Plants and seeds of hybrid corn variety CH756602 Number:7,521,614 from the United States Patent and Trademark Office (PTO) owispatent According to the invention, there is provided seed and plants of the hybrid corn variety designated CH756602. The invention thus relates to the plants, seeds and tissue cultures of the variety CH756602, and to methods for producing a corn plant produced by crossing a corn plant of variety CH756602 with itself or with another corn plant, such as a plant of another variety. The invention further relates to genetic complements of plants of variety CH756602.<H CH756602, variety, Plants, and, seed, 7521614.html, Patent, pto, 7521614

Title: Plants and seeds of hybrid corn variety CH756602

Abstract: According to the invention, there is provided seed and plants of the hybrid corn variety designated CH756602. The invention thus relates to the plants, seeds and tissue cultures of the variety CH756602, and to methods for producing a corn plant produced by crossing a corn plant of variety CH756602 with itself or with another corn plant, such as a plant of another variety. The invention further relates to genetic complements of plants of variety CH756602.

Patent Number: 7,521,614 Issued on 04/21/2009 to Short, et al.

Inventors: Short; Kent (Coralville, IA), Stangland; Gary R. (Cedar Rapids, IA), Eichhorn; Chris (Williamsburg, IA), Stoltzfus; David L. (Wellman, IA)
Assignee: Monsanto Technology LLC (St. Louis, MO)

Appl. No.: 11/746,555

Filed: May 9, 2007

Current U.S. Class: 800/320.1 ; 435/412; 435/418; 435/424; 435/468; 530/370; 536/23.1; 800/260; 800/278; 800/303

Current International Class: A01H 1/00 (20060101); C07K 14/415 (20060101); C12N 5/14 (20060101)

Field of Search: 435/468,412,418,424 530/370 536/23.1 800/320.1,260,278,303

References Cited [Referenced By]

U.S. Patent Documents


4517763	May 1985	Beversdorf et al.
4658084	April 1987	Beversdorf et al.
4658085	April 1987	Beversdorf et al.
4677246	June 1987	Armond et al.
4731499	March 1988	Puskaric et al.
5276263	January 1994	Foley
5523520	June 1996	Hunsperger et al.
5773683	June 1998	Foley
6433261	August 2002	Hotchkiss
7087821	August 2006	Colbert

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Duvick, "Genetic Contributions to Yield Gains of U.S. Hybrid Maize, 1930 to 1980," Genetic Contributions to Yield Gains of Five Major Crop Plants: Proceedings of a Symposium sponsored by Div. C-1, Crop Science Society of America, Dec. 2, 1981 in Atlanta, Georgia; W.R. Fehr, Crop Science Society of America and American Society of Agronomy, Madison, Wisconsin, pp. 15-47. cited by other .
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Fehr (ed.), Principles of Cultivar Development, vol. I: Theory and Technique, pp. 360-376, 1987. cited by other .
Hallauer et al., "Corn Breeding," Corn and Corn Improvement, eds., Sprague et al., Madison, Wisconsin, Ch. 8, pp. 463-564, 1988. cited by other .
Kraft et al., "Linkage disequilibrium and fingerprinting in sugar beet," Theor Appl Genet, 101:323-326, 2000. cited by other .
Larson & Hanway, "Corn Production," Corn and Corn Improvement, ed. G.F. Sprague, No. 18 in Agronomy Series, American Society of Agronomy, Inc., Madison, Wisconsin, pp. 625-669, 1977. cited by other .
Meghji et al., "Inbreeding depression, inbred and hybrid grain yields, and other traits of maize genotypes representing three eras," Crop Science, 24:545-549, 1984. cited by other .
Poehlman & Sleper (eds), Breeding Field Crops, 4th Ed., pp. 172-175, 1995. cited by other .
Poehlman, Breeding Field Crops, 3rd ed., AVI Publishing Company, Westport, Connecticut, pp. 469-481, 1987. cited by other .
Rieger et al., Glossary of Genetics and Cytogenetics, Classical and Molecular, Springer-Verlag, Berlin, p. 116, 1976. cited by other .
Sprague & Eberhart, "Corn Breeding," Corn and Corn Improvements, ed. G.F. Sprague, No. 18 in Agronomy Series, American Society of Agronomy, Inc., Madison, Wisconsin, pp. 305-323, 1977. cited by other .
Troyer, "A retrospective view of corn genetic resources," Journal of Heredity, 81:17-24, 1990. cited by other .
Wych, "Production of hybrid seed corn," Corn and Corn Improvement, eds., Sprague et al, editors, Madison, Wisconsin, Ch. 9, pp. 565-607, 1988. cited by other.

Primary Examiner: Bui; Phuong T
Attorney, Agent or Firm: Sonnenschein Nath & Rosenthal LLP

Claims

What is claimed is:

1. A seed of the hybrid corn variety CH756602, produced by crossing a first plant of variety I282610 with a second plant of variety CV253048, wherein representative seed of said varieties I282610 and CV253048 have been deposited under ATCC Accession numbers PTA-8768 and PTA-9712, respectively.

2. A plant of the hybrid corn variety CH756602 grown from the seed of claim 1.

3. A plant part of the plant of claim 2.

4. The plant part of claim 3, further defined as an ear, ovule, pollen or cell.

5. A tissue culture of cells of the plant of claim 2.

6. The tissue culture of claim 5, wherein cells of the tissue culture are from a tissue selected from the group consisting of leaf, pollen, embryo, root, root tip, anther, silk, flower, kernel, ear, cob, husk, stalk and meristem.

7. The seed of claim 1, wherein one or both of the first and second plants further comprises a transgene.

8. The seed of claim 7, wherein the transgene confers a trait selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

9. The seed of claim 7, wherein the first and second plants each comprise a different transgene.

10. The seed of claim 7, wherein one or both of the first and second plants comprises a single locus conversion, wherein the single locus conversion confers a trait selected from the group consisting of male sterility, herbicide tolerance. insect resistance, disease resistance, waxy starch, modified fatty acid metabolism. modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

11. A method of producing hybrid corn seed comprising crossing a plant of variety 1282610 with a plant of variety CV253048, wherein representative seed of variety 1282610 and variety CV253048 have been deposited under ATCC Accession numbers PTA-8768 and PTA-9712, respectively.

12. The method of claim 11, defined as comprising pollinating a plant of inbred variety 1282610 with pollen from a plant of variety CV253048.

13. The method of claim 11, defined as comprising pollinating a plant of inbred variety CV253048 with pollen from a plant of variety 1282610.

14. A method for producing corn grain comprising growing the plant of claim 2 until grain is produced and collecting the grain.

15. A method of introducing a heritable trait into hybrid corn variety CH756602 comprising the steps of: (a) crossing a first plant of a first inbred corn variety selected from the group consisting of variety 1282610 and variety CV253048 with another corn plant that heritably carries the trait to produce progeny plants, at least some of which heritably carry the trait, wherein representative samples of seed of variety 1282610 and variety CV253048 have been deposited under ATCC Accession numbers PTA-8768 and PTA-9712, respectively; (b) selecting progeny plants that heritably carry the trait; (c) crossing selected progeny plants with another plant of the first inbred corn variety to produce next-generation progeny plants at least some of which heritably carry the trait; (d) selecting next-generation progeny plants that heritably carry the trait and exhibit morphological and physiological characteristics of the first inbred corn variety; (e) repeating steps (c) and (d) three or more times to produce at least a first selected progeny plant that heritably carries the trait and exhibits essentially all of the morphological and physiological characteristics of the inbred corn variety; and (f) crossing a progeny plant of step (e) with a plant of the other inbred corn variety of the group consisting of 1282610 and CV253048 to produce a plant comprising the trait and essentially all of the characteristics of hybrid corn variety CH756602 when grown under the same environmental conditions.

16. The method of claim 15, wherein the trait is selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

17. The method of claim 16, further comprising repeating steps (a)-(f) at least once to introduce at least a second trait into hybrid corn variety CH756602, wherein the second trait is selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

18. A plant produced by the method of claim 15.

19. A method of introducing a desired trait into hybrid corn variety CH756602 comprising the steps of: (a) introducing a transgene conferring the trait into a first inbred corn variety selected from the group consisting of 1282610 and CV253048 to produce a transgenic plant heritably carrying the trait, wherein representative seeds of varieties 1282610 and CV253048 have been deposited under ATCC Accession numbers PTA-8768 and PTA-9712, respectively; and (b) crossing the transgenic plant or an isogenic progeny plant thereof with a plant of the other inbred corn variety to produce seed of the hybrid corn variety CH756602 that heritably carries and expresses the transgene and otherwise has essentially all of the morphological and physiological characteristics of hybrid corn variety CH756602 when grown under the same environmental conditions.

20. The method of claim 19, wherein the desired trait selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

21. The method of claim 19, further comprising repeating steps (a) and (b) at least once to introduce at least a second trait into hybrid corn variety CH756602, wherein the second trait is selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

22. A plant produced by the method of claim 19.

23. The plant of claim 22, wherein the plant comprises a trait selected from the group consisting of male sterility, herbicide tolerance, insect resistance, disease resistance, waxy starch, modified fatty acid metabolism, modified phytic acid metabolism, modified carbohydrate metabolism and modified protein metabolism.

24. A method of producing a corn plant derived from the hybrid corn variety CH756602, comprising crossing the plant of claim 2 with a second corn plant to produce a progeny corn plant derived from the hybrid corn variety CH756602.

25. The method of claim 24, further defined as comprising producing an inbred corn plant derived from the hybrid corn variety CH756602, the method comprising the steps of: (a) crossing the progeny corn plant derived from the hybrid corn variety CH756602 with itself or a second plant to produce a seed of a progeny plant of a subsequent generation; (b) growing a progeny plant of a subsequent generation from the seed and crossing the progeny plant of a subsequent generation with itself or a second plant; and (c) repeating steps (a) and (b) for an additional 3-10 generations with sufficient inbreeding to produce an inbred corn plant derived from the hybrid corn variety CH756602.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of corn breeding. In particular, the invention relates to corn seed and plants of the hybrid variety designated CH756602, and derivatives and tissue cultures thereof.

2. Description of Related Art

The goal of field crop breeding is to combine various desirable traits in a single variety/hybrid. Such desirable traits include greater yield, better stalks, better roots, resistance to insecticides, herbicides, pests, and disease, tolerance to heat and drought, reduced time to crop maturity, better agronomic quality, higher nutritional value, and uniformity in germination times, stand establishment, growth rate, maturity, and fruit size.

Breeding techniques take advantage of a plant's method of pollination. There are two general methods of pollination: a plant self-pollinates if pollen from one flower is transferred to the same or another flower of the same plant. A plant cross-pollinates if pollen comes to it from a flower on a different plant.

Corn plants (Zea mays L.) can be bred by both self-pollination and cross-pollination. Both types of pollination involve the corn plant's flowers. Corn has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the ear shoot.

Plants that have been self-pollinated and selected for type over many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny, a homozygous plant. A cross between two such homozygous plants produces a uniform population of hybrid plants that are heterozygous for many gene loci. Conversely, a cross of two plants each heterozygous at a number of loci produces a population of hybrid plants that differ genetically and are not uniform. The resulting non-uniformity makes performance unpredictable.

The development of uniform corn plant hybrids requires the development of homozygous inbred plants, the crossing of these inbred plants, and the evaluation of the crosses. Pedigree breeding and recurrent selection are examples of breeding methods used to develop hybrid parent plants from breeding populations. Those breeding methods combine the genetic backgrounds from two or more inbred plants or various other broad-based sources into breeding pools from which new inbred plants are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred plants and the hybrids from these crosses are evaluated to determine which of those have commercial potential.

North American farmers plant tens of millions of acres of corn at the present time and there are extensive national and international commercial corn breeding programs. A continuing goal of these corn breeding programs is to develop corn hybrids that are based on stable inbred plants and have one or more desirable characteristics. To accomplish this goal, the corn breeder must select and develop superior inbred parental plants.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a corn plant of the hybrid variety designated CH756602. Also provided are corn plants having all the physiological and morphological characteristics of the hybrid corn variety CH756602. A hybrid corn plant of the invention may further comprise a cytoplasmic or nuclear factor that is capable of conferring male sterility or otherwise preventing self-pollination, such as by self-incompatibility. Parts of the corn plant of the present invention are also provided, for example, pollen obtained from a hybrid plant and an ovule of the hybrid plant. The invention also concerns seed of the hybrid corn variety CH756602. The hybrid corn seed of the invention may be provided as a population of corn seed of the variety designated CH756602.

In another aspect of the invention, the hybrid corn variety CH756602 is provided comprising an added desired trait. The desired trait may be a genetic locus that is a dominant or recessive allele. In certain embodiments of the invention, the genetic locus confers traits such as, for example, male sterility, waxy starch, herbicide resistance, insect resistance, resistance to bacterial, fungal, nematode or viral disease, and altered fatty acid, phytate or carbohydrate metabolism. The genetic locus may be a naturally occurring corn gene introduced into the genome of a parent of the variety by backcrossing, a natural or induced mutation, or a transgene introduced through genetic transformation techniques. When introduced through transformation, a genetic locus may comprise one or more transgenes integrated at a single chromosomal location.

In yet another aspect of the invention, a hybrid corn plant of the variety designated CH756602 is provided, wherein a cytoplasmically-inherited trait has been introduced into said hybrid plant. Such cytoplasmically-inherited traits are passed to progeny through the female parent in a particular cross. An exemplary cytoplasmically-inherited trait is the male sterility trait. Cytoplasmic-male sterility (CMS) is a pollen abortion phenomenon determined by the interaction between the genes in the cytoplasm and the nucleus. Alteration in the mitochondrial genome and the lack of restorer genes in the nucleus will lead to pollen abortion. With either a normal cytoplasm or the presence of restorer gene(s) in the nucleus, the plant will produce pollen normally. A CMS plant can be pollinated by a maintainer version of the same variety, which has a normal cytoplasm but lacks the restorer gene(s) in the nucleus, and continue to be male sterile in the next generation. The male fertility of a CMS plant can be restored by a restorer version of the same variety, which must have the restorer gene(s) in the nucleus. With the restorer gene(s) in the nucleus, the offspring of the male-sterile plant can produce normal pollen grains and propagate. A cytoplasmically inherited trait may be a naturally occurring maize trait or a trait introduced through genetic transformation techniques.

In another aspect of the invention, a tissue culture of regenerable cells of a plant of variety CH756602 is provided. The tissue culture will preferably be capable of regenerating plants capable of expressing all of the physiological and morphological characteristics of the variety, and of regenerating plants having substantially the same genotype as other plants of the variety. Examples of some of the physiological and morphological characteristics of the variety CH756602 include characteristics related to yield, maturity, and kernel quality, each of which is specifically disclosed herein. The regenerable cells in such tissue cultures will preferably be derived from embryos, meristematic cells, immature tassels, microspores, pollen, leaves, anthers, roots, root tips, silk, flowers, kernels, ears, cobs, husks, or stalks, or from callus or protoplasts derived from those tissues. Still further, the present invention provides corn plants regenerated from the tissue cultures of the invention, the plants having all the physiological and morphological characteristics of variety CH756602.

In still another aspect, the invention provides a method of producing hybrid corn seed comprising crossing a plant of variety 1282610 with a plant of variety CV253048. In a cross, either parent may serve as the male or female. Processes are also provided for producing corn seeds or plants, which processes generally comprise crossing a first parent corn plant with a second parent corn plant, wherein at least one of the first or second parent corn plants is a plant of the variety designated CH756602. In such crossing, either parent may serve as the male or female parent. These processes may be further exemplified as processes for preparing hybrid corn seed or plants, wherein a first hybrid corn plant is crossed with a second corn plant of a different, distinct variety to provide a hybrid that has, as one of its parents, the hybrid corn plant variety CH756602. In these processes, crossing will result in the production of seed. The seed production occurs regardless of whether the seed is collected or not.

In one embodiment of the invention, the first step in "crossing" comprises planting, preferably in pollinating proximity, seeds of a first and second parent corn plant, and preferably, seeds of a first corn plant and a second, distinct corn plant. Where the plants are not in pollinating proximity, pollination can nevertheless be accomplished by transferring a pollen or tassel bag from one plant to the other as described below.

A second step comprises cultivating or growing the seeds of said first and second parent corn plants into plants that bear flowers (corn bears both male flowers (tassels) and female flowers (silks) in separate anatomical structures on the same plant). A third step comprises preventing self-pollination of the plants, i.e., preventing the silks of a plant from being fertilized by any plant of the same variety, including the same plant. This is preferably done by emasculating the male flowers of the first or second parent corn plant, (i.e., treating or manipulating the flowers so as to prevent pollen production, in order to produce an emasculated parent corn plant). Self-incompatibility systems may also be used in some hybrid crops for the same purpose. Self-incompatible plants still shed viable pollen and can pollinate plants of other varieties but are incapable of pollinating themselves or other plants of the same variety.

A fourth step may comprise allowing cross-pollination to occur between the first and second parent corn plants. When the plants are not in pollinating proximity, this is done by placing a bag, usually paper or glassine, over the tassels of the first plant and another bag over the silks of the incipient ear on the second plant. The bags are left in place for at least 24 hours. Since pollen is viable for less than 24 hours, this assures that the silks are not pollinated from other pollen sources, that any stray pollen on the tassels of the first plant is dead, and that the only pollen transferred comes from the first plant. The pollen bag over the tassel of the first plant is then shaken vigorously to enhance release of pollen from the tassels, and the shoot bag is removed from the silks of the incipient ear on the second plant. Finally, the pollen bag is removed from the tassel of the first plant and is placed over the silks of the incipient ear of the second plant, shaken again and left in place. Yet another step comprises harvesting the seeds from at least one of the parent corn plants. The harvested seed can be grown to produce a corn plant or hybrid corn plant.

The present invention also provides corn seed and plants produced by a process that comprises crossing a first parent corn plant with a second parent corn plant, wherein at least one of the first or second parent corn plants is a plant of the variety designated CH756602. In one embodiment of the invention, corn seed and plants produced by the process are first generation hybrid corn seed and plants produced by crossing an inbred with another, distinct inbred. The present invention further contemplates seed of an F.sub.1 hybrid corn plant. Therefore, certain exemplary embodiments of the invention provide an F.sub.1 hybrid corn plant and seed thereof, specifically the hybrid variety designated CH756602.

Such a plant can be analyzed by its "genetic complement." This term is used to refer to the aggregate of nucleotide sequences, the expression of which defines the phenotype of, for example, a corn plant, or a cell or tissue of that plant. A genetic complement thus represents the genetic make up of an cell, tissue or plant. The invention thus provides corn plant cells that have a genetic complement in accordance with the corn plant cells disclosed herein, and plants, seeds and diploid plants containing such cells.

Plant genetic complements may be assessed by genetic marker profiles, and by the expression of phenotypic traits that are characteristic of the expression of the genetic complement, e.g., marker typing profiles. It is known in the art that such complements may also be identified by marker types including, but not limited to, SSRs, Simple Sequence Length Polymorphisms (SSLPs) (Williams et al., 1990), Randomly Amplified Polymorphic DNAs (RAPDs), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Arbitrary Primed Polymerase Chain Reaction (AP-PCR), Amplified Fragment Length Polymorphisms (AFLPs) (EP 534 858, specifically incorporated herein by reference in its entirety), and Single Nucleotide Polymorphisms (SNPs) (Wang et al., 1998).

DETAILED DESCRIPTION OF THE INVENTION

I. Definitions of Plant Characteristics

Barren Plants: Plants that are barren, i.e., lack an ear with grain, or have an ear with only a few scattered kernels.

Cg: Colletotrichum graminicola rating. Rating times 10 is approximately equal to percent total plant infection.

CLN: Corn Lethal Necrosis (combination of Maize Chlorotic Mottle Virus and Maize Dwarf Mosaic virus) rating: numerical ratings are based on a severity scale where 1=most resistant to 9=susceptible.

Cn: Corynebacterium nebraskense rating. Rating times 10 is approximately equal to percent total plant infection.

Cz: Cercospora zeae-maydis rating. Rating times 10 is approximately equal to percent total plant infection.

Dgg: Diatraea grandiosella girdling rating (values are percent plants girdled and stalk lodged).

Dropped Ears: Ears that have fallen from the plant to the ground.

Dsp: Diabrotica species root ratings (1=least affected to 9=severe pruning).

Ear-Attitude: The attitude or position of the ear at harvest scored as upright, horizontal, or pendant.

Ear-Cob Color: The color of the cob, scored as white, pink, red, or brown.

Ear-Cob Diameter: The average diameter of the cob measured at the midpoint.

Ear-Cob Strength: A measure of mechanical strength of the cobs to breakage, scored as strong or weak.

Ear-Diameter: The average diameter of the ear at its midpoint.

Ear-Dry Husk Color: The color of the husks at harvest scored as buff, red, or purple.

Ear-Fresh Husk Color: The color of the husks 1 to 2 weeks after pollination scored as green, red, or purple.

Ear-Husk Bract: The length of an average husk leaf scored as short, medium, or long.

Ear-Husk Cover: The average distance from the tip of the ear to the tip of the husks. Minimum value no less than zero.

Ear-Husk Opening: An evaluation of husk tightness at harvest scored as tight, intermediate, or open.

Ear-Length: The average length of the ear.

Ear-Number Per Stalk: The average number of ears per plant.

Ear-Shank Internodes: The average number of internodes on the ear shank.

Ear-Shank Length: The average length of the ear shank.

Ear-Shelling Percent: The average of the shelled grain weight divided by the sum of the shelled grain weight and cob weight for a single ear.

Ear-Silk Color: The color of the silk observed 2 to 3 days after silk emergence scored as green-yellow, yellow, pink, red, or purple.

Ear-Taper (Shape): The taper or shape of the ear scored as conical, semi-conical, or cylindrical.

Ear-Weight: The average weight of an ear.

Early Stand: The percent of plants that emerge from the ground as determined in the early spring.

ER: Ear rot rating (values approximate percent ear rotted).

Final Stand Count: The number of plants just prior to harvest.

GDUs: Growing degree units which are calculated by the Barger Method, where the heat units for a 24-h period are calculated as GDUs=[(Maximum daily temperature+Minimum daily temperature)/2]-50. The highest maximum daily temperature used is 86.degree. F. and the lowest minimum temperature used is 50.degree. F.

GDUs to Shed: The number of growing degree units (GDUs) or heat units required for a variety to have approximately 50% of the plants shedding pollen as measured from time of planting. GDUs to shed is determined by summing the individual GDU daily values from planting date to the date of 50% pollen shed.

GDUs to Silk: The number of growing degree units for a variety to have approximately 50% of the plants with silk emergence as measured from time of planting. GDUs to silk is determined by summing the individual GDU daily values from planting date to the date of 50% silking.

Hc2: Helminthosporium carbonum race 2 rating. Rating times 10 is approximately equal to percent total plant infection.

Hc3: Helminthosporium carbonum race 3 rating. Rating times 10 is approximately equal to percent total plant infection.

Hm: Helminthosporium maydis race 0 rating. Rating times 10 is approximately equal to percent total plant infection.

Ht1: Helminthosporium turcicum race 1 rating. Rating times 10 is approximately equal to percent total plant infection.

Ht2: Helminthosporium turcicum race 2 rating. Rating times 10 is approximately equal to percent total plant infection.

HtG: Chlorotic-lesion type resistance. +=indicates the presence of Ht chlorotic-lesion type resistance; -=indicates absence of Ht chlorotic-lesion type resistance; and .+-.=indicates segregation of Ht chlorotic-lesion type resistance. Rating times 10 is approximately equal to percent total plant infection.

Kernel-Aleurone Color: The color of the aleurone scored as white, pink, tan, brown, bronze, red, purple, pale purple, colorless, or variegated.

Kernel-Cap Color: The color of the kernel cap observed at dry stage, scored as white, lemon-yellow, yellow, or orange.

Kernel-Endosperm Color: The color of the endosperm scored as white, pale yellow, or yellow.

Kernel-Endosperm Type: The type of endosperm scored as normal, waxy, or opaque.

Kernel-Grade: The percent of kernels that are classified as rounds.

Kernel-Length: The average distance from the cap of the kernel to the pedicel.

Kernel-Number Per Row: The average number of kernels in a single row.

Kernel-Pericarp Color: The color of the pericarp scored as colorless, red-white crown, tan, bronze, brown, light red, cherry red, or variegated.

Kernel-Row Direction: The direction of the kernel rows on the ear scored as straight, slightly curved, spiral, or indistinct (scattered).

Kernel-Row Number: The average number of rows of kernels on a single ear.

Kernel-Side Color: The color of the kernel side observed at the dry stage, scored as white, pale yellow, yellow, orange, red, or brown.

Kernel-Thickness: The distance across the narrow side of the kernel.

Kernel-Type: The type of kernel scored as dent, flint, or intermediate.

Kernel-Weight: The average weight of a predetermined number of kernels.

Kernel-Width: The distance across the flat side of the kernel.

Kz: Kabatiella zeae rating. Rating times 10 is approximately equal to percent total plant infection.

Leaf-Angle: Angle of the upper leaves to the stalk scored as upright (0 to 30 degrees), intermediate (30 to 60 degrees), or lax (60 to 90 degrees).

Leaf-Color: The color of the leaves 1 to 2 weeks after pollination scored as light green, medium green, dark green, or very dark green.

Leaf-Length: The average length of the primary ear leaf.

Leaf-Longitudinal Creases: A rating of the number of longitudinal creases on the leaf surface 1 to 2 weeks after pollination. Creases are scored as absent, few, or many.

Leaf-Marginal Waves: A rating of the waviness of the leaf margin 1 to 2 weeks after pollination. Rated as none, few, or many.

Leaf-Number: The average number of leaves of a mature plant. Counting begins with the cotyledonary leaf and ends with the flag leaf.

Leaf-Sheath Anthocyanin: A rating of the level of anthocyanin in the leaf sheath 1 to 2 weeks after pollination, scored as absent, basal-weak, basal-strong, weak or strong.

Leaf-Sheath Pubescence: A rating of the pubescence of the leaf sheath. Ratings are taken 1 to 2 weeks after pollination and scored as light, medium, or heavy.

Leaf-Width: The average width of the primary ear leaf measured at its widest point.

LSS: Late season standability (values times 10 approximate percent plants lodged in disease evaluation plots).

Moisture: The moisture of the grain at harvest.

On1: Ostrinia nubilalis 1st brood rating (1=resistant to 9 susceptible).

On2: Ostrinia nubilalis 2nd brood rating (1=resistant to 9 susceptible).

Relative Maturity: A maturity rating based on regression analysis. The regression analysis is developed by utilizing check hybrids and their previously established day rating versus actual harvest moistures. Harvest moisture on the hybrid in question is determined and that moisture value is inserted into the regression equation to yield a relative maturity.

Root Lodging: Root lodging is the percentage of plants that root lodge. A plant is counted as root lodged if a portion of the plant leans from the vertical axis by approximately 30 degrees or more.

Seedling Color: Color of leaves at the 6 to 8 leaf stage.

Seedling Height: Plant height at the 6 to 8 leaf stage.

Seedling Vigor: A visual rating of the amount of vegetative growth on a 1 to 9 scale, where 1 equals best. The score is taken when the average entry in a trial is at the fifth leaf stage.

Selection Index: The selection index gives a single measure of hybrid's worth based on information from multiple traits. One of the traits that is almost always included is yield. Traits may be weighted according to the level of importance assigned to them.

Sr: Sphacelotheca reiliana rating is actual percent infection.

Stalk-Anthocyanin: A rating of the amount of anthocyanin pigmentation in the stalk. The stalk is rated 1 to 2 weeks after pollination as absent, basal-weak, basal-strong, weak, or strong.

Stalk-Brace Root Color: The color of the brace roots observed 1 to 2 weeks after pollination as green, red, or purple.

Stalk-Diameter: The average diameter of the lowest visible internode of the stalk.

Stalk-Ear Height: The average height of the ear measured from the ground to the point of attachment of the ear shank of the top developed ear to the stalk.

Stalk-Internode Direction: The direction of the stalk internode observed after pollination as straight or zigzag.

Stalk-Internode Length: The average length of the internode above the primary ear.

Stalk Lodging: The percentage of plants that did stalk lodge. Plants are counted as stalk lodged if the plant is broken over or off below the ear.

Stalk-Nodes With Brace Roots: The average number of nodes having brace roots per plant.

Stalk-Plant Height: The average height of the plant as measured from the soil to the tip of the tassel.

Stalk-Tillers: The percent of plants that have tillers. A tiller is defined as a secondary shoot that has developed as a tassel capable of shedding pollen.

Staygreen: Staygreen is a measure of general plant health near the time of black layer formation (physiological maturity). It is usually recorded at the time the ear husks of most entries within a trial have turned a mature color. Scoring is on a 1 to 9 basis where 1 equals best.

STR: Stalk rot rating (values represent severity rating of 1=25% of inoculated internode rotted to 9=entire stalk rotted and collapsed).

SVC: Southeastern Virus Complex (combination of Maize Chlorotic Dwarf Virus and Maize Dwarf Mosaic Virus) rating; numerical ratings are based on a severity scale where 1=most resistant to 9=susceptible (1988 reactions are largely Maize Dwarf Mosaic Virus reactions).

Tassel-Anther Color: The color of the anthers at 50% pollen shed scored as green-yellow, yellow, pink, red, or purple.

Tassel-Attitude: The attitude of the tassel after pollination scored as open or compact.

Tassel-Branch Angle: The angle of an average tassel branch to the main stem of the tassel scored as upright (less than 30 degrees), intermediate (30 to 45 degrees), or lax (greater than 45 degrees).

Tassel-Branch Number: The average number of primary tassel branches.

Tassel-Glume Band: The closed anthocyanin band at the base of the glume scored as present or absent.

Tassel-Glume Color: The color of the glumes at 50% shed scored as green, red, or purple.

Tassel-Length: The length of the tassel measured from the base of the bottom tassel branch to the tassel tip.

Tassel-Peduncle Length: The average length of the tassel peduncle, measured from the base of the flag leaf to the base of the bottom tassel branch.

Tassel-Pollen Shed: A visual rating of pollen shed determined by tapping the tassel and observing the pollen flow of approximately five plants per entry. Rated on a 1 to 9 scale where 9=sterile, 1=most pollen.

Tassel-Spike Length: The length of the spike measured from the base of the top tassel branch to the tassel tip.

Test Weight: Weight of the grain in pounds for a given volume (bushel) adjusted to 15.5% moisture.

Yield: Yield of grain at harvest adjusted to 15.5% moisture.

II. Other Definitions

Allele: Any of one or more alternative forms of a gene locus, all of which alleles relate to one trait or characteristic. In a diploid cell or organism, the two alleles of a given gene occupy corresponding loci on a pair of homologous chromosomes.

Backcrossing: A process in which a breeder repeatedly crosses hybrid progeny back to one of the parents, for example, a first generation hybrid (F.sub.1) with one of the parental genotypes of the F.sub.1 hybrid.

Crossing: The pollination of a female flower of a corn plant, thereby resulting in the production of seed from the flower.

Cross-pollination: Fertilization by the union of two gametes from different plants.

Diploid: A cell or organism having two sets of chromosomes.

Emasculate: The removal of plant male sex organs or the inactivation of the organs with a chemical agent or a cytoplasmic or nuclear genetic factor conferring male sterility.

F.sub.1 Hybrid: The first generation progeny of the cross of two plants.

Genetic Complement: An aggregate of nucleotide sequences, the expression of which sequences defines the phenotype in corn plants, or components of plants including cells or tissue.

Genotype: The genetic constitution of a cell or organism.

Haploid: A cell or organism having one set of the two sets of chromosomes in a diploid.

Marker: A readily detectable phenotype, preferably inherited in codominant fashion (both alleles at a locus in a diploid heterozygote are readily detectable), with no environmental variance component, i.e., heritability of 1.

Phenotype: The detectable characteristics of a cell or organism, which characteristics are the manifestation of gene expression.

Quantitative Trait Loci (QTL): Genetic loci that contribute, at least in part, certain numerically representable traits that are usually continuously distributed.

Regeneration: The development of a plant from tissue culture.

Self-pollination: The transfer of pollen from the anther to the stigma of the same plant.

Single Locus Converted (Conversion) Plant: Plants which are developed by a plant breeding technique called backcrossing wherein essentially all of the desired morphological and physiological characteristics of an inbred are recovered in addition to the characteristics conferred by the single locus transferred into the inbred via the backcrossing technique. A single locus may comprise one gene, or in the case of transgenic plants, one or more transgenes integrated into the host genome at a single site (locus).

Tissue Culture: A composition comprising isolated cells of the same or a different type or a collection of such cells organized into parts of a plant.

Transgene: A genetic sequence which has been introduced into the nuclear or chloroplast genome of a corn plant by a genetic transformation technique.

III. Variety Descriptions

In accordance with one aspect of the present invention, there is provided a novel hybrid corn plant variety designated CH756602. Hybrid variety CH756602 was produced from a cross of the inbred varieties designated 1282610 and CV253048. The inbred parents have been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to show uniformity and stability within the limits of environmental influence.

In accordance with one aspect of the invention, there is provided a corn plant having the physiological and morphological characteristics of corn plant CH756602. An analysis of such morphological traits was carried out, the results of which are presented in Table 1.

TABLE-US-00001 TABLE 1 Morphological Traits for Corn Hybrid CH756602 CHARACTERISTIC VALUE 1. STALK Plant Height (cm) 302.4 Ear Height (cm) 121.4 Anthocyanin Absent Nodes With Brace Roots 1.7 Brace Root Color Faint Internode Direction Zig-Zag Internode Length cm. 20.6 2. LEAF Color Dark Green Length cm. 94.7 Width cm. 9.9 Sheath Anthocyanin Absent Sheath Pubescence Moderate Marginal Waves Moderate Longitudinal Creases Moderate 3. TASSEL Length cm. 53.4 Spike Length cm. 33.6 Peduncle Length cm. 10.6 Branch Number 3.9 Anther Color Yellow Glume Color Pale Purple Glume Band Absent 4. EAR Silk Color Yellow Number Per Stalk 1 Position (attitude) Upright Length cm. 17.6 Shape Cylindrical Diameter cm. 4.7 Shank Length cm. 7.5 Husk Bract Short Husk Cover cm. 4.6 Husk Opening Tight Husk Color Fresh Green Husk Color Dry Buff Cob Diameter cm. 2.5 Cob Color Red Shelling Percent 89.7 5. KERNEL Row Number 16 Number Per Row 38.4 Row Direction Straight Type Flint Cap Color Deep Yellow Side Color Yellow-Orange Length (depth) mm. 13.2 Width mm. 7.9 Thickness 3.9 Endosperm Type Normal Endosperm Color Yellow *These are typical values. Values may vary due to environment. Other values that are substantially equivalent are also within the scope of the invention.

During the development of a hybrid plant detailed evaluations of the phenotype are made including formal comparisons with other commercially successful hybrids. Because the corn is grown in close proximity, environmental factors that affect gene expression, such as moisture, temperature, sunlight, and pests, are minimized. For a decision to be made to commercialize a hybrid, it is not necessary that the hybrid be better than all other hybrids. Rather, significant improvements must be shown in at least some traits that would create improvements in some niches. Examples of such comparative performance data for the hybrid corn plant CH756602 are set forth herein below in Table 2.

TABLE-US-00002 TABLE 2 Comparison of Hybrid Variety CH756602 With Selected Hybrid Varieties Entries Compared SELIN YLD YM STLP RTLP DRPC FNSC SDV PHT EHT STG TWT CH756602 0 184.06 8.35 3.27 1.38 0 0 3.47 98.38 46.41 5.29 58.27 DKC66-80 0 167.41 7.66 4.04 4.09 0 0 3.66 100.06 53.56 5.32 56.07 Dev. 0 16.65 0.69 -0.77 -2.71 0 0 -0.19 -1.68 -7.15 -0.03 2.19 Sig. ** ** ** * ** ** CH756602 0 184.59 8.45 3.26 1.38 0 0 3.52 98.38 46.41 5.29 58.4 DKC67-23 0 193.44 9.28 2.93 14.92 0 0 3.97 100.85 49.94 4.71 56.66 Dev. 0 -8.85 -0.83 0.33 -13.54 0 0 -0.45 -2.47 -3.53 0.58 1.73 Sig. ** ** ** ** ** ** * ** CH756602 0 184.44 8.47 3.28 1.38 0 0 3.52 98.38 46.41 5.29 58.25 DKC67-60 0 159.47 7.33 4.16 3.42 0 0 4.85 104.74 51.82 4.35 57.29 Dev. 0 24.98 1.14 -0.88 -2.04 0 0 -1.33 -6.35 -5.41 0.94 0.96 Sig. ** ** ** ** ** ** ** ** Significance levels are indicated as: + = 10%, * = 5%, ** = 1% LEGEND ABBREVIATIONS: HYBD = Hybrid NTEST = Research/FACT SELIN = Selection Index (percent of check) YLD = Yield (bushels/acre) YM = Yield divided by percent moisture STLP = Stalk Lodging (percent) RTLP = Root Lodging (percent) DRPC = Dropped Ears (actual count) SDV = Seedling Vigor Rating FNSC = Final Stand Count (actual count) PHT = Plant Height (inches) EHT = Ear Height (inches) BAR % = Barren Plants (percent) STG = Staygreen Rating TWT = Test Weight (pounds) FGDU = GDUs to Shed

In accordance with another aspect of the present invention, there is provided a corn plant having the physiological and morphological characteristics of corn plant I282610. A description of the physiological and morphological characteristics of corn plant I282610 is presented in Table 3.

TABLE-US-00003 TABLE 3 Morphological Traits for Corn Variety I282610 VALUE CHARACTERISTIC I282610 1. STALK Diameter (width) cm. 2.0 Anthocyanin Absent Brace Root Color Faint Nodes With Brace Roots 2.0 Internode Direction Straight Internode Length cm. 16.0 2. LEAF Color Green Length cm. 80.0 Width cm. 9.0 Sheath Anthocyanin Absent Sheath Pubescence None Marginal Waves Moderate Longitudinal Creases Moderate 3. TASSEL Length cm. 53.0 Spike Length cm. 32.0 Peduncle Length cm. 10.0 Branch Number 5.0 Anther Color Yellow Glume Color Pale purple Glume Band Absent 4. EAR Silk Color Yellow Number Per Stalk 1.0 Position (attitude) Upright Length cm. 16.1 Shape Semi-conical Diameter cm. 4.1 Shank Length cm. 8.0 Husk Bract Short Husk Cover cm. 7.5 Husk Opening Tight Husk Color Fresh Green Husk Color Dry Buff Cob Diameter cm. 2.7 Cob Color Red Shelling Percent 79.6 5. KERNEL Row Number 16.4 Number Per Row 25.8 Row Direction Straight Type Dent Cap Color Yellow-orange Side Color Orange Length (depth) mm. 9.6 Width mm. 7.2 Thickness 4.2 Endosperm Type Normal Endosperm Color Orange *These are typical values. Values may vary due to environment. Other values that are substantially equivalent are also within the scope of the invention.

In accordance with yet another aspect of the present invention, there is provided a corn plant having the physiological and morphological characteristics of corn plant CV253048. A description of the physiological and morphological characteristics of corn plant CV253048 is presented in Table 4.

TABLE-US-00004 TABLE 4 Physiological and Morphological Traits for Corn Variety CV253048 VALUE CHARACTERISTIC CV253048 1. STALK Diameter (width) cm. 1.7 Anthocyanin Basal Weak Brace Root Color Faint Nodes With Brace Roots 2.2 Internode Direction Straight Internode Length cm. 14.2 2. LEAF Color Green Length cm. 59.4 Width cm. 7.4 Sheath Anthocyanin Absent Sheath Pubescence Light Marginal Waves Few Longitudinal Creases Moderate 3. TASSEL Length cm. 39.9 Spike Length cm. 25.8 Peduncle Length cm. 7.6 Branch Number 3.0 Anther Color Yellow Glume Color Purple Glume Band Absent 4. EAR Silk Color Yellow Number Per Stalk 1.0 Position (attitude) Upright Length cm. 16.4 Shape Semi-Conical Diameter cm. 3.7 Shank Length cm. 9.4 Husk Bract Short Husk Cover cm. 3.0 Husk Opening Tight Husk Color Fresh Green Husk Color Dry Buff Cob Diameter cm. 2.1 Cob Color Pink Shelling Percent 81.4 5. KERNEL Row Number 13.0 Number Per Row 28.4 Row Direction Straight Type Flint Cap Color Deep Yellow Side Color Yellow-Orange Length (depth) mm. 10.8 Width mm. 8.0 Thickness 4.0 Endosperm Type Normal Endosperm Color Orange *These are typical values. Values may vary due to environment. Other values that are substantially equivalent are also within the scope of the invention.

IV. Deposit Information

A deposit of at least 2500 seeds of inbred parent plant varieties 1282610 (U.S. application Ser. No. 11/380,387, filed Apr. 26, 2006, the entire disclosure of which is incorporated herein by reference) and CV253048 (U.S. Prov. Appl. Ser. No. 60/914,885, filed Apr. 30, 2007, the entire disclosure of which is incorporated herein by reference) has been made with the American Type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Va. 20110-2209 USA, and assigned ATCC Accession Nos. PTA-8768, and PTA-9712, respectively. The seeds were deposited with the ATCC on Nov. 12, 2007, and Jan. 16, 2009, respectively. Access to this deposit will be available during the pendency of the application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. The deposits will be maintained in the ATCC Depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the enforceable life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Applicant does not waive any infringement of their rights granted under this patent or under the Plant Variety Protection Act (7 U.S.C. 2321 et seq.).

V. Further Embodiments of the Invention

In certain further aspects, the invention provides plants modified to include at least a first desired trait. Such plants may, in one embodiment, be developed by a plant breeding technique called backcrossing, wherein essentially all of the desired morphological and physiological characteristics of a variety are recovered in addition to a genetic locus transferred into the hybrid via the backcrossing technique. By essentially all of the desired morphological and physiological characteristics, it is meant that all of the characteristics of a plant are recovered that are otherwise present when compared in the same environment, other than an occasional variant trait that might arise during backcrossing or direct introduction of a transgene. In one embodiment, such traits may be determined, for example, relative to the traits listed in Table 1 as determined at the 5% significance level when grown under the same environmental conditions.

Backcrossing methods can be used with the present invention to improve or introduce a trait in a hybrid via modification of its inbred parent(s). The term backcrossing as used herein refers to the repeated crossing of a hybrid progeny back to one of the parental corn plants for that hybrid. The parental corn plant which contributes the locus or loci for the desired trait is termed the nonrecurrent or donor parent. This terminology refers to the fact that the nonrecurrent parent is used one time in the backcross protocol and therefore does not recur.

The parental corn plant to which the locus or loci from the nonrecurrent parent are transferred is known as the recurrent parent as it is used for several rounds in the backcrossing protocol (Poehlman et al., 1995; Fehr, 1987; Sprague and Dudley, 1988). In a typical backcross protocol, the original parent hybrid of interest (recurrent parent) is crossed to a second variety (nonrecurrent parent) that carries the genetic locus of interest to be transferred. The resulting progeny from this cross are then crossed again to the recurrent parent and the process is repeated until a corn plant is obtained wherein essentially all of the desired morphological and physiological characteristics of the recurrent parent are recovered in the converted plant, in addition to the transferred locus from the nonrecurrent parent. The backcross process may be accelerated by the use of genetic markers, such as SSR, RFLP, SNP or AFLP markers to identify plants with the greatest genetic complement from the recurrent parent.

The selection of a suitable recurrent parent is an important step for a successful backcrossing procedure. The goal of a backcross protocol is to add or substitute one or more new traits in the original inbred and hybrid progeny therefrom. To accomplish this, a genetic locus of the recurrent parent is modified or substituted with the desired locus from the nonrecurrent parent, while retaining essentially all of the rest of the desired genetic, and therefore the desired physiological and morphological constitution of the original plant. The choice of the particular nonrecurrent parent will depend on the purpose of the backcross; one of the major purposes is to add some commercially desirable, agronomically important trait to the plant. The exact backcrossing protocol will depend on the characteristic or trait being altered to determine an appropriate testing protocol. Although backcrossing methods are simplified when the characteristic being transferred is a dominant allele, a recessive allele may also be transferred. In this instance it may be necessary to introduce a test of the progeny to determine if the desired characteristic has been successfully transferred.

Many traits have been identified that are not regularly selected for in the development of a new variety but that can be improved by backcrossing techniques. A genetic locus conferring the traits may or may not be transgenic. Examples of such traits known to those of skill in the art include, but are not limited to, male sterility, waxy starch, herbicide resistance, resistance for bacterial, fungal, or viral disease, insect resistance, male fertility and enhanced nutritional quality. These genes are generally inherited through the nucleus, but may be inherited through the cytoplasm. Some known exceptions to this are genes for male sterility, some of which are inherited cytoplasmically, but still act as a single locus trait.

Direct selection may be applied where a genetic locus acts as a dominant trait. An example of a dominant trait is the herbicide resistance trait. For this selection process, the progeny of the initial cross are sprayed with the herbicide prior to the backcrossing. The spraying eliminates any plants which do not have the desired herbicide resistance characteristic, and only those plants which have the herbicide resistance gene are used in the subsequent backcross. This process is then repeated for all additional backcross generations.

Many useful traits are those which are introduced by genetic transformation techniques. Methods for the genetic transformation of corn are known to those of skill in the art. For example, methods which have been described for the genetic transformation of corn include electroporation (U.S. Pat. No. 5,384,253), electrotransformation (U.S. Pat. No. 5,371,003), microprojectile bombardment (U.S. Pat. No. 5,550,318; U.S. Pat. No. 5,736,369, U.S. Pat. No. 5,538,880; and PCT Publication WO 95/06128), Agrobacterium-mediated transformation (U.S. Pat. No. 5,591,616 and E.P. Publication EP672752), direct DNA uptake transformation of protoplasts (Omirulleh et al., 1993) and silicon carbide fiber-mediated transformation (U.S. Pat. No. 5,302,532 and U.S. Pat. No. 5,464,765).

It is understood to those of skill in the art that a transgene need not be directly transformed into a plant, as techniques for the production of stably transformed corn plants that pass single loci to progeny by Mendelian inheritance is well known in the art. Such loci may therefore be passed from parent plant to progeny plants by standard plant breeding techniques that are well known in the art.

A. Male Sterility

Examples of genes conferring male sterility include those disclosed in U.S. Pat. No. 3,861,709, U.S. Pat. No. 3,710,511, U.S. Pat. No. 4,654,465, U.S. Pat. No. 5,625,132, and U.S. Pat. No. 4,727,219, each of the disclosures of which are specifically incorporated herein by reference in their entirety. Male sterility genes can increase the efficiency with which hybrids are made, in that they eliminate the need to physically emasculate the corn plant used as a female in a given cross.

Where one desires to employ male-sterility systems with a corn plant in accordance with the invention, it may be beneficial to also utilize one or more male-fertility restorer genes. For example, where cytoplasmic male sterility (CMS) is used, hybrid seed production requires three inbred lines: (1) a cytoplasmically male-sterile line having a CMS cytoplasm; (2) a fertile inbred with normal cytoplasm, which is isogenic with the CMS line for nuclear genes ("maintainer line"); and (3) a distinct, fertile inbred with normal cytoplasm, carrying a fertility restoring gene ("restorer" line). The CMS line is propagated by pollination with the maintainer line, with all of the progeny being male sterile, as the CMS cytoplasm is derived from the female parent. These male sterile plants can then be efficiently employed as the female parent in hybrid crosses with the restorer line, without the need for physical emasculation of the male reproductive parts of the female parent.

The presence of a male-fertility restorer gene results in the production of fully fertile F.sub.1 hybrid progeny. If no restorer gene is present in the male parent, male-sterile hybrids are obtained. Such hybrids are useful where the vegetative tissue of the corn plant is utilized, e.g., for silage, but in most cases, the seeds will be deemed the most valuable portion of the crop, so fertility of the hybrids in these crops must be restored. Therefore, one aspect of the current invention concerns the hybrid corn plant CH756602 comprising a genetic locus capable of restoring male fertility in an otherwise male-sterile plant. Examples of male-sterility genes and corresponding restorers which could be employed with the plants of the invention are well known to those of skill in the art of plant breeding and are disclosed in, for instance, U.S. Pat. No. 5,530,191; U.S. Pat. No. 5,689,041; U.S. Pat. No. 5,741,684; and U.S. Pat. No. 5,684,242, the disclosures of which are each specifically incorporated herein by reference in their entirety.

B. Herbicide Resistance

Numerous herbicide resistance genes are known and may be employed with the invention. An example is a gene conferring resistance to a herbicide that inhibits the growing point or meristem, such as an imidazalinone or a sulfonylurea. Exemplary genes in this category code for mutant ALS and AHAS enzyme as described, for example, by Lee et al., (1988); Gleen et al., (1992); and Miki et al., (1990).

Resistance genes for glyphosate (resistance conferred by mutant 5-enolpyruvl-3 phosphikimate synthase (EPSP) and aroA genes, respectively) and other phosphono compounds such as glufosinate (phosphinothricin acetyl transferase (PAT) and Streptomyces hygroscopicus phosphinothricin-acetyl transferase (bar) genes) may also be used. See, for example, U.S. Pat. No. 4,940,835 to Shah, et al., which discloses the nucleotide sequence of a form of EPSPS which can confer glyphosate resistance. A DNA molecule encoding a mutant aroA gene can be obtained under ATCC accession number 39256, and the nucleotide sequence of the mutant gene is disclosed in U.S. Pat. No. 4,769,061 to Comai. European patent application No. 0 333 033 to Kumada et al., and U.S. Pat. No. 4,975,374 to Goodman et al., disclose nucleotide sequences of glutamine synthetase genes which confer resistance to herbicides such as L-phosphinothricin. The nucleotide sequence of a phosphinothricin-acetyltransferase gene is provided in European application No. 0 242 246 to Leemans et al. DeGreef et al., (1989), describe the production of transgenic plants that express chimeric bar genes coding for phosphinothricin acetyl transferase activity. Exemplary of genes conferring resistance to phenoxy propionic acids and cycloshexones, such as sethoxydim and haloxyfop are the Acct-S1, Accl-S2 and Acct-S3 genes described by Marshall et al., (1992).

Genes are also known conferring resistance to a herbicide that inhibits photosynthesis, such as a triazine (psbA and gs+ genes) and a benzonitrile (nitrilase gene). Przibilla et al., (1991), describe the transformation of Chlamydomonas with plasmids encoding mutant psbA genes. Nucleotide sequences for nitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, and DNA molecules containing these genes are available under ATCC Accession Nos. 53435, 67441, and 67442. Cloning and expression of DNA coding for a glutathione S-transferase is described by Hayes et al., (1992).

C. Waxy Starch

The waxy characteristic is an example of a recessive trait. In thi