EP1100309A1 - Tomate apyrene et technique de production de tomate apyrene et de plants de tomate hybrides capables de produire ces tomates apyrenes - Google Patents

Tomate apyrene et technique de production de tomate apyrene et de plants de tomate hybrides capables de produire ces tomates apyrenes

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Publication number
EP1100309A1
EP1100309A1 EP00939185A EP00939185A EP1100309A1 EP 1100309 A1 EP1100309 A1 EP 1100309A1 EP 00939185 A EP00939185 A EP 00939185A EP 00939185 A EP00939185 A EP 00939185A EP 1100309 A1 EP1100309 A1 EP 1100309A1
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EP
European Patent Office
Prior art keywords
seedless
tomato plant
tomato
plant
tomatoes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00939185A
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German (de)
English (en)
Inventor
Gerardus Johannes Aloysius Van Vliet
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Western Seed Espana SA
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Western Seed Espana SA
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Publication date
Application filed by Western Seed Espana SA filed Critical Western Seed Espana SA
Priority claimed from PCT/NL2000/000380 external-priority patent/WO2000074468A1/fr
Publication of EP1100309A1 publication Critical patent/EP1100309A1/fr
Withdrawn legal-status Critical Current

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Definitions

  • the present application relates to a seedless tomato, a method for obtaining said seedless tomato, as well as a method for processing the seedless tomato thus obtained to products, in particular food products.
  • WO 98/24301 in the name of applicant describes a seedless tomato and a method for producing said tomato, in which a first tomato plant that is homozygote recessive with regard to the properties parthenocarpy (pk,pk) and functional sterility (fs,fs) is crossed with a second tomato plant that is also homozygote recessive with regard to the properties parthenocarpy (pk,pk) and functional sterility (fs,fs).
  • 98/24301 in that it provides hybrids (and seed therefor) that allow for reliable production of seedless tomatoes under all enviromental conditions, including different light and temperature conditions as may be prevalent in both the tropics as well as moderate climates. This is necessary in order to provide hybrids and seed
  • Seedless Tomatoes describe a method for obtaining tomato plants that carry completely seedless tomato fruits, by combining in one cultivar the homozygous genes for parthenocarpy > ⁇ t- 2 and the homozygous gene for autosterility of flowers ps-2.
  • the pat-2, ps-2 cultivar thus obtained carries completely seedless tomato fruits (as shown in Tables 1 and 2 of the Georgiev reference). Georgiev et al. further
  • Applicant has also developed a general method for obtaining parent plants or lines that contain this pk-complex and i-complex, starting from known lines that only contain the double recessive pat-2 gene or the double recessive ps-2 gene, or starting from the pat-2, ps-2 line developed by Georgiev, above.
  • One step of this method may involve crossing a known seedless line such as the pat-2, ps-2 line of Georgiev with a non-seedless tomato plant known per se, in order to provide a non-seedless FI . From this FI, after several further generations, parent plants or lines may then be developed in which the pic-complex and fs- complex have become sufficiently "fixated" for these plants to be used as parent lines for the production of hybrid seed.
  • seedless plants are in fact very uncommon (i.e. limited to about 1 or 2 plants out of 100 F2 plants) or may even not occur at all, and may then not even occur when the functionally sterile plants from the F2 thus obtained are self-pollinated to provide an F3.
  • the invention therefore provides a method for producing tomato plants that stably and reliably produce seedless tomatoes under all environmental, climatic and/or growing conditions, as well as seed for such tomato plants, by crossing two parent tomato plants or lines which carry both the "pk complex” and the "fs complex", as further described below. These two parent plants are referred to herein as the "/- ⁇ s-parents".
  • tomatoes are most often grown by the grower/producer on hybrid tomato plants grown from hybrid tomato seed.
  • the production of such hybrid seed is usually not carried out by the producer himself, but by highly specialized firms of plant breeders who develop and commerialize such hybrid seed, and who through stringent quality control can assure the uniform quality of the seed.
  • hybrid seed is obtained by crossing two different parent tomato plants, which most often belong to different lines.
  • cultivation techniques and plant breeding techniques known per se such hybrids can be provided with highly specific, desired properties, which makes it possible to "design" the hybrids, i.e. to confer to the hybrid plants predetermined inheritable characteristics.
  • such parent lines will be genetically homozygote and identical (i.e. as a result of inbreeding) so that they can provide, in a stable and reliable manner, genetically uniform -albeit heterozygote- hybrid line combinations, which (can) combine the properties of the parent lines.
  • the aim is on the one hand to cross certain properties from the parent lines as purely as possible into the seed, while on the other hand use is made of the known effect of heterosis or inbred growth, which can provide (improved) properties regarding -inter alia- the growth of plants and fruits and thereby of the yield.
  • This heterosis effect is obtained when/because the parent lines used are not related with respect to certain genetic properties (i.e. when the parent lines genetically "lie far apart").
  • a plant is called homozygous ' ' ' ' ' for a gene when it contains the same alleles of said gene, and heterozygous" for a gene when it contains two different alleles of said gene.
  • the use of capital letters indicates a dominant (form of a) gene and the use of small letters denotes a recessive gene: "XJC therefore denotes a homozygote dominant genotype for gene or property X; " ⁇ r x" and "xJC denote heterozygote genotypes; and “jt,x” denotes a homozygote recessive genotype.
  • XJC therefore denotes a homozygote dominant genotype for gene or property X
  • ⁇ r x and "xJC denote heterozygote genotypes
  • jt,x denotes a homozygote recessive genotype.
  • only the homozygote recessive genotype will generally provide the corresponding recessive phenotype
  • heterozygotic and homozygote dominant genotypes will generally provide the corresponding dominant phenotype (i.e. lead to a plant that shows the property or trait "X"), unless other genes and/or factors such as multiple alleles, suppressors, codominance etc. (also) play a role in determining the phenotype.
  • the tomatoes that are currently on the market have the disadvantage that they contain seeds (pips).
  • seeds for many consumers detracts from the attractiveness of the tomato.
  • the seeds have to be removed, for instance by sieving, optionally after prior pureeing, boiling or mashing, which involves further processing steps. This is true for both the preparation of food products on industrial scale, such as puree, soups, juices or sauces on tomato basis, as for the household preparation of dishes or food products.
  • the tomato flower consists of an ovary, above which there is a pistil. Around the pistil there are several stamen, that produce pollen. In the ovary, there are several pre-embryo's/embryo's which develop (after pollination with the pollen) into seeds.
  • the tomato plant can be considered as an "obligatory self-pollinator", which means that almost exclusively only its own pollen ends up on the stamen of the flowers of the same plant and thereby pollinates the pre-embryo's.
  • the ovary starts to grow into a tomato (fruit) containing within it, at the same time, the developing seed. In principle, fruits will only be formed when pollinated seeds are developing in the ovary; if the embryo's or pre-embryo's are not pollinated, no fruit will develop.
  • pat-2 also sometimes referred to as path-2
  • path-2 a gene is known, called the pat-2 (also sometimes referred to as path-2) gene, which codes for the property of parthenocarpy.
  • This gene when present as a double recessive (pat-2 , pat-2) leads to developments of fruit (fruit flesh) without concomitant development of seed. In other words, a parthenocarpic plant may develop fruits even without pollination.
  • parthenocarpy in nature, or in the greenhouse, (the phenotype of) parthenocarpy will usually only be partial; the factors which are responsible for the absence or partial presence of seeds are present on alleles.
  • seeds are or may be formed in (another) part of the fruit, with the result that the fruit will develop or grow irregularly. Partial parthenocarpy therefore leads to irregular forms of the fruit, and the resulting deformed fruits are highly unattractive for the consumer.
  • the gene of partenocarpy is extremely rare in nature. This is because, when a fruit is formed on the basis of total parthenocarpy, no seed is developed within the fruit, so that the genes coding for parthenocarpy are not passed on to the next generation, and the generational line is ended. For the tomato breeder, the phenotype of total parthenocarpy leads to fruits without seed, which makes seed production impossible.
  • parthenocarpy resides in several alleles.
  • the phenotype of total parthenocarpy can only occur when the "mother” (i.e. the tomato plant, the flower of which is pollinated with pollen) as well as the “father” (i.e. the tomato plant that provides the pollen) both are genetically homozygous with regard to the parthenocarpic property.
  • the fruit "in statu nascendi" there are usually several developing seeds, at least one of which may not become homozygote recessive for partenocarpy if one of the parents is a heterozygote.
  • Partial parthenocarpy in the developing tomato, as the result of at least one seed which is not double recessive with regard to parthenocarpy again may cause the fruit to develop in a deformed manner.
  • parthenocarpy i.e. besides low seed yield and very uneven fruits in size and form within the clusters or within the plants due to partial presence or non-presence of seed in the fruits, is a strong dependence on the environment (temperature, light conditions).
  • FS functional sterility
  • the pollen of a tomato plant which has the double recessive ("fs,fs") phenotype can only be released by physically opening the pollen tube by hand (by cutting or scissoring), after which - in practice - the pollen has to be removed by hand from the opened pollen tube, i.e. by scraping.
  • the pollen then has to be applied to the pistil of the flower, which in practice also must be carried out manually.
  • any other "natural" way i.e. without the abovementioned human intervention
  • the pollen of a functional sterile flower is not released and therefore not available for fertilization of a pre-embryo.
  • a double recessive, functionally sterile plant therefore does not fertilize pre-embryo's, thereby ending the generational line so that the recessive genes for functional sterility are not passed on to the next generation.
  • no fertilization of the pre-embryo's will take place so that no fruit (tomato) will be formed.
  • tomato fruit
  • Functional sterility is considered a form of a more general property of that occurs in tomato called auto-sterility, which can occur in two types, i.e: male sterile: self pollination is not possible because of the absence of viable pollen (ms) or degenerated stamens (si, stamenless).
  • male sterile self pollination is not possible because of the absence of viable pollen (ms) or degenerated stamens (si, stamenless).
  • seed seed hybrid tomato
  • the grower has to sow double the amount of seed and to remove before planting the 50% of heterozygous ms pk plants, recognizable by a marker gene for ms. This is not fully possible by overcrossing problems.
  • functional sterile viable pollen is present but cannot reach the pistil due to some morphological deviation of the flowers.
  • Functional sterility itself can also be distinguished in four different types, i.e.: ps-type: an exerted style phenomenon as a result of strong twisting and shorting of the stamens; this property generally provides for easy self pollination and lower receptivity of the style, which makes it not very suitable for hybrid seed production.
  • ps-type an exerted style phenomenon as a result of strong twisting and shorting of the stamens; this property generally provides for easy self pollination and lower receptivity of the style, which makes it not very suitable for hybrid seed production.
  • - ps-2-type a non opening anther bags type successivefully used in hybrid seed production.
  • ex-type exerted style over the stamens easy self pollination and low receptivity of the sigma make it less suitable for hybrid seed production.
  • short style-type the stigma is located below the anthers, the main disadvantage is its high level of self pollination.
  • Hr.Geordiev and B.Atanassova describe the use of a ps-2 sterile line with short style in the production of hybrid tomato seed.
  • Philouze also uses the line " 75/59" to produce seedless tomatoes, by a treatment involving emasculation without pollination.
  • the appearance and weight of the seedless fruits thus obtained were comparable to those of the seeded fruits obtained by hand-pollination of the flowers of this line.
  • tomatoes without seeds/pips can be produced with advantage using -very preferably hybrid- tomato plants that combine a complex of - most probably recessive - genes encoding the phenotype of parthenocarpy and a complex of- most probably recessive - genes encoding the phenotype of functional sterility.
  • These complexes are referred to as the "pk-comp ⁇ ex” and the "ys-complex", respectively, and when combined in a single tomato plant, line or hybrid are referred to as the pkfs-complex.
  • the two parent plants or lines that contain these complexes and that are used to provide the seedless hybrids of the invention are referred to herein as the "pk,fs-pa ⁇ ents”.
  • the invention therefore in a first aspect relates to a method for producing a seedless tomato, a plant carrying seedless tomatoes or capable of carrying seedless tomatoes, or cultivation material for such a tomato plant such as seed, comprising a. providing a first tomato plant that contains the pkfs-complex (i.e. a first pkfs- parent); b. providing a second tomato plant that contains the / j s'-complex (i.e. a second pkfs '-parent); c. crossing the first and second tomato plant for the production of cultivation material, such as seed, which contains the & ⁇ -complex; d. optionally cultivating the cultivation material thus obtained into a tomato plant capable of carrying seedless tomatoes; e. optionally growing said tomato plant until it carries the seedless tomatoes, and harvesting the seedless tomatoes thus obtained.
  • the invention relates to such a method comprising a. providing a first tomato plant that contains the pkfs-complex and that is further homozygote dominant with respect to at least one property desired for breeding tomatoes; b. providing a second tomato plant that contains the pkfs-complex and that is further homozygote recessive with regard to at least one property desired for the breeding of tomatoes; c. crossing the first and second tomato plant for the production of cultivation material, such as seed, which contains the/?&,/-s-complex and that is further heterozygote with regard to at least one property desired for the breeding of tomatoes; d. optionally cultivating the cultivation material thus obtained into a tomato plant capable of carrying seedless tomatoes; e.
  • step c preferably comprises the following steps: cl . providing pollen derived from the first or second tomato plant, respectively, c2. fertilizing the (pre-embryo's of the) second or first tomato plant respectively, with the pollen obtained in step cl.
  • the cultivation material obtained in step c) is preferably hybrid seed or seedlings obtained from such seed, so that (also) the tomato plant obtained from said cultivation material in step d) is a hybrid tomato plant, with the ensuing advantages known per se associated with the known effect of heterosis, increased vigor, etc..
  • hybrid both this hybrid cultivation material as well as these hybrid tomato plants are comprised, regardless of whether the latter (already) carry the seedless tomatoes according to the invention.
  • the first and second tomato plant provided in step a) and b) respectively prefererably belong to stable inbred lines, and consequently are herein denoted as the pkfs-pa ⁇ ent lines.
  • These parent lines are preferably genetically stable, such as obtained by cultivation/inbreeding over several generations, as further described below.
  • the first tomato plant can serve as the "father” (i.e. the plant from which the pollen is obtained) and the second tomato plant can serve as the "mother” (i.e. the plant of which the pistil/the pre-embryo's are fertilized with the pollen of the father), or vice versa.
  • the father i.e. the plant from which the pollen is obtained
  • the second tomato plant can serve as the "mother” (i.e. the plant of which the pistil/the pre-embryo's are fertilized with the pollen of the father), or vice versa.
  • This is not essential for the method of the invention, as in both cases a hybrid with the desired pk,fs-complex, and therefore with the desired stable seedless fenotype, will be obtained.
  • the invention in another aspect, relates to a method for providing a hybrid seedless tomato plant or seed or other cultivating material for such a plant, comprising at least a step of pollinating a first seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two factors provide said first seedless tomato plant with some phenotypical properties of partenocarpy and at least two factors provide said first seedless tomato plant with some phenotypical properties of functional sterility; with pollen obtained from a second seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two factors provide the tomato plant with some phenotypical properties of partenocarpy and at least two factors provide the tomato plant with some phenotypical properties of functional sterility, and in which said phenotypical
  • the step of pollinating the first seedless tomato plant with pollen from the second tomato plant involves the steps of opening - preferably manually- the closed off pollen tube of the second tomato plant; removing - preferably manually- pollen from the pollen tube of the second tomato plant: and applying -preferably manually - said pollen to the pistil of the first tomato plant.
  • the first and second tomato seedless tomato plant preferably belong to inbred lines, more preferably to two different inbred lines.
  • This aspect of the invention may optionally comprise the further steps of allowing the first seedless tomato plant thus fertilized to form fruits that contain hybrid seed and harvesting said hybrid seed from the fruits; and may also optionally comprise the yet further steps of cultivating a generation of seedless hybrid tomato plants from said hybrid seed, allowing said seedless hybrid tomato plants to form fruits (i.e. seedless tomatoes), and harvesting said seedless tomatoes.
  • Yet other aspects of the invention relate to the hybrid seed thus obtained, or optionally to other cultivating material obtained from said seed such as seedlings; to the seedless hybrid tomato plants thus obtained; and to the seedless tomatoes obtained as fruits from said seedless hybrid tomato plants.
  • Yet another aspect of the invention relates to processed products, in particular processed food products, obtained from or using the seedless tomatoes thus obtained.
  • processed products in particular processed food products, obtained from or using the seedless tomatoes thus obtained.
  • two essentially sterile as well as seedless parents are made - through human intervention - to form hybrid seed.
  • the invention relates to a seedless tomato plant, in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two provide the tomato plant with some phenotypical properties of partenocarpy and at least two provide the tomato plant with some phenotypical properties of functional sterility, and in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the tomato plant.
  • this seedless tomato plant belongs to an inbred line, and can be used as a parent line to provide hybrid offspring.
  • this seedless tomato plant is a hybrid obtained from two such, different inbred seedless parent lines, and may be used to grow or obtain seedless tomatoes.
  • the invention relates to the use of a seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two provide the tomato plant with some phenotypical properties of partenocarpy and at least two provide the tomato plant with some phenotypical properties of functional sterility, in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the tomato plant; as a parent plant for obtaining seedless hybrid offspring.
  • This aspect of the invention can be carried out either by pollinating said seedless tomato plant with pollen obtained from another seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two provide the tomato plant with some phenotypical properties of partenocarpy and at least two provide the tomato plant with some phenotypical properties of functional sterility, and in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the tomato plant; and/or by using pollen from said seedless tomato plant to pollinate another seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two provide the tomato plant with some phenotypical properties of partenocarpy and at least two provide the tomato plant with some phenotypical properties of functional
  • the step of pollinating the first seedless tomato plant with pollen from the second tomato plant involves the steps of opening - preferably manually- the closed off pollen tube of the second tomato plant; removing - preferably manually- pollen from the pollen tube of the second tomato plant and applying -preferably manually -said pollen to the pistil of the first tomato plant.
  • Another aspect of the invention relates to a method for maintaining seedless tomato plant, in particular for maintaining an inbred line of seedless tomato plants, and/or for obtaining seed or other cultivating material for such a plant or line, comprising at least a step of pollinating a seedless tomato plant in which the seedless fenotype is due to the presence of an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two factors provide said first seedless tomato plant with some phenotypical properties of partenocarpy and at least two factors provide said first seedless tomato plant with some phenotypical properties of functional sterility; with pollen obtained from the same plant, or with pollen from another plant belonging to the same inbred line.
  • the step of pollinating the seedless tomato plant with its pollen involves the steps of opening - preferably manually- its closed off pollen tube; removing - preferably manually- pollen from the pollen tube; and applying -preferably manually -said pollen to the pistil of the tomato plant.
  • This aspect of the invention may optionally comprise the further steps of allowing the seedless tomato plant thus fertilized to form fruits that contain seed and harvesting said seed from the fruits; and may also optionally comprise the yet further steps of cultivating a further generation of seedless tomato plants from said seed. Further aspects of the invention will become clear from the description hereinbelow.
  • the essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors comprises at least the genes pat-2 and ps-2, as well as at least 2, preferably at least 3, more preferably at least 4 additional genes, more preferably so that the p ⁇ t-2 gene and at least one, preferably at least two, additional genetic factors provide the tomato plant with some phenotypical properties of partenocarpy, and so that the ps-2 gene and at least one, preferably at least two additional genetic factors provide the tomato plant with some phenotypical properties of functional sterility, in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the tomato plant.
  • the invention will be illustrated by reference to the enclosed Figure, which shows the cross between the pkfs-parent lines, and also schematically illustrates a general method for developing the pk/s-pa ⁇ ent line(s), i.e. by means of a preferred example of this method involving generating an F6 generation starting from a known seedless tomato line, i.e. the p ⁇ t-2, ps-2 line of Georgiev.
  • the tomato plants shown in the Figure are as follows:
  • Original seedless parent Tomato plant used as the first parent (line) to obtain the /s,/?£-parents of the invention.
  • the original seedless parent can be used as the male or female.
  • the original seedless parent will have a seedless fenotype. i.e. a combination of a partenocarpic fenotype and a functionally sterile fenotype.
  • the partenocarpic fenotype of the original seedless parent is due to the presence of homozygote recessive pat-2 gene (pat-2, pat-2), but it may also be due to the presence of the pat gene, the pat-31 pat-4 genes, the pat-5 gene, or another gene.
  • the functionally sterile fenotype of the original seedless parent is due to the presence of the homozygote recessive ps-2 gene (ps-2, ps-2).
  • the original seedless parent can be obtained in a manner known per se, for instance starting from a known tomato line that contains one of the known partenocarpy genes and/or that has a partenocarpic fenotype, such as Severianin or the pat-2 lines described by Georgiev, Michailov and Popova in the references from the Eucarpia Tomato Working Group, or by Philouze in the Agronomie reference, or partenocarpic lines containing the pat, pat-3, pat-4, or pat-5 genes, such as those described in the art; and from a known tomato line with a functionally sterile fenotype, such as the ps-2 containing lines described by Georgiev and Atanassova in the reference from the Eucarpia Tomato Working Group. These are then crossed and selected to provide the original seedless parent, usually in an F2, F3 or further generation, and/or until a stable seedless seedless
  • a seedless line known per se is used as the original seedless parent, such as the ps-2, pat-2 line described by Georgiev et al., in the Eucarpia Tomato reference. Again, such a line can also be obtained de novo from a source of a pat-2 gene and a ps-2 gene, i.e. analogous to the methods described in the above art.
  • the original seedless parent can be used as the male or female.
  • the original non-seedless parent has a non-seedless fenotype, and preferably also not a partenocarpic or functionally sterile fenotype (although the use of a tomato plant or line with either a partenocarpic or functionally sterile fenotype is not excluded, and -for the purposes of description of the original non-seedless line - are included within the term "non seedless" and "original non-seedless parent").
  • any known tomato plant, line or hybrid known per se can be used, including but not limited to all lines or hybrids that are commercially available, such as those mentioned in for instance the B-list of NAKG, the Netherlands, as well as all lines proprietary to plant breeders.
  • a tomato plant belonging to an inbred line or a hybrid tomato is used.
  • Types of tomato which were found to be particularly suited for use as a non- seedless parent in the invention were lines belonging to the cherry tomatoes, determinant tomato lines, and/or tomato lines that carry genes for cold resistance such as Lucia or Havana.
  • Suitable, commerially available lines include Danielle and MHOne, although commercial breeders may, and usually will, use their own proprietary lines.
  • Other suitable lines can be determined by the skilled person on the basis of the teaching given hereinbelow.
  • Tomato plant that contains the pkfs complex as defined herein, and that can be used to provide a seedless hybrid by crossing with another pkfs parent.
  • the pkfs parent will be in the form of a line, more particularly an inbred line.
  • the pkfs parents can be obtained - by means of human intervention as described below- from the original seedless parent and the original non seedless parent (optionally though additional backcrosses), or starting from an already established pkfs parent. It is envisaged that the present invention will usually be commercialized either by marketing the pkfs parent line, or by marketing hybrid seed obtained from two pkfs parent.
  • Seedless hybrid Hybrid tomato plant, obtained from two different ⁇ -parents by human intervention as described below.
  • the seedless hybrid is the plant that will be used by the grower/producer to grow and produce the seedless tomatoes.
  • the seedless hybrid will have inherited the >£, s-complex from its two pkfs-paxents, and will therefor show the seedless phenotype, i.e. grow fruits from its flowers without prior pollination.
  • FIG. 1 One method for obtaining the pk,fs parents is shown in Figure 1 and generally comprises the following steps, further discussed below: a. Crossing an "original seedless parent" as defined herein with a "original non seedless parent” as defined herein to provide a non-seedless FI generation; b. Self-pollinating the FI generation thus obtained to provide a further generation, herein referred to as the F2 generation. cl . Selecting any plant(s) of the F2 thus obtained with a seedless fenotype and causing these seedless plants to self-pollinate, to provide a first F3 generation; as well as c2.
  • the pkfs complex in the plants thus obtained will have sufficiently stabilized, i.e. become “fixated”, for the tomato plant to be used as a pkfs parent in the invention, or to be used as a starting plant or line for obtaining other (lines of) pkfs parents, i.e. by crossing in further properties or by means of backcrosses.
  • F3, F4, F5, F6 and further generations have a seedless fenotype - or in the case of the "second F3 generation" at least a functionally sterile fenotype- obtaining the F4, F5, F6 and further generations, as well as maintaining the pkfs parent lines for production of the seedless hybrids, will require human intervention as defined hereinbelow. This requirement for human intervention to provide a further generation is also generally referred to herein as "causing self-pollination" .
  • the F2 will usually only contain at most about 1 or 2 seedless plants in 100 F2 plants, but may also provide no seedless plants, depending upon the orginal seedless parent and in particular the orginal non-seedless parent used. Even when seedless F2 plants are obtained, it was found that the amount thereof (i.e. 1-5%) is significantly less than the 8,25 % (i.e. 1 plant out of 16) that was to be expected according to Mendelian principles if the presence of double recessive pat-2 and ps-2 genes by itself were sufficient to provide a seedless phenotype. This shows that the cross with the original non-seedless parent apparently introduces some - probably dominant - genes, alleles or other genetic factors that negatively influence the occurrance of the seedlees phenotype in the F2.
  • the F2 will usually contain some functionally sterile plants, i.e. usually about 10-15 plants out of 100, again depending upon the orginal seedless parent and in particular the orginal non-seedless parent. This again is less than the 25% that was to be expected according to Mendelian principles if the presence of double recessive ps- 2 by itself were sufficient to provide a functionally sterile phenotype. This shows that also the presence of the desired functionally sterile fenotype is determined by a complex of genetic factors.
  • the seedless plants from the F2 are selected and caused to self-pollinate, so as to provide an F3, herein referred to as the "first F3 generation".
  • the plants of the first F3 generation that show the seedless fenotype are selected, and caused to self-pollinate so as to provide an F4. Again, it is usually found that not all F4 plants obtained from the seedless F3 plants will show the seedless phenotype: the amount of seedless F4 plants may vary from 0-100%, and is usually about 10-20% of all F4 plants. Also, not all F4 plants are found to be seedless under all environmental conditions. This again shows that the pkfs complex has not yet become sufficiently fixated in these F3 of F4 plants for them to be used as pkfs parents in the invention.
  • the seedless plants from the F4 are then again caused to self-pollinate to provide an F5, and said the seedless plants from the F5 are caused to self-pollinate to produce an F6.
  • F5 some non-seedless plants are obtained because the pkfs complex was not yet sufficiently fixated in the seedless F4 or F5, respectively.
  • the pkfs complex in the seedless F6 plants will be sufficiently stable, so that all seedless F6 plants exclusively provide seedless F7 plants when caused to self-pollinate. This also is an indication that the F6 inbreds thus obtained can be used as pkfs parents in the invention.
  • the F7 may again be caused to self-pollinate to provide an F8, etc., until a generation is obtained in which the pkfs complex is sufficiently fixated.
  • this is usually not required and also not preferred.
  • the pkfs complex has still not become sufficiently fixated, it will usually be assumed that this inbred line cannot be used as an pkfs parent line in the invention.
  • the seedless F2 plants will "make it" to the F6, depending upon the orginal seedless parent but in particular the orginal non- seedless parent used.
  • some selection pressure may be applied in order to test the stabilty and reliablity of the seedless phenotype under all environmental conditions. For instance, factors such as light, temperature can be used to "test” and/or fixate the stability of the seedless fenotype of the F3, F4. F5 or F6.
  • the F2 plants that only show a phenotype of functional sterility are caused to self-pollinate, so as to provide an F3 generation, herein referred to as the "second F3 generation".
  • This second F3 generation will usually comprise essentially all functionally sterile plants, and may comprise some seedless plants, i.e. about 1-3 out of 40 F3 plants (which can be easily recognized and selected because they are the only ones in this second F3 that will grow fruits). If so, these seedless F3 plants are caused to self-pollinate to provide an F4, followed by an
  • the invention is not limited to any specific explanation or hypothesis as to what gene(s), alleles or other genetic factors make up the pkfs complex according to the invention, nor to whether or not, and if so which or how many, genes or genetic factors (such as suppressors, modulators etc.) are necessary for the expression of the desired parthenocarpic fenotype and/or functionally sterile fenotype of the invention.
  • genes, alleles or factors which form the pkfs complex present in the pkfs parents of the invention may also differ from one pkfs parent plant or parent line to another, dependant upon which original seedless parent and non-seedless parent were used to obtain the pkfs parent(s).
  • pkfs complex included within the term “pkfs complex” as used herein are in fact several different combinations of genes, alleles or other genetic factors, which all give the desired seedless phenotype in a manner sufficiently stable to reliably provide seedless offspring when combined with another pkfs parent (although if this is the case, such different complexes will usually have some, and probably most, of the most important genes, alleles or other genetic factors in common.)
  • the "pkfs" complex comprises at least the partenocarpy gene or allele of the original seedless parent, combined with at least one further genetic genetic factor (i.e.
  • gene, allele or other factor that may influence expression of parthenocarpy comprises at least the functional sterility gene of the original seedless parent also combined with at least one further genetic genetic factor (i.e. gene, allele or other factor that may influence expression of functional sterility), or a combination thereof.
  • the pkfs complex probably consists of recessive genes, alleles or genetic factors, in that the phenotype of seedlessness is only uniformly inherited by hybrids obtained with another pkfs parent. Because of this, for the purposes of this invention, the entire pkfs-complex will be considered "essentially recessive"; and a cross with another pkfs parent will usually be nessesary ensure that all genes, alleles or factors that make up the complex are uniformly inherited and expressed by the hybrid thus generated.
  • the pkfs complex of the invention comprises one or more genes, alleles or other genetic factors (or a combination thereof) for either partenocarpy and or for functional sterility that have not yet been described per se in the art.
  • the pkfs complex of the invention comprises one or more of the known partenocarpy genes such as p ⁇ t-2, p ⁇ t-3, p ⁇ t-4 or pat-5 (or a combination thereof), possibly in combination with one or more as yet unknown genes, alleles or other genetic factors that influence expression of partenocarpy; as well as one or more of the known functional sterility genes such as ps, ex or short style, again possibly in combination with one or more as yet unknown genes, alleles or other genetic factors that influence expression of functional sterility.
  • the pkfs complex of the invention comprises a single recessive gene for partenocarpy (such s pat-2), in combination with a complex of genes for functional sterility; or a single recessive gene for functional sterility (such as ps-2), in combination with a complex of genes for partenocarpy.
  • the pkfs complex may be considered to comprise a "pk part" (i.e. those genes, alleles or other inheritable factors that can influence the formation of the partenocarpic properties in the seedless phenotype) and a "fs part” (i.e. those genes, alleles or other inheritable factors that can influence the formation of the functioanlly sterile properties in the seedless phenotype).
  • pk part i.e. those genes, alleles or other inheritable factors that can influence the formation of the partenocarpic properties in the seedless phenotype
  • fs part i.e. those genes, alleles or other inheritable factors that can influence the formation of the functioanlly sterile properties in the seedless phenotype
  • pl ⁇ nt ⁇ pl ⁇ nt ⁇
  • some genetic factors from the "pk” part may also influence or be necessary for the "fs part", or visa versa; and there may also occur factors which influence or even are required for both the "pk part” and the "fs part", and consequently may be considered to belong to both.
  • the "pk part" of the pkfs complex comprises at least two, and preferably at least three genetic factors; and the "fs part” of thep k,fs complex also comprises at least two, and preferably at least three genetic factors (in which factors that influence both the partenocarpic properties as well as the functional sterility of the plant are counted as belonging both to the "pk part” as well as the "fs part”. Similarly, a factor from the "pk part” that influences the "fs part”, or visa versa, are also counted as belonging to both).
  • the "genetic factors” may be genes, alleles, multiple alleles or a combination thereof, as well as other factors that may influence expression, such as suppressors or promoter, co-dominance, incomplete dominance etc.
  • plants or lines in which the "pk part” consists of only a single genetic factor, and the “fs part” consists of only two genetic factors, or in which the "pk part” consists of only two factors, and the “fs part” consists of a single genetic factors are generally not within the scope of the terms "pkfs complex'Or “pkfs parent” as used herein, as these combinations are apparently sufficient to explain the inheritance of the pk,fs complex and/or seedless fenotype found in the invention.
  • the pkfs complex could also be described as an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, of which at least two factors provide said first seedless tomato plant with some phenotypical properties of partenocarpy and at least two factors provide said first seedless tomato plant with some phenotypical properties of functional sterility, and in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the plant.
  • tomato plants with a pkfs complex according to this definition have not yet been described or provided by the art.
  • the original seedless parent is a pat-2, ps-2 plant or line, such as the pat-2, ps-2 line described by Georgiev.
  • the "pk part" of the pkfs parent derived from the original pat-2, ps-2 seedless parent comprises the pat-2 gene, combined with at least one additional genetic factor (i.e. a gene, allele or other factor that influences expression of parthenocarpy); and that the "fs part” comprises at least the ps-2 gene, combined with at least one additional genetic factor (i.e. gene, allele or other factor that influences expression of functional sterility), or a combination thereof.
  • this embodiment of the pkfs complex can also be described as an essentially recessive complex of at least 4, preferably at least 5, more preferably at least 6 genetic factors, comprises at least the genes pat-2 and ps-2, as well as at least 2, preferably at least 3, more preferably at least 4 additional genes, more preferably so that the pat-2 gene and at least one, preferably at least two, additional genetic factors provide the tomato plant with some phenotypical properties of partenocarpy, and so that the ps-2 gene and at least one, preferably at least two additional genetic factors provide the tomato plant with some phenotypical properties of functional sterility, and in which said phenotypical properties of partenocarpy and functional sterility contribute to the overall seedless phenotype of the tomato plant.
  • the method for obtaining the pkfs parent lines of the invention is specfically described starting from a known seedless line, such as a pat-2, ps-2 line.
  • the pkfs parent lines are preferably such that they confer to their seedless hybrid offspring a number of predetermined properties which are desired for breeding, cultivating and/or growing tomato plants, and/or for the tomatoes produced by such plants.
  • These properties are not specifically limited and for example comprise early development, increased growth, increased production, any form of the plant or fruit (including round, cylindrical, pear or cherry), the size or quality of the fruit, increased resistance against virusses or other diseases, increased cold resistance, long shelf life, etc., as will be clear to the person skilled in the art.
  • the pkfs parent lines of the invention can be "designed" with the desired properties, for instance by appropriate choice of (the properties of) the original seedless and in particular non-seedless parents (as long as the original non-seedless parent provides the additional genes necessary to "complete" the pkfs complex).
  • pkfs parent lines with the desired properties are obtained starting from an already available/established pkfs parent plant or line (such as those obtained as an F6 above), by introducing the desired property or properties into the pkfs parent from a tomato line known per se, i.e. in a manner analogous to breeding techniques known per se.
  • a tomato line known per se that carries the desired property (which will usually be a non-seedless tomato, but may also be a partenocarpic, functionally sterile or even other seedless line) is crossed or caused to cross with a pkfs parent line to provide an FI (which will usually not be seedless), which is then self-pollinated to provide an F2, from which the seedless plants can then be selected and again caused to self-pollinate into an F3, F4, F5 etc., until a stable inbred line that carries the desired properties as well as the pkfs complex is obtained.
  • FI which will usually not be seedless
  • this method can be essentially the same as the method described above, albeit that now a pkfs parent used as a starting material instead of an "original seedless parent".
  • a pkfs parent used as a starting material instead of an "original seedless parent.
  • an entire range of pkfs parent lines with desired properties can be obtained, which can then be crossed with each other - i.e. by means of human intervention - so as to provide the desired seedless hybrids.
  • the use of a pkfs parent as a starting material in this method will generally have the advantage that it will be ensured ⁇ b initio that all genes required to make up the pkfs complex are present in starting material.
  • the seedless hybrids of the invention can also be used as a source of the pkfs complex for establishing new pkfs parent lines, again essentially as described above).
  • the above method for obtaining the fs,pk parents of the invention may therefore comprise the further steps of g. causing the F6 (pkfs parent) thus obtained to cross with a tomato plant that carries at least one desired property to generate an FT generation; and h. repeating steps b) to f) on the FT thus obtained to generate an F6.
  • Another alternative is to carry out -i.e. as a part of the method described above- a backcross of the seedless plants of the (first or second) F3, F4 or F5 generation obtained from the original seedless and non-seedless parent, with a(nother) tomato plant or line that carries the desired property.
  • the generation thus obtained is then used and further treated in the same way as the FI generation obtained from the cross between the original seedless parent and the original non- seedless parent, i.e. via steps b) - f) as described above, to provide another pkfs parent line.
  • such an F3, F4 or F5 backcross may be repeated more than once (i.e.
  • any desired properties can be introduced in the parent lines during and as part of the programme for developing the pkfs parent, in less generations than would be required for introducing them into an established/? ⁇ parent line.
  • the above method for obtaining the pkfs parents may therefore comprise the further steps of i. causing the plants of the first F3, second F3, F4 or F5 obtained after step cl), c2), e) or f) respectively to cross with a tomato plant that carries at least one desired property to generate an FI" generation; and j. repeating steps b) to f) on the FI " thus obtained to generate an F6.
  • the pkfs parent plants or lines are very preferably homozygote with regard to the one or more of the desired further properties, in which one parent plant will be homozygote dominant, and the other plant will be homozygote recessive, so that the resulting hybrid will be heterozygote with regard to said property, as is generally known per se for obtaining hybrid tomato plants by breeding.
  • the number, as well as the nature, of the properties for which the one parent will be homozygote recessive and the other will be homozygote dominant will preferably be chosen such that the desired effect of heterosis is obtained in the resulting hybrid.
  • the homozygote dominant and homozygote recessive genotypes can be distributed over the parent plants in any desired combination, which means that one parent plant can be homozygote dominant with respect to one desired property, and homozygote recessive with respect to another property, in which case the other parent plant will be homozygote recessive and homozygote dominant respectively, with respect to these properties. All this will be clear to the person skilled in the art of plant breeding.
  • the uniformity of the hybrid will be essential for both the seed producer as well as the tomato grower, as this will not only ensure uniform quality of the cultivation material, but also of the hybrid plants and the eventually produced tomatoes. This is especially important for growing tomatoes on a large scalem, as well as for the final user, i.e. both industrial producers of tomato products as well as consumers.
  • the preferred manner for ensuring, in a repeatable and reliable manner, the uniformity of a hybrid is to use "pure" parent lines, obtained by inbreeding over several generations.
  • inbred lines are generally also required for obtaining heterosis, for which the parent lines generally must be genetically "far apart".
  • the above methods for obtaining the pkfs parents as an inbred F6 i.e. starting from either an original seedless parent, from another pkfs parent line, or obtained by a F3, F4 or F5 backcross as described above
  • will at the same time ensure that the resulting pkfs patent lines are also sufficiently pure for any other desired properties.
  • the presence of the pkfs complex in the pkfs parent lines also means that these lines are not capable of reproduction by themselves (i.e. of self-pollination).
  • the invention comprises providing and maintaining two different sterile inbred parent lines, and than deriving seed as well as hybrid offspring from these two sterile as well as seedless lines. This cannot occur in nature. For this reason also, the pkfs parent lines as well as the seedless hybrids generally cannot be considered a variety in the sense of the UPOV -treaty).
  • This human intervention generally comprises fertilizing the pre-embryo's of the flower of the first or second pkfs parent, respectively, with pollen obtained from the second or first pkfs parent, respectively, dependent upon the choice of the father and the mother. Because the pollen tube of the father plant is closed, as a result of the functionally sterile phenotype, the pollen must be provided by opening said pollen tube, by machine or preferably by hand, in practice by cutting or scissoring the pollen tube.
  • the pollen is removed from the pollen tube, preferably again by hand, for instance by scraping, after which the pollen thus obtained is applied to the flower/pistil of the mother plant, again preferably by hand, such as by brushing or another suitable manner, such as spraying, to fertilize the (pre-embryo's of the) mother plant.
  • the mother plant thus "fertilized” can be further cultivated until it carries tomatoes, which will contain the hybrid seed of the invention.
  • This hybrid seed can then be collected in a manner known per se, optionally be processed further, as well as packaged for storage, transport or sale.
  • Said hybrid seed, optionally in packaged form forms an important aspect of the invention from a commercial point of view, as will be clear to the skilled person.
  • the hybrid seeds can be sown in a manner known per se, or be made to germinate in another manner known per se in the art, and then be cultivated to tomato plants, which (can) carry the seedless tomatoes of the invention.
  • the seedless tomatoes thus obtained can then be harvested and marketed and/or consumed as such, optionally after one or more further processing steps, such as sorting, washing or packaging.
  • the invention therefore in further aspects relates to cultivation material for tomatoes such as seed or seedlings (optionally in a container), as well as seedless tomatoes obtained and/or obtainable as described hereinabove, and/or suited for use in the method(s) described herein.
  • the seedless tomatoes according to the invention can also be processed further in a manner known per se to tomato products, in particular food products, which may or may not be in a form ready or suited for final use.
  • the tomatoes according to the invention have the advantage that they can be processed directly, without a further step for removing the seeds/pips in the production process.
  • the invention in a further aspect therefore relates to products, in particular food products, obtained from the seedless tomatoes according to the invention, as well as to a method for obtaining said food products, in which the tomatoes are processed to these products without a separate step for removing the seeds.
  • Such a method can therefore -inter alia- comprise pureeing or mashing in another way of the tomatoes, optionally followed by incorporating or adding further desired ingredients, and packaging the tomato product thus obtained, without seeds or the residues thereof, in suitable containers for storage, transport or sale, in which said method does not comprise a step for removing any pips/seeds between the mashing of the tomatoes and the packaging of the product.
  • another advantage of the seedless tomatoes of the invention is that they will have a higher content of fruit flesh (expressed as dry weight) compared to non-seedless tomatoes harvested at a corresponding time, i.e.
  • seedless lines are obtained by crossing with lines on the B list of NAKG, The Netherlands; with non listed hybrids or with open pollinated varieties of different countries (usually fresh market and industry tomato varieties with properties such as long shelf life, high exterior quality of the fruits disease resistances and so on.)

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  • Breeding Of Plants And Reproduction By Means Of Culturing (AREA)

Abstract

La présente invention concerne une technique de production de tomate apyrène, de plant porteur de tomates apyrènes ou capable d'en porter, ou des éléments permettant de cultiver ce plant de tomate tels que des graines. Cette technique consiste: a) à prendre un premier plant de tomate contenant le complexe pk2fs, b) à prendre un second plant de tomate contenant le complexe pk2fs, c) à croiser le premier et le second plant de tomate afin de produire des éléments de culture, tels que des graines, qui contiennent le complexe pk2fs, d) à cultiver éventuellement ces éléments ainsi obtenus en un plant de tomate capable de porter des tomates apyrènes, e) à faire pousser éventuellement ledit plant jusqu'à ce qu'il porte ces tomates apyrènes, et à récolter ces tomates apyrènes ainsi obtenues. Cette invention concerne aussi un plant de tomate hybride, capable de porter des tomates apyrènes, obtenu par ladite technique, des graines ou des éléments permettant de cultiver ce plant de tomate hybride, et une tomate apyrène, fruit de ce plant de tomate hybride. Cette invention concerne en outre des produits transformés, en particulier des produits alimentaires transformés obtenus à partir de cette tomate apyrène ou utilisant ou encore contenant cette tomate.
EP00939185A 1999-06-04 2000-06-05 Tomate apyrene et technique de production de tomate apyrene et de plants de tomate hybrides capables de produire ces tomates apyrenes Withdrawn EP1100309A1 (fr)

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US13743199P 1999-06-04 1999-06-04
EP99201781 1999-06-04
US137431P 1999-06-04
PCT/NL2000/000380 WO2000074468A1 (fr) 1999-06-04 2000-06-05 Tomate apyrene et technique de production de tomate apyrene et de plants de tomate hybrides capables de produire ces tomates apyrenes

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