United States Patent
`Piper
`
`[54] HYBRID MAIZE PLANT AND SEED (3730)
`
`(75]
`
`Inventor: Todd Elliott Piper, Eau Claire, Wis.
`
`[73] Assignee: Pioneer Hi-Bred International, Inc.,
`Des Moines, Iowa
`
`[21] Appl. No.: 610,905
`
`[22] Filed:
`
`Mar. 5, 1996
`
`Related U.S. Application Data
`
`[63] Continuation of Ser. No. 398,481, Mar. 3, 1995, abandoned.
`[51] Trt, Ce icccssccsssssescssssnsene A01H 5/00; A01H 4/00;
`C12N 5/04
`[52] U.S. C1. caccccssssseanen 800/200; 800/250; 800/DIG. 56;
`435/412; 435/424; 435/430; 435/430.1;
`47/58; 47/DIG. 1
`[58] Field of Search 20.0.0...cecssssessscsseees 800/200, 205,
`800/DIG. 56; 435/172.1, 240.4, 240.45,
`240.49, 240.5, 412, 424, 430; 47/58, DIG. 1
`
`[S6]}
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3/1989 Segebart .
`4,812,599
`FOREIGN PATENT DOCUMENTS
`
`160390 11/1985 European Pat. Off. .
`OTHER PUBLICATIONS
`
`Conger, B.V., et al. (1987) “Somatic Embryogenesis From
`Cultured Leaf Segments of Zea Mays”, Plant Cell Reports,
`6:345-347.
`Duncan, D.R., et al. (1985) “The Production of Callus
`Capable of Plant Regeneration From Immature Embryos of
`Numerour Zea Mays Genotypes”, Planta, 165:322-332.
`Edallo, et al. (4981) “Chromosomal Variation and Fre-
`quency of Spontaneous Mutation Associated with in Vitro
`Culture and Plant Regeneration in Maize”, Maydica,
`XXVI39-56.
`Green, et al., (1975) “Plant Regeneration From Tissue
`Cultures of Maize”, Crop Science, vol. 15, pp. 417-421.
`Green, C.E., et al. (1982) “Plant Regeneration in Tissue
`Cultures of Maize” Maize for Biological Research, pp.
`367-372.
`
`0EO
`
`US005689036A
`
`[11] Patent Number:
`
`[45] Date of Patent:
`
`5,689,036
`Nov. 18, 1997
`
`Hallauer, A-R.et al. (1988) “Corn Breeding” Com and Corn
`Improvement, No. 18, pp. 463-481.
`Meghii, M.R., et al. (1984). “Inbreeding Depression, Inbred
`& Hybrid Grain Yields, and Other Traits of Maize Geno-
`types Representing Three Eras”, Crop Science, vol. 24, pp.
`545-549.
`Phillips, et al. (1988) “Cell/Tissue Culture and In Vitro
`Manipulation”, Corn & Corn Improvement, 31rd Ed., ASA
`Publication, No. 18, pp. 345-387.
`PoehIman (1987) Breeding Field Crop, AVI Publication Co.,
`Westport, Ct., pp. 237-246.
`Rao, K.V., et al., (1986) “Somatic Embryogenesis in Glume
`Callus Cultures”, Maize Genetics Cooperative Newsletter,
`No. 60, pp. 64-65.
`Sass, John FE. (1977) “Morphology”, Corn & Corn Improve-
`ment, ASA Publication. Madison, Wisconsin, pp. 89-109.
`Songstad, D.D.
`et
`al.
`(1988)
`“Effect
`of ACC
`(1-aminocyclopropane—1—carboxyclic acid), Silver Nitrate
`& Norbonadiene on Plant Regeneration From Maize Callus
`Cultures”, Plant Cell Reports, 7:262-265.
`Tomes,et al. (1985) “The Effect of Parental Genotype on
`Initiation of Embryogenic Callus From Elite Maize (Zea
`Mays L.) Germplasm”, Theor, Appl. Genet., vol. 70, pp.
`505-509.
`Troyer, et al. (1985) “Selection for Early Flowering in Corn:
`10 Late Synthetics”, Crop Science, vol. 25, pp. 695-697.
`Umbeck, et al. (1983) “Reversion of Male—Sterile T—Cyto-
`plasm Maize to Male Fertility in Tissue Culture”, Crop
`Science, vol. 23, pp. 584-588.
`/
`Wright, Harold (1980) “Commercial Hybrid Seed Produc-
`tion”, Hybridization of Crop Plants, Ch. 8: 161-176.
`Wych, Robert D, (1988) “Production of Hybrid Seed”, Corn
`and Corn Improvement, Ch. 9, pp. 565-607.
`
`Primary Examiner—Gary Benzion
`Attorney, Agent, or Firm—Pioneer Hi-Bred. International,
`Inc.
`
`(57]
`
`ABSTRACT
`
`According to the invention,there is provided a hybrid maize
`plant, designated as 3730, produced by crossing two Pioneer
`Hi-Bred International, Inc. proprietary inbred maize lines.
`This invention relates to the hybrid seed 3730, the hybrid
`plant produced from the seed, and variants, mutants, and
`trivial modifications of hybrid 3730.
`
`6 Claims, No Drawings
`
`Inari Exhibit 1091
`Inari Exhibit 1091
`Inari v. Pioneer
`Inari v. Pioneer
`
`

`

`5,689,036
`
`1
`HYBRID MAIZE PLANT AND SEED (3730)
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`This is a continuation of application Ser. No. 08/398,481,
`filed Mar. 3, 1995, now abandoned.
`
`FIELD OF THE INVENTION
`
`This invention is in the field of maize breeding, specifi-
`cally relating to a hybrid maize line designated 3730.
`
`BACKGROUND OF THE INVENTION
`
`Plant Breeding
`
`Field crops are bred through techniques that take advan-
`tage 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
`cross-pollinated if the pollen comes from a flower on a
`different plant.
`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 homozygouslines
`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 hybrid 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 theears.
`The developmentof a hybrid maize variety 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 gen-
`erations to produce a series of inbred lines, which, although
`different from each other, breed true and are highly uniform;
`and (3) crossing the selected inbred lines with unrelated.
`inbred lines to produce the hybrid progeny (F,). During the
`inbreeding process in maize, the vigor ofthe lines decreases.
`Vigor is restored when twodifferent inbred lines are crossed
`to produce the hybrid progeny (F,). An important conse-
`quence of the homozygosity and homogeneity of the inbred
`lines is that the hybrid created by crossing a defined pair of
`inbreds will always be the same. Oncethe 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.
`Large scale commercial maize hybrid production, asit is
`practiced today, requires the use of some form of male
`sterility system which controls or inactivates male fertility.
`Areliable method of controlling male fertility in plants also
`offers the opportunity for improved plant breeding. This is
`especially true for development of maize hybrids, which
`relies upon some sort of male sterility system. There are
`several options for controlling male fertility available to
`breeders, such as: manual or mechanical emasculation (or
`detasseling), cytoplasmic male sterility, genetic male
`sterility, gametocides and the like.
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`65
`
`2
`Hybrid maize seed is typically produced by a male
`sterility system incorporating manual or mechanical detas-
`seling. Alternate strips of two inbred varieties of maize are
`planted in a field, and the pollen-bearing tassels are removed
`from one of the inbreds (female). Providing that there is
`sufficient isolation from sources of foreign maize pollen, the
`ears of the detasseled inbred will be fertilized only from the
`other inbred (male), and the resulting seed is therefore
`hybrid and will form hybrid plants.
`The laborious, and occasionally unreliable, detasseling
`process can be avoided by using cytoplasmic male-sterile
`(CMS)inbreds. Plants of a CMS inbred are male sterile as
`a result of factors resulting from the cytoplasmic, as opposed
`to the nuclear, genome. Thus, this characteristic is inherited
`exclusively throughthe female parent in maize plants, since
`only the female provides cytoplasm to the fertilized seed.
`CMSplants are fertilized with pollen from another inbred
`that is not male-sterile. Pollen from the second inbred may
`or may not contribute genes that make the hybrid plants
`male-fertile. Usually seed from detasseled fertile maize and
`CMS produced seed of the same hybrid are blended to insure
`that adequate pollen loads are available for fertilization
`when the hybrid plants are grown.
`There are several methods of conferring genetic male
`sterility available, such as multiple mutant genes at separate
`locations within the genome that confer maiesterility, as
`disclosed in U.S. Pat. Nos. 4,654,465 and 4.727.219 to Brat
`et al. and chromosomal
`translocations as described by
`Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. These
`andall patents referred to are incorporated by reference. In
`addition to these methods, Albertsen et al., of Pioneer
`Hi-Bred, U.S. patent application Ser. No. 07/848,433, have
`developed a system of nuclear malesterility which includes:
`identifying a gene whichis critical to malefertility; silenc-
`ing this native gene which is critical to male fertility;
`removing the native promoter from the essential male fer-
`tility gene and replacing it with an inducible promoter;
`inserting this genetically engineered gene back into the
`pliant; and thus creating a plant that is male sterile because
`the inducible promoter is not “on” resulting in the male
`fertility gene not being transcribed. Fertility is restored by
`inducing, or turning “on”, the promoter, which in turn allows
`the gene that confers male fertility to be transcribed.
`There are many other methods of conferring genetic male
`sterility in the art, each with its own benefits and drawbacks.
`These methods use a variety of approaches such as deliv-
`ering into the plant a gene encoding a cytotoxic substance
`associated with a male tissue specific promoter or an anti-
`sense system in which a genecritical to fertility is identified
`and an antisense to that gene is inserted in the plant (see:
`Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,
`308 and PCT application PCT/CA90/00037 published as
`WO 90/08828).
`Another system useful in controlling malesterility makes
`use of gametocides. Gametocides are not a genetic system,
`but rather a topical application of chemicals. These chemi-
`cals affect cells that are critical to male fertility. The appli-
`cation of these chemicals affects fertility in the plants only
`for the growing season in which the gametocide is applied
`(see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Applica-
`tion of the gametocide, timing of the application and geno-
`type specificity often limit the usefulness of the approach.
`The use of male sterile inbreds is but one factor in the
`production of maize hybrids. The development of maize
`hybrids requires, in general, the development of homozy-
`gous inbred lines,
`the crossing of these lines, and the
`
`

`

`5,689,036
`
`3
`evaluation of the crosses. Breeding programs combine the
`genetic backgrounds from two or more inbred lines or
`various other broad-based sources into breeding pools from
`which new inbred lines are developed by selfing and selec-
`tion of desired phenotypes. The new inbreds are crossed
`with other inbred lines and the hybrids from these crosses
`are evaluated to determine which of those have commercial
`potential.
`There are many important factors to be considered in the
`att of plant breeding, such as the ability to recognize
`important morphological and physiological characteristics,
`the ability to design evaluation techniques for genotypic and
`phenotypictraits 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 line develop-
`ment programs is to develop new inbred lines to produce
`hybrids that combine to produce high grain yields and
`superior agronomic performance. The primary trait 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. Suchtraits include percent grain mois-
`ture at harvest, relative maturity, resistance to stalk
`breakage, resistance to root lodging, grain quality, and
`disease and insect resistance. In addition, the lines per se
`must have acceptable performancefor parental traits such as-
`seed yields, kernel sizes, pollen production, all of which
`affect ability to provide parental lines in sufficient quantity
`and quality for hybridization. These traits have been shown
`to be under genetic control and many if notall of the traits
`are affected by multiple genes.
`
`Pedigree Breeding
`
`The pedigree method of breeding is the mostly widely
`used methodology for new hybrid line development.
`In general terms this procedure consists of crossing two
`inbred lines to produce the non-segregating F, generation,
`and self pollination of the F, generation to produce the F,
`generation that segregates for all factors for which the inbred
`parents differ. An example of this process is set forth below.
`Variations of this generalized pedigree method are used, but
`all these variations produce a segregating generation which
`contains a range of variation for the traits of interest.
`
`EXAMPLE 1
`
`Hypothetical Example of Pedigree Breeding
`Program
`Consider a cross between two inbred lines that differ for
`alleles at five loci. The parental genotypes are:
`Parent 1AbCdeF/AbCdeF
`Parent 2aBcDE flaBcDEf
`the F, from a cross between these two parentsis:
`F,AbCdeFaBcDEf
`Selling F, will produce an F, generation including the
`following genotypes:
`
`ABcDE fabCdeF
`ABcDefabCdEF
`ABcDeflabCdeF
`
`
`10
`
`15
`
`20
`
`4
`Each inbred parent which is used in breeding crosses
`represents a unique combination of genes, and the combined
`. effects of the genes define the performanceof the inbred and
`its performance in hybrid combination. There is published
`evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen, R,.A.
`Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each
`of the lines are different and can be uniquely identified on
`the basis of genetically-controlled molecular markers.
`It has been shown (Hallauer, Arnel R. and Miranda,J. B.
`Fo. Quantitative Genetics in Maize Breeding, Iowa State
`University Press, Ames Iowa, 1981) that most traits of
`economic value in maize are under the genetic control of
`multiple genetic loci, and that there are a large number of
`unique combinations of these genes present in elite maize
`germplasm. If not, genetic progress using elite inbred lines
`would no longer be possible. Studies by Duvick and Russell
`(Duvick, D. N., Maydica 37:69-79, (1992); Russell, W. A.,
`Maydica XX1X:375-390 (1983)) have shownthat over the
`last 50 years the rate of genetic progress in commercial
`hybrids has been between one and two percent per year.
`The number of genes affecting the trait of primary eco-
`nomic importance in maize, grain yield, has been estimated
`to be in the range of 10-1000. Inbred lines which are used
`as parents for breeding crosses differ in the number and
`combination of these genes. These factors make the plant
`breeders task more difficult. Compounding this is evidence
`that no one line contains the favorable allele at all loci, and
`that different alleles have different economic values depend-
`ing on the genetic background and field environment in
`which the hybrid is grown. Fifty years of breeding experi-
`ence suggests that there are many genesaffecting grain yield
`and each of these has a relatively small effect on this trait.
`The effects are small compared to breeders ability to mea-
`sure grain yield differences in evaluation trials. Therefore,
`the parents of the breeding cross must differ at several of
`these loci so that the genetic differences in the progeny will
`be large enough that breeders can develop a line that
`increases the economic worth of its hybrids over that of
`hybrids made with either parent.
`If the number of loci segregating in a cross between two
`inbred lines is n, the number of unique genotypesin the F,
`generation is 3” and the number of unique inbred lines from
`this cross is {(2”)}-2}. Only a very limited number of these
`combinations are useful. Only about 1 in 10,000 of the
`progeny from F,.’s are commercially useful.
`By way of example, if it is assumed that the number of
`segregating loci in F., is somewhere between 20 and 50, and
`that each parent is fixed for half the favorable alleles,it is
`then possible to calculate the approximate probabilities of
`finding an inbred that has the favorableallele at {(n/2}+m}
`loci, where n/2 is the number of favorable alleles in each of
`the parents and m is the number of additional favorable
`alleles in the new inbred. See Example 2 below. The number
`mis assumedto be greater than three because eachallele has
`so small an effect that evaluation techniques are not sensitive
`enough to detect differences due to three or less favorable
`alleles. The probabilities in Example 2 are on the order of
`107or smaller and they are the probabilities that at least one
`genotype with (n/2)=m favorable alleles will exist.
`To putthis in perspective, the number of plants grown on
`60 million acres (approximate United States corn acreage) at
`25,000 plants/acre is 1.5x10'?.
`EXAMPLE 2
`
`30
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`55
`
`The number of genotypes in the F, is 3° for six segre-
`gating loci (729) and will produce (2°}2 possible new
`inbreds, (62 for six segregating loci).
`
`65
`
`Probability of Finding an Inbred with m of n
`Favorable Alleles
`
`Assume each parent has n/2 of the favorable alleles and.
`only 4% of the combinations of loci are economically useful.
`
`

`

`5,689,036
`
`5
`
`
`No. of
`No.of favorable
`No.additional
`segregating
`alleles in Parents
`favorable alleles in
`Probability that
`
`loci (0)
`(n/2)
`new inbred
`genotype occurs*
`20
`10
`14
`3x 10%
`24
`12
`16
`2x 10%
`28
`14
`18
`1x 10%
`32
`16
`20
`8x 10%
`36
`18
`22
`5x 10%
`40
`20
`24
`3x 10%
`44
`22
`26
`2x 104
`
`24 2848 1x 10*
`
`
`
`*Probability that a useful combination exists, does not include the probability
`of identifying this combination if it does exist.
`
`The possibility of having a usably high probability of
`beingable to identify this genotype based onreplicated field
`testing would be most likely smaller than this, and is a
`function of how large a population of genotypes is tested and
`how testing resources are allocated in the testing program.
`Pioneer research station staff propose about 400 to 500
`new inbreds each year from over 2,000,000 pollinations. Of
`those proposed new inbreds, less than 50, and more com-
`monly less than 30, are actually selected for commercial use.
`
`SUMMARY OF THE INVENTION
`
`According to the invention, there is provided a hybrid
`maize plant, designated as 3730, produced by crossing two
`Pioneer Hi-Bred International, Inc proprietary inbred maize
`lines. This inventionthus relates to the hybrid seed 3730, the
`hybrid plant produced from the seed, and variants, mutants,
`and trivial modifications of hybrid 3730. This hybrid maize
`plant is characterized by high yield, strong stalks, excellent
`early season growth and rapid dry-down after reaching
`maturity. It is best adapted for the North Central Region of
`the United States.
`
`DEFINITIONS
`
`In the description and 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: ABSis in absolute terms
`and %MN is percent of the mean for the experiments in
`which the inbred or hybrid was grown. 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.
`ANT ROT=ANTHRACNOSE STALK ROT
`(Colletotrichum graminicola), A 1 to 9 visual rating indi-
`cating the resistance to Anthracnose Stalk Rot. A higher
`score indicates a higher resistance.
`BAR PLT=BARREN PLANTS.Thepercent of plants per
`plot that were not barren (lack ears).
`BRT STK=BRITTLE STALES. 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 in paired
`comparisons and on a 1 to 9 scale (9=highest resistance) in
`Characteristics Charts.
`
`10
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`25
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`30
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`45
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`50
`
`355
`
`BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain
`at harvest in bushels per acre adjusted to 15.5% moisture.
`CLN=CORN LETHAL NECROSIS (synergistic interac-
`tion of maize chlorotic mottle virus (MCMV)in combina-
`tion with either maize dwarf mosaic virus (MDMV-A or
`
`65
`
`6
`MDMV-B)or wheat streak mosaic virus (WSMY)). A 1 to
`9 visual rating indicating the resistance to Corn Lethal
`Necrosis. A higher score indicates a higher resistance.
`COM RST=COMMONRUST (Puccinia sorghum). A 1
`to 9 visual rating indicating the resistance to Common Rust.
`A higher score indicates a higher resistance.
`CRM=COMPARATIVE RELATIVE MATURITY (see
`PRM).
`D/D=DRYDOWN.This represents the relative rate at
`which a hybrid will reach acceptable harvest moisture
`compared to other hybrids on a 1—9 rating scale. A high score
`indicates a hybrid that dries relatively fast while a low score
`indicates a hybrid that dries slowly.
`D/E=DROPPED EARS.Represented in a 1 to 9 scale in
`the Characteristics Chart, where 9 is the rating representing
`the least, or no, dropped ears.
`DIP ERS=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.
`DRP EAR=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.
`D/T=DROUGHT TOLERANCE.This represents a 1-9
`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.
`EAR HT=EAR HEIGHT. The ear height is a measure
`from the ground to the highest placed developed ear node
`attachment and is measured in inches. This is represented in
`a 1 to 9 scale in the Characteristics Chart, where 9 is highest.
`EAR MLD=General Ear Mold. Visual rating (1-9 score)
`where a “1” is very susceptible and a “O”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.
`EAR SZ=EAR SIZE.A 1 to 9 visual rating of ear size. The
`higher the rating the larger the ear size.
`ECB 1LF=EUROPEAN CORN BORER FIRST GEN-
`ERATION 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.
`ECB 2IT=EUROPEAN CORN BORER SECOND GEN-
`ERATION INCHES OF TUNNELING(Ostrinia nubitalis).
`Average inches of tunneling per plant in the stalk.
`ECB 2SC=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 European Corn Borer, Second Gen-
`eration. A higher score indicates a higher resistance.
`ECB DPE=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 corn borer infestation.
`E/G=EARLY GROWTH.This represents a 1 to 9 rating
`for early growth, scored when twoleaf collars are visible.
`EST CNT=EARLY STAND COUNT.This is a measure
`of the stand establishment in the spring and represents the
`number of plants that emerge on per plotbasis for the inbred
`or hybrid.
`EYE SPI=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.
`
`

`

`5,689,036
`
`7
`FUS ERS=FUSARIUM EAR ROT SCORE (Fusariurn
`moniliforme or Fusarium subglutinans). A 1 to 9 visual
`rating indicating the resistance to Fusarium ear rot. A higher
`score indicates a higher resistance.
`G/A=GRAIN APPEARANCE.Appearanceofgrain in the
`grain tank (scored down for mold, cracks, read streak, etc.).
`GDU=Growing Degree Units. Using the Barger Heat Unit
`Theory,
`that assumes that maize growth occurs in the
`temperature range 50° F-86° 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.
`GDU PHY=GDU TO PHYSIOLOGICAL MATURITY.
`The numberof growing degree units required for an inbred
`or hybrid line to have approximately 50 percent of plants at
`physiological maturity from time of planting. Growing
`degree units are calculated by the Barger method.
`GDU SHD=GDU TO SHED. The number of growing
`degree units (GDUs) or heat units required for an inbred line
`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:
`
`GDU = (Max. temp. +Min temp) _ 59
`
`The highest maximum temperature used is 86° F. and the
`lowest minimum temperature used is 50° F. For each inbred
`or hybrid it takes a certain number of GDUsto reach various
`stages of plant development.
`GDU SLK=GDU TO SILK. The number of growing
`degree units required for an inbred line 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.
`GIB ERS=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.
`GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A1
`to 9 visual rating indicating the resistance to Gray Leaf Spot.
`A higher score indicates a higher resistance.
`GOS WLT=Goss’ Wilt (Corynebacteriurn nebraskense).
`A1 to 9 visual rating indicating the resistance to Goss’ Wilt.
`A higher score indicates a higher resistance.
`GRN APP=GRAIN APPEARANCE.This is a 1 to 9
`rating for the general appearanceofthe 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
`telatively high plant densities on 1-9 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.
`HC BLT=HELMINTHOSPORIUM CARBONUM LEAF
`BLIGHT (Helminthosporium carbonum). A 1 to 9 visual
`Tating indicating the resistance to Helminthosporium infec-
`tion. A higher score indicates a higher resistance.
`HD SMT=HEAD SMUT (Sphacelotheca reiliana). This
`score indicates the percentage of plants not infected.
`INC D/A=GROSS INCOME (DOLLARS PER ACRE).
`Relative incomeper acre assuming drying costs of two cents
`
`8
`per point above 15.5 percent harvest moisture and current
`market price per bushel.
`INCOME/ACRE.Income advantage of hybrid to be pat-
`ented over other hybrid on per acre basis.
`INC ADV=GROSS INCOME ADVANTAGE. GROSS
`INCOME advantage of variety #1 over variety #2.
`L/POP=YIELD AT LOW DENSITY. Yield ability at
`relatively low plant densities on a 1-9 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.
`MDM CPX=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.
`MST=HARVEST MOISTURE.Themoistureis the actual
`percentage moisture of the grain at harvest.
`MST ADV=MOISTURE ADVANTAGE. The moisture
`advantage of variety #1 over variety #2 as calculated by:
`MOISTURE of variety #2—-MOISTURE of variety
`#1=MOISTURE ADVANTAGEofvariety #1.
`NLF BLT=Northern Leaf Blight (Helminthosporiurn
`turcicum or Exserohilum turcicum). A 1 to 9 visual rating
`indicating the resistance to Northern Leaf Blight. A higher
`score indicates a higher resistance.
`PHY CRM=CRM at physiological maturity.
`PLT HT=PLANT HEIGHT. This is a measure of the
`height of the plant from the groundtothe tip of the tassel in
`inches. This is represented as a 1 to 9 scale, 9 highest, in the
`Characteristics Chart.
`
`POL SC=POLLEN SCORE.A 1 to 9 visual rating indi-
`cating the amount of pollen shed. The higher the score the
`more polien shed.
`POL WT=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.
`through
`It should be understood that the inbred can,
`routine manipulation of cytoplasmic or other factors, be
`produced in a male-sterile form. Such embodiments are also
`contemplated within the scope of the present claims.
`POP K/A=PLANT POPULATIONS. Measured as 1000s
`per acre.
`POP ADV=PLANT POPULATION ADVANTAGE.The
`plant population advantage of variety #1 over variety #2 as
`calculated by PLANT POPULATIONofvariety #2=PLANT
`POPULATION of variety #1=PLANT POPULATION
`ADVANTAGEofvariety #1.
`PRM=PREDICTED Relative Maturity. This trait, pre-
`dicted relative maturity, is based on the harvest moisture of
`the grain. The relative maturity rating is based on a known
`set of checks andutilizes standard linear regression analyses
`and is referred to as the Comparative Relative Maturity
`Rating System that is similar to the Minnesota Relative
`Maturity Rating System.
`PRM SHD=Arelative 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 onrelative maturity of commercial checks.
`PRO=PROTEIN RATING. Rating on a 1 to 9 scale
`comparing relative amount of protein in the grain compared.
`to hybrids of similar maturity. A “1” score difference rep-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`35
`
`65
`
`

`

`5,689,036
`
`9
`resents a 0.4 point change in grain protein percent (e.g.,
`8.0% to 8.4%).
`P/Y=PROTEIN/YIELD RATING.Indicates, on a 1 to 9
`scale, the economic value of a hybrid for swine and poultry
`feeders. This takes into account the income due to yield,
`moisture and protein content.
`ROOTS(%)=Percent of stalks NOT root lodged at har-
`vest.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`Pioneer Brand Hybrid 3730 is a single cross, yellow
`endosperm, dent maize hybrid with high yield in its matu-
`rity. Hybrid 3730 demonstrates an unexpected, excellent
`early season growth that is very rapid relative to other
`hybrids for its maturity. In addition, Hybrid 3730 has very
`good stalks and rapid dry-down after reaching maturity.
`Hybrid 3730 also demonstrates improved staygreen over
`other hybrids in its maturity.
`:
`This hybrid hasthe following characteristics based on the
`data collected primarily at Johnston, Iowa.
`
`TABLE 1
`VARIETY DESCRIPTION INFORMATION
`HYBRID = PIONEER BRAND 3730
`
`Region Best Adapted: North
`Type: Dent
`
`B.
`
`10
`TAS WT=TASSEL WEIGHT.Thisis the average weight
`of a tassel (grams) just prior to pollen shed.
`TEX EAR=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).
`TIL LER=TILLERS.A count of the number oftillers per
`plot that could possibly shed pollen was taken. Data is given
`R/L=ROOT LODGING.A1to 9 rating indicating the
`as a percentage oftillers: number oftillers per plot divided
`10
`level of root lodging resistance. The higher score represents
`by number of plants per plot.
`higher levels of resistance.
`TST WT (CHARACTERISTICS CHART)=Test weight
`RT LDG=ROOT LODGING.Rootlodging is the percent-
`on a 1 to 9 rating scale with a 9 being thehighest rating.
`age of plants that do not root lodge; plants that lean from the
`TST WT=TEST WEIGHT (UNADJUSTED). The mea-
`vertical axis as an approximately 30° angle or greater would
`sure of the weightof the grain in pounds for a given volume
`be counted as root lodged.
`RTL ADV=ROOT LODGING ADVANTAGE. Theroot
`(bushel).
`lodging advantage of variety #1 over variety #2.
`TST WTA=TEST WEIGHT ADJUSTED.The measure of
`S/L=STALK LODGING. A 1 to 9 rating indicating the
`the weight of the grain in pounds for a given volume
`level of stalk lodging resistance. The higher scores represent
`(bushel) adjusted for 15.5 percent moisture,
`higher levels of resistance.
`TSW ADV=TEST WEIGHT ADVANTAGE.The test
`SCT GRN=SCATTER GRAIN. A | to 9 visual rating
`weight advantage of v