aspects, production of fertile putative sorghum x maize and/or maize x sorghum hybrid plants by direct hybridisation and selection of progeny from Fl and/or subsequent generations via selfing or backcrossing using available cytogenetic and/or molecular biology tools as comprising novel and/or unique genotypes with potential for evolution into novel sub-species or species is contemplated to be within the scope of the present invention.

In line with the crosses carried out as described above no embryo rescue was carried out following pollination to obtain viable sorghum x maize and/or maize x sorghum intergeneric hybrid plants. All seed that developed and possessed an embryo and functional endosperm was planted directly into soil in pots and in the garden. It should be noted however, that in circumstances were wild type or normal maize endosperm lines are used as female, it might be necessary to employ embryo rescue techniques to isolate immature embryos as the inventors did observe seed grow to the blister stage and then degenerate about 7-10 days post pollination due to endosperm breakdown (Figure 21A-F).

The present invention reports for the first time development of fertile putative, sorghum x maize and/or maize x sorghum intergeneric hybrid seed and plants derived therefrom. Due to limited resources and expertise in performing different biological techniques to confirm putative intergeneric sorghum x maize and/or maize x sorghum hybrid plants as true crosses and not merely the result of selfing or pollination with pollen from another plant from the same species, photographic evidence of the phenotype of the maize and sorghum parent plants and progeny derived therefrom is presented as the first line of verification for existence of the sorghum x maize and/or maize x sorghum cross. In specific aspects, the characteristics described herein allow one of skill in the art to phenotypically identify a plant as resulting from an intergeneric cross between a sorghum parent plant and a maize parent plant based on the physical or morphological characteristics of either crop species.

In addition to phenotype, biochemical analysis was attempted as a preliminary means to verify the existence of the sorghum x maize cross using the starch potassium iodide/iodine test. This was because, the original sorghum x maize cross was carried out using a white waxy male sterile sorghum line ATx630 as female and a yellow waxy endosperm maize near isogenic line

as male in the screen house during the season 2009B. The seed obtained from the cross exhibited sheds of brown, were slightly larger in size than the sorghum parent seed and had fully developed endosperm (Figure 3A-C). The colour of putative Fl intergeneric hybrid seed provided the first line of phenotypic evidence for the sorghum x maize cross. From a genetics point of view, when within species crosses are carried out involving a wild type or normal endosperm maize or sorghum plant with a second plant comprising mutant endosperm such as waxy, the Fl progeny obtained from the crossing would be heterozygous normal endosperm. The Fl progeny starch if analysed would be wild type starch, which is dominant over waxy starch giving the characteristic deep blue color in solution with the potassium iodide/iodine complex (Figure 20). In this test, since the original sorghum x maize cross involved both waxy mutant endosperm starch types, it was not possible for the inventors to determine using starch biochemical analysis the type of starch present in endosperms of the putative Fl sorghum x maize intergeneric hybrid seeds. For this reason as well as to unambiguously determine repeatability of the cross, a second sorghum x maize cross was carried out in the screen house during the season 201 OA between the white waxy male sterile sorghum line ATx630 as female and a white maize inbred line, CML182 as male comprising the mutant allele opaque-2 (o2) in the endosperm but with normal or wild type starch.

Other techniques and/or tools important in confirming the present disclosure with minimal environmental influence include but are not limited to genetic markers such as simple sequence repeats (SSR), restriction fragment length polymorphism (RFLP), isozymes and single nucleotide polymorphism (SNP) to identify a plant of the invention. Advanced molecular tools that may also be applied to the invention include Diversity Arrays Technology (DArT), genomic in situ hybridisation (GISH), and fluorescent in situ hybridisation (FISH). In yet further aspects of the present invention, cytogenetic analyses including karyotype analysis and flow cytometry may be used to determine chromosome numbers and DNA content of hybrid plants respectively at early development stages of plant growth.

Introgression

In certain embodiments of the invention, are provided methods for improvement of agronomic traits of sorghum, the method comprising the steps; a-1) obtaining a sorghum parent plant NOT homozygous recessive for iap allele, may or may not comprise mutant homozygous recessive endosperm allele and may or may not be male sterile and is used as female in the cross; b-1) crossing the sorghum plant with maize pollen comprising mutant genotype wx and/or o2 c-1) obtaining a sorghum x maize Fl progeny derived from the crossing. In still further aspects, pollen from a non-sorghum Andropogoneae plant comprising mutant genotype may be used, d-1) selecting an intergeneric hybrid plant from among the sorghum x maize Fl and/or subsequent filial generations obtained via selfing, wherein the intergeneric hybrid plant possesses superior agronomic and/or industrial characteristics compared with either one of the crops and/or plant species used in the cross; e- 1) backcrossing the sorghum x maize intergeneric hybrid plant with a maize plant to obtain a first backcross (BC1) progeny wherein the BC1 progeny has improved agronomic and/or industrial characteristics. In yet further embodiments, this method may comprise: f-1) inbreeding the sorghum x maize progeny to produce progeny homozygous for important agronomic and/or industrial traits.

In still further embodiments of the invention, are provided methods for improvement of agronomic traits of maize, the method comprising the steps; a-2) obtaining a maize parent plant homozygous single or double recessive for mutant endosperm alleles and is used as female; b-2) crossing the maize plant with sorghum pollen and obtaining a maize x sorghum Fl progeny. In still further aspects, pollen from a non-maize Andropogoneae plant may be used, c-1) selecting an intergeneric hybrid plant from among the maize x sorghum Fl and/or subsequent filial generations obtained via selfing, wherein the intergeneric hybrid plant possesses superior agronomic and/or industrial characteristics compared with either one of the parent crops and/or plant species used in the cross; d-1) backcrossing the maize x sorghum intergeneric hybrid plant with a sorghum plant to obtain a first backcross (BC1) progeny wherein, the BC1 progeny has improved agronomic and/or industrial characteristics. In yet further embodiments, this method may comprise: e-1) inbreeding the maize x sorghum progeny to produce progeny homozygous for important agronomic and/or industrial traits.

Selection for improved agricultural and industrial traits

Within the scope of the present invention, intergeneric hybridisation of sorghum with maize and/or maize with sorghum may be used to improve important agricultural and industrial characteristics of either one of the two crops and/or plants within the Andropogoneae. Selection for higher or improved agricultural or industrial characteristics can be carried out using standard plant breeding proceedures and identifying intergeneric hybrid plants for desired agricultural and/or industrial characteristics. In addition to standard plant breeding proceedures, standard industrial analytical proceedures may be applied to the invention.

In specific aspects, agricultural and/or industrial characteristics may include but are not limited to disease resistance, aflatoxin resistance, increased plant biomass, drought and heat tolerance, improved grain quality (protein, starch, Beta carotene, digestibility), plant height, stem diameter, seed size, germination, photoperiod insensitivity, fertility, saline soil tolerance, acid soil tolerance, water logging tolerance, seed viability after storage and/or any other characteristics commonly known in the art.

Genetic transformation of putative sorghum x maize and/or maize x sorghum intergeneric hybrid plants

Plant transformation involves the construction of an expression vector, which will function in plant cells. Such a vector comprises DNA comprising a gene under control or operatively linked to a regulatory element such as a promoter (Bunn, 2011). Vectors may be in the form of plasmids or any other form known to those in the art and may be used in isolation or in combination with other plasmids to provide transformed sorghum x maize and/or maize x sorghum intergeneric hybrid plants. It is important to note that the DNA segment chosen for cellular introduction will often encode a protein that will be expressed in the resultant recombinant cells resulting in a selectable trait and/or which will impart an improved phenotype to the resulting transgenic plant (Rooney et ah, 2010). However, in some cases, non-expressed transgenes may be incorporated into transgenic plants and are also contemplated to be within the scope of the present invention. Important agronomic traits may be introduced into elite crop backgrounds by backcrossing as well as by direct introgression into an intergeneric hybrid plant. These traits can similarly be introduced by genetic transformation techniques and include but are not limited to herbicide resistance, disease resistance, insect resistance, male sterility, modified fatty acid, phytate and carbohydrate metabolism, drought tolerance, foreign protein genes and agronomic genes, terminator genes for seeds of improved crop cultivars and any other characteristics known to those of skill in the art. Genetic plant transformation may therefore find use in the present invention to insert selected transgenes into a plant or may, alternatively, be used for the preparation of transgenes, which can be introduced by backcrossing. Techniques used in plant transformation are well known to those of skill in the art and are applicable to several crop species including but are not limited to electroporation, microprojectile bombardment, Agrobacterium-mediated transformation, and direct DNA uptake by protoplasts.

Production of putative haploid plants from a cross between maize and sorghum

In certain aspects, haploid plants may be produced from wide hybridisations. As such, putative haploid sorghum and/or maize plants may be produced from crosses between sorghum and maize. In some aspects of the invention, haploid sorghum plants may be produced from a cross involving sorghum as the female parent plant and maize as the male parent plant. In still further aspects of the present invention, haploid maize plants may be produced from a cross between maize and sorghum wherein the maize plant is used as the female. It follows therefrom that putative haploid sorghum and/or maize plants produced from wide crosses involving sorghum and/or maize are within the scope of the present invention. In some aspects of the invention, dihaploid sorghum and/or maize lines may be developed from sorghum x maize and/or maize x sorghum systems of crosses and are contemplated to be within the scope of the present invention.

Deposit information

The maize x sorghum and/or sorghum x maize invention is still at the initial development stages and as such, no deposits of seeds and/or plant materials of any kind have been made with any type culture collection centre. However, deposits should be made as soon as proof of concept and refinement of the sorghum x maize and/or maize x sorghum technology in the present invention is complete.

Examples The techniques and observations disclosed in the examples that follow represent techniques discovered by the inventor to result in successful crosses between maize and sorghum. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention (Rooney et al, 2010).

Example 1:

Development and characterisation of fertile sorghum x maize intergeneric hybrid plants with sorghum parent line ATx630 and maize parent lines wxlHill and CML182

During the season 2009B, the inventors out of curiosity and without prior knowledge of experiments on sorghum x maize and/or maize x sorghum crosses pollinated one male sterile sorghum plant of sorghum line ATx630 comprising white, waxy endosperm with pollen obtained from a yellow endosperm near isogenic maize line wx/Hi27 comprising waxy background (Figure 2A-D). The cross was carried out in the screen house at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). Briefly, one male sterile sorghum parent plant was covered with a pollination bag to avoid contamination from extraneous pollen upon observing the male sterile phenotype on the panicle. Pollen obtained from maize line wx Hi27 comprising waxy genotype was dusted onto the male sterile panicle of sorghum plant ATx630. The cross ATx630 x wx7Hi27 was successful yielding at least 150 seeds with fully functional endosperm. Putative Fl intergeneric hybrid seeds from the cross ATx630 x w 7Hi27 comprised different shades of brown in colour and were larger in size compared with the sorghum parent seeds (Figure 3A-C).

To test viability of putative Fl intergeneric sorghum x maize hybrid seed, direct planting of seed was made in the field and in pots at the screen house during the season 2010B. The Fl putative sorghum x maize hybrid seed germinated with similar rates as normal sorghum and hybrid plants exhibited variation in plant growth, panicle size and shape, seed size and colour, and for the most part, plants looked more like sorghum (Figure 4, Figure 5A-B, and Figure 6A-D). All putative Fl sorghum x maize intergeneric hybrid plants produced F2 seed that were viable (Figure 6A-D). These observations attest that fertilisation was successful. The fact that sorghum line ATx630 used as female in the original sorghum x maize cross of the present invention does not comprise the sorghum homozygous recessive iap allele implies that some other unreported factor is responsible for the success of the cross (Bill Rooney, Personal Communication; "No. Only in Tx3361 possess the iap gene. Bill"). No embryo rescue was used in the present invention as putative Fl intergeneric sorghum x maize hybrid seed comprised an embryo and well developed endosperm.

To determine if F2 putative sorghum x maize hybrid seed would be viable, one self- pollinated Fl panicle grown from season 201 OB was selected at random and forty F2 seeds obtained therefrom. The forty F2 seeds were planted into pots at the screen house at MUARIK during season 2011 A. The inventors observed segregation among F2 plants for traits including but not limited to seed color, seed size, fertility, panicle size and shape, plant stem appearance, and plant vigour (Figure 7, Figure 9A-H, Figure lOA-C, and Figure 11A- E). An important feature observed by the inventors at or after the 8^th leaf stage was segregation of putative F2 sorghum x maize intergeneric hybrid plants derived from seed obtained from a single Fl hybrid plant panicle for plant stature. Some F2 plants segregated to resemble the maize parent plant and others segregated to resemble the female sorghum parent plant (Figure 7, and Figure 8A-C). Of the 40 F2 putative hybrid seeds planted, 20 plants segregated to resemble the maize parent plant while the remaining 20 plants segregated to resemble the female sorghum parent plant giving a segregation ratio of about 1 :1. The inflorescence however remained that of sorghum though there was variation in inflorescence/panicle size, shape, compactness and as well as size and colour of seed that developed (Figure 9A-H, and Figure 11 A-E). Putative F2 hybrid plants were allowed to grow to maturity and fertile plants that segregated phenotypically to resemble either maize or sorghum selected to provide F3 seed and subsequent generations. F3 seed from individual panicles of plants selected as resembling either maize or sorghum was obtained and planted into pots in the screen house at MUARIK during season 201 IB to ascertain whether further segregation would be observed. Interestingly, among F3 progeny plants, the inventors observed that plants tended to be uniform in some aspects of phenotype; for example, plant stature, plant height, seed size and shape (Figure 12A-F, and Figure 13). One particular feature observed among seed obtained from F3 putative progeny plants and subsequent generations that segregated to resemble maize was a collapsed endosperm among some seed on the same panicle likely due to post-zygotic incompatibility (Figure 14B-C). It is important to note that the phenotype of shrivelled seeds or collapsed endosperm attributed to possible post-zygotic incompatibility was also observed by the inventors on one Fl sorghum x maize panicle (Figure 14A). The maize parent line wxiHi27 is characterised as being highly susceptible to turcicum leaf blight (TLB) caused by Exerohilum turcicum (Pass.) Leonard & Suggs (teleomorph = Setosphaeria turcica (Luttr.) K. J. Leonard & Suggs; syn. = Helminthosporium turcicum Pass.) (Brewbaker, 1997). The phenotype of TLB lesions on the maize parent plant observed at seedling stage were also manifested in the putative Fl sorghum x maize intergeneric hybrid plants at the same growth stage but later disappeared, as the plants grew older (Figure 26B). The observations of the TLB disease phenotype and the orange/brown colour on the Fl seed are but a few indications that likely, some introgression however small must have occurred with the sorghum x maize cross.

To unambiguously determine repeatability of the sorghum x maize cross, the male sterile sorghum line ATx630 comprising waxy background was crossed to two CIMMYT maize inbred lines comprising white endosperm but with normal or wild type starch and was carried out during season 201 OA. The CIMMYT maize lines included, CML182, a quality protein maize (QPM) or high lysine inbred line comprising opaque-2 endosperm and CML078 comprising normal endosperm. In addition to determining repeatability using a different germplasm source, the rationale for using maize lines with wild type starch was to provide a preliminary clue in confirming the hybrids using starch biochemical analyses as true crosses. The genetic basis is that when a waxy endosperm plant is crossed with a plant of wild type starch, the Fl progeny will posses wild type starch in its endosperm, which is dominant over waxy starch attributed to the recessive mutant waxy allele. The starch-potassium iodide/iodine complex thus formed will be the characteristic deep blue colour typical of high amy lose in the sample (Figure 20).

Table 1. Data on germination, survival and yielding characteristics of fertile putative Fl hybrid plants from the cross ATx630 X CML182 sorted by the inventor according to seed phenotype.

No. Panicles Per Plant

Sorghum x Maize Seed No. Seed No. Plants No. Plants No. Plants 1 2 Cross (Fl) Phenotype Planted Germinated Survived Dead

ATx630 X CML182 Maize-like 40 4 4 - 1 3

ATx630 X CML182 Sorghum-like 40 31 20 11 15 5

Table 2. Phenotypic traits of the Fl hybrid cross ATx630 X wxlHiU relative to the female sorghum parent plant ATx630 Phenotypic trait ATx630 Fl (ATx630 X wxlHffl)

Stalk borer Low Low

Anthracnose Low Intermediate

Lodging Low Low

Glume covering 25% covered 25% covered

Glume colour Sienna Sienna

Panicle compactness and shape Semi-loose erect primary branches Loose drooping primary branches Panicle exersion Well exerted Well exerted

Panicle length (cm) 3.3 13.7

Panicle width (cm) 1.4 3.7

Plant height (cm) 91.7 138.6

Seed shape Rounded Oval with base pointed, also has dent

Grain color (appearance) White, waxy Light shades of yellow and brown Endosperm color White Off-white, light brown

Characterisation carried out according to IBPGR & ICRISAT hand book (IBPGR and ICRISAT, 1993).

Eight sorghum plants of male sterile line ATx630 were pollinated during the season 201 OA in the screen house at MUARIK; six sorghum plants were pollinated with pollen from the high lysine maize inbred line CML182 (ATx630 x CML182) (Figure 15A-B) and 2 sorghum plants pollinated with pollen from CIMMYT maize inbred line CML078 (ATx630 x CML078). The cross ATx630 x CML182 set seed much more easily compared with the cross ATx630 x CML078 but was variable (Figure 16A-B). Seed obtained from the cross ATx630 x CML182 were observed to exhibit two phenotypes; some appeared maize-like and others appeared sorghum-like (Figure 16C-D). The sorghum-like seed were the majority. We separated and planted out these two phenotypes in pots in the screen house to determine their viability.

Germination was poor for the maize-like seed types while the sorghum-like phenotypes exhibited vigor (Figure 17A-B). The plants that grew out of the maize-like phenotypes exhibited slow growth (Figure 18A-B). Out of the 4 plants that germinated from the maizelike seed and survived to maturity, 1 plant produced one tiller at 1 month while the other 3 plants produced two harvestable tillers each that emerged and matured at the same time (Table 1). The second tiller was observed to emerge at the same leaf position at which the ear from the maize parent plant emerges (Figure 19). In terms of growth, plants from the sorghum-like seed exhibited vigour similar to the sorghum parent plant and appeared to grow normally (Figure 17C).

Advancement of fertile putative sorghum x maize intergeneric Fl populations

The Fl putative sorghum x maize intergeneric hybrid population was advanced to subsequent F2, F3 and F4 generations by self-pollinating individual hybrid plants. Backcrosses have been carried out to the sorghum and maize parent plants and seed obtained. Backcross progeny are yet to be planted out in the field and/or green house.

Confirming putative sorghum x maize intergeneric hybrid plants

Preliminary confirmation of putative sorghum x maize intergeneric hybrid plants as true crosses was initially ascertained by plant morphology. In terms of plant stand, Fl putative sorghum x maize intergeneric hybrid plants were not uniform and exhibited various traits including but not limited to plant height, panicle size and shape, seed colour and seed size that varied from the sorghum parent plant (Figure 3A-C, Figure 4, Figure 5A-B, Figure 6A- B). Nonetheless, Fl hybrid plants were more like the sorghum parent plant with little evidence of traits passed on from the maize parent plant in this generation. In the subsequent F2 generation developed by self-pollinating individual Fl plant panicles and planting seed obtained therefrom, segregation for plant characteristics including but not limited to plant stature, fertility, seed colour and size, and panicle size and shape were observed (Figure 7, Figure 8A-C, Figure 9A-H, Figure lOA-C, Figure 11A-E). Morphological characterisation of putative Fl sorghum x maize hybrid plants relative to the sorghum parent plant was based on phenotypic parameters that included but not limited to plant height, resistance to biotic stress, glume color, glume covering, plant pigmentation, lodging (Table 2). In addition to characterisation by morphology, preliminary confirmation of the sorghum x maize cross was carried out by performing starch biochemical analysis based on the repeat cross ATx630 x CML182 involving sorghum line ATx630 comprising waxy endosperm with waxy starch and the maize inbred line CML182 comprising normal endosperm with wild type starch. Biochemical characterisation of putative sorghum x maize intergeneric hybrid seeds for selected starch physicochemical properties

Plant material

Table 3. Pedigrees and source of sorghum and maize materials used in the starch biochemical analysis

Genotype Pedigree Genus Species Source

wx7Hi27 CM 104 (India) (=A Theo 21 (B)#) Zea mays J. Brewbaker, HARC

C L078 G32C19H32-l-#2-B-###-3-B Zea mays NaCRRI

CML182 WOMTAl-B-l-l-l -BB Zea mays NaCRRI

52R Mexico R.linel5xSDSL91078DL-2 Sorghum bicolor KARI, KATUMANI

RTx2907 0SCS3234 Sorghum bicolor Rooney, B. Texas, A&M

ATx630 02C55594x5593 Sorghum bicolor Rooney, B. Texas, A&M

HARC - Hawaii Agricultural Research Center; KARI - Kenya Agricultural Research Institute; NaCRRI - National Crops Resources Research Institute.

Starch isolation

Seed obtained from the cross ATx630 x CML182 was harvested from six sorghum pollinated plant panicles and pooled to obtain sufficient seed for analysis. Starch was extracted from maize line CML182, sorghum line ATx630 and Fl progeny seed by steeping in 0.05M H₂S0₄ at 50°C for 48 hrs followed by grinding and mashing using a Waring blender (Waring, Restaurant Equipment World™, Orlando, FL, USA). The resultant mash was filtered using two layers of cheesecloth. Starch was obtained after a brief centrifugation of the filtrate, decanting the supernatant and drying the residue at 40°C in an oven for 24 hours prior to performing any analysis (Nuwamanya et ah, 2011).

Amylose quantification

Starch obtained from maize, sorghum and Fl hybrid seed was dispersed into ethanol and gelatinised with 0.1M monosodium hydroxide. An aliquot of the gelatinised starch was treated with 0.1M citric acid prior to further treatment with iodine solution. Optical density readings were measured in duplicate and reported as absolute blue values (BV) using a spectrophotometer 6405 UV/vis (JENWAY Bibby Scientific Limited, Beacon Road, Stone, Staffordshire ST15 0SA, UK) at 680 nm (Nuwamanya et al, 2011). Standard amylase maize (64%) (Megazyme International Ireland Ltd. Wicklow, Ireland) was used as a standard in the analysis.

Paste clarity Paste clarity was determined by preparing a 1% aqueous solution of starch and boiling at 93°C with repeated shaking for 30 minutes (Ceballos et al., 2007). The solution was transferred into a cuvette after cooling and duplicate absorbance readings taken at 650 nm using a spectrophotometer UV/Vis 6405 (JENWAY Bibby Scientific Limited, Beacon Road, Stone, Staffordshire ST 15 0SA, UK).

Starch amylosis/ Reducing sugars determination

Starch amylosis was determined by treating O.lg of starch with hot ethanol (95%) followed by digestion with -amylase. Glucose released into solution (0.1 ml) was quantified after 4 hours as total reducing sugars in solution using the Megazyme total carbohydrate kit (Megazyme International Ireland Ltd. Wicklow, Ireland).

Results/Observations

The results presented in table 4 on starch physicochemical characteristics of maize, sorghum, the sorghum x sorghum and sorghum x maize hybrids respectively are absolute values of individual starch samples. Based on the genetics, the results of the sorghum x sorghum Fl cross did behave as expected giving rise to progeny with wild type starch (BV of 0.2) resulting from crossing a sorghum plant of waxy background with another sorghum plant comprising normal or wild type starch. On the contrary, the sorghum x maize Fl cross, showed a blue value result skewed to the sorghum female parent plant (BV of 0.03) considered waxy. This observed distortion from known genetic principles of dominance of the expected starch type might suggest indeed, the sorghum x maize cross was successful with a possible subsequent effect on the starch and likely, other yet to be determined plant physiological and/or metabolic pathways or processes. Furthermore, the inventors did observe some apparent heterosis in the putative sorghum x maize Fl cross relative to the sorghum and maize parents for traits including starch yield and clarity of the starch paste. These observations indicate there is potential to improve either sorghum or maize for important starch properties that may be useful in the food/ non-food industry.

Table 4. Comparison of maize and sorghum parental lines and the putative sorghum x maize Fl hybrid cross for selected starch physicochemical characteristics

CML182 Maize, inbred line, white endosperm, 19.9 0.2 6.7 1.5 normal type starch, comprising opaque-2

allele

CML078 Maize, inbred line, white endosperm, 39.8 0.3 8.1 3.2

normal type starch, not comprising mutant

allele

ATX630 Sorghum inbred, male sterile, white 44.0 0.03 22.6 1.8

endosperm, comprising waxy starch and

allele

52R Sorghum inbred, white endosperm, normal/ 35.0 0.4 8.2 9.5

wild type starch, not comprising mutant

allele

RTx2907 Sorghum inbred, white endosperm, 36.3 0.05 28.2 12.3 comprising waxy starch and allele

52R X RTx2907 F 1 sorghum x sorghum cross 47.6 0.2 6.1 6.2

ATx630 X CML182 F 1 sorghum x maize cross 53.5 0.03 48.1 1.5

The data presented in this table are absolute values for the respective sample analysed. BV = Blue value and estimates the amount of amylose in a given starch sample; NIL = Near isogenic line; Fl = First filial generation of a cross between two plants.

Important to note is that environment plays a significant role in influencing enzymes involved in the starch biosynthetic pathway impacting on different starch physicochemical properties. As such, the type of starch and its physicochemical properties will vary with location and genotype of the plant in question.

Example 2:

Development of fertile maize x sorghum intergeneric hybrid plants with maize parent lines M>xlHi27, 115-28, Longe-5 and CML078 and sorghum parent lines BTx630, BTx623, Epuripur, and Seredo.

Following successful observation and production of fertile putative sorghum x maize hybrid plants from the crosses described in example 1 above wherein, sorghum was the female parent plant, the inventors attempted a maize x sorghum cross using maize as the female parent plant in season 201 OA. The first maize x sorghum cross was carried out in a backyard garden on Lake Drive, Port Bell, Luzira, a Kampala suburb on the shores of Lake Victoria and involved the cross CML078 x RTx2907 (Figure 21A-B). The maize line CML078 is an elite CIMMYT maize inbred line obtained from the National Crops Resources Research Institute (NaCRRI), Namulonge comprising white and normal endosperm and was used as the female parent plant in the cross. The sorghum plant of line RTx2907 is a restorer line comprising white and waxy endosperm provided by Bill Rooney from Texas A&M and was used as the male parent plant in the cross. Two plants of maize line CML078 had their tassels and ears covered with pollination and shoot bags respectively to prevent self- and/or cross- pollination. Pollen observed to be viable was obtained from two sorghum plants of line RTx2907 and dusted onto silks of the two maize plants at about 11 am in the morning and pollinated ears kept bagged thereafter. Pollinated ears were checked for seed development 3- 4 days after pollination and there was evidence of fertilisation as seed was observed to develop up to the blister stage (Figure 21C-D). However, 7-10 days later, all developing seed desiccated or degenerated likely due to failure of endosperm development (Figure 2 IE).

In season 2012 A, the inventors repeated the maize x sorghum cross using maize lines differing in endosperm background including maize lines wxlHi27, 115-28, Longe-5, and CML078. The maize line wx7Hi27 is a near isogenic line comprising waxy and yellow endosperm and is susceptible to turcicum leaf blight (TLB). Maize line 1 15-28 is an F3 derived population from the cross CML182 x wxlHill, comprising yellow endosperm and is homozygous double recessive for the waxy (wx) and opaque-2 (o2) alleles. The maize parent line CML182 is a CIMMYT inbred line comprising white endosperm and homozygous recessive for the opaque-2 (o2) gene and is used for quality protein maize (QPM) development in breeding programmes. Maize line Longe-5 developed by the cereals program of the National Crops Resources Research Institute (NaCRRI), Namulonge is an open pollinated variety (OPV) introgressed with the opaque-2 gene and comprising white endosperm. Maize line CML078 is an inbred line comprising white and normal endosperm. The sorghum lines used as male in the crosses included BTx630, BTx623, Epuripur and Seredo. All sorghum lines used were white seeded and comprised normal endosperm with the exception of BTx630, which comprised waxy endosperm.

At least 5 plants of each maize line were crossed with sorghum. Maize x sorghum crosses involving maize lines with homozygous recessive mutant alleles in endosperms as female including w 7Hi27, 115-28 and Longe-5 set seed when pollinated with sorghum lines BTx630, BTx623, Epuripur and Seredo. Seed set on average ranging from 1 to at least 30 seeds per ear pollinated (Figure 22A-H, Figure 24A-E, Figure 30A-B). As with the first maize x sorghum cross carried out in season 201 OA, crosses involving maize line CML078 did not set seed when pollinated with pollen obtained from sorghum lines BTx630, BTx623, Epuripur, or Seredo (Figure 2 IF). However, the control experiment in which ears of maize line CML078 were self-pollinated with pollen from tassels of CML078 plants showed 100 percent seed set (Figure 21G). These observations by the inventors with maize genotypes of differing genetic backgrounds suggests that homozygous recessive mutant alleles in maize might have an influencing role on the success of maize x sorghum crosses.

Seed treatment

All seed that set on pollinated maize ears were allowed to develop to maturity. Ears were harvested by hand; sun dried and seed stored in khaki envelopes in a cool and well ventilated room. No chemical treatment has been applied to the seed in storage.

Advancement of fertile maize x sorghum intergeneric Fl populations

Putative Fl intergeneric hybrid seed from the cross wx/Hi27 x BTx630 was advanced by first pre-germinating the seed on moist paper towels in plastic petri dishes and then transplanting into a backyard garden on Lake Drive, Port Bell, Luzira, a Kampala suburb on the shores of Lake Victoria during the season 2012B. At the 3 leaf stage of plant growth, the inventors observed some putative Fl hybrid plants to possess white leaves with loss of the green chlorophyll, color characteristic of chlorophyll mutants (Figure 23). The chlorophyll mutant phenotype observed among the maize x sorghum hybrid plants of the cross wxiHi27 x BTx630 have been observed and characterised among plants of the species Delphinium malabaricum (Huth) Munz. as albina green (Kolar et al., 201 1). However, as the putative hybrid plants developed, beyond the 4^th leaf stage, the chlorophyll mutant phenotype was lost and plants grew normally. All plants were shorter in height compared with the maize parent plant, produced a small tassel and ear. Ear emergence in some plants appeared to delay compared with the maize parent plant. Other observations among the cross wx7Hi27 x BTx630 was susceptibility of the Fl putative hybrid plants to turcicum leaf blight disease (Figure 26C). Backcrosses of the sorghum x maize cross BTx630 x wxlHiU to the maize parent plant wxiHi27 were also been carried out using the maize parent plant as female and seed obtained (Figure 221).

During the season 2013 A, 4 Putative Fl hybrid seeds derived from the cross wx/Hi27 x BTx623 were sown directly into the soil in the backyard garden on Lake Drive, Port Bell, Luzira, a Kampala suburb on the shores of Lake Victoria. All 4 putative Fl hybrid plants grew normally but were shorter than the maize parent plant wx7Hi27 with the first plant flowering at 7 weeks after emergence. Unlike the maize x sorghum cross wx7Hi27 x BTx630 that displayed a susceptible phenotype in the Fl generation, the Fl cross wx7Hi27 x BTx623 exhibited a resistance phenotype to turcicum leaf blight disease (Figure 26C-D and Figure 27). This observation can be explained from the point of view that known maize mutant genotypes including opaque-2 (o2) and waxy (wx) are associated with major pleiotropic effects including susceptibility to disease. The fact that the putative Fl hybrid from the cross wxiHi27 x BTx623 displayed a resistance or tolerant phenotype to turcicum leaf blight suggests that some introgression from the sorghum parent plant BTx623 comprising normal endosperm likely occurred hence contributing to suppression of disease expression.

Confirmation of maize x sorghum intergeneric hybrid plants

The present invention reports for the first time the existence of fertile intergeneric hybrid plants from a cross between maize and sorghum using either plant species as female or male in a given cross. The invention also describes how fertile hybrid seed and plants may be developed between maize and sorghum. To confirm putative maize x sorghum hybrid plants as true crosses, karyotype analysis to establish somatic chromosome number of hybrid plants needs to be carried out as the first basic step. This will form part of the next steps of providing the proof of concept in unravelling the maize x sorghum hybrid plants as true crosses. Procedures for carrying out chromosome spreads have been reported previously and will similarly be applied to the putative maize x sorghum and/or sorghum x maize intergeneric hybrid plants (Ma et ah, 1996).

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Claims

Claims: The following form part of what is claimed in the present patent application

1. A sorghum x maize intergeneric hybrid plants produced by crossing a sorghum parent plant with a maize parent plant, wherein the sorghum parent plant is female and does NOT comprise a mutant homozygous recessive iap allele.

2. A maize x sorghum intergeneric hybrid plants produced by crossing a maize parent plant with a sorghum parent plant, wherein the maize parent plant is female and comprises a homozygous single or double recessive mutant endosperm allele.

3. The mutant endosperm alleles comprised in the maize plant of claim 2, wherein the alleles include but are not limited to amylose extender (ae), dull (du), waxy (wx), sugary-1 (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken-1 (sh), shrunken-2 (sh2), shrunken-4 (sh4), opaque-2 (o2), opaque-7 (o7) and/or floury-2 (jl2).

4. The plant of claim 1, wherein the sorghum parent plant is a sorghum bicolor plant of line ATx630, ATx623 and is male sterile.

5. The plant of claim 1, wherein the maize parent plant is a Zea mays plant of line wx7Hi27, sub-species Zea mays var. Ceratina, produces viable pollen comprising of waxy genotype and is used as the male parent plant in the cross.

6. The plant of claim 2, wherein the maize parent plant is an open pollinated variety, inbred line, hybrid plant or near isogenic Zea mays plant including maize lines Longe- 5, CML182, 115-28 or wxlYtill respectively.

7. The plant of claim 2, wherein the sorghum parent plant is a male fertile Sorghum bicolor plant of line BTx630, BTx623, Epuripur or Seredo and is used as the male parent plant.

8. The plant of claim 1 and/or 2, further comprising a transgene wherein the transgene confers enhanced starch content and/or quality, protein quality, aflatoxin resistance, disease resistance, insect and/or pest resistance, herbicide resistance, drought tolerance, acidic soil tolerance, salt tolerance, water logging, male sterility, Beta carotene or increased biomass.

9. A plant part of the plant of claim 1 and/or 2; the plant part further being defined a cell, seed, petiole, gamete, meristem, pistil, anther, flower, embryo, stalk, protoplast, panicle, leaf or root.

10. The plant part of claim 9, further defined as a 2n plant gamete.

11. A seed that produces a plant of claim 1 and/or 2; the seed further being treated with a protectant or growth enhancing agent or other substance to improve seed mechanical handling properties, seed germination, seedling establishment or growth, a fungicide or pesticide.

12. A progeny plant of the plant according to claim 1 and/or 2, wherein the progeny comprises at least a first chromosome or segment thereof from the sorghum parent plant and least a first chromosome or segment thereof from the Zea parent plant.

13. A tissue culture of regenerable cells of the plant of claim 1 and/or 2; the tissue culture of regenerable cells being obtained from embryos, meristematic cells, pollen, roots, leaves, root tips, seed, pistil, anther, boll or stem.

14. A plant regenerated from the tissue culture of claim 14 including pollen and ovule from the said plant.

15. A commercial product obtained according to claim 1 and/or 2 or a part thereof including the method of production thereof; the commercial product further including but not limited to food, bread, animal feed, industrial product such as couscous, fermented foods and beverages, malt extracts, dumplings, alcoholic or non-alcoholic beverage including beers, malt beverages, ethanol or fermentable biofuel feed stock.

16. A sorghum plant comprising a male sterility trait, wherein the plant is NOT homozygous for a recessive iap allele.

17. A seed that produces the sorghum plant of claim 16.

18. A method for producing sorghum x maize intergeneric hybrid embryo or seed, the method comprising crossing a sorghum parent plant with a maize parent plant, wherein the sorghum parent plant does NOT comprise a homozygous recessive sorghum iap allele and is used as the female parent plant.

19. A method for producing maize x sorghum intergeneric hybrid embryo or seed, the method comprising crossing a maize parent plant with a sorghum parent plant, wherein the maize parent plant comprises homozygous single or double recessive endosperm alleles and is used as the female parent plant.

20. The method of claim 18 and/or 19, comprising a sexual step and NOT comprising rescuing an embryo resulting from the crossing.

21. The method of claim 18 and/or 19, comprising growing an embryo or seed from the crossing to produce a sorghum x maize and/or maize x sorghum intergeneric hybrid plant.

22. The method of claim 18 and/or 19, wherein the embryo is comprised in a seed having a functional endosperm.

23. The method of claim 1 and/or 2, further comprising inbreeding the sorghum x maize and/or maize x sorghum intergeneric hybrid plants to obtain subsequent filial and/or segregating populations of hybrid plants resulting into pure lines or unique novel genotypes with mixed genomic content from the sorghum and maize parent plants.

24. The method according to claim 23, further comprising obtaining segregating populations of sorghum x maize and/or maize x sorghum intergeneric hybrid plants with phenotypic and physiological characteristics of the sorghum parent plant or the maize parent plant.

25. The plant of claim 1 and/or 2, further comprising backcrossing the intergeneric sorghum x maize and/or maize x sorghum hybrid plants to obtain a third monocot plant.

26. A method of preparing a hybrid plant between sorghum and maize using sorghum x maize and/or maize x sorghum intergeneric hybrids plants by directly crossing maize or sorghum with a second monocot plant or as a bridging species: a) performing a first cross between compatible sorghum and maize lines; and then b) crossing one or more sorghum x maize and/or maize x sorghum hybrid plants from (a) with a Zea, Sorghum or other monocot plant selected from the Poaceae family to form novel hybrid plants.

27. The methods according claims 26 further comprising inbreeding the third monocot plant to produce introgressed progeny homozygous for at least one or more introgressed traits or genes.

28. A method for producing an intergeneric hybrid embryo or seed, or plant, the method comprising crossing a sorghum parent plant with a second monocot parent plant, wherein the sorghum plant is NOT homozygous for a recessive sorghum iap allele and is used as a female parent; the second monocot plant used as male comprising pollen of homozygous mutant genotype including but not limited to amylose extender (ae), dull (du), waxy (wx), sugary-l (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken-1 (sh), shrunken-2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2

29. A method for producing an intergeneric hybrid embryo or seed, or plant, the method comprising crossing a maize parent plant with a second monocot parent plant, wherein the maize parent plant comprises homozygous single or double recessive endosperm mutant alleles including but not limited to amylose extender {ae), dull (dii), waxy (wx), sugary-1 (su), sugary-2 (su2), brittle-1 (btl), brittle-2 (bt2), shrunken-1 (sh), shrunken-2 (sh2), shrunken-4 (sh4), opaque-2 (o2), and/or floury-2 (fl2) and is used as the female parent plant.

30. The method of I) claim 28, wherein crossing a sorghum parent plant with a second monocot plant comprises, a) collecting pollen comprising recessive mutant genotype from the second monocot parent plant; b) pollinating a flower on the sorghum parent plant with the said pollen. II) Claim 29, wherein crossing a maize parent plant comprising homozygous recessive mutant endosperm alleles with a second monocot parent plant comprises, a) collecting pollen from the second monocot parent plant; b) pollinating a receptive ear on the maize parent plant with the said pollen.

31. The method of claim 28 and/or 29, comprising a sexual reproductive step and NOT comprising rescuing an embryo resulting from the crossing.

32. The method of claim 28 and/or 29, comprising growing an embryo resulting from the crossing to produce an intergeneric hybrid plant.

33. The method of claim 28 and/or 29, wherein the embryo comprises a seed having a functional endosperm.

34. The method of claim 28 and/or 29, wherein the second monocot parent plant is selected from the Poaceae family and the group consisting of Zea, Saccharum, Panicum, Miscanthus, Erianthus, Sorghastrum and Pennisetum.

35. The plant of claim 28 and/or 29, wherein the second monocot parent plant is a Zea mays mays, Zea mays var. amylacea (flour corn), Zea mays var. everta (popcorn), Zea mays var. indentata (dent corn), Zea mays var. indurate (flint corn), Zea mays var. saccharata (sweet corn) and Zea mays var. rugosa, Zea mays (amylomaize), Zea mays var. tunicata (Pod corn), Zea mays var. ceratina, Zea mays var. japonica (Striped maize), Zea mays huehuetenangensis, Zea mays mexicana, Zea mays parviglumis, Zea nicaraguensis, Zea perennis, Zea diploperennis, Zea luxurians, Zea diploperennis, Saccharum officinarum, Saccharum spontaneum, Saccharum officinarum x Saccharum spontaneum hybrid plant, Pennisetum purpureum, Pennisetum ciliare, Pennisetum glaucum, Panicum virgatum, Sorghastrum nutans, Sorghum bicolor, and wild relatives Andropogon gerardii, Andropogon hallii, Arundo donax, Tripsicum dactyloides, Sporobolus airoides, Schizachyrium scoparium, Miscanthus floridulus, or Miscanthus sinensis plant.

36. The method of claim 28 and/or 29, wherein the intergeneric hybrid plant comprises a transgene which, confers enhanced starch content and/or quality, protein quality, afiatoxin resistance, disease resistance, insect and/or pest resistance, herbicide resistance, drought tolerance, acid soils tolerance, salt tolerance, water logging, male sterility, Beta carotene or increased biomass.

37. A plant part of the plant of claim 28 and/or 29 further being defined a protoplast, gamete, root, root tip, cell, meristem, anther, flower, seed, embryo, stalk, petiole, leaf or pistil.

38. A seed that produces a plant of claim 28 and/or 29.

39. A commercial product obtained from a plant according to claim 28 and/or 29 including the method of production thereof, wherein the commercial products include but are not limited to food, animal feed, industrial product such as alcoholic or nonalcoholic beverage, ethanol or fermentable biofuel feed stock or malt extracts or beverages, cane juice, molasses, bagasse, biodiesel, sugar.

40. Use of intergenenc hybrid plants or parts thereof, according to claim 39.

41. A progeny plant of the plant according to claim 28 and/or 29, wherein the progeny comprises at least a first chromosome or segment thereof from the sorghum parent plant and least a first chromosome or segment thereof from the second monocot parent plant.

42. An intergeneric hybrid plant or part thereof, produced by asexual propagation of plant of claim 28 and/or 29.

43. A plant regenerated from asexual propagation according to claim 42 including pollen and ovule from the said plant.

44. A tissue culture of regenerable cells of the plant of claim 28 and/or 29, wherein the regenerable cells are from meristematic cells, pollen, ovule, leaves, roots, root tips, embryos, anther, pistil, flower, seed, boll, endosperm or stem.

45. A plant regenerated from the tissue culture of claim 44 including pollen and ovule from the said plant.

46. The method according to claims 28 and/or 29, further comprising inbreeding the intergeneric hybrid plants to obtain subsequent segregating populations resulting into pure lines or unique novel genotypes with mixed genomic contents from the crossing of sorghum and/or maize parent plants with the second monocot parent plants.

47. The method according to claim 46, further comprising obtaining segregating populations of intergeneric hybrid plants with phenotypic and physiological characteristics of the sorghum and/or maize parent plant or the second monocot parent plant.

48. The plant of claim 28 and/or 29, further comprising backcrossing the intergeneric hybrid plants to either one of the parent plants to obtain a third monocot plant.

49. A method comprising crossing two intergeneric hybrid plants to obtain a third monocot plant.

50. The methods according to claims 47, 48 and/or 49 , further comprising inbreeding the third monocot hybrid embryo, seed or plant to produce introgressed progeny homozygous for at least one or more introgressed traits or genes.

51. The method of claim 28 and/or 29, wherein the intergeneric hybrid plant or seed is treated with a chromosome-doubling agent wherein the chromosome-doubling agent is a chemical doubling agent.

52. A method of obtaining haploid sorghum plants wherein, the maize parent plant is used as the male parent in the cross and induces haploid production in sorghum.

53. A method of obtaining haploid maize plants wherein, the sorghum parent plant is used as the male parent in the cross and induces haploid production in maize.