Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01H—NEW PLANTS OR NON-TRANSGENIC PROCESSES FOR OBTAINING THEM; PLANT REPRODUCTION BY TISSUE CULTURE TECHNIQUES
  • A01H5/00—Angiosperms, i.e. flowering plants, characterised by their plant parts; Angiosperms characterised otherwise than by their botanic taxonomy
  • A01H5/10—Seeds
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01H—NEW PLANTS OR NON-TRANSGENIC PROCESSES FOR OBTAINING THEM; PLANT REPRODUCTION BY TISSUE CULTURE TECHNIQUES
  • A01H6/00—Angiosperms, i.e. flowering plants, characterised by their botanic taxonomy
  • A01H6/46—Gramineae or Poaceae, e.g. ryegrass, rice, wheat or maize
  • A01H6/4684—Zea mays [maize]

Definitions

• Corn oil is composed of saturated and unsaturated fatty acids with carbon chain lengths ranging from 12 to 24. Approximately 95% or more of the total oil content is composed of palmitic (16:0), stearic (18:0), oleic (18: 1), and linoleic (18:2) acids, Jellum (1970) J. Agric. Food Chem., 18:365-70.
• Palmitic and stearic acids are saturated fatty acids; thus, corn oil having less of these two fatty acids would be highly desirable.
• the published literature on saturated fatty acid content in corn indicates the presence of diverse genes, located on different chromosomes, that affect saturated fatty acid content in a manner not clearly understood. This fact, combined with the virtual absence of information regarding the molecular biology of fatty acid profile in corn, has complicated the task of modifying the saturate level in corn and, in particular, has rendered the breeding endeavor of selecting for corn saturate content highly unpredictable a priori. Moreover, there has been no basis to date for a reasonable expectation of success in obtaining mean saturate levels less than 8%.
• the present invention relates to corn material having a saturated fatty acid
• the present invention relates to corn seeds which have a saturate content of less than about 7.0% by weight relative to the total fatty acid content of the seed (hereinafter expressed as percent by weight, or simply percent).
• the seed has a saturate content of less than about 6.0%.
• the invention further relates to a corn plant which produces seeds having a mean saturate content of less than about 7.0% by weight.
• Yet another aspect of the present invention is directed to a corn oil having a saturate content less than about 7.0%.
• Selection Occurs when plants with desired phenotypes or genotypes are chosen for additional plant breeding procedures and breeding projects.
• Intermating Denotes the practice of planting seeds of selected plant phenotypes in individual rows, such that normal germination, emergence and plant maturation occur, and (at the onset of pollen-shed and silk extrusion) systematically crossing plants from each of these rows to plants from as many other rows as possible, thereby to maximize the number of crosses between unrelated individuals in the population.
• “Backcrossing” - as used herein refers to the crossing of a progeny plant or line with its parent plant or line.
• "Variety” refers to a group of plants within a species, such as Zea mays L., which share certain constant characters that separate them from other possible varieties within that species. While possessing at least one distinctive trait, a variety can also be characterized by a substantial amount of variation between individuals within the variety, based primarily on the Mendelian segregation of traits among the progeny of succeeding generations.
• "Line” - a line as distinguished from “variety” and “cultivar” refers to a group of plants which are substantially uniform in their traits except that there is relatively minor variation within the group and such variation can be characterized.
• “Bulked Seed” - can be constituted, for example, from a plurality of seeds of a single cob (a kernel bulk"), from the combined seed from all or a particular part of a genetically related family of plants, or from the seed of a plant introduction (defined below).
• a "Plant Introduction" (P.I.) - is a sample of seeds of a given species (e.g., Zea mays L.) that can be grown into plants having a common discernible (gross) morphology. Generally designated by country of origin, a P.I. often represents germplasm native and/or adapted to that country, and hence may embody considerable genetic variability. A P.I. can also represent the germplasm of an inbred line.
• Example 1 Determination of Fatty Acid Content
• the screening can be effected, for example, by a half-seed technique, in which the seed scutulum is excised and the oil extracted is assayed by GLC, see Jellum & Worthington (1966) Crop Sci. 6:251-253, or by similarly analyzing oil extracted from a whole seed. The latter approach does not save the embryo for germination.
• GLC analysis can be conducted on a five- (or more) kernel bulk sample and on a one-half kernel sample, which allows the planting of the remaining half-seed for further breeding.
• the screening can be performed before an initial selfing step or, if a greater degree of segregation is desired, after a self-pollination of plants grown from the bulk seed.
• the fatty acid composition of corn seeds developed in the breeding program was determined by GLC in accordance with the procedures described below.
• the oil was obtained by using a corn oil extraction protocol having the following steps:
• a small piece of the scutellum was removed with a razor blade.
• a sample of scutellar tissue was then placed in a mortar with a small amount of ether, approximately 1 to 1.5 ml.
• the sample was crushed and stirred for approximately 10 seconds with a pestle, and the solution drawn up through non-absorbent cotton and placed in a test tube.
• a 0.5 ml sample of the ether extractant was then treated in the manner described above.
• the fatty acid analysis of one half-seed allowed planting of the remaining half-kernel in a breeding nursery and conducting of additional research and development with this genotype.
• the GLC analyses were accomplished using a 5890A Hewlett-Packard gas liquid chromatograph equipped with a flame ionization detector and a Hewlett-Packard 3396A integrator.
• the column used was a Supelco 2330 fused silica capillary column (having a film thickness of 0.2 micron and column dimensions of 15 m. x 0.25 mm.).
• the operating conditions for the GLC analysis included an injector temperature of 250 degrees Celsius and a detector temperature of 300 degrees Celsius. Column flow was 2.0 ml/min. of helium.
• Each chromatographic run was temperature-programmed to begin at 170 degrees Celsius and remain at that temperature for 1.0 min. The temperature was then increased to 180 degrees Celsius at a rate of 1 or 2 degrees Celsius/min. After this period of time, the chromatograph was completed and the column prepared for the next run.
• Example 2 Production of Mutant Lines
• Two high oleic corn lines from the source population HOLEISYN were selected to see if low saturate lines could be developed. These two lines were crossed and the FI seed was grown and selfed. The F2 seed was planted, and before pollination, approximately 200 ears were shootbagged. Tassels that were shedding were selected and the ear shoots were cut back to ensure good silk exposure. A day later the corn pollen was collected using tassel bags. The pollen was placed on a small screen to filter out pollen from anthers and other foreign material. The pollen was then poured into a solution of 1 ml EMS and 100 mis Fisher parafin oil (stock diluted by 1 ml and 15 mis oil solution).
• the solution was mixed every minute for the first five minutes and then every five minutes for 45 minutes to keep the pollen suspended. After 45 minutes the pollen/parafin solution was brushed onto the silks of developing ears. A tassel bag was used to cover the ear to prevent contamination. The ear was picked at maturity and then tested for fatty acid content using the half-seed GLC analysis procedures outlined above.
• Resulting seeds from the EMS mutagenesis procedure were screened for low saturate content. Plants derived from half seeds designated as lines LSI 498- 18, LS288-04, and L0417-12 which showed promising levels of saturates and oleic acid were selfed to produce sufficient seed for these experiments. As soon as fully mature seed could be harvested from plants derived from this seed, five kernels from each plant were subjected to fatty acid methyl ester (FAME) analysis to determine fatty acid profiles. Saturates levels were then determined and statistical analysis was performed to identify those sublines (tracing back to individual selfed plants) which were significantly lower in total saturates. Seeds from these identified sublines were planted and selfed to produce another cycle of seed which was then analyzed.
• FAME fatty acid methyl ester
• Greenhouse produced seed from the lines produced in Example 2 was pooled across several sublines within each mutant line in order to supply a sufficient number of kernels for planting. Plants were selfed and fatty acid content was analyzed. About a 15% further reduction in saturates was observed from field produced seed compared to kernels from the greenhouse. Greenhouse produced seed had total saturate levels between 7.7% and 8.8%, whereas the field produced seed had saturate levels below 7% (Table 2). These results seemed to be consistent with observations of Canola seed which showed 1-2% reduction in saturates for field compared to greenhouse grown seed.
• Kernel Elite low saturate corn lines can be developed by crossing the low saturate line (derived from a low saturate P.I. population) with an agronomically elite line for a given maturity region.
• CS405 is an elite corn inbred line which has a saturate content of about 1 1.4%.
• LS288-04-506-502 is the designation for a low saturate line developed by the procedures of this invention.
• the lines resulting from this breeding effort can exhibit low saturate content along with acceptable agronomic traits such as plant vigor, good stalks and roots, disease resistance, and the like.
• Crossing low saturate lines with a number of elite lines and selfing and selecting from these crosses can produce numerous new low saturate corn lines. These lines can be adapted to any maturity region desired by selecting the appropriate maturity level in the elite corn parent and selecting for the desired maturity in subsequent selfing generations.
• the low saturate lines developed by the present invention can be used as one or more parents in corn hybrids.
• one or more backcrosses to the elite recurrent parent can be accomplished to incorporate a higher percentage of the elite germplasm characteristics while retaining the low saturate trait.
• an inbred line that is true-breeding for a low saturate phenotype according to the present invention is advantageously employed in a backcrossing program to introgress the low saturate trait into other, more agronomically desirable lines.
• a true-breeding inbred line of the present invention can be the donor parent for backcrossing to a waxy corn line, to thereby produce a high oleic, low saturate, waxy hybrid or line.
• a "hybrid" would be an offspring obtained by crossing parent plants of different lineage.
• the starch in the outer surface of a non-waxy endosperm stains blue, turning quickly to black, with an iodine (I 2 )-potassium iodide (KI) solution, while that of material homozygous for the waxy allele (wxl ) stains reddish brown, turning soon to dark brown.
• I 2 iodine
• KI iodine-potassium iodide
• the uniqueness of the waxy trait allows for the ready backcrossing to a recurrent waxy parent of progeny that are (low saturate x waxy) hybrids, according to the present invention, against a donor waxy (wxl/wxl) parent. That is, progress can be readily monitored for a backcrossing generation whereby the germplasm contribution of the low saturate donor, save for the expression of a mean saturate value of about 7% or less, is virtually eliminated.
• Introgression of a low saturate phenotype as described above can also be accomplished with regard to genetic backgrounds characterized by traits other than waxy.
• Illustrative of traits that could be combined with a low saturate phenotype, pursuant to the present invention, are those listed in Table 3.
• Bt the expression of Bt genes, synthetic or native, can impart insect resistance to a wide array of insects. See e.g., U.S. Patent No. 5,380,831 whose teachings are incorporated herein in their entirety.
• Hm2 confers resistance, in the presence of homozygous recessive hml, that is lower initially but becomes progressively stronger as the plant develops.
• various approaches to imparting male sterility in com can be used to produce male-sterile, low saturate material within the present invention, which material can be employed in turn to produce hybrids which also display a low saturate phenotype according to the present invention.
• An inbred line possessing such a low saturate phenotype can thus be advantageously employed in a backcrossing program as a recurrent parent to cytoplasmic- genetic, male-sterile donors containing both nuclear and cytoplasmic factors imparting male sterility (A lines), to donors containing nuclear but not cytoplasmic factors imparting male sterility (B lines), and to donors containing nuclear and cytoplasmic factors that restore fertility to male-sterile material (R lines), as described, for example, by Coe et al. (1988), at pages 195- 98 and pages 206-09, and Poehlman, "Breeding Field Crops" (2d ed.), AVI Publishing Co. (1979), at pages 292-95.
• cytoplasmic male-sterility (cms) and fertility restoration (Rf) factors include Holden's Foundation Seeds, Inc., P.O. Box 839, Williamsburg, Iowa 52361 (cms-S and cms-C); Illinois Foundation Seeds, Inc., P.O. Box 722, Champaign, Illinois 61820 (cms-S and cms-C); and Agronomy Department, University of Illinois, Urbana, Illinois (cms-T, cms-S, cms-C and various Rf determinations).

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• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Physiology (AREA)
• Botany (AREA)
• Developmental Biology & Embryology (AREA)
• Environmental Sciences (AREA)
• Natural Medicines & Medicinal Plants (AREA)
• Breeding Of Plants And Reproduction By Means Of Culturing (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)

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• 1999
  • 1999-06-16 AR ARP990102884A patent/AR019679A1/es unknown
  • 1999-06-16 WO PCT/US1999/013546 patent/WO1999065294A1/en not_active Application Discontinuation
  • 1999-06-16 EP EP99928695A patent/EP1087656A1/de not_active Withdrawn
  • 1999-06-16 AU AU45698/99A patent/AU4569899A/en not_active Abandoned

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