Maize hybrid variety X5T123 Number:7,521,610 from the United States Patent and Trademark Office (PTO) owispatent

Title: Maize hybrid variety X5T123

Abstract: A novel hybrid maize variety designated X5T123 and seed, plants and plant parts thereof, produced by crossing Pioneer Hi-Bred International, Inc. proprietary inbred maize varieties. Methods for producing a maize plant that comprises crossing hybrid maize variety X5T123 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into X5T123 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. This invention relates to the maize hybrid_variety X5T123, the hybrid seed, the hybrid plant produced from the seed, and variants, mutants, and minor modifications of hybrid maize variety X5T123. This invention further relates to methods for producing maize varieties derived from hybrid maize variety X5T123 and to the maize varieties derived by the use of those methods.

Patent Number: 7,521,610 Issued on 04/21/2009 to Pinnisch

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Inventors:	Pinnisch; Russel Miles (Machesney Park, IL)
Assignee:	Pioneer Hi-Bred International, Inc. (Johnston, IA)
Appl. No.:	11/669,211
Filed:	January 31, 2007

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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); C07H 21/04 (20060101); C12N 15/00 (20060101); C07K 14/415 (20060101)
Field of Search:	435/468,412,418,424 530/370 536/23.1 800/320.1,260,278,303

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References Cited [Referenced By]

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U.S. Patent Documents

6891090	May 2005	Weber
7112728	September 2006	Kramer
7235723	June 2007	Wilson
2006/0107415	May 2006	Garcia et al.

Primary Examiner: Bui; Phuong T
Attorney, Agent or Firm: McKee, Voorhees & Sease, P.L.C.

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Claims

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What is claimed is:

1. A maize variety X5T123, produced by crossing a first plant of variety GE3288530 with a second plant of variety GE24918222, wherein representative seed of said varieties GE3288530 and GE24918222 have been deposited under ATCC Accession Number PTA-9619 and PTA-9620, respectively.

2. A seed of the maize variety of claim 1.

3. A plant of the maize variety of claim 1.

4. A plant part of the maize variety of claim 1.

5. Pollen of the plant of claim 3.

6. An ovule or ovules of the plant of claim 3.

7. The seed of claim 2, further comprising a transgene.

8. The seed of claim 7, wherein the transgene confers a trait selected from the group consisting of male sterility, site-specific recombination, abiotic stress tolerance, altered phosphorus, altered antioxidants, altered fatty acids, altered essential amino acids, altered carbohydrates, herbicide resistance, insect resistance and disease resistance.

9. The plant of claim 3, further comprising a transgene.

10. The plant of claim 9, wherein the transgene confers a trait selected from the group consisting of selected from the group consisting of male sterility, site-specific recombination, abiotic stress tolerance, altered phosphorus, altered antioxidants, altered fatty acids, altered essential amino acids, altered carbohydrates, herbicide resistance, insect resistance and disease resistance.

11. A process for producing a maize seed, comprising crossing the plant of claim 3 with itself or a different maize plant and harvesting the resultant maize seed.

12. The process of claim 11, wherein said different maize plant is a haploid inducer.

13. The process of claim 11, further comprising of producing an inbred corn plant derived from maize variety X5T123, the method further comprising the steps of: (a) planting the resultant maize seed to produce at least one progeny plant derived from maize variety X5T123; (b) crossing the progeny plant with itself or a second plant to produce seed of a progeny plant of a subsequent generation; (c) growing a progeny plant of a subsequent generation from said maize seed and crossing the progeny plant of a subsequent generation with itself or a second plant; and (d) repeating steps (b) and (c) for an additional 3-10 generations to produce an inbred corn plant derived from the maize variety X5T123.

14. A process of producing a conversion of maize variety X5T123 comprising at least one new trait, the process comprising: (a) crossing a first maize inbred variety parent plant selected from the group consisting of variety GE3288530 and variety GE24918222, representative seed of which have been deposited under ATCC Accession Number(s) as PTA-9619 and PTA-9620 respectively, with plants of another maize variety that comprise at least one new trait to produce F1 seed,; (b) harvesting and planting the F1 seed to produce at least one progeny plant of the F1 generation, said progeny plant comprising the at least one new trait; (c) crossing the at least one progeny plant with said maize inbred variety parent plant to produce backcross progeny seed; (d) harvesting and planting the backcross progeny seed to produce at least one backcross progeny plant, said backcross progeny plant comprising the at least one new trait; (e) repeating steps (c) and (d) for at least three additional generations to produce at least a first progeny plant, wherein said first progeny plant comprises the at least one new trait; (f) crossing the progeny plant of step (e) with a plant of the other maize inbred variety of the group consisting of variety GE3288530 and variety GE24918222 to produce a seed that produces a converted plant of variety X5T123, wherein the converted plant of variety X5T 123 comprises the at least one new trait.

15. The process of claim 14, wherein the at least one new trait is selected from the group consisting of male sterility, site-specific recombination, increased transformability, abiotic stress tolerance, herbicide resistance, insect resistance, resistance to bacterial, fungal, nematode or viral disease, altered phosphorus, altered antioxidants, altered fatty acids, altered essential amino acids and altered carbohydrates.

16. The process of claim 14, further comprising repeating steps (a)-(f) at least once to introduce at least a second trait into corn variety X5T123, wherein the second trait is selected from the group consisting of male sterility, site-specific recombination, increased transformability, abiotic stress tolerance, herbicide resistance, insect resistance, resistance to bacterial, fungal, nematode or viral disease, altered phosphorus, altered antioxidants, altered fatty acids, altered essential amino acids and altered carbohydrates.

17. A converted seed produced by the process of claim 14.

18. A converted plant produced from the seed of claim 17.

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Description

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FIELD OF THE INVENTION

This invention relates generally to the field of maize breeding, specifically relating to hybrid maize designated X5T123.

BACKGROUND OF THE INVENTION

The goal of hybrid development is to combine, in a single hybrid, various desirable traits. For field crops, these traits may include resistance to diseases and insects, resistance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality. With mechanical harvesting of many crops, uniformity of plant characteristics such as germination, stand establishment, growth rate, maturity, and plant and ear height is important. Traditional plant breeding is an important tool in developing new and improved commercial crops.

SUMMARY OF THE INVENTION

According to the invention, there is provided a maize hybrid variety, seed, plant, and its parts designated as X5T123, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary maize inbred varieties. This invention relates to the maize hybrid X5T123, the hybrid seed, the hybrid plant and its parts produced from the seed, and variants, mutants and minor modifications of maize hybrid X5T123. This invention also relates to processes for making a maize plant containing in its genetic material one or more traits introgressed into X5T123 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced by such introgression. This invention further relates to methods for producing maize varieties derived from hybrid maize X5T123 and to the maize varieties produced by the use of those processes. This maize hybrid variety is characterized by high grain yield and very good agronomics.

Definitions

Certain definitions used in the specification are provided below. Also in the examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. NOTE: ABS is in absolute terms and %MN is percent of the mean for the experiments in which the inbred or hybrid was grown. PCT designates that the trait is calculated as a percentage. %NOT designates the percentage of plants that did not exhibit a trait. For example, STKLDG %NOT is the percentage of plants in a plot that were not stalk lodged. These designators will follow the descriptors to denote how the values are to be interpreted. Below are the descriptors used in the data tables included herein.

ABIOTIC STRESS TOLERANCE. Resistance to non-biological sources of stress conferred by traits such as nitrogen utilization efficiency, altered nitrogen responsiveness, drought resistance cold, and salt resistance.

ABTSTK=ARTIFICIAL BRITTLE STALK. A count of the number of "snapped" plants per plot following machine snapping. A snapped plant has its stalk completely snapped at a node between the base of the plant and the node above the ear. Expressed as percent of plants that did not snap.

ADF=PERCENT ACID DETERGENT FIBER. The percent of dry matter that is acid detergent fiber in chopped whole plant forage.

ALLELE. Any of one or more alternative forms of a genetic sequence. In a diploid cell or organism, the two alleles of a given sequence typically occupy corresponding loci on a pair of homologous chromosomes.

ALTER. The utilization of up-regulation, down-regulation, or gene silencing.

ANTHESIS. The time of a flower's opening.

ANTIOXIDANT. A chemical compound or substance that inhibits oxidation, including but not limited to tocopherol or tocotrienols.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9 visual rating indicating the resistance to Anthracnose Stalk Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

BACKCROSSING. Process in which a breeder crosses a hybrid progeny variety back to one of the parental genotypes one or more times.

BACKCROSS PROGENY. Progeny plants produced by crossing a maize inbred parent of X5T123 plant parts with plant parts of another maize line that comprise a desired trait or locus, selecting F1 progeny plants that comprise the desired trait or locus, and crossing the selected F1 progeny plants with the X5T123 plants 1 or more times to produce backcross progeny plants that comprise said trait or locus.

BARPLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BORBMN=ARTIFICIAL BRITTLE STALK MEAN. The mean percent of plants not "snapped" in a plot following artificial selection pressure. A snapped plant has its stalk completely snapped at a node between the base of the plant and the node above the ear. Expressed as percent of plants that did not snap. A high number is good and indicates tolerance to brittle snapping.

BRENGMN=BRITTLE STALK ENERGY MEAN. The mean amount of energy per unit area needed to artificially brittle snap a corn stalk. A high number is good and indicates tolerance to brittle snapping.

BREEDING. The genetic manipulation of living organisms.

BREEDING CROSS. A cross to introduce new genetic material into a plant for the development of a new variety. For example, one could cross plant A with plant B, wherein plant B would be genetically different from plant A. After the breeding cross, the resulting F1 plants could then be selfed or sibbed for one, two, three or more times (F1, F2, F3, etc.) until a new inbred variety is developed. For clarification, such new inbred variety would be within a pedigree distance of one breeding cross of plants A and B. The process described above would be referred to as one breeding cycle.

BRLPNE=ARTIFICIAL ROOT LODGING EARLY SEASON. The percent of plants not root lodged in a plot following artificial selection pressure applied prior to flowering. A plant is considered root lodged if it leans from the vertical axis at an approximately 30 degree angle or greater. Expressed as percent of plants that did not root lodge. A high number is good and indicates tolerance to root lodging.

BRLPNL=ARTIFICIAL ROOT LODGING LATE SEASON. The percent of plants not root lodged in a plot following artificial selection pressure during grain fill. A plant is considered root lodged if it leans from the vertical axis at an approximately 30 degree angle or greater. Expressed as percent of plants that did not root lodge. A high number is good and indicates tolerance to root lodging.

BRTSTK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap. Data are collected only when sufficient selection pressure exists in the experiment measured.

CARBOHYDRATE. Organic compounds comprising carbon, oxygen and hydrogen, including sugars, starches and cellulose.

CELL. Cell as used herein includes a plant cell, whether isolated, in tissue culture or incorporated in a plant or plant part.

CLDTST=COLD TEST. The percent of plants that germinate under cold test conditions.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chlorotic mottle virus (MCMV) in combination with either maize dwarf mosaic virus (MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visual rating indicating the resistance to Corn Lethal Necrosis. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

COMRST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicating the resistance to Common Rust. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

CP=PERCENT OF CRUDE PROTEIN. The percent of dry matter that is crude protein in chopped whole plant forage.

CROSS POLLINATION. A plant is cross pollinated if the pollen comes from a flower on a different plant from a different family or variety. Cross pollination excludes sib and self pollination.

CROSSING. The combination of genetic material by traditional methods such as a breeding cross or backcross, but also including protoplast fusion and other molecular biology methods of combining genetic material from two sources.

CRWNIS=CORN ROOTWORM NODE INJURY SCALE (Diabrotica sp.). A 0-3 visual rating based on the proportion of roots pruned by corn rootworm larvae to less than 1.5 inches of the crown. 0 indicates no feeding, 3 indicates a total of 3 entire nodes of roots pruned.

D/D=DRYDOWN. This represents the relative rate at which a hybrid will reach acceptable harvest moisture compared to other hybrids on a 1 to 9 rating scale. A high score indicates a hybrid that dries relatively fast while a low score indicates a hybrid that dries slowly.

DIPERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodia macrospora). A 1 to 9 visual rating indicating the resistance to Diplodia Ear Mold. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

DIPLOID PLANT PART. Refers to a plant part or cell that has the same diploid genotype as X5T123.

DIPROT=DIPLODIA STALK ROT SCORE. Score of stalk rot severity due to Diplodia (Diplodia maydis). Expressed as a 1 to 9 score with 9 being highly resistant. Data are collected only when sufficient selection pressure exists in the experiment measured.

DM=PERCENT OF DRY MATTER. The percent of dry material in chopped whole plant silage.

DRPEAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest. Data are collected only when sufficient selection pressure exists in the experiment measured.

D/T=DROUGHT TOLERANCE. This represents a 1 to 9 rating for drought tolerance, and is based on data obtained under stress conditions. A high score indicates good drought tolerance and a low score indicates poor drought tolerance. Data are collected only when sufficient selection pressure exists in the experiment measured.

EARHT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in centimeters.

EARMLD=GENERAL EAR MOLD. Visual rating (1 to 9 score) where a 1 is very susceptible and a 9 is very resistant. This is based on overall rating for ear mold of mature ears without determining the specific mold organism, and may not be predictive for a specific ear mold. Data are collected only when sufficient selection pressure exists in the experiment measured.

EARSZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

EBTSTK=EARLY BRITTLE STALK. A count of the number of "snapped" plants per plot following severe winds when the corn plant is experiencing very rapid vegetative growth in the V5-V8 stage. Expressed as percent of plants that did not snap. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinia nubilalis). A 1 to 9 visual rating indicating the resistance to preflowering leaf feeding by first generation European Corn Borer. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB21T=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING (Ostrinia nubilalis). Average inches of tunneling per plant in the stalk. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECB2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1 to 9 visual rating indicating post flowering degree of stalk breakage and other evidence of feeding by second generation European Corn Borer. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECBDPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Dropped ears due to European Corn Borer. Percentage of plants that did not drop ears under second generation European Corn Borer infestation. Data are collected only when sufficient selection pressure exists in the experiment measured.

ECBLSI=EUROPEAN CORN BORER LATE SEASON INTACT (Ostrinia nubilalis). A 1 to 9 visual rating indicating late season intactness of the corn plant given damage (stalk breakage above and below the top ear) caused primarily by 2.sup.nd and/or 3.sup.rd generation ECB larval feeding before harvest. A higher score is good and indicates more intact plants. Data are collected only when sufficient selection pressure exists in the experiment measured.

EGRWTH=EARLY GROWTH. This is a measure of the relative height and size of a corn seedling at the 2-4 leaf stage of growth. This is a visual rating (1 to 9), with 1 being weak or slow growth, 5 being average growth and 9 being strong growth. Taller plants, wider leaves, more green mass and darker color constitute a higher score. Data are collected only when sufficient selection pressure exists in the experiment measured.

ELITE INBRED. An inbred that contributed desirable qualities when used to produce commercial hybrids. An elite inbred may also be used in further breeding for the purpose of developing further improved varieties.

ERTLDG=EARLY ROOT LODGING. The percentage of plants that do not root lodge prior to or around anthesis; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

ERTLPN=EARLY ROOT LODGING. An estimate of the percentage of plants that do not root lodge prior to or around anthesis; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be considered as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

ERTLSC=EARLY ROOT LODGING SCORE. Score for severity of plants that lean from a vertical axis at an approximate 30 degree angle or greater which typically results from strong winds prior to or around flowering recorded within 2 weeks of a wind event. Expressed as a 1 to 9 score with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

ESSENTIAL AMINO ACIDS. Amino acids that cannot be synthesized de novo by an organism and therefore must be supplied in the diet.

ESTCNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on a per plot basis for the inbred or hybrid.

EYESPT=EYE SPOT (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visual rating indicating the resistance to Eye Spot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

EXPRESSING. Having the genetic potential such that under the right conditions, the phenotypic trait is present.

FATTY ACID. A carboxylic acid (or organic acid), often with a long aliphatic tail (long chains), either saturated or unsaturated.

F1 PROGENY. Progeny plants produced by crossing plant parts of maize variety X5T123 with plant parts of another maize line.

FUSERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusarium subglutinans). A 1 to 9 visual rating indicating the resistance to Fusarium Ear Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, which assumes that maize growth occurs in the temperature range 50 degrees F.-86 degrees F. and that temperatures outside this range slow down growth; the maximum daily heat unit accumulation is 36 and the minimum daily heat unit accumulation is 0. The seasonal accumulation of GDU is a major factor in determining maturity zones.

GDUSHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred variety or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are:

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The highest maximum temperature used is 86 degrees F. and the lowest minimum temperature used is 50 degrees F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDUSLK=GDU TO SILK. The number of growing degree units required for an inbred variety or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GENE SILENCING. The interruption or suppression of the expression of a gene at the level of transcription or translation.

GENOTYPE. Refers to the genetic constitution of a cell or organism.

GIBERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visual rating indicating the resistance to Gibberella Ear Rot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GIBROT=GIBBERELLA STALK ROT SCORE. Score of stalk rot severity due to Gibberella (Gibberella zeae). Expressed as a 1 to 9 score with 9 being highly resistant. Data are collected only when sufficient selection pressure exists in the experiment measured.

GLFSPT=GRAY LEAF SPOT (Cercospora zeae-maydis). A 1 to 9 visual rating indicating the resistance to Gray Leaf Spot. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GOSWLT=GOSS' WILT (Corynebacterium nebraskense). A 1 to 9 visual rating indicating the resistance to Goss' Wilt. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

GRNAPP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plant densities on a 1 to 9 relative rating system with a higher number indicating the hybrid responds well to high plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to increased plant density.

HAPLOID PLANT PART. Refers to a plant part or cell that has the same haploid genotype as X5T123.

HCBLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum). A 1 to 9 visual rating indicating the resistance to Helminthosporium infection. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates the percentage of plants not infected. Data are collected only when sufficient selection pressure exists in the experiment measured.

HSKCVR=HUSK COVER. A 1 to 9 score based on performance relative to key checks, with a score of 1 indicating very short husks, tip of ear and kernels showing; 5 is intermediate coverage of the ear under most conditions, sometimes with thin husk; and a 9 has husks extending and closed beyond the tip of the ear. Scoring can best be done near physiological maturity stage or any time during dry down until harvested.

HYBRID VARIETY. A substantially heterozygous hybrid and minor genetic modifications thereof that retain the overall genetics of the hybrid including but not limited to a locus conversion, a mutation, or a somoclonal variant.

INBRED. A variety developed through inbreeding or doubled haploidy that preferably comprises homozygous alleles at about 95% or more of its loci.

INBRED VARIETY. A substantially homozygous inbred line and minor modifications thereof that retain the overall genetics of the inbred line including but not limited to a locus conversion, a mutation, or a somoclonal variant.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acre assuming drying costs of two cents per point above 15.5 percent harvest moisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybrid on per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. Gross income advantage of variety #1 over variety #2.

INTROGRESSION. The process of transferring genetic material from one genotype to another.

KERUNT=KERNELS PER UNIT AREA (Acres or Hectares).

KERPOP=KERNEL POP SCORE. The visual 1-9 rating of the amount of rupturing of the kernel pericarp at an early stage in grain fill. A higher score is good and indicates no popped (ruptured) kernels.

KER WT=KERNEL NUMBER PER UNIT WEIGHT (Pounds or Kilograms). The number of kernels in a specific measured weight; determined after removal of extremely small and large kernels.

KSZDCD=KERNEL SIZE DISCARD. The percent of discard seed; calculated as the sum of discarded tip kernels and extra large kernels.

LINKAGE. Refers to a phenomenon wherein alleles on the same chromosome tend to segregate together more often than expected by chance if their transmission was independent.

LINKAGE DISEQUILIBRIUM. Refers to a phenomenon wherein alleles tend to remain together in linkage groups when segregating from parents to offspring, with a greater frequency than expected from their individual frequencies.

LOCUS. A specific location on a chromosome.

LOCUS CONVERSION. A locus conversion refers to plants within a variety that have been modified in a manner that retains the overall genetics of the variety and further comprises one or more loci with a specific desired trait, such as insect, disease or herbicide resistance. Synonymous with introgression.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plant densities on a 1 to 9 relative system with a higher number indicating the hybrid responds well to low plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to low plant density.

LRTLDG=LATE ROOT LODGING. The percentage of plants that do not root lodge after anthesis through harvest; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

LRTLPN=LATE ROOT LODGING. An estimate of the percentage of plants that do not root lodge after anthesis through harvest; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be considered as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

LRTLSC=LATE ROOT LODGING SCORE. Score for severity of plants that lean from a vertical axis at an approximate 30 degree angle or greater which typically results from strong winds after flowering. Recorded prior to harvest when a root-lodging event has occurred. This lodging results in plants that are leaned or "lodged" over at the base of the plant and do not straighten or "goose-neck" back to a vertical position. Expressed as a 1 to 9 score with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

MALE STERILITY. A male sterile plant is one which produces no viable pollen. Male sterility prevents self pollination and the pollination of neighboring plants. These male sterile plants are therefore useful in hybrid plant production.

MDMCPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus and MCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating the resistance to Maize Dwarf Mosaic Complex. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

MSTADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 over variety #2 as calculated by: MOISTURE of variety #2-MOISTURE of variety #1=MOISTURE ADVANTAGE of variety #1.

NEI DISTANCE. A quantitative measure of percent similarity between two varieties. Nei's distance between varieties A and B can be defined as 1-(2*number alleles in common/(number alleles in A+number alleles in B). For example, if lines A and B are the same for 95 out of 100 alleles, the Nei distance would be 0.05. If varieties A and B are the same for 98 out of 100 alleles, the Nei distance would be 0.02. Free software for calculating Nei distance is available on the internet at multiple locations such as, for example, at: evolution.genetics.washington.edu/phylip.html. See Nei, Proc Natl Acad Sci, 76:5269-5273 (1979) which is incorporated by reference for this purpose.

NLFBLT=NORTHERN LEAF BLIGHT (Helminthosporium turcicum or Exserohilum turcicum). A 1 to 9 visual rating indicating the resistance to Northern Leaf Blight. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

OILT=GRAIN OIL. Absolute value of oil content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

PEDIGREE DISTANCE. Relationship among generations based on their ancestral links as evidenced in pedigrees. May be measured by the distance of the pedigree from a given starting point in the ancestry.

PERCENT IDENTITY. Percent identity as used herein refers to the comparison of the alleles of two plants or varieties as scored by matching loci. Percent identity is determined by comparing a statistically significant number of the loci of two plants or varieties and scoring a match when the same two alleles are present at the same loci for each plant. For example, a percent identity of 90% between hybrid maize X5T123 and another plant means that the two plants have the same two alleles at 90% of their loci.

PERCENT SIMILARITY. Percent similarity as used herein refers to the comparison of the alleles of two plants or varieties as scored by matching alleles. Percent similarity is determined by comparing a statistically significant number of the loci of two plants or varieties and scoring one allele match when the same allele is present at the same loci for each plant and two allele matches when the same two alleles are present at the same loci for each plant. A percent similarity of 90% between hybrid maize X5T123 and another plant means that the two plants have 90% matching alleles.

PLANT. As used herein, the term "plant" includes reference to an immature or mature whole plant, including a plant that has been detasseled or from which seed or grain has been removed. Seed or embryo that will produce the plant is also considered to be the plant.

PLANT PARTS. As used herein, the term "plant parts" includes leaves, stems, roots, seed, grain, embryo, pollen, ovules, flowers, ears, cobs, husks, stalks, root tips, anthers, pericarp, silk, tissue, cells and the like.

PLTHT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in centimeters.

POLPRD=POLLEN PRODUCTION SCORE. The estimated total amount of pollen produced by tassels based on the number of tassel branches and the density of the spikelets.

POLSC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POLWT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

POP K/A=PLANT POPULATIONS. Measured as 1000's per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage of variety #1 over variety #2 as calculated by PLANT POPULATION of variety #2-PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety #1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relative maturity, is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is also referred to as the Comparative Relative Maturity Rating System that is similar to the Minnesota Relative Maturity Rating System.

PRMSHD=A relative measure of the growing degree units (GDU) required to reach 50% pollen shed. Relative values are predicted values from the linear regression of observed GDU's on relative maturity of commercial checks.

PROT=GRAIN PROTEIN. Absolute value of protein content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

RESISTANCE. Synonymous with tolerance. The ability of a plant to withstand exposure to an insect, disease, herbicide or other condition. A resistant plant variety will have a level of resistance higher than a comparable wild-type variety.

RTLDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis at an approximately 30 degree angle or greater would be counted as root lodged. Data are collected only when sufficient selection pressure exists in the experiment measured.

RTLADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1 over variety #2. Data are collected only when sufficient selection pressure exists in the experiment measured.

SCTGRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDGVGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEED. Fertilized and ripened ovule, consisting of the plant embryo, varying amounts of stored food material, and a protective outer seed coat. Synonymous with grain.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A maize breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

SIL DMP=SILAGE DRY MATTER. The percent of dry material in chopped whole plant silage.

SELF POLLINATION. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant.

SIB POLLINATION. A plant is sib-pollinated when individuals within the same family or variety are used for pollination.

SINGLE LOCUS CONVERSION TRAIT. A trait that can be introgressed into a corn variety through introgression and/or transformation of a single locus. Examples of such single locus traits include mutant genes, transgenes and native traits finely mapped to a single locus. One or more single locus conversion traits may be introduced into a single corn variety.

SITE SPECIFIC INTEGRATION. Genes that create a site for site specific DNA integration. This includes the introduction of FRT sites that may be used in the FLP/FRT system and/or Lox sites that may be used in the Cre/Loxp system. For example, see Lyznik, et al., Site-Specific Recombination for Genetic Engineering in Plants, Plant Cell Rep (2003) 21:925-932 and WO 99/25821.

SLFBLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolaris maydis). A 1 to 9 visual rating indicating the resistance to Southern Leaf Blight. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

SOURST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual rating indicating the resistance to Southern Rust. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

SPKDSC=SPIKLET DENSITY SCORE. The visual 1-9 rating of how dense spikelets are on the middle tassel branches. A higher score indicates higher spikelet density.

STAGRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STARCH=PERCENT OF STARCH. The percent of dry matter that is starch in chopped whole plant forage.

STDADV=STALK STANDING ADVANTAGE. The advantage of variety #1 over variety #2 for the trait STK CNT.

STKCNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STKLDG=STALK LODGING REGULAR. This is the percentage of plants that did not stalk lodge (stalk breakage) at regular harvest (when grain moisture is between about 20 and 30%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STKLDS=STALK LODGING SCORE. A plant is considered as stalk lodged if the stalk is broken or crimped between the ear and the ground. This can be caused by any or a combination of the following: strong winds late in the season, disease pressure within the stalks, ECB damage or genetically weak stalks. This trait should be taken just prior to or at harvest. Expressed on a 1 to 9 scale with 9 being no lodging. Data are collected only when sufficient selection pressure exists in the experiment measured.

STLLPN=LATE STALK LODGING. This is the percent of plants that did not stalk lodge (stalk breakage or crimping) at or around late season harvest (when grain moisture is below 20%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break or crimp below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STLPCN=STALK LODGING REGULAR. This is an estimate of the percentage of plants that did not stalk lodge (stalk breakage) at regular harvest (when grain moisture is between about 20 and 30%) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear. Data are collected only when sufficient selection pressure exists in the experiment measured.

STLTIP=STERILE TIPS SCORE. The visual 1 to 9 rating of the relative lack of glumes on the tassel central spike and branches. A higher score indicates less incidence of sterile tips or lack of glumes on the tassel.

STRT=GRAIN STARCH. Absolute value of starch content of the kernel as predicted by Near-infrared Transmittance and expressed as a percent of dry matter.

STWWLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual rating indicating the resistance to Stewart's Wilt. A higher score indicates a higher resistance. Data are collected only when sufficient selection pressure exists in the experiment measured.

SSRs. Genetic markers based on polymorphisms in repeated nucleotide sequences, such as microsatellites. A marker system based on SSRs can be highly informative in linkage analysis relative to other marker systems in that multiple alleles may be present.

TASBLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at the time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting. Data are collected only when sufficient selection pressure exists in the experiment measured.

TASBRN=TASSEL BRANCH NUMBER. The number of tassel branches, with anthers originating from the central spike.

TASSZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TDM/HA=TOTAL DRY MATTER PER HECTARE. Yield of total dry plant material in metric tons per hectare.

TEXEAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data are given as a percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in kilograms for a given volume (cubic meter).

TSWADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1 over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YIELD BU/A=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushels per acre adjusted to 15% moisture.

YLDADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety #2 as calculated by: YIELD of variety #1--YIELD variety #2=YIELD ADVANTAGE of variety #1.

YLDSC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

2. Definitions for Area of Adaptability

When referring to area of adaptability, such term is used to describe the location with the environmental conditions that would be well suited for this maize variety. Area of adaptability is based on a number of factors, for example: days to maturity, insect resistance, disease resistance, and drought resistance. Area of adaptability does not indicate that the maize variety will grow in every location within the area of adaptability or that it will not grow outside the area. Central Corn Belt: Iowa, Illinois, Indiana Drylands: non-irrigated areas of North Dakota, South Dakota, Nebraska, Kansas, Colorado and Oklahoma Eastern U.S.: Ohio, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia North central U.S.: Minnesota and Wisconsin Northeast: Michigan, New York, Vermont, and Ontario and Quebec Canada Northwest U.S.: North Dakota, South Dakota, Wyoming, Washington, Oregon, Montana, Utah, and Idaho South central U.S.: Missouri, Tennessee, Kentucky, Arkansas Southeast U.S.: North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, and Louisiana Southwest U.S.: Texas, Oklahoma, New Mexico, Arizona Western U.S.: Nebraska, Kansas, Colorado, and California Maritime Europe: Northern France, Germany, Belgium, Netherlands and Austria

DETAILED DESCRIPTION OF THE INVENTION AND FURTHER EMBODIMENTS

All tables discussed in the Detailed Description of the Invention and Further Embodiments section can be found at the end of the section.

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant. A plant is sib pollinated when individuals within the same family or line are used for pollination. A plant is cross-pollinated if the pollen comes from a flower on a different plant from a different family or line.

Plants that have been self-pollinated and selected for type for many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two different homozygous lines produces a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants each heterozygous at a number of gene loci will produce a population of heterogeneous plants that differ genetically and will not be uniform.

Maize (Zea mays L.), often referred to as corn in the United States, can be bred by both self-pollination and cross-pollination techniques. Maize has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in maize when wind blows pollen from the tassels to the silks that protrude from the tops of the ears.

There are many important factors to be considered in the art of plant breeding, such as the ability to recognize important morphological and physiological characteristics, the ability to design evaluation techniques for genotypic and phenotypic traits of interest, and the ability to search out and exploit the genes for the desired traits in new or improved combinations.

The objective of commercial maize hybrid variety development resulting from a maize plant breeding program is to develop new inbred varieties to produce hybrids that combine to produce high grain yields and superior agronomic performance. Thus, maize hybrids need to be highly homogeneous, heterozygous and reproducible to be useful as commercial hybrids. One of the primary traits breeders seek is yield. However, many other major agronomic traits are of importance in hybrid combination and have an impact on yield or otherwise provide superior performance in hybrid combinations. Such traits include percent grain moisture at harvest, relative maturity, resistance to stalk breakage, resistance to root lodging, grain quality, and disease and insect resistance.

The utility of hybrid maize variety X5T123 also extends to crosses with other species. Commonly, suitable species will be of the family Graminaceae, and especially of the genera Zea, Tripsacum, Coix, Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribe Maydeae. Potentially suitable for crosses with X5T123 may be the various varieties of grain sorghum, Sorghum bicolor (L.) Moench.

Morphological and Physiological Characteristics of X5T123

Pioneer Brand Hybrid X5T123 is characterized by good grain yield for its maturity. Hybrid X5T123 further demonstrates excellent stalk and root lodging resistance, short plant stature and good test weight. The hybrid is particularly suited to the Northwest U.S., Northcentral U.S., Northeast, and U.S. Drylands.

Pioneer Brand Hybrid Maize Variety X5T123 is a single cross, yellow endosperm maize hybrid. Hybrid Maize Variety X5T123 has a relative maturity of approximately 82 based on the Comparative Relative Maturity Rating System for harvest moisture of grain.

The hybrid has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1, found at the end of the section). The inbred parents of this hybrid have been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure the homozygosity and phenotypic stability necessary for use in commercial hybrid seed production. The variety has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in X5T123.

Hybrid maize variety X5T123 can be reproduced by planting seeds of the inbred parent varieties, growing the resulting maize plants under cross pollinating conditions, and harvesting the resulting seed using techniques familiar to the agricultural arts.

Genotypic Characteristics of X5T123

In addition to phenotypic observations, a plant can also be described by its genotype. The genotype of a plant can be characterized through a genetic marker profile which can identify plants of the same variety or a related variety or be used to determine or validate a pedigree. For example, the genotype can be used to determine the pedigree of a plant. There are many laboratory-based techniques available for the analysis, comparison and characterization of plant genotype; among these are Isozyme Electrophoresis, Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs) which are also referred to as Microsatellites, and Single Nucleotide Polymorphisms (SNPs). For example, see Berry, Don, et al., "Assessing Probability of Ancestry Using Simple Sequence Repeat Profiles: Applications to Maize Hybrids and Inbreds", Genetics, 2002, 161: 813-824, and Berry, Don et al., "Assessing Probability of Ancestry Using Simple Sequence Repeat Profiles: Applications to Maize Inbred Lines and Soybean Varieties", Genetics, 2003, 165: 331-342, which are incorporated by reference herein in their entirety.

Particular markers used for these purposes may include any type of marker and marker profile which provides a means of distinguishing varieties. In addition to being used for identification of inbred parents, hybrid variety X5T123, a hybrid produced through the use of X5T123 or its parents, and the identification or verification of pedigree for progeny plants produced through the use of X5T123, the genetic marker profile is also useful in developing an introgressed trait conversion of X5T123.

Means of performing genetic marker profiles using SSR polymorphisms are well known in the art. SSRs are genetic markers based on polymorphisms in repeated nucleotide sequences, such as microsatellites. A marker system based on SSRs can be highly informative in linkage analysis relative to other marker systems in that multiple alleles may be present. Another advantage of this type of marker is that, through use of flanking primers, detection of SSRs can be achieved, for example, by the polymerase chain reaction (PCR), thereby eliminating the need for labor-intensive Southern hybridization. The PCR.TM. detection is done by use of two oligonucleotide primers flanking the polymorphic segment of repetitive DNA. Repeated cycles of heat denaturation of the DNA followed by annealing of the primers to their complementary sequences at low temperatures, and extension of the annealed primers with DNA polymerase, comprise the major part of the methodology.

Following amplification, markers can be scored by gel electrophoresis of the amplification products. Scoring of marker genotype is based on the size of the amplified fragment, which may be measured by the base pair weight or molecular weight of the fragment. While variation in the primer used or in laboratory procedures can affect the reported molecular weight, relative values should remain constant regardless of the specific primer or laboratory used. When comparing plants it is preferable if all SSR profiles are performed in the same lab. An SSR service is available to the public on a contractual basis by DNA Landmarks in Saint-Jean-sur-Richelieu, Quebec, Canada.

Primers used for SSRs are publicly available and may be found in the Maize GDB on the World Wide Web at maizegdb.org (sponsored by the USDA Agricultural Research Service), in Sharopova et al. (Plant Mol. Biol. 48(5-6):463-481Lee et al. (Plant Mol. Biol. 48(5-6); 453-461). Primers may be constructed from publicly available sequence information. Some marker information may be available from DNA Landmarks.

The scope of the invention includes use of methods, for example, Isozyme Electrophoresis, Restriction Fragment Length Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs), Amplified Fragment Length Polymorphisms (AFLPs), Simple Sequence Repeats (SSRs), and Single Nucleotide Polymorphisms (SNPs), with transgenic or backcross conversions of maize hybrid variety X5T123. One such embodiment is a method of developing a variety genetically similar to hybrid maize variety X5T123 in breeding that involves the repeated backcrossing of an inbred parent of, or a double haploid inbred variety derived from, hybrid maize variety X5T123.

Comparisons for Pioneer Hybrid Maize X5T123

A breeder uses various methods to help determine which plants should be selected from segregating populations and ultimately which inbred varieties will be used to develop hybrids for commercialization. In addition to knowledge of the germplasm and plant genetics, a part of the selection process is dependent on experimental design coupled with the use of statistical analysis. Experimental design and statistical analysis are used to help determine which plants, which family of plants, and finally which inbred varieties and hybrid combinations are significantly better or different for one or more traits of interest. Experimental design methods are used to assess error so that differences between two inbred varieties or two hybrid varieties can be more accurately evaluated. Statistical analysis includes the calculation of mean values, determination of the statistical significance of the sources of variation, and the calculation of the appropriate variance components. One of ordinary skill in the art of plant breeding would know how to evaluate the traits of two plant varieties to determine if there is no significant difference between the two traits expressed by those varieties. For example, see Fehr, Walt, Principles of Cultivar Development, pages 261-286 (1987). Mean trait values may be used to determine whether trait differences are significant. Trait values should preferably be measured on plants grown under the same environmental conditions, and environmental conditions should be appropriate for the traits or traits being evaluated. Sufficient selection pressure should be present for optimum measurement of traits of interest such as herbicide, insect or disease resistance. A locus conversion of X5T123 for herbicide resistance should be compared with an isogenic counterpart in the absence of the converted trait. In addition, a locus conversion for insect or disease resistance should be compared to the isogenic counterpart, in the absence of disease pressure or insect pressure.

In Table 2 (Table 2, found at the end of the section), data from traits and characteristics of hybrid maize X5T123 per se are given and compared to other maize hybrid. The following are the results of these comparisons. The results in Table 2 show hybrid maize variety X5T123 has significantly different traits compared to other maize hybrid varieties.

Comparisons of characteristics for Pioneer Brand Hybrid Maize X5T123 were made against Hybrid 39F59 and 39H84.

Table 2A compares Pioneer Brand Hybrid Maize X5T123 and Hybrid 39F59, a hybrid with a similar area of adaptation. The results show Hybrid Maize X5T123 has significantly different yield, test weight and resistance to head smut compared to Hybrid 39F59.

Table 2B compares Pioneer Brand Hybrid Maize X5T123 and Hybrid 39H84, a hybrid with a similar area of adaptation. The results show Hybrid Maize X5T123 differs significantly over multiple traits including yield and plant height when compared to Hybrid 39H84.

Development of Maize Hybrids using X5T123

During the inbreeding process in maize, the vigor of the varieties decreases. However, vigor is restored when two different inbred varieties are crossed to produce the hybrid progeny (F1). An important consequence of the homozygosity and homogeneity of the inbred varieties is that the hybrid between a defined pair of inbreds may be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained. Once the inbreds that create a superior hybrid have been identified, a continual supply of the hybrid seed can be produced using these inbred parents and the hybrid corn plants can then be generated from this hybrid seed supply.

The development of a maize hybrid in a maize plant breeding program involves three steps: (1) the selection of plants from various germplasm pools for initial breeding crosses; (2) the selfing of the selected plants from the breeding crosses for several generations to produce a series of inbred varieties, which, individually breed true and are highly uniform; and (3) crossing a selected inbred variety with an unrelated inbred variety to produce the hybrid progeny (F1). After a sufficient amount of inbreeding successive filial generations will merely serve to increase seed of the developed inbred.

X5T123 may be used to produce a double cross hybrid or a three-way hybrid. A single cross hybrid is produced when two inbred varieties are crossed to produce the F1 progeny. A double cross hybrid is produced from four inbred varieties crossed in pairs (A.times.B and C.times.D) and then the two F1 hybrids are crossed again (A.times.B).times.(C.times.D). A three-way cross hybrid is produced from three inbred varieties where two of the inbred varieties are crossed (A.times.B) and then the resulting F1 hybrid is crossed with the third inbred variety (A.times.B).times.C. In each case, pericarp tissue from the female parent will be a part of and protect the hybrid seed.

Hybrid seed production requires elimination or inactivation of pollen produced by the female parent. Incomplete removal or inactivation of the pollen provides the potential for self-pollination. This inadvertently self-pollinated seed may be unintentionally harvested and packaged with hybrid seed. Also, because the male parent plant is grown in rows, that are typically destroyed prior to seed development, next to the female parent in the field there is the very low probability that the male selfed seed could be unintentionally harvested and packaged with the hybrid seed. Once the seed from the hybrid bag is planted, it is possible to identify and select these self-pollinated plants. These self-pollinated plants will be one of the inbred varieties or F1's used to produce the hybrid. Though the possibility of selfs being included in a hybrid seed bag exists, the occurrence is very low because much care is taken by seed companies to avoid such inclusions. It is worth noting that hybrid seed is sold to growers for the produc