# Patent

## Title
Sweet corn hybrid SV1580SC and parents thereof

## Abstract

The invention provides seed and plants of sweet corn hybrid SV1580SC and the parent lines thereof. The invention thus relates to the plants, seeds and tissue cultures of sweet corn hybrid SV1580SC and the parent lines thereof, and to methods for producing a sweet corn plant produced by crossing such plants with themselves or with another sweet corn plant, such as a plant of another genotype. The invention further relates to seeds and plants produced by such crossing. The invention further relates to parts of such plants, including the parts of such plants.

## Background
FIELD OF THE INVENTION
The present invention relates to the field of plant breeding and, more specifically, to the development of sweet corn hybrid SV1580SC and the inbred sweet corn lines SHW817-409 and SYW-6RLAC068.
BACKGROUND OF THE INVENTION
The goal of vegetable breeding is to combine various desirable traits in a single variety/hybrid. Such desirable traits may include any trait deemed beneficial by a grower and/or consumer, including 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, sugar content, uniformity in germination times, stand establishment, growth rate and maturity, among others.
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 or plant variety. A plant cross-pollinates if pollen comes to it from a flower of a different plant variety.
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 of different genotypes 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 varieties 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 that have been used to develop inbred plants from breeding populations. Those breeding methods combine the genetic backgrounds from two or more plants or various other broad-based sources into breeding pools from which new lines and hybrids derived therefrom are developed by selfing and selection of desired phenotypes. The new lines and hybrids are evaluated to determine which of those have commercial potential.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a plant of the sweet corn hybrid designated SV1580SC, the sweet corn line SHW817-409 or sweet corn line SYW-6RLAC068. Also provided are corn plants having all the physiological and morphological characteristics of such a plant. Parts of these corn plants are also provided, for example, including pollen, an ovule, and a cell of the plant.
In another aspect of the invention, a plant of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 comprising an added heritable trait is provided. The heritable trait may comprise a genetic locus that is, for example, a dominant or recessive allele. In one embodiment of the invention, a plant of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 is defined as comprising a single locus conversion. In specific embodiments of the invention, an added genetic locus confers one or more traits such as, for example, male sterility, herbicide resistance, insect resistance, resistance to bacterial, fungal, sugar content, nematode or viral disease, and altered fatty acid, phytate or carbohydrate metabolism. In further embodiments, the trait may be conferred by a naturally occurring gene introduced into the genome of a line by backcrossing, a natural or induced mutation, or a transgene introduced through genetic transformation techniques into the plant or a progenitor of any previous generation thereof. When introduced through transformation, a genetic locus may comprise one or more genes integrated at a single chromosomal location.
The invention also concerns the seed of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068. The corn seed of the invention may be provided, in one embodiment of the invention, as an essentially homogeneous population of corn seed of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068. Essentially homogeneous populations of seed are generally free from substantial numbers of other seed. Therefore, seed of hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 may, in particular embodiments of the invention, be provided forming at least about 97% of the total seed, including at least about 98%, 99% or more of the seed. The seed population may be separately grown to provide an essentially homogeneous population of sweet corn plants designated SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068.
In yet another aspect of the invention, a tissue culture of regenerable cells of a sweet corn plant of hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 is provided. The tissue culture will preferably be capable of regenerating corn plants capable of expressing all of the physiological and morphological characteristics of the starting plant, and of regenerating plants having substantially the same genotype as the starting plant. Examples of some of the physiological and morphological characteristics of the hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 include those traits set forth in the tables herein. The regenerable cells in such tissue cultures may be derived, for example, 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 a tissue culture of the invention, the plants having all the physiological and morphological characteristics of hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068.
In still yet another aspect of the invention, processes are provided for producing corn seeds, plants and parts thereof, 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 sweet corn line SHW817-409 or sweet corn line SYW-6RLAC068. These processes may be further exemplified as processes for preparing hybrid corn seed or plants, wherein a first corn plant is crossed with a second corn plant of a different, distinct genotype to provide a hybrid that has, as one of its parents, a plant of sweet corn line SHW817-409 or sweet corn line SYW-6RLAC068. 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 seeds of a first and second parent corn plant, often in proximity so that pollination will occur for example, naturally or manually. Where the plant is self-pollinated, pollination may occur without the need for direct human intervention other than plant cultivation. For hybrid crosses, it may be beneficial to detassel or otherwise emasculate the parent used as a female.
A second step may comprise cultivating or growing the seeds of first and second parent corn plants into mature plants. A third step may comprise preventing self-pollination of the plants, such as by detasseling or other means.
A fourth step for a hybrid cross may comprise cross-pollination between the first and second parent corn plants. 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 the corn seeds 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 sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068. In one embodiment of the invention, corn seed and plants produced by the process are first generation (F1) hybrid corn seed and plants produced by crossing a plant in accordance with the invention with another, distinct plant. The present invention further contemplates plant parts of such an F1 hybrid corn plant, and methods of use thereof. Therefore, certain exemplary embodiments of the invention provide an F1 hybrid corn plant and seed thereof.
In still yet another aspect, the present invention provides a method of producing a plant derived from hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068, the method comprising the steps of: (a) preparing a progeny plant derived from hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068, wherein said preparing comprises crossing a plant of the hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 with a second plant; and (b) crossing the progeny plant with itself or a second plant to produce a seed of a progeny plant of a subsequent generation. In further embodiments, the method may additionally comprise: (c) growing a progeny plant of a subsequent generation from said seed of a progeny plant of a subsequent generation and crossing the progeny plant of a subsequent generation with itself or a second plant; and repeating the steps for an additional 3-10 generations to produce a plant derived from hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068. The plant derived from hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 may be an inbred line, and the aforementioned repeated crossing steps may be defined as comprising sufficient inbreeding to produce the inbred line. In the method, it may be desirable to select particular plants resulting from step (c) for continued crossing according to steps (b) and (c). By selecting plants having one or more desirable traits, a plant derived from hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 is obtained which possesses some of the desirable traits of the line/hybrid as well as potentially other selected traits.
In certain embodiments, the present invention provides a method of producing food or feed comprising: (a) obtaining a plant of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068, wherein the plant has been cultivated to maturity, and (b) collecting at least one ear of corn from the plant.
In still yet another aspect of the invention, the genetic complement of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 is provided. The phrase “genetic complement” is used to refer to the aggregate of nucleotide sequences, the expression of which sequences defines the phenotype of, in the present case, a sweet corn plant, or a cell or tissue of that plant. A genetic complement thus represents the genetic makeup of a cell, tissue or plant, and a hybrid genetic complement represents the genetic make up of a hybrid 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 seeds and 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., isozyme typing profiles. It is understood that hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 could be identified by any of the many well known techniques such as, for example, Simple Sequence Length Polymorphisms (SSLPs) (Williams et al., Nucleic Acids Res., 1 8:6531-6535, 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., Science, 280:1077-1082, 1998).
In still yet another aspect, the present invention provides hybrid genetic complements, as represented by corn plant cells, tissues, plants, and seeds, formed by the combination of a haploid genetic complement of a corn plant of the invention with a haploid genetic complement of a second corn plant, preferably, another, distinct corn plant. In another aspect, the present invention provides a corn plant regenerated from a tissue culture that comprises a hybrid genetic complement of this invention.
In still yet another aspect, the invention provides a method of determining the genotype of a plant of sweet corn hybrid SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 comprising detecting in the genome of the plant at least a first polymorphism. The method may, in certain embodiments, comprise detecting a plurality of polymorphisms in the genome of the plant. The method may further comprise storing the results of the step of detecting the plurality of polymorphisms on a computer readable medium. The invention further provides a computer readable medium produced by such a method.
Any embodiment discussed herein with respect to one aspect of the invention applies to other aspects of the invention as well, unless specifically noted.
The term “about” is used to indicate that a value includes the standard deviation of the mean for the device or method being employed to determine the value. The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive. When used in conjunction with the word “comprising” or other open language in the claims, the words “a” and “an” denote “one or more,” unless specifically noted otherwise. The terms “comprise,” “have” and “include” are open-ended linking verbs. Any forms or tenses of one or more of these verbs, such as “comprises,” “comprising,” “has,” “having,” “includes” and “including,” are also open-ended. For example, any method that “comprises,” “has” or “includes” one or more steps is not limited to possessing only those one or more steps and also covers other unlisted steps. Similarly, any plant that “comprises,” “has” or “includes” one or more traits is not limited to possessing only those one or more traits and covers other unlisted traits.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and any specific examples provided, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.


DETAILED DESCRIPTION OF THE INVENTION
The invention provides methods and compositions relating to plants, seeds and derivatives of sweet corn hybrid SV1580SC, sweet corn line SHW817-409 and sweet corn line SYW-6RLAC068. The hybrid SV1580SC was produced by the cross of parent lines SHW817-409 and SYW-6RLAC068. The parent lines show uniformity and stability within the limits of environmental influence. By crossing the parent lines, uniform seed hybrid SV1580SC can be obtained.
Inbred line SYW-6RLAC068 is a white sweet corn homozygous for recessive genes sh2 and su1. SHY-6RLAC068 has the RpG gene which provides resistance to some races of Puccinia sorghi (common rust).
Hybrid SV1580SC is a white supersweet sweet corn hybrid with 8-8.5×1.9 inch ears and 16-20 kernel rows. The hybrid has one parent which is homozygous for both the recessive sh2 and su1 alleles so that about 75% of the kernels on an ear will be just homozygous recessive sh2 and about 25% will be homozygous for both recessive sh2 and recessive su1. These double mutant kernels provide added sweetness for the hybrid. The hybrid carries both the RpG and Rp1D alleles which provide resistance to some races of Puccinia sorghi (common rust).
The development of sweet corn hybrid SV1580SC and its parent lines is summarized below.
A. ORIGIN AND BREEDING HISTORY OF SWEET CORN HYBRID SV1580SC
The hybrid SV1580SC was produced by the cross of parent lines SHW817-409 and SYW-6RLAC068.
Line SYW-6RLAC068 is a white sweet corn inbred which is homozygous for the recessive sh2 gene and the recessive su1 gene. The line has the RpG gene which provides resistance to some races of Puccinia sorghi. The line also has the Ht1 gene which gives resistance to some races of Exserohilum turcicum, which causes northern corn leaf blight. SYW-6RLAC068 resembles inbred lines SYY093-678, SYY-6R07001, and SYY-6R07003.
The line was created as follows:

    Winter Year 1-Year 2: Seeds of the inbred SHW084-SHSMHG9W (a proprietary Seminis inbred) were planted. Plants were cross pollinated by the inbred SYY093-678 (a proprietary Seminis inbred). This resulted in the F1 generation. One cross pollinated ear was given the source name E02: 8564×5387.
    Winter Year 2-Year 3: Seeds of the F1 source E02: 8564×5387 were planted. Plants were cross pollinated by the inbred SYY093-678. This resulted in the BC1 generation. A bulk of cross pollinated ears was given the source name E03: 9214×9205/B1 Summer Year 3: Seeds of the BC1 source E03: 9214×9205/B1 were planted. Plants were self pollinated to make the BC1F2 generation. One self pollinated ear was given the source name N03: 5459/1*. This ear segregated for white and yellow kernels.
    Winter Year 3-Year 4: Seeds of the BC1F2 source N03: 5459/1* were planted. White kernels were selected for planting. Plants were self pollinated to make the BC1F3 generation. One self pollinated ear was given the source name E04:-5783/1.
    Summer Year 4: Seeds of the BC1F3 source E04:-5783/1. were planted. Plants were self pollinated to make the BC1F4 generation. One self pollinated ear was given the source name N04:-4492/1.
    Winter Year 4-Year 5: Seeds of the BC1F4 source N04:-4492/1. were planted. Plants were self pollinated to make the BC1F5 generation. One self pollinated ear was given the source name E05:-8812/2.
    Summer Year 5: Seeds of the BC1F5 source E05:-8812/2. were planted. Plants were self pollinated to make the BC1F6 generation. One self pollinated ear was given the source name N05:-5370/1.
    Winter Year 5-Year 6: Seeds of the BC1F6 source N05:-5370/1. were planted. Plants were cross pollinated by the inbred SYY093-678. Cross pollinated plants resulted in the F1 generation. One F1 ear was given the source 05 10 6R 6R MSME-E2—00021—00029—3_/
    Summer Year 6: Seeds of the F1 source 05 10 6R 6R MSME-E2—00021—00029—3_/ were planted. Plants were cross pollinated by the inbred SYY093-678. Cross pollinated ears resulted in the BC1 generation. One BC1 ear was given the source name 06 04 6R 6R WIDE-IB5—00009—00028—1_>
    Winter Year 6-Year 7: Seeds of the BC1 source 06 04 6R 6R WIDE-IB5—00009—00028—1_> were planted. Plants were cross pollinated by the inbred SYY-6R07003 (a proprietary Seminis inbred). Cross pollinated ears resulted in the F1 generation. Inbred line SYY-6R07003 has the RpG gene and was the source of RpG. One F1 ear was given the source name 06 10 6R 6R MSME-E2—00010—00078—1_/
    Summer Year 7: Seeds of the F1 source 06 10 6R 6R MSME-E2—00010—00078—1_/ were planted. Plants were cross pollinated by the inbred SYY-6R07003. Cross pollinated ears resulted in the BC1 generation. One BC1 ear was given the source name 07 04 6R 6R WIDE-IB1—00013—00022—3>
    Winter Year 7-Year 8: Seeds of the BC1 source 07 04 6R 6R WIDE-1131—00013—00022—3> were planted. Plants were self pollinated to make the BC1F2 generation. One resulting ear was given the source 07 10 6R 6R MSME-E2—00018—00003—3_. This ear segregated for white and yellow kernels.
    Summer Year 8: Seeds of the BC1F2 source 07 10 6R 6R MSME-E2—00018—00003—3— were planted. White kernels were selected for planting. Plants were self pollinated to make the BC1F3 generation. One resulting ear was given the source 08 04 6R 6R WIDE-IB1—00020—00012—1_.
    Winter Year 8-Year 9: Seeds of the BC1F3 source 08 04 6R 6R WIDE-IB1—00020—00012—1— were planted. Plants were self pollinated to make the BC1F4 generation. One resulting ear was given the source 08 10 6R 6R MSME-E1—00028—00011—68_. At the BC1F4 generation, this line was given the name SYW-6RLAC068.
    Summer Year 9: Seeds of the BC1F4 source 08 10 6R 6R MSME-E1—00028—00011—68— were planted. Plants were self pollinated to make the BC1F5. One resulting ear was given the source 09 04 6R 6R WIDE-IB2—00004—00037—1—
    Winter Year 9-Year 10: Seeds of the BC1F5 source 09 04 6R 6R WIDE-IB2—00004—00037—1— were planted. Plants were self pollinated to make the BC1F6 generation. Plants and harvested ears were observed to be uniform for all traits observed. Forty of the harvested ears from these plots were given the source designation 09 10 6R 6R MSME-E1—00031—00026—1— thru 09 10 6R 6R MSME-E1—00031—00026—40— These ears were sent to Foundation Seed as the breeder's seed increase of this inbred.


In Winter Year 9-Year 10, 21 plants from source 09 04 6R 6R WIDE-IB2—00004—00037—1_. were grown in the greenhouse and inoculated with a d-virulent isolate of Puccinia sorghi. All 21 plants were resistant which verified the presence of the RpG gene in this stock and indicates the line is homozygous for this allele.
In Winter Year 10-Year 11, 18 plants of SYW-6RLAC068 from Foundation seed source FSCP 1710-10 were inoculated with a race 0 isolate of Exserohilum turcicum, the pathogen causing northern corn leaf blight. All 18 plants showed the chlorotic hypersensitive reaction caused by the Ht1 gene. 29 more plants of SYW-6RLAC068 from Foundation Seed source FSCC 1733-11 were tested in winter Year 11-Year 12 to the same race 0 isolate, and all 29 plants showed the Ht1 resistance. This verifies the presence of the Ht1 gene in this stock and indicates the line is homozygous for the allele.
Sweet corn inbred SYW-6RLAC068 was reproduced using self pollination in the winter Year 9-Year 10 nursery and was judged to be stable. 40 single ears were sent to Foundation Seed as Breeder's Seed. Inbred SYW-6RLAC068 is uniform for all traits observed. SYW-6RLAC068 shown no variants other than what would normally be expected due to environment or that would occur for almost any character during the course of repeated sexual reproduction.
B. PHYSIOLOGICAL AND MORPHOLOGICAL CHARACTERISTICS OF SWEET CORN HYBRID SV1580SC, Sweet Corn Line SHW817-409 and Sweet Corn Line SYW-6RLAC068
In accordance with one aspect of the present invention, there is provided a plant having the physiological and morphological characteristics of sweet corn hybrid SV1580SC and the parent lines thereof. A description of the physiological and morphological characteristics of such plants is presented in Tables 1-2.







TABLE 1







Physiological and Morphological Characteristics


of Hybrid SV1580SC











Comparison:


Characteristic
SV1580SC
Devotion





Type
sweet
sweet


Maturity in the Region of


Best Adaptability


from emergence to 50% of
days: 51
days: 53


plants in silk
heat units: 999
heat units: 1037.8


from emergence to 50% of
days: 48
days: 50


plants in pollen
heat units: 936.4
heat units: 975.1


from 10% to 90% pollen shed
days: 6
days: 5



heat units: 109.8
heat units: 88.3


from 50% silk to optimum
days: 20
days: 21


edible quality
heat units: 409.7
heat units: 432.1


from 50% silk to harvest at
days: 52
days: 60


25% moisture
heat units: 1051.8
heat units: 1207.1


foliage: intensity of green
dark
dark


color


first leaf: anthocyanin
absent or very weak
absent or very weak


coloration of sheath


first leaf: shape of apex
pointed
pointed


leaf: undulation of margin of
intermediate
intermediate


blade


leaf: angle between blade and
medium (±50°)
medium (±50°)


stem (on leaf just above upper


ear)


leaf: curvature of blade
moderately recurved
moderately recurved


leaf: anthocyanin coloration
absent or very weak
absent or very weak


of sheath (in middle of plant)


leaf: width of blade
medium
medium


leaf: width of ear node leaf in
8.4 cm
9.6 cm


centimeters
standard deviation:
standard deviation:



0.45
0.71



sample size: 15
sample size: 15


leaf: length of ear node leaf in
76.1 cm
85.7 cm


centimeters
standard deviation:
standard deviation:



3.01
3.1



sample size: 15
sample size: 15


leaf: number of leaves above
5.8
6


top ear
standard deviation:
standard deviation:



0.41
0.65



sample size: 15
sample size: 15


leaf: degrees leaf angle
35°
45°


leaf: color
5GY3/4
5GY4/4


leaf: sheath pubescence
7
8


leaf: marginal waves
4
4


leaf: longitudinal creases
4
3


stem: degree of zig-zag
absent or very slight
absent or very slight


stem: anthocyanin coloration
absent or very weak
absent or very weak


of brace roots


stem: anthocyanin coloration
absent or very weak
absent or very weak


of internodes


Plant


only inbred lines and varieties
medium
long


with ear type of grain: sweet


or pop: plant length (tassel


included)


ratio height of insertion of
large
medium


peduncle of upper ear to plant


length


peduncle: length
long
long


plant height (to tassel tip)
190.7 cm
198.2 cm



standard deviation:
standard deviation



8.27
12.03



sample size: 15
sample size: 15


ear height (to base of top ear
63.4 cm
83.8 cm


node)
standard deviation:
standard deviation



8.67
8.96



sample size: 15
sample size: 15


length of top ear internode
16.5 cm
12.6 cm



standard deviation:
standard deviation



0.88
1.28



sample size: 15
sample size: 15


average number of tillers
3.3 cm
1.5 cm



standard deviation:
standard deviation:



0.72
0.64



sample size: 15
sample size: 15


average number of ears per
2.2 avg
1.4 avg


stalk
standard deviation:
standard deviation



0.46
0.51



sample size: 15
sample size: 15


anthocyanin of brace roots
absent
absent


Tassel


time of anthesis
early to medium
early to medium


anthocyanin coloration at base
absent or very weak
absent or very weak


of glume


anthocyanin coloration of
absent or very weak
absent or very weak


glumes excluding base


anthocyanin coloration of
absent or very weak
absent or very weak


anthers (in middle third of


main axis)


angle between main axis and
large (±75°)
medium (±50°)


lateral branches (in lower


third of tassel


curvature of lateral branches
strongly recurved
moderately recurved


(in lower third of tassel)


number of primary lateral
medium
many


branches


density of spikelets
medium
moderately dense


length of main axis above
medium
long


lowest later branch (A-B)


length of main axis above
very long
medium


highest lateral branch (C-D)


length of lateral branch
long
long


number of primary lateral
24.2
27


branches
standard deviation:
standard deviation:



2.68
3.16



sample size: 15
sample size: 15


branch angle from central
45.3°
56°


spike
standard deviation:
standard deviation:



8.12
14.04



sample size: 15
sample size: 15


tassel length (from top leaf
39.6 cm
35.5 cm


collar to tassel tip) in
standard deviation:
standard deviation:


centimeters
1.77
4.17



sample size: 15
sample size: 15


pollen shed
3
4


anther color
2.5GY8/8
5GY6/6


glume color
5GY5/8
5GY6/4


bar glumes (glume bands)
absent
absent


Ear


(unhusked data): silk color
2.5GY8/8
2.5GY8/8


(unhusked data): fresh husk
5GY6/8
5GY7/8


color


(unhusked data): dry husk
5GY8/4
2.5GY8/4


color


(unhusked data): position of
upright
upright


ear at dry husk stage


(unhusked data): husk
7
8


tightness


(unhusked data): husk
medium (<8 cm)
medium (<8 cm)


extension (at harvest)


(husked ear data): ear length
19.8 cm
20 cm


in centimeters
standard deviation:
standard deviation:



1.09
1.32



sample size: 15
sample size: 15


(husked ear data): ear
44.6 mm
46.2 cm


diameter at mid-point in
standard deviation:
standard deviation:


millimeters
2.85
3.38



sample size: 15
sample size: 15


(husked ear data): ear weight
103.6 gm
133 gm


in grams
standard deviation:
standard deviation:



22.72
31.84



sample size: 15
sample size: 15


(husked ear data): number of
17.8
18


kernel rows
standard deviation:
standard deviation:



2.03
2.02



sample size: 15
sample size: 15


(husked ear data): kernel rows
distinct
distinct


(husked ear data): row
slightly curved
slightly curved


alignment


(husked ear data): shank
21.8 cm
19 cm


length in centimeters
standard deviation:
standard deviation:



5.7
5.19



sample size: 15
sample size: 15


(husked ear data): ear taper
average
average


length
medium
medium


diameter (in middle)
medium
medium


shape
cylindrical
cylindrical


number of rows of grain
many
medium


number of colors of grains
two
one


(only varieties with ear type


of grain: sweet or waxy)


grain: intensity of yellow
dark
medium


color (only varieties with ear


type of grain: sweet)


grain: length (only varieties
long
long


with ear type of grain: sweet)


grain: width (only varieties
medium
medium


with ear type of grain)


type of grain
sweet
sweet


shrinkage of top of grain (only
medium
medium


varieties with ear type of


grain: sweet)


color of top of grain
yellowish white
yellowish white


anthocyanin coloration of
absent or very weak
absent or very weak


glumes of cob


time of silk emergence (50%
early to medium
early to medium


of plants)


anthocyanin coloration of
absent or very weak
absent or very weak


silks


Cob


diameter at mid-point
28.4 mm
29.5 mm



standard deviation:
standard deviation:



1.25
2.02



sample size: 15
sample size: 15


color
5Y 8/4
5Y 8/4


Kernel (dried)


length
11 mm
11.9 mm



standard deviation:
standard deviation:



0.68
0.6



sample size: 15
sample size: 15


width
5.9 mm
7 mm



standard deviation:
standard deviation:



0.7
0.61



sample size: 15
sample size: 15


thickness
3.7 mm
4.1 mm



standard deviation:
standard deviation



0.65
0.9



sample size: 15
sample size: 15


% round kernels (shape grade)
0.30%
0%



sample size: n/a
sample size: n/a


aleurone color pattern
homozygous
homozygous


aleurone color
2.5Y8/4
2.5Y8/4


hard endosperm color
2.5Y8/4
2.5Y8/4


endosperm type
sweet (su1)
sweet


weight per 100 kernels
12 gm
17.0 gm


(unsized sample)
sample size: n/a
sample size: n/a


Agronomic Traits


stay green (at 65 days after
6
7


anthesis) (from 1 = worst to


9 = excellent)


dropped ears
0%
0%


% pre-anthesis brittle
0%
0%


snapping


% pre-anthesis root lodging
0%
0%


post-anthesis root lodging
0%
0%





*These are typical values. Values may vary due to environment. Other values that are substantially equivalent are also within the scope of the invention.













TABLE 2







Physiological and Morphological Characteristics


of Sweet Corn Line SYW-6RLAC068









Characteristic
SYW-6RLAC068
Comparison: FA 32





Type
sweet
sweet


Maturity in the Region of


Best Adaptability


from emergence to 50% of
days: 57
days: 63


plants in silk
heat units: 1121.9
heat units: 1241.7


from emergence to 50% of
days: 53
days: 60


plants in pollen
heat units: 1045.1
heat units: 1180.2


from 10% to 90% pollen shed
days: 10
days: 14



heat units: 202.7
heat units: 276.2


from 50% silk to optimum
days: 21
days: 20


edible quality
heat units: 441.9
heat units: 429.7


from 50% silk to harvest at
days: 43
days: 40


25% moisture
heat units: 866.2
heat units: 807.4


foliage: intensity of green
dark
dark


color


first leaf: anthocyanin
absent or very weak
absent or very weak


coloration of sheath


first leaf: shape of apex
pointed
pointed


leaf: undulation of margin of
intermediate
intermediate


blade


leaf: angle between blade and
small (±25°)
small (±25°)


stem (on leaf just above upper


ear)


leaf: curvature of blade
slightly recurved
slightly recurved


leaf: anthocyanin coloration
absent or very weak
absent or very weak


of sheath (in middle of plant)


leaf: width of blade
narrow
medium


leaf: width of ear node leaf in
7.1 cm
6.6 cm


centimeters
standard deviation:
standard deviation:



0.49
0.54



sample size: 15
sample size: 15


leaf: length of ear node leaf in
53.4 cm
75.5 cm


centimeters
standard deviation:
standard deviation:



5.05
5.48



sample size: 15
sample size: 15


leaf: number of leaves above
6.4
5.6


top ear
standard deviation:
standard deviation:



0.74
0.9



sample size: 15
sample size: 15


leaf: degrees leaf angle
45°
30°


leaf: color
5GY3/4
5GY3/4


leaf: sheath pubescence
7
5


leaf: marginal waves
4
4


leaf: longitudinal creases
9
4


stem: degree of zig-zag
absent or very slight
slight


stem: anthocyanin coloration
absent or very weak
absent or very weak


of brace roots


stem: anthocyanin coloration
absent or very weak
absent or very weak


of internodes


Plant


only inbred lines and varieties
very short
short


with ear type of grain: sweet


or pop: plant length (tassel


included)


ratio height of insertion of
very small
small


peduncle of upper ear to plant


length


peduncle: length
medium
long


plant height (to tassel tip)
99.5 cm
152.1 cm



standard deviation:
standard deviation



8.22
10.32



sample size: 15
sample size: 15


ear height (to base of top ear
15.1 cm
40 cm


node)
standard deviation:
standard deviation



4.36
6.99



sample size: 15
sample size: 15


length of top ear internode
8.3 cm
11.4 cm



standard deviation:
standard deviation



1.46
1.31



sample size: 15
sample size: 15


average number of tillers
2.2 cm
3.7 cm



standard deviation:
standard deviation:



0.68
1.39



sample size: 15
sample size: 15


average number of ears per
2 avg
1.5 avg


stalk
standard deviation:
standard deviation



0.7
0.64



sample size: 15
sample size: 15


anthocyanin of brace roots
absent
absent


Tassel


time of anthesis
early to medium
medium to late


anthocyanin coloration at base
absent or very weak
absent or very weak


of glume


anthocyanin coloration of
absent or very weak
absent or very weak


glumes excluding base


anthocyanin coloration of
absent or very weak
absent or very weak


anthers (in middle third of


main axis)


angle between main axis and
small (±25°)
medium (±50°)


lateral branches (in lower


third of tassel


curvature of lateral branches
slightly recurved
moderately recurved


(in lower third of tassel)


number of primary lateral
medium
medium


branches


density of spikelets
medium
medium


length of main axis above
long
medium


lowest later branch (A-B)


length of main axis above
long
medium


highest lateral branch (C-D)


length of lateral branch
short
long


number of primary lateral
27.3
20


branches
standard deviation:
standard deviation:



3.09
4.64



sample size: 15
sample size: 15


branch angle from central
32.6°
47.6°


spike
standard deviation:
standard deviation:



6.51
8.63



sample size: 15
sample size: 15


tassel length (from top leaf
29.9 cm
44.8 cm


collar to tassel tip) in
standard deviation:
standard deviation:


centimeters
3.03
5.53



sample size: 15
sample size: 15


pollen shed
7
4


anther color
2.5GY6/6
5GY7/6


glume color
5GY6/4
5GY6/4


bar glumes (glume bands)
absent
absent


Ear


(unhusked data): silk color
2.5GY8/4
2.5GY7/6


(unhusked data): fresh husk
5GY6/6
5GY7/4


color


(unhusked data): dry husk
5Y8/4
2.5GY8/4


color


(unhusked data): position of
upright
upright


ear at dry husk stage


(unhusked data): husk
4
6


tightness


(unhusked data): husk
medium (<8 cm)
medium (<8 cm)


extension (at harvest)


(husked ear data): ear length
11.8 cm
11.1 cm


in centimeters
standard deviation:
standard deviation:



0.99
2.09



sample size: 15
sample size: 15


(husked ear data): ear
42 mm
24.1 cm


diameter at mid-point in
standard deviation:
standard deviation:


millimeters
2.29
5.74



sample size: 15
sample size: 15


(husked ear data): ear weight
36.6 gm
23.2 gm


in grams
standard deviation:
standard deviation:



11.31
11.48



sample size: 15
sample size: 15


(husked ear data): number of
18.2
6.1


kernel rows
standard deviation:
standard deviation:



1.37
3.7



sample size: 15
sample size: 15


(husked ear data): kernel rows
distinct
indistinct


(husked ear data): row
straight
slightly curved


alignment


(husked ear data): shank
14.6 cm
22.7 cm


length in centimeters
standard deviation:
standard deviation:



3.86
7.95



sample size: 15
sample size: 15


(husked ear data): ear taper
average
average


length
short
short


diameter (in middle)
medium
small


shape
conico-cylindrical
cylindrical


number of rows of grain
medium
very few


number of colors of grains
one
one


(only varieties with ear type


of grain: sweet or waxy)


grain: intensity of yellow
light
medium


color (only varieties with ear


type of grain: sweet)


grain: length (only varieties
medium
short


with ear type of grain: sweet)


grain: width (only varieties
medium
broad


with ear type of grain)


type of grain
sweet
sweet


shrinkage of top of grain (only
medium
medium


varieties with ear type of


grain: sweet)


color of top of grain
yellowish white
yellow


anthocyanin coloration of
absent or very weak
absent or very weak


glumes of cob


time of silk emergence (50%
early to medium
medium to late


of plants)


anthocyanin coloration of
absent or very weak
absent or very weak


silks


Cob


diameter at mid-point
25.9 mm
23.3 mm



standard deviation:
standard deviation:



1.06
4.02



sample size: 15
sample size: 15


color
5Y 8/4
5Y 8/4


Kernel (dried)


length
10.6 mm
6.7 mm



standard deviation:
standard deviation:



0.93
0.92



sample size: 15
sample size: 15


width
7 mm
7.4 mm



standard deviation:
standard deviation:



1.08
1.01



sample size: 15
sample size: 15


thickness
3.6 mm
4.3 mm



standard deviation:
standard deviation



0.92
0.95



sample size: 15
sample size: 15


% round kernels (shape grade)
3%
1.00%  


aleurone color pattern
homozygous
homozygous


aleurone color
2.5Y8/4
2.5Y8/8


hard endosperm color
2.5Y8/4
2.5Y8/8


endosperm type
sweet (su1)
sweet


weight per 100 kernels
7 gm
9.0 gm


(unsized sample)
sample size: n/a
sample size: n/a


Agronomic Traits


stay green (at 65 days after
8
5


anthesis) (from 1 = worst to


9 = excellent)


dropped ears
0%
0%


% pre-anthesis brittle
0%
0%


snapping


% pre-anthesis root lodging
0%
0%


post-anthesis root lodging
0%
0%





*These are typical values. Values may vary due to environment. Other values that are substantially equivalent are also within the scope of the invention.






C. BREEDING CORN PLANTS
One aspect of the current invention concerns methods for producing seed of sweet corn hybrid SV1580SC involving crossing sweet corn lines SHW817-409 and SYW-6RLAC068. Alternatively, in other embodiments of the invention, hybrid SV1580SC, line SHW817-409, or line SYW-6RLAC068 may be crossed with itself or with any second plant. Such methods can be used for propagation of hybrid SV1580SC and/or the sweet corn lines SHW817-409 and SYW-6RLAC068, or can be used to produce plants that are derived from hybrid SV1580SC and/or the sweet corn lines SHW817-409 and SYW-6RLAC068. Plants derived from hybrid SV1580SC and/or the sweet corn lines SHW817-409 and SYW-6RLAC068 may be used, in certain embodiments, for the development of new corn varieties.
The development of new varieties using one or more starting varieties is well known in the art. In accordance with the invention, novel varieties may be created by crossing hybrid SV1580SC followed by multiple generations of breeding according to such well known methods. New varieties may be created by crossing with any second plant. In selecting such a second plant to cross for the purpose of developing novel lines, it may be desired to choose those plants which either themselves exhibit one or more selected desirable characteristics or which exhibit the desired characteristic(s) when in hybrid combination. Once initial crosses have been made, inbreeding and selection take place to produce new varieties. For development of a uniform line, often five or more generations of selfing and selection are involved.
Uniform lines of new varieties may also be developed by way of double-haploids. This technique allows the creation of true breeding lines without the need for multiple generations of selfing and selection. In this manner true breeding lines can be produced in as little as one generation. Haploid embryos may be produced from microspores, pollen, anther cultures, or ovary cultures. The haploid embryos may then be doubled autonomously, or by chemical treatments (e.g. colchicine treatment). Alternatively, haploid embryos may be grown into haploid plants and treated to induce chromosome doubling. In either case, fertile homozygous plants are obtained. In accordance with the invention, any of such techniques may be used in connection with a plant of the invention and progeny thereof to achieve a homozygous line.
Backcrossing can also be used to improve an inbred plant. Backcrossing transfers a specific desirable trait from one inbred or non-inbred source to an inbred that lacks that trait. This can be accomplished, for example, by first crossing a superior inbred (A) (recurrent parent) to a donor inbred (non-recurrent parent), which carries the appropriate locus or loci for the trait in question. The progeny of this cross are then mated back to the superior recurrent parent (A) followed by selection in the resultant progeny for the desired trait to be transferred from the non-recurrent parent. After five or more backcross generations with selection for the desired trait, the progeny have the characteristic being transferred, but are like the superior parent for most or almost all other loci. The last backcross generation would be selfed to give pure breeding progeny for the trait being transferred.
The plants of the present invention are particularly well suited for the development of new lines based on the elite nature of the genetic background of the plants. In selecting a second plant to cross with SV1580SC and/or sweet corn lines SHW817-409 and SYW-6RLAC068 for the purpose of developing novel corn lines, it will typically be preferred to choose those plants which either themselves exhibit one or more selected desirable characteristics or which exhibit the desired characteristic(s) when in hybrid combination. Examples of desirable traits may include, in specific embodiments, male sterility, herbicide resistance, resistance for bacterial, fungal, or viral disease, insect resistance, male fertility, sugar content, and enhanced nutritional quality.
D. PERFORMANCE CHARACTERISTICS
As described above, hybrid SV1580SC exhibits desirable agronomic traits. The performance characteristics of hybrid SV1580SC were the subject of an objective analysis of the performance traits relative to other varieties. The results of the analysis are presented below.







TABLE 3







Performance data for Hybrid SV1580SC from Georgia PCM3 trials






















PUR
PA
SC_PR
SC_FG
SC_SE
HSC
SC_HE
SC_TF
SC_SH
ELEN
EDIA
KRNLR
QR
SC_FR
























QHW6RH1229
AVG
3.50
3.00
3.89
3.78
3.11
3.22
3.22
3.00
7.83
1.83
16.22
3.11
3.44



STD DEV
0.53
0.00
0.93
0.97
0.33
0.44
0.44
0.00
0.28
0.09
1.20
0.33
0.53



STD ERROR
0.19
0.00
0.31
0.32
0.11
0.15
0.15
0.00
0.09
0.03
0.40
0.11
0.18


SV5074SC
AVG
3.25
3.89
3.67
3.44
3.56
3.11
2.78
3.11
7.36
1.92
17.33
3.22
3.78



STD DEV
0.46
0.78
0.50
0.53
0.73
0.33
0.44
0.33
0.28
0.12
1.00
0.83
0.67



STD ERROR
0.16
0.26
0.17
0.18
0.24
0.11
0.15
0.11
0.09
0.04
0.33
0.28
0.22


SV1580SC
AVG
3.63
3.33
3.33
3.11
4.11
3.11
3.00
3.11
7.83
1.82
16.67
3.44
3.33



STD DEV
0.52
0.50
0.71
0.33
0.60
0.33
0.00
0.33
0.13
0.14
1.41
0.53
0.50



STD ERROR
0.18
0.17
0.24
0.11
0.20
0.11
0.00
0.11
0.04
0.05
0.47
0.18
0.17





All subjective scores are on a 1-9 rating scale with 1 being most preferred and 9 being least preferred


TRAIT EXPLANATION OF TRAIT


PA = Plant type


SC_PR = ease of harvest


SC_FG = flag leaf appearance


SC_SE = appearance of the ear in the husk after harvest


HSC = husk cover


SC_HE = appearance of the ear after husking


SC_TF = tip fill


SC_SH = length of shank


ELEN = ear length of husked ear in inches


EDIA = ear diameter of husked ear in inches


KRNLR = typical kernel row number


SCPFW = overall eating quality


SC_FR = overall rating of the hybrid






E. FURTHER EMBODIMENTS OF THE INVENTION
In certain aspects of the invention, plants described herein are provided modified to include at least a first desired heritable trait. Such plants may, in one embodiment, be developed by a plant breeding technique called backcrossing, wherein essentially all of the morphological and physiological characteristics of a variety are recovered in addition to a genetic locus transferred into the plant via the backcrossing technique. The term single locus converted plant as used herein refers to those corn plants which are developed by a plant breeding technique called backcrossing, wherein essentially all of the morphological and physiological characteristics of a variety are recovered in addition to the single locus transferred into the variety via the backcrossing technique. By essentially all of the morphological and physiological characteristics, it is meant that 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.
Backcrossing methods can be used with the present invention to improve or introduce a characteristic into the present variety. The parental corn plant which contributes the locus for the desired characteristic 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.
In a typical backcross protocol, the original variety of interest (recurrent parent) is crossed to a second variety (nonrecurrent parent) that carries the single 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 morphological and physiological characteristics of the recurrent parent are recovered in the converted plant, in addition to the single transferred locus from the nonrecurrent 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 alter or substitute a single trait or characteristic in the original variety. To accomplish this, a single locus of the recurrent variety 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 variety. 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 trait to the plant. The exact backcrossing protocol will depend on the characteristic or trait being altered and the genetic distance between the recurrent and nonrecurrent parents. Although backcrossing methods are simplified when the characteristic being transferred is a dominant allele, a recessive allele, or an additive allele (between recessive and dominant), 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.
In one embodiment, progeny corn plants of a backcross in which a plant described herein is the recurrent parent comprise (i) the desired trait from the non-recurrent parent and (ii) all of the physiological and morphological characteristics of corn the recurrent parent as determined at the 5% significance level when grown in the same environmental conditions.
New varieties can also be developed from more than two parents. The technique, known as modified backcrossing, uses different recurrent parents during the backcrossing. Modified backcrossing may be used to replace the original recurrent parent with a variety having certain more desirable characteristics or multiple parents may be used to obtain different desirable characteristics from each.
With the development of molecular markers associated with particular traits, it is possible to add additional traits into an established germ line, such as represented here, with the end result being substantially the same base germplasm with the addition of a new trait or traits. Molecular breeding, as described in Moose and Mumm, 2008 (Plant Physiology, 147: 969-977), for example, and elsewhere, provides a mechanism for integrating single or multiple traits or QTL into an elite line. This molecular breeding-facilitated movement of a trait or traits into an elite line may encompass incorporation of a particular genomic fragment associated with a particular trait of interest into the elite line by the mechanism of identification of the integrated genomic fragment with the use of flanking or associated marker assays. In the embodiment represented here, one, two, three or four genomic loci, for example, may be integrated into an elite line via this methodology. When this elite line containing the additional loci is further crossed with another parental elite line to produce hybrid offspring, it is possible to then incorporate at least eight separate additional loci into the hybrid. These additional loci may confer, for example, such traits as a disease resistance or a fruit quality trait. In one embodiment, each locus may confer a separate trait. In another embodiment, loci may need to be homozygous and exist in each parent line to confer a trait in the hybrid. In yet another embodiment, multiple loci may be combined to confer a single robust phenotype of a desired trait.
Many single locus traits have been identified that are not regularly selected for in the development of a new inbred but that can be improved by backcrossing techniques. Single locus traits may or may not be transgenic; examples of these traits include, but are not limited to, male sterility, waxy starch, herbicide resistance, resistance for bacterial, fungal, or viral disease, insect resistance, sugar content, 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 the single locus acts as a dominant trait. For this selection process, the progeny of the initial cross are assayed for viral resistance and/or the presence of the corresponding gene prior to the backcrossing. Selection eliminates any plants that do not have the desired gene and resistance trait, and only those plants that have the trait are used in the subsequent backcross. This process is then repeated for all additional backcross generations.
Selection of corn plants for breeding is not necessarily dependent on the phenotype of a plant and instead can be based on genetic investigations. For example, one can utilize a suitable genetic marker which is closely genetically linked to a trait of interest. One of these markers can be used to identify the presence or absence of a trait in the offspring of a particular cross, and can be used in selection of progeny for continued breeding. This technique is commonly referred to as marker assisted selection. Any other type of genetic marker or other assay which is able to identify the relative presence or absence of a trait of interest in a plant can also be useful for breeding purposes. Procedures for marker assisted selection are well known in the art. Such methods will be of particular utility in the case of recessive traits and variable phenotypes, or where conventional assays may be more expensive, time consuming or otherwise disadvantageous. Types of genetic markers which could be used in accordance with the invention include, but are not necessarily limited to, Simple Sequence Length Polymorphisms (SSLPs) (Williams et al., Nucleic Acids Res., 1 8:6531-6535, 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., Science, 280:1077-1082, 1998).
F. PLANTS DERIVED BY GENETIC ENGINEERING
Many useful traits that can be introduced by backcrossing, as well as directly into a plant, are those which are introduced by genetic transformation techniques. Genetic transformation may therefore be used to insert a selected transgene into a plant of the invention or may, alternatively, be used for the preparation of transgenes which can be introduced by backcrossing. Methods for the transformation of plants that are well known to those of skill in the art and applicable to many crop species include, but are not limited to, electroporation, microprojectile bombardment, Agrobacterium-mediated transformation and direct DNA uptake by protoplasts.
To effect transformation by electroporation, one may employ either friable tissues, such as a suspension culture of cells or embryogenic callus or alternatively one may transform immature embryos or other organized tissue directly. In this technique, one would partially degrade the cell walls of the chosen cells by exposing them to pectin-degrading enzymes (pectolyases) or mechanically wound tissues in a controlled manner.
An efficient method for delivering transforming DNA segments to plant cells is microprojectile bombardment. In this method, particles are coated with nucleic acids and delivered into cells by a propelling force. Exemplary particles include those comprised of tungsten, platinum, and preferably, gold. For the bombardment, cells in suspension are concentrated on filters or solid culture medium. Alternatively, immature embryos or other target cells may be arranged on solid culture medium. The cells to be bombarded are positioned at an appropriate distance below the macroprojectile stopping plate.
An illustrative embodiment of a method for delivering DNA into plant cells by acceleration is the Biolistics Particle Delivery System, which can be used to propel particles coated with DNA or cells through a screen, such as a stainless steel or Nytex screen, onto a surface covered with target cells. The screen disperses the particles so that they are not delivered to the recipient cells in large aggregates. Microprojectile bombardment techniques are widely applicable, and may be used to transform virtually any plant species.
Agrobacterium-mediated transfer is another widely applicable system for introducing gene loci into plant cells. An advantage of the technique is that DNA can be introduced into whole plant tissues, thereby bypassing the need for regeneration of an intact plant from a protoplast. Modern Agrobacterium transformation vectors are capable of replication in E. coli as well as Agrobacterium, allowing for convenient manipulations (Klee et al., Bio-Technology, 3(7):637-642, 1985). Moreover, recent technological advances in vectors for Agrobacterium-mediated gene transfer have improved the arrangement of genes and restriction sites in the vectors to facilitate the construction of vectors capable of expressing various polypeptide coding genes. The vectors described have convenient multi-linker regions flanked by a promoter and a polyadenylation site for direct expression of inserted polypeptide coding genes. Additionally, Agrobacterium containing both armed and disarmed Ti genes can be used for transformation.
In those plant strains where Agrobacterium-mediated transformation is efficient, it is the method of choice because of the facile and defined nature of the gene locus transfer. The use of Agrobacterium-mediated plant integrating vectors to introduce DNA into plant cells is well known in the art (Fraley et al., Bio/Technology, 3:629-635, 1985; U.S. Pat. No. 5,563,055).
Transformation of plant protoplasts also can be achieved using methods based on calcium phosphate precipitation, polyethylene glycol treatment, electroporation, and combinations of these treatments (see, e.g., Potrykus et al., Mol. Gen. Genet., 199:183-188, 1985; Omirulleh et al., Plant Mol. Biol., 21(3):415-428, 1993; Fromm et al., Nature, 312:791-793, 1986; Uchimiya et al., Mol. Gen. Genet., 204:204, 1986; Marcotte et al., Nature, 335:454, 1988). Transformation of plants and expression of foreign genetic elements is exemplified in Choi et al. (Plant Cell Rep., 13: 344-348, 1994), and Ellul et al. (Theor. Appl. Genet., 107:462-469, 2003).
A number of promoters have utility for plant gene expression for any gene of interest including but not limited to selectable markers, scoreable markers, genes for pest tolerance, disease resistance, nutritional enhancements and any other gene of agronomic interest. Examples of constitutive promoters useful for plant gene expression include, but are not limited to, the cauliflower mosaic virus (CaMV) P-35S promoter, which confers constitutive, high-level expression in most plant tissues (see, e.g., Odel et al., Nature, 313:810, 1985), including in monocots (see, e.g., Dekeyser et al., Plant Cell, 2:591, 1990; Terada and Shimamoto, Mol. Gen. Genet., 220:389, 1990); a tandemly duplicated version of the CaMV 35S promoter, the enhanced 35S promoter (P-e35S); 1 the nopaline synthase promoter (An et al., Plant Physiol., 88:547, 1988); the octopine synthase promoter (Fromm et al., Plant Cell, 1:977, 1989); and the figwort mosaic virus (P-FMV) promoter as described in U.S. Pat. No. 5,378,619 and an enhanced version of the FMV promoter (P-eFMV) where the promoter sequence of P-FMV is duplicated in tandem; the cauliflower mosaic virus 19S promoter; a sugarcane bacilliform virus promoter; a commelina yellow mottle virus promoter; and other plant DNA virus promoters known to express in plant cells.
A variety of plant gene promoters that are regulated in response to environmental, hormonal, chemical, and/or developmental signals can also be used for expression of an operably linked gene in plant cells, including promoters regulated by (1) heat (Callis et al., Plant Physiol., 88:965, 1988), (2) light (e.g., pea rbcS-3A promoter, Kuhlemeier et al., Plant Cell, 1:471, 1989; maize rbcS promoter, Schaffner and Sheen, Plant Cell, 3:997, 1991; or chlorophyll a/b-binding protein promoter, Simpson et al., EMBO J., 4:2723, 1985), (3) hormones, such as abscisic acid (Marcotte et al., Plant Cell, 1:969, 1989), (4) wounding (e.g., wunl, Siebertz et al., Plant Cell, 1:961, 1989); or (5) chemicals such as methyl jasmonate, salicylic acid, or Safener. It may also be advantageous to employ organ-specific promoters (e.g., Roshal et al., EMBO J., 6:1155, 1987; Schernthaner et al., EMBO J., 7:1249, 1988; Bustos et al., Plant Cell, 1:839, 1989).
Exemplary nucleic acids which may be introduced to plants of this invention include, for example, DNA sequences or genes from another species, or even genes or sequences which originate with or are present in the same species, but are incorporated into recipient cells by genetic engineering methods rather than classical reproduction or breeding techniques. However, the term “exogenous” is also intended to refer to genes that are not normally present in the cell being transformed, or perhaps simply not present in the form, structure, etc., as found in the transforming DNA segment or gene, or genes which are normally present and that one desires to express in a manner that differs from the natural expression pattern, e.g., to over-express. Thus, the term “exogenous” gene or DNA is intended to refer to any gene or DNA segment that is introduced into a recipient cell, regardless of whether a similar gene may already be present in such a cell. The type of DNA included in the exogenous DNA can include DNA which is already present in the plant cell, DNA from another plant, DNA from a different organism, or a DNA generated externally, such as a DNA sequence containing an antisense message of a gene, or a DNA sequence encoding a synthetic or modified version of a gene.
Many hundreds if not thousands of different genes are known and could potentially be introduced into a corn plant according to the invention. Non-limiting examples of particular genes and corresponding phenotypes one may choose to introduce into a corn plant include one or more genes for insect tolerance, such as a Bacillus thuringiensis (B.t.) gene, pest tolerance such as genes for fungal disease control, herbicide tolerance such as genes conferring glyphosate tolerance, and genes for quality improvements such as yield, nutritional enhancements, environmental or stress tolerances, or any desirable changes in plant physiology, growth, development, morphology or plant product(s). For example, structural genes would include any gene that confers insect tolerance including but not limited to a Bacillus insect control protein gene as described in WO 99/31248, herein incorporated by reference in its entirety, U.S. Pat. No. 5,689,052, herein incorporated by reference in its entirety, U.S. Pat. Nos. 5,500,365 and 5,880,275, herein incorporated by reference in their entirety. In another embodiment, the structural gene can confer tolerance to the herbicide glyphosate as conferred by genes including, but not limited to Agrobacterium strain CP4 glyphosate resistant EPSPS gene (aroA:CP4) as described in U.S. Pat. No. 5,633,435, herein incorporated by reference in its entirety, or glyphosate oxidoreductase gene (GOX) as described in U.S. Pat. No. 5,463,175, herein incorporated by reference in its entirety.
Alternatively, the DNA coding sequences can affect these phenotypes by encoding a non-translatable RNA molecule that causes the targeted inhibition of expression of an endogenous gene, for example via antisense- or cosuppression-mediated mechanisms (see, for example, Bird et al., Biotech. Gen. Engin. Rev., 9:207, 1991). The RNA could also be a catalytic RNA molecule (i.e., a ribozyme) engineered to cleave a desired endogenous mRNA product (see for example, Gibson and Shillito, Mol. Biotech., 7:125, 1997). Thus, any gene which produces a protein or mRNA which expresses a phenotype or morphology change of interest is useful for the practice of the present invention.
G. DEFINITIONS
In the description and tables herein, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, the following definitions are provided:
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, for example a first generation hybrid (F1), back to one of the parents of the hybrid progeny. Backcrossing can be used to introduce one or more single locus conversions from one genetic background into another.
Crossing: The mating of two parent plants.
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 cytoplasmic or nuclear genetic factor or a chemical agent conferring male sterility.
Enzymes: Molecules which can act as catalysts in biological reactions.
F1 Hybrid: The first generation progeny of the cross of two nonisogenic plants.
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.
Linkage: A phenomenon wherein alleles on the same chromosome tend to segregate together more often than expected by chance if their transmission was independent.
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): Quantitative trait loci (QTL) refer to genetic loci that control to some degree numerically representable traits that are usually continuously distributed.
Resistance: As used herein, the terms “resistance” and “tolerance” are used interchangeably to describe plants that show no symptoms to a specified biotic pest, pathogen, abiotic influence or environmental condition. These terms are also used to describe plants showing some symptoms but that are still able to produce marketable product with an acceptable yield. Some plants that are referred to as resistant or tolerant are only so in the sense that they may still produce a crop, even though the plants are stunted and the yield is reduced.
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 morphological and physiological characteristics of a corn variety are recovered in addition to the characteristics of the single locus transferred into the variety via the backcrossing technique and/or by genetic transformation.
Substantially Equivalent: A characteristic that, when compared, does not show a statistically significant difference (e.g., p=0.05) from the mean.
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 locus comprising a sequence which has been introduced into the genome of a corn plant by transformation.
H. DEPOSIT INFORMATION
A deposit of sweet corn hybrid SV1580SC and parent line SYW-6RLAC068, disclosed above and recited in the claims, has been made with the American Type Culture Collection (ATCC), 10801 University Blvd., Manassas, Va. 20110-2209. The date of the deposit was Mar. 10, 2014. The accession numbers for those deposited seeds of sweet corn hybrid SV1580SC and parent line SYW-6RLAC068 are ATCC Accession Number PTA-121074 and ATCC Accession Number PTA-121077, respectively. Upon issuance of a patent, all restrictions upon the deposits will be removed, and the deposits are intended to meet all of the requirements of 37 C.F.R. §1.801-1.809. The deposits will be maintained in the depository for a period of 30 years, or 5 years after the last request, or for the effective life of the patent, whichever is longer, and will be replaced if necessary during that period.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims.
All references cited herein are hereby expressly incorporated herein by reference.

## Claims

1. A corn plant comprising at least a first set of the chromosomes of corn line SYW-6RLAC068, a sample of seed of said line having been deposited under ATCC Accession Number PTA-121077.

2. A seed comprising at least a first set of the chromosomes of corn line SYW-6RLAC068, a sample of seed of said line having been deposited under ATCC Accession Number PTA-121077.

3. The plant of claim 1, which is an inbred.

4. The plant of claim 1, which is a hybrid.

5. The seed of claim 2, which is an inbred.

6. The seed of claim 2, which is a hybrid.

7. The plant of claim 4, wherein the hybrid plant is corn hybrid SV1580SC, a sample of seed of said hybrid SV1580SC having been deposited under ATCC Accession Number PTA-121074.

8. The seed of claim 6, defined as a seed of corn hybrid SV1580SC, a sample of seed of said hybrid SV1580SC having been deposited under ATCC Accession Number PTA-121074.

9. The seed of claim 2, defined as a seed of line SYW-6RLAC068.

10. A plant part of the plant of claim 1.

11. The plant part of claim 10, further defined as an ear, ovule, pollen or cell.

12. A corn plant having all the physiological and morphological characteristics of the corn plant of claim 7.

13. A tissue culture of regenerable cells of the plant of claim 1.

14. The tissue culture according to claim 13, comprising cells or protoplasts from a plant part selected from the group consisting of leaf, pollen, embryo, root, root tip, anther, silk, flower, kernel, ear, cob, husk, stalk and meristem.

15. A corn plant regenerated from the tissue culture of claim 13, wherein said plant otherwise comprises all of the morphological and physiological characteristics of the corn plant comprising at least a first set of the chromosomes of corn line SYW-6RLAC068, a sample of seed of said line having been deposited under ATCC Accession Number PTA-121077 when grown under the same environmental conditions.

16. A method of vegetatively propagating the plant of claim 1 comprising the steps of:
(a) collecting tissue capable of being propagated from a plant according to claim 1;
(b) cultivating said tissue to obtain proliferated shoots; and
(c) rooting said proliferated shoots to obtain rooted plantlets.

17. The method of claim 16, further comprising growing at least a first plant from said rooted plantlets.

18. A method of introducing a desired trait into a corn line comprising:
(a) utilizing as a recurrent parent, a plant of corn line SYW-6RLAC068, by crossing a plant of line SYW-6RLAC068 with a second corn plant that comprises a desired trait to produce F1 progeny, a sample of seed of said line having been deposited under ATCC Accession Number PTA-121077;
(b) selecting an F1 progeny that comprises the desired trait;
(c) backcrossing the selected F1 progeny with a plant of line SYW-6RLAC068 to produce backcross progeny;
(d) selecting backcross progeny comprising the desired trait and the physiological and morphological characteristic of corn line SYW-6RLAC068; and
(e) repeating steps (c) and (d) three or more times to produce selected fourth or higher backcross progeny that comprise the desired trait.

19. A corn plant produced by the method of claim 18.

20. A method of producing a plant comprising an added trait, the method comprising introducing a transgene conferring the trait into a plant of hybrid SV1580SC, or line SYW-6RLAC068, a sample of seed of said hybrid and line having been deposited under ATCC Accession Number PTA-121074, and ATCC Accession Number PTA-121077, respectively.

21. A plant produced by the method of claim 20.

22. The plant of claim 1, further comprising a transgene.

23. The plant of claim 22, wherein the transgene confers a trait selected from the group consisting of male sterility, herbicide tolerance, insect resistance, pest resistance, disease resistance, modified fatty acid metabolism, environmental stress tolerance, modified carbohydrate metabolism and modified protein metabolism.

24. The plant of claim 1, further comprising a single locus conversion, wherein said plant otherwise comprises essentially all of the morphological and physiological characteristics of the corn plant comprising at least a first set of the chromosomes of corn line SYW-6RLAC068, a sample of seed of said line having been deposited under ATCC Accession Number PTA-121077 when grown under the same environmental conditions.

25. The plant of claim 24, wherein the single locus conversion confers a trait selected from the group consisting of male sterility, herbicide tolerance, insect resistance, pest resistance, disease resistance, modified fatty acid metabolism, environmental stress tolerance, modified carbohydrate metabolism and modified protein metabolism.

26. A method for producing a seed of a plant derived from at least one of hybrid SV1580SC, or line SYW-6RLAC068 comprising the steps of:
(a) crossing a corn plant of hybrid SV1580SC, or line SYW-6RLAC068 with itself or a second corn plant; a sample of seed of said hybrid and line having been deposited under ATCC Accession Number PTA-121074, and ATCC Accession Number PTA-121077, respectively; and
(b) allowing seed of a hybrid SV1580SC, or line SYW-6RLAC068-derived corn plant to form.

27. The method of claim 26, further comprising the steps of:
(c) selfing a plant grown from said hybrid SV1580SC, or SYW-6RLAC068-derived corn seed to yield additional hybrid SV1580SC, or line SYW-6RLAC068-derived corn seed;
(d) growing said additional hybrid SV1580SC, or line SYW-6RLAC068-derived corn seed of step (c) to yield additional hybrid SV1580SC, or line SYW-6RLAC068-derived corn plants; and
(e) repeating the crossing and growing steps of (c) and (d) to generate at least a first further hybrid SV1580SC, or line SYW-6RLAC068-derived corn plant.

28. The method of claim 26, wherein the second corn plant is of an inbred corn line.

29. The method of claim 27, further comprising:
(f) crossing the further hybrid SV1580SC, or SYW-6RLAC068-derived corn plant with a second corn plant to produce seed of a hybrid progeny plant.

30. A plant part of the plant of claim 7.

31. The plant part of claim 30, further defined as a fruit, a ovule, pollen, a leaf, or a cell.

32. A method of producing a corn seed comprising crossing the plant of claim 1 with itself or a second corn plant and allowing seed to form.

33. A method of producing an ear of corn comprising:
(a) obtaining a plant according to claim 1, wherein the plant has been cultivated to maturity; and
(b) collecting an ear of corn from the plant.