Inbred maize variety PH1T9 Number:7,521,611 from the United States Patent and Trademark Office (PTO) owispatent

Title: Inbred maize variety PH1T9

Abstract: A novel inbred maize variety designated PH1T9 and seed, plants and plant parts thereof. Methods for producing a maize plant that comprise crossing inbred maize variety PH1T9 with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into PH1T9 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. Hybrid maize seed, plant or plant part produced by crossing the inbred variety PH1T9 or a trait conversion of PH1T9 with another maize variety. Inbred maize varieties derived from inbred maize variety PH1T9, methods for producing other inbred maize varieties derived from inbred maize variety PH1T9 and the inbred maize varieties and their parts derived by the use of those methods.

Patent Number: 7,521,611 Issued on 04/21/2009 to Cunnyngham

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Inventors:	Cunnyngham; Charles Thomas (Tipton, IN)
Assignee:	Pioneer Hi-Bred International, Inc. (Johnston, IA)
Appl. No.:	11/669,272
Filed:	January 31, 2007

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Current U.S. Class:	800/320.1 ; 800/260; 800/275
Current International Class:	A01H 1/02 (20060101); A01H 1/00 (20060101); A01H 5/00 (20060101)

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References Cited [Referenced By]

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U.S. Patent Documents

5506367	April 1996	Keaschall
5523520	June 1996	Hunsperger et al.
5557034	September 1996	Williams et al.
6114613	September 2000	Colbert et al.
6747196	June 2004	Hoffbeck
7015386	March 2006	Dolan et al.
7091407	August 2006	Carrigan
2006/0107416	May 2006	Dolan

Other References

Kraft et al (2000, Theor. Appl. Genet. 101:323-326). cited by examiner . Eshed et al (1996, Genetics 143:1807-1817). cited by examiner . Plant Variety Protection Certificate No. 9200086, Corn PHN18, issued Jun. 30, 1992. cited by other . Plant Variety Protection Certificate No. 200400195, Corn PHA9G, issued Aug. 21, 2006. cited by other . Plant Variety Protection Certificate No. 9900357, Corn PH3GR, issued Nov. 6, 2001. cited by other . Plant Variety Protection Certificate No. 9000250, Corn PHP38, issued Aug. 30, 1991. cited by other . Plant Variety Protection Certificate No. 200200257, Corn PH3RC, issued Jul. 5, 2006. cited by other.

Primary Examiner: Baum; Stuart F.
Attorney, Agent or Firm: McKee, Voorhees & Sease, P.L.C.

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Claims

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What is claimed is:

1. Maize inbred variety PH1T9, representative seed of said variety having been deposited under ATCC accession number PTA-9259.

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

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

4. A maize plant part comprising all of the alleles of the maize inbred variety of claim 1 at the SSR loci listed in Table 2.

5. An F1 hybrid maize seed produced by crossing the plant part of claim 3 with a different maize plant.

6. A maize plant produced by growing the F1 hybrid maize seed of claim 5.

7. A maize plant part produced by growing the F1 hybrid maize seed of claim 5.

8. A method for developing a maize plant comprising crossing the plant part of claim 3 with a plant part of a different maize plant.

9. A method for developing a maize plant comprising crossing the plant part of claim 7 with a plant part of a different maize plant.

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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 an inbred maize variety designated PH1T9.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine, in a single variety or 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, plant height 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 novel inbred maize variety, designated PH1T9 and processes for making PH1T9. This invention relates to seed of inbred maize variety PH1T9, to the plants of inbred maize variety PH1T9, to plant parts of inbred maize variety PH1T9, and to processes for making a maize plant that comprise crossing inbred maize variety PH1T9 with another maize plant. This invention also relates to processes for making a maize plant containing in its genetic material one or more traits introgressed into PH1T9 through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced by such introgression. This invention further relates to a hybrid maize seed, plant or plant part produced by crossing the inbred variety PH1T9 or an introgressed trait conversion of PH1T9 with another maize variety. This invention also relates to inbred maize varieties derived from inbred maize variety PH1T9 to processes for making other inbred maize varieties derived from inbred maize variety PH1T9 and to the inbred maize varieties and their parts produced by the use of those processes.

DEFINITIONS

INBRED 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.

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 PH1T9 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 PH1T9 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 varieties 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.

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 source.

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 PH1T9.

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.

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.

ECB1 LF=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.

ECB2IT=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 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 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 PH1T9 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 visual quality.

HAPLOID PLANT PART. Refers to a plant part or cell that has the same haploid genotype as PH1T9.

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.

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

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.

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 varieties 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 homozygous alleles of two inbred varieties. Each inbred plant will have the same allele (and therefore be homozygous) at almost all of their loci. Percent identity is determined by comparing a statistically significant number of the homozygous alleles of two inbred varieties. For example, a percent identity of 90% between inbred PH8JV and other inbred variety means that the two inbred varieties have the same homozygous alleles at 90% of their loci.

PERCENT SIMILARITY. Percent similarity as used herein refers to the comparison of the homozygous alleles of an inbred plant with another plant. The homozygous alleles of PH1T9 are compared with the alleles of a non-inbred plant, such as a hybrid, and if the allele of the inbred matches at least one of the corresponding alleles from the hybrid then they are scored as similar. Percent similarity is determined by comparing a statistically significant number of loci and recording the number of loci with similar alleles as a percentage. For example, a percent similarity of 90% between inbred PH1T9 and a hybrid maize plant means that the inbred variety matches at least one of the hybrid alleles at 90% of the loci. In the case of a hybrid produced from PH1T9 as the male or female parent, such hybrid will comprise two sets of alleles, one set of which will comprise substantially the same alleles as the homozygous alleles of inbred variety PH1T9.

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.

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.

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

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.

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.

TSTWT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

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

VARIETY. A substantially homozygous inbred line and minor genetic 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.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YIELD BU/A=YIELD (BUSHELS/ACRE). Yield of the grain at harvest by weight or volume (bushels) per unit area (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.

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 found at the end of the section.

Morphological and Physiological Characteristics of PH1T9

Inbred maize variety PH1T9 may be used as either a male or female in the production of the first generation F1 maize hybrid although PH1T9 may be best suited for use as a female. Inbred maize line PH1T9 is best adapted to the central, south central corn belt and western regions and can be used to produce hybrids in the 113 CRM maturity range. PH1T9 has good tolerance to Northern leaf blight and has good female production yield. It is a white endosperm inbred with very good color and adequate hardness. In hybrid combination, PH1T9 demonstrates good stalk and root strength while making earlier maturity white hybrids.

The inbred 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 has 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 PH1T9.

Inbred maize variety PH1T9, being substantially homozygous, can be reproduced by planting seeds of the variety, growing the resulting maize plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed using techniques familiar to the agricultural arts.

Genotypic Characteristics of PH1T9

In addition to phenotypic observations, a plant can also be identified 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. The SSR profile of Inbred PH1T9 can be found in Table 2 at the end of this section.

As a result of inbreeding, PH1T9 is substantially homozygous. This homozygosity has been characterized at the loci shown in the marker profile provided herein. An F1 hybrid made with PH1T9 would substantially comprise the marker profile of PH1T9 shown herein. This is because an F1 hybrid is the sum of its inbred parents, e.g., if one inbred parent is homozygous for allele x at a particular locus, and the other inbred parent is homozygous for allele y at that locus, the F1 hybrid will be x.y (heterozygous) at that locus. The profile can therefore be used to identify hybrids comprising PH1T9 as a parent, since such hybrids will comprise two sets of alleles, one set of which will be from PH1T9. The determination of the male set of alleles and the female set of alleles may be made by profiling the hybrid and the pericarp of the hybrid seed, which is composed of maternal parent cells. One way to obtain the paternal parent profile is to subtract the pericarp profile from the hybrid profile.

Subsequent generations of progeny produced by selection and breeding are expected to be of genotype x (homozygous), y (homozygous), or x.y (heterozygous) for these locus positions. When the F1 plant is used to produce an inbred, the resulting inbred should be either x or y for that allele. In that regard, a unique allele or combination of alleles unique to that inbred can be used to identify progeny plants developed with PH1T9.

Therefore, in accordance with the above, an embodiment of this invention is a PH1T9 progeny maize plant or plant part that is a first generation (F1) hybrid maize plant comprising two sets of alleles, wherein one set of the alleles is the same as PH1T9 at substantially all of the SSR loci listed in Table 2. A maize cell wherein one set of the alleles is the same as PH1T9 at substantially all of the SSR loci listed in Table 2 is also an embodiment of the invention. This maize cell may be a part of a hybrid seed, plant or plant part produced by crossing PH1T9 with another inbred maize plant.

Genetic marker profiles can be obtained by techniques such as 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.

Particular markers used for these purposes are not limited to the set of markers disclosed herein, but 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 maize variety PH1T9, a hybrid produced through the use of PH1T9, and the identification or verification of pedigree for progeny plants produced through the use of PH1T9, the genetic marker profile is also useful in developing an introgressed trait conversion of PH1T9.

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 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 electrophoresis of the amplification products. Scoring of marker genotype is based on the size of the amplified fragment, which may be measured by the number of base pairs of the fragment. While variation in the primer used or in laboratory procedures can affect the reported fragment size, 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. The SSR analyses reported herein were conducted in-house at Pioneer Hi-Bred. 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 the SSRs reported herein 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):463-481), Lee et al. (Plant Mol. Biol. 48(5-6); 453-461), or may be constructed from sequences if reported herein. Primers may be constructed from publicly available sequence information. Some marker information may also be available from DNA Landmarks.

Map information is provided by chromosome position and location. Bin numbers, position and location corresponding to these loci are reported in the Maize GDB for the IBM 2 and/or IBM 2 Neighbors maps. Map positions are also available on the Maize GDB for a variety of different mapping populations.

PH1T9 and its plant parts can be identified through a molecular marker profile. An inbred corn plant cell having the SSR genetic marker profile shown in Table 2 is an embodiment of the invention. Such plant cell may be either diploid or haploid.

Also encompassed within the scope of the invention are plants and plant parts substantially benefiting from the use of PH1T9 in their development, such as PH1T9 comprising a introgressed trait through backcross conversion or transformation, and which may be identified by having an SSR molecular marker profile with a high percent identity to PH1T9, such as at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% identity. Likewise, percent similarity at these percentages may be used to identify plants produced by the use of PH1T9.

Comparing PH1T9 to Other Inbreds

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. Either a five or a one percent significance level is customarily used to determine whether a difference that occurs for a given trait is real or due to the environment or experimental error. 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, p. 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 PH1T9 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 3, data from traits and characteristics of inbred maize variety PH1T9 per se are given and compared to other maize inbred varieties and hybrids. The following are the results of these comparisons. The results in Table 3 show inbred PH1T9 has significantly different traits compared to other maize inbred varieties.

The results in Table 3A compare inbred PH1T9 to inbred PHA9G. The results show inbred PH1T9 has significantly different moisture, plant height and ear height compared to PHA9G.

The results in Table 3B compare inbred PH1T9 to inbred PHN18. The results show inbred PH1T9 differs significantly over multiple traits including 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 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 when compared to inbred PHN18.

Development of Maize Hybrids using PH1T9

A single cross maize hybrid results from the cross of two inbred varieties, each of which has a genotype that complements the genotype of the other. A hybrid progeny of the first generation is designated F1. In the development of commercial hybrids in a maize plant breeding program, only the F1 hybrid plants are sought. F1 hybrids are more vigorous than their inbred parents. This hybrid vigor, or heterosis, can be manifested in many polygenic traits, including increased vegetative growth and increased yield.

PH1T9 may be used to produce hybrid maize. One such embodiment is the method of crossing inbred maize variety PH1T9 with another maize plant, such as a different maize inbred variety, to form a first generation F1 hybrid seed. The first generation F1 hybrid seed, plant and plant part produced by this method is an embodiment of the invention. The first generation F1 seed, plant and plant part will comprise an essentially complete set of the alleles of inbred variety PH1T9. One of ordinary skill in the art can utilize either breeder books or molecular methods to identify a particular F1 hybrid plant produced using inbred variety PH1T9. Further, one of ordinary skill in the art may also produce F1 hybrids with transgenic, male sterile and/or backcross conversions of inbred variety PH1T9

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, such as PH1T9, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred varieties with different inbred varieties to produce the hybrids. During the inbreeding process in maize, the vigor of the varieties decreases, and so one would not be likely to use PH1T9 directly to produce grain. However, vigor is restored when PH1T9 is crossed to a different inbred variety to produce a commercial F1 hybrid. An important consequence of the homozygosity and homogeneity of the inbred variety 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.

PH1T9 may be used to produce a single cross hybrid, 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 (A.times.B).times.C. In each case, pericarp tissue from the female parent will be a part of and protect the hybrid seed.

Combining Ability of PH1T9

Combining ability of a variety, as well as the performance of the variety per se, is a factor in the selection of improved maize inbreds. Combining ability refers to a variety's contribution as a parent when crossed with other varieties to form hybrids. The hybrids formed for the purpose of selecting superior varieties may be referred to as test crosses, and include comparisons to other hybrid varieties grown in the same environment (same cross, location and time of planting). One way of measuring combining ability is by using values based in part on the overall mean of a number of test crosses weighted by number of experiment and location combinations in which the hybrid combinations occurs. The mean may be adjusted to remove environmental effects and known genetic relationships among the varieties.

General combining ability provides an overall score for the inbred over a large number of test crosses. Specific combining ability provides information on hybrid combinations formed by PH1T9 and a specific inbred parent. A variety such as PH1T9 which exhibits good general combining ability may be used in a large number of hybrid combinations.

A general combining ability report for inbred PH1T9 is provided in Table 4. This data represents the overall mean value for these traits over hundreds of test crosses. Table 4 demonstrates that inbred PH1T9 shows good general combining ability for hybrid production.

Hybrid Comparisons

These hybrid comparisons represent specific hybrid crosses with PH1T9 and a comparison of these specific hybrids with other hybrids with favorable characteristics. These comparisons illustrate the good specific combining ability of PH1T9.

The results in Table 5 compare a specific hybrid for which inbred PH1T9 is a parent with other hybrids. The results show that inbred PH1T9 shows good specific combining ability.

The data in Table 6 show that numerous species of the genus of F1 hybrids created with PH1T9 have been reduced to practice. Phenotypic data are presented for these hybrids and are based on replicated field trials. Of course, many more species of this genus may be created by one of ordinary skill in the art without undue experimentation by crossing PH1T9 with a multitude of publicly available inbred varieties. For example, see J. T. Gerdes et al., Compilation of North American Maize Breeding Germplasm, pp. 1-87 (Crop Science Society of America, 1993) which is incorporated by reference for this purpose.

Introgression of a New Locus or Trait into PH1T9

PH1T9 represents a new base genetic variety into which a new locus or trait may be introgressed. Direct transformation and backcrossing represent two important methods that can be used to accomplish such an introgression. The term locus conversion is used to designate the product of such an introgression.

Locus Conversions of PH1T9

A locus conversion of PH1T9 will retain the genetic integrity of PH1T9. The molecular marker data provided in table # as well as the availability of the seed deposit for determining the genetic profile illustrates the genetic integrity of PH1T9. A locus conversion of PH1T9 will comprise at least 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the base genetics of PH1T9. For example, a locus conversion of PH1T9 can be developed when DNA sequences are introdu