GENETIC LINKAGES BETWEEN AGRONOMICALLY IMPORTANT GENES AND RESTRICTION FRAGMENT LENGTH POLYMORPHISMS

Abstract: The invention concerns methods for finding correlations between agronomically important genes in corn and restriction fragment length polymorphisms and DNA probes shown to reveal polymorphisms.

Description: - 1 - TITLE OF THE INVENTION GENETIC LINKAGES BETWEEN AGRONOMICALLY IMPORTANT GENES AND RESTRICTION FRAGMENT LENGTH POLYMORPHISMS This is a continuation-in-part of application Serial No. 158,469, filed February 22, 1988. Field of the Invention This invention is in the field of genetic engineering and corn breeding. More specifically, the invention concerns methods for finding correlations between agronomically important genes in corn and restriction fragment length polymorphisms through the use of DNA probes that are shown to reveal polymorphisms. Background of the Invention The goal of plant breeding is to combine in a single variety/hybrid various desirable traits of the parental lines and to exploit the heterosis exhibited by the cross of the parental lines. For field crops, these traits may include resistance to diseases and insects, tolerance 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 characteristies such as germination and stand establishment, growth rate, maturity and fruit size are important. Field crops are bred through techniques that use the plant's method of pollination. A plant is defined as self- pollinating 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 ho ozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two homozygous plants from differing backgrounds or two homozygous lines (inbred lines) produces a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants, each heterozygous at a number of gene loci, will produce a population of hybrid plants. Each of these plants differ genetically and the population will not be uniform. Corn ( Zea mays L.) plants are bred by both self- poll nation and cross-pollination techniques. Corn has male flowers, located on the tassel, and female flowers, located on the ear, on the same plant. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the incipient ears. The development of corn hybrids requires the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Pedigree breeding and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs are designed to combine desirable traits from two or more inbred lines or various broad-based sources into breeding pools from which new inbred lines are developed by selfing and selection of desirable phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which have commercial potential as F hybrids. -3- The identification of desirable agronomic traits has traditionally been done by phenotypic selection. It would be valuable to plant breeders to be able to identify genes affecting agronomic traits on the plant genome through the identification of linked genetic markers. Technology now provides a method for identifying genetic markers with potential application in plant breeding through the use of restriction fragment length polymorphisms (RFLPs). It is therefore of great importance to investigate the possibility of using genetic linkage analysis between DNA polymorphisms and traits of agronomic importance in order to identify agronomically important genes, to classify inbreds, hybrids and breeding populations according to their genes, and to then more effectively incorporate these genes into improved inbreds and hybrids. Summary of the Invention The invention is based on the use of RFLPs to identify genetic linkages with agronomically important genes. This invention consists of three major parts: (1) DNA probes shown to reveal polymorphisms between two parent inbred lines and having known chromosomal locations, (2) statistical techniques that can find correlations between the inheritance of one or more DNA probes and the phenotype of the plants under investigation, and (3) methods for using the identified genetic linkage between specific probes and genetic components of agrono ically important traits in plant breeding. In particular, this invention relates to a method for determining a particular trait in a maize plant which comprises analyzing each maize chromosome for DNA polymorphisms linked to a particular trait. Any of a variety of RFLPs, probes and restriction enzymes can be used, as illustrated herein. The invention also relates to specific DNA probes that can be used in the method of this invention. The invention further relates to use of newly-identified relationships -4- between agronomic traits and genetic markers to enhance plant breeding. Detailed Description of the Invention 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: Restriction Endonuclease. A restriction endonuclease or restriction enzyme is an enzyme that recognizes a specific base sequence in a double-stranded DNA molecule, and will cleave both strands of the DNA molecule at every place where this sequence appears. Restriction Fragments. The DNA molecules produced by digestion with a restriction endonuclease are referred to as restriction fragments. Any given genome will be digested by a particular restriction endonuclease into a discrete set of restriction fragments. The DNA fragments that result from restriction enzyme cutting are separated and displayed by electrophoresis through agarose gels. Restriction Fragment Length Polymorphism (RFLP). The genomic DNA of two individuals in a species, for example, will differ in sequence at many sites. When these differences occur in the recognition site for a restriction endonuclease, the enzyme will not cleave the DNA molecule at that point. Likewise, a variation may introduce a recognition site where none exists in the other individual, causing the DNA to be cut by the restriction enzyme at that point. Because of this, digestion of the two individuals' DNA will produce fragments having different lengths. A polymorphism in the length of restriction fragments produced by digestion of the DNA of the two individuals will result. -5- Aoarose Gel Electrophoresis. To detect a polymorphism in the length of restriction fragments, an analytical method for fractioning double-stranded DNA molecules on the basis of size is required. The most commonly used technique for achieving such fractionation is agarose gel electrophoresis. The rate at which DNA fragments move in such gels depends on their size; thus, the distances traveled decrease as the fragment lengths increase. The DNA fragments fractionated by agarose gel electrophoresis can be visualized directly by a staining procedure if the number of fragments included in the pattern is small. However, most genomes, including the maize genome, contain far too many DNA sequences to produce a simple pattern of restriction fragments. In order to visualize a small subset of these fragments, a methodology referred to as the Southern hybridization procedure can be applied. Southern Hybridization Procedure. The purpose of the Southern hybridization procedure, also referred to as Southern blotting, is to transfer physically DNA fractionated by agarose gel electrophoresis onto a support such as nylon membrane or nitrocellulose filter paper while retaining the relative positions of DNA fragments resulting from the fractionation procedure. The methodology used to accomplish the transfer from agarose gel to the support is to draw the DNA from the gel into the support by capillary action. Nucleic Acid Hybridization. Nucleic acid hybridization is used to detected related DNA sequences by hybridization of single-stranded DNA on supports such as nylon membrane or nitrocellulose filter papers. Nucleic acid molecules that have complementary base sequences will reform the double- stranded structure if mixed in solution under the proper conditions. The double-stranded structure will be formed between two complementary single-stranded nucleic acids even if one is immobilized on a support. In the Southern hybridization procedure, the latter situation occurs. As noted previously, the maize genomic DNA is digested with a restriction endonuclease, fractionated by agarose gel electrophoresis, converted to the single stranded form, -6- and transferred to the support, making it available for reannealing to the hybridization probe. Hybridization Probe. To detect a particular DNA sequence in the Southern hybridization procedure, a labeled DNA molecule or hybridization probe is reacted to the fractionated DNA bound to a support such as nylon membrane or nitrocellulose filter paper. The areas on the filter that carry DNA sequences complementary to the labeled DNA probe become labeled themselves as a consequence of the reannealing reaction. The areas of the filter that exhibit such labeling can then be detected according to the type of label used. The hybridization probe is generally produced by molecular cloning of a specific DNA sequence from the maize genome. Description of the Preferred Embodiments This invention is based on the use of restriction fragment length polymorphism (RFLP) to identify genetic linkages to agronomically important genes. This invention consists of methods for locating agronomically important genes based on RFLPs and of novel DNA probes for use in the methods. Specifically this invention is based on the identification of restriction fragments from the ten chromosomes of maize that define genetic linkages between specific chromosomes and agronomically important traits using analysis techniques that can find correlations between the inheritance of one or more DNA sequences and the phenotype of the plant under investigation. Identifying RFLPs involves the use of restriction endonucleases, DNA mapping, and cloned DNA probes. Restriction endonucleases cleave the genomic DNA molecules at specific sites. Cloned RFLPs are detected as the differences in the size of restriction fragments observed in Southern blotting experiments using cloned DNA probes free of repetitive sequences. Certain polymorphisms can thus be genetic markers that are associated with a specific agronomic trait. -7- Establishment of such an association permits the monitoring of heritable sequences of genomic DNA. Probes that can detect sequences associated with specific traits can therefore be derived from known gene loci or from anonymous DNA segments. RFLPs appear to be present in all regions of the maize genome, thus making it feasible to construct a detailed maize genetic linkage map and thereby localize agronomically important genes. RFLPs that identify genetic characteristics are particularly useful in breeding programs in order to select for certain traits. Other uses of RFLPs may include varietal identification, identification and mapping of quantitative trait loci (QTL), quantification of genetic diversity in a crop population, screening genetic resource strains, or populations for useful quantitative trait alleles and their marker-assisted introgression from the resource strain to a commercial variety, and marker-assisted early selection of reco binant inbred lines in plant pedigree breeding programs. In accordance with the invention, RFLPs are used to identify genetic linkage to agronomically important genes. This invention consists of three major parts: (1) DNA probes shown to reveal polymorphisms between two parent inbred lines and having known chromosomal locations, (2) statistical techniques that can find correlations between the inheritance of one or more DNA probes and the phenotype of the plants under investigation, and (3) use of the identified genetic linkages between specific probes and genetic components of agronomically important traits as an aid in selecting plants and populations in "classical" plant breeding based on Mendelian genetics. More particularly, the invention comprises determining a particular trait in a maize plant by analyzing maize chromosomes for DNA polymorphisms and linkage to that trait. Specific traits determined include adjusted yield, plant yield, plant height, ear height, GDU shed, GDI) silk, grain moisture, root lodging, stalk lodging, and stay green. A definition of each of these traits is as fol1ows: Adjusted Yield, Bushels/Acre. The yield in bushels/acre is the actual yield of the grain at harvest adjusted to 15.5% moisture. Plant Yield. The plant yield is the field weight divided by the number of plants per plot. Plant Height. This is a measure of the height of the hybrid from the ground to the tip of the tassel. Ear Height. The ear height is a measure from the ground to the top ear node attachment. GPU Shed. The GDU is the number of growing degree units (GDU) required for an inbred line or hybrid to shed pollen from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: (Max. + Min.) GDU = 50 2 The highest maximum used is 86°F and the lowest minimum used is 50°F. For each hybrid it takes a certain number of GDUs to reach various stages of plant development. GDUs are a way of measuring plant maturity. Grain Moisture. The grain moisture is the percentage moisture of the grain at harvest. Root Lodging. The root lodging is the percentage of plants that do not root lodge; i.e., those that lean from the vertical axis at an approximately 30° angle or greater would be counted as root lodged. Stalk Lodging. This is the percentage of plants that do not stalk lodge, i.e., stalk breakage, as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break off below the ear. Stay Green. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). In general, to identify a polymorphism according to this invention, DNA is extracted from the plant cell and digested with a -9- given restriction endonuclease. After the digest is obtained, and the same is separated by a standard technique such, as, for example, agarose gel electrophoresis, the separated bands are probed with a DNA fragment coding for the RFLP sequence. Specific probes that may be used in this invention are discussed in the Examples detailed below. Other probes for the polymorphisms can be obtained. For example, methods for generating additional new DNA fragments also linked with the gene for a particular trait are as follows: A first method is to test randomly chosen maize DNA fragments (either genomic or c-DNA clones) that map to the appropriate region of the maize genomic map. Such mapping can be achieved by two techniques: (a) jϋ situ hybridization to metaphase chromosome spreads; or (b) genetic linkage to any marker as already mapped to the region. For method, (a), the new fragment need not be polymorphic, but for (b), polymorphisms must first be identified by comparing the restriction pattern of the genomic DNA at the new site in unrelated plants. In method (a), the mapped fragment must still be shown to detect a polymorphism in maize DNA. The polymorphism which represents a genetic marker can then be tested for genetic linkage with genes affecting agronomic traits or can be tested for linkage to other DNA probes, such as those described below. Another method for obtaining DNA clones is to construct a library from maize DNA isolated from metaphase chromosomes that have been sorted on a fluorescence activated sorter. This method can sometimes yield purified chromosomes of 95% or greater purity. A final method of obtaining new DNA probes from the region of the chromosome containing the agronomically important gene is to use any probes already mapped to the region in order to "fish out" adjacent overlapping pieces of DNA from genomic libraries (commonly called "chromosome walking"). -10- In all the cases outlined above, a probe must ultimately be found to detect a polymorphism if it is to be useful for testing for the desired trait. The polymorphism must be found to be linked to genes affecting traits or to other useful markers in studies, or to be immediately adjacent to preexisting markers. The particular probe can be of any desired sequence length as long as it is capable of identifying the polymorphism in the involved DNA region or locus. It can be a DNA fragment by itself, or be present in longer genetic sequences or fragments, or even in a plasmid or other appropriate vehicle. Labelling and hybridization conditions can be readily determined by those of skill in the art. Usually, the stringency is standard for unique sequence DNA from within the species. A genetic linkage map was constructed from the data presented in the Examples by utilizing the algorithms described by E. Lander et al., Genomics. 1:174-181 (1987), herein incorporated by reference. These genetic linkage groups were assigned to chromosome arms by (1) using as probes DNA sequences whose location was known, and/or (2) using as markers isozyme loci whose location was known. By applying statistical analysis to maps, markers, and observed traits in field testing, a detailed table has now been constructed which associates specific genetic markers with the loci of genes which influence specific agronomic traits at a high degree of statistical significance (p<0.05), and quantitates the amount of the variation in the observed trait which is accounted for by the genes associated with individual markers. As a result, this invention also provides methods for augmenting conventional plant breeding by identification of individual plants which have the desired genotype at a genetic marker locus associated with one of the foregoing traits, comprising the steps of constructing a preferred RFLP profile for genetic markers identified herein as being associated with the trait or traits in question; -11 - deter ining the RFLP profiles of individuals in a segregating population with respect to the associated genetic markers; and selecting individuals from the population having RFLP profiles which most closely match the preferred profile. The construction of the preferred RFLP profile is a matter within the skill of the typical plant breeder. For example, the breeder will select a particular allele which provides a desirable contribution in terms of ear circumference. The contribution viewed as "desirable" will vary according to the objectives of the breeding program. In one instance, a large ear circumference be be desirable, while in another, a small ear circumference may be preferred. In yet another instance, the ear circumference per se_ may be unimportant, but the breeder may be working to develop a plant which is homozygous, i.e., has the same contribution from both parents, with respect to that trait. In any event, it will be a simple matter for the breeder to prepare a list of desired traits and to construct a preferred RFLP profile for the ideal plant from that list and the genetic marker linkages identified herein. A segregating population of plants is easy to obtain, and is typically found, for example, in the progeny of selfed F j hybrids of two different inbred lines. Once the population has been identified, RFLP profiles of each plant are performed using the well-known techniques described above. Selection of the individuals having RFLP profiles which most closely match the ideal profile simply involves comparison of each individual profile with the ideal profile. Some judgement may be required in this comparison, but the exercise of such judgment will be well within the skill of the typical plant breeder. For example, it will be extremely unlikely, and depending upon the population examined it may be genetically impossible, for any individual to have an RFLP profile which precisely matches the ideal. However, one or more individuals will have a greater percentage of matches to the ideal than the remainder of the population. Where two individuals have approximately equal matches to the ideal, the breeder will make tradeoffs among traits. One individual may offer the desired allele for ear circumference and kernel row length, but lack the desired allele for stay green. Another individual will offer the desired allele for ear circumference and stay green, but will lack the desired allele for kernel row length. Selection between the two will simply involve a decision by the breeder on whether it is preferable to have the allele for kernel row length or for stay green, and in fact such decisions will be a relatively trivial exercise compared to the judgements made in conventional plant breeding, which are based on less clear-cut information about the genetic makeup of the individuals. The breeder also has the option of proceeding to the next stage of breeding with both individuals. The following tables identify specific trait-marker linkages for a number of agronomic traits commonly involved in plant breeding. Markers identified by the prefix PIO- are available commercially from Pioneer Hi-Bred International, Des Moines, IA 50309. Markers identified by the prefixes BNL- and UMC- are publicly available markers which can be obtained from Brookhaven National Laboratory and the University of Missouri, respectively. The remainder of the markers are either published isozyme markers of known genetic location, such as AMP1, MDH2 and GLU1, or are probes for specific mutant genes which are well known and whose location has been identified, as mentioned above. These Tables identify linkages observed in bulk F4 populations, which reflect inbred performance, and in topcross trials, which reflect performance in hybrids. As might be expected, some overlap is observed between the two sets of linkages. Traits not self-explanatory and not identified elsewhere herein include: Grain quality. This is a subjective score based on visual grading of the shelled corn in terms of moldy and cracked kernels. -13- Cold test germination. This is a percentage germination test performed in a cold chamber, and evaluates germination performance under adverse conditions. Soak test germination. This is a test of percentage germination under ideal germination conditions, but after the seed has been soaked prior to planting. Bulk density, ad.iusted. This is a measure of weight per unit volume of bulk seed, adjusted to 15.5% moisture. Dropped ears. This is a raw count of ears found on the ground per two-row test plot. European corn borer second brood tolerance. This is a visual evaluation of plant damage caused by infestation by the second annual brood of the European corn borer caterpillar. Plant yield. This is the yield of a test plot divided by the number of plants in the test plot. Early stand count. This is a raw count of plants per test plot (or number of seeds planted) after emergence and before thinning. Bare tip. Also called nose back, this is a visual grade based upon the amount of ear tip which is devoid of kernels. "Statistically transformed" measurements involve the same physical measurements or evaluations as the raw scores, but the raw scores have then been put through a standard statistical transformation to fit them to a normal curve. Unless otherwise indicated, all values measured are averages over the individual ear, plant, test plot or larger field. Tabl e 1 List of genetic markers associated with quantitative traits evaluated in topcross progeny. TRAIT=Yield. Bushels/Acre (BU ACR) BNL6.20 PI020576 PI020508 PI020508 BNL10.24 BNL6.16 PI02071 PI020589 PI020708 PI020684 UMC1I0 BNL8.32 PI020714 TRAIT= % Moisture (MST) ■ 15- T=Yield/% moisture (YLDMST) TRAIT=Dropped Ears, Statistically transformed (FOGDE) P1020690 TRAIT=Ear height (EARHT) UMC120 PI020626 PI02075 - 17- TRAIT=Root lodging (RT LDG) UMC057 UMC044 TRAIT=Stalk lodging, statistically transformed (FOGSTL) PI020537 PI01012 PI0205 E8 PI020558 PI020597 PI020622 PI0612 PI01524 UMC065 PI01537 UMC110 PI020626 PI02075 PI020646 PI01513 UMC057 BNL10.13 UMC044 Table 2 List of genetic markers associated with quantitative traits as identified in bulk f4 progeny TRAIT=Yield. Bushels/Acre (BU ACR) BNL5.59 BNL6.20 UMC043 PI020622 PI01518 PI020589 PI01513 TRAIT=Plant yield (PLNTYLD) PI020537 PI020518 BNL6.20 UMC043 PI01518 PI020589 PI0105 SHI TRAIT=Weight of 100 kernels (CKWT) PI020603 PI020689 PI020682 PI020674 BNL8.23 PI067 UMC110 PI020714 BNL14.28 UMC057 TRAIT=Dropped ears, statistically transformed (FOGDE) PI0205 PI02017 PI020558 PI020508 UMC066 UMC019 PI01518 PI020531 PI020527 PI020528 PI067 BNL8.39 PI020593 • 19- TRAIT=Cold test germination (CTST) UMC034 BNL8.33 UMC065 UMC021 PI020708 PI020684 BNL8.32 BNL8.39 GLU1 PI020646 TRAIT=Soak test germination (SKTST) PI020518 PI020511 PI020509 BNL8.33 PI020569 PI020708 PI020746 BNL9.11 PI02052 GLU1 TRAIT=Earlv stand count (ESTCNT) UMC061 PI020713 PI020725 PI020597 UMC042 BNL7.65 BNL8.33 PI01016 PI065 TRAIT=Ear circumference EARCIR TRAIT=Ear diameter (EARDIA) PI020509 PI020508 BNL10.24 UMC999 PI02071 PI01025 PI01518 PI020595 PI01537 PI020708 UMC081 TRAIT=Ear length (EARLGT) • 21 - TRAIT=Bare tip (NOSBAC) PI01040 SHI PI020626 TRAIT=Number of kernel rows per ear KERROW ■ 23- T=Yield/% moisture (YLDMST) BNL10.39 UMC120 PI0105 -25- TRAIT=Root lodging (RT .DG) PI02075 UMC057 TRAIT=Stalk lodging, statistically transformed (FOGSTL) BNL8.39 PI020593 PI01033 UMC057 BNL10.13 -27- Having now defined the invention, the same will be understood by means of specific examples which are, however, not intended to be limiting unless otherwise specified. EXAMPLE 1 Determination of Agronomically Useful Phenotypes Development of Progenies for Field Testing The inbreds B73 and Mol7 were crossed to produce the F j hybrid designated B73/Mol7. Hybrid seed was planted, several plants selfed, and the seed bulked to produce the F2 generation designated B73/Mol7)X. 175 seeds from the F2 generation were planted in peat pots in a greenhouse. Seedlings were transplanted to the field at normal planting time. Each plant was self-pollinated using the usual procedures for pollination of corn to produce the F3 ears designated B73/Mol7)Xn where n ranged from 1 to 175 and represents the specific F3 ear. Ears were harvested, identified to plant number, and kept separate. Each ear therefore contained seed that would generate an F3 family. A winter nursery was used to produce seed for field testing from the F3 ears. Twenty-four kernels from each of 112 F3 ears were planted in an isolated crossing block. Interplanted around those 112 rows were rows of Pioneer inbred V78. Tassels were removed by hand from every plant of the 112 F3 families. Thus, the ear of each F3 plant from the B73/Mol7 cross was pollinated by the inbred V78. For each of the 112 F3 families, each ear from the 24 plants were harvested, dried, shelled, and bulked together. These 112 entities of seed were considered as 112 F3 topcrosses to inbred V78. In addition, a separate 24 kernels from each F3 ear were planted in 112 rows, one for each F3 family. Within each row, ten plants were self-pollinated to derive F4 ears. For each of the 112 F3 families, each of the self-pollinated ears were harvested, dried, shelled, and bulked together. These 112 entities of seed were considered as 112 F4 bulks. Determination of Whole Plant Phenotype The 112 F3 topcrosses and 112 F4 bulks were evaluated in field performance tests (yield tests). The tests were conducted according to standard yield test procedures as used in the profession of agronomy and crop breeding. Each of the 112 F3 topcrosses comprised an entry in a randomized complete block design. Check entries were added making a total entry list of 125. The experiment was grown in two replications at each of four locations in central Iowa. Each replication of an entry was planted in a two-row plot. Plots were 5.3 meters long with .76 meters between rows. Plots were overplanted and thinned to even and uniform stand of 50 plants per plot. These plants were allowed to grow to maturity and data were collected for various traits throughout the season. The 112 F4 bulks were tested identically except there were three test locations instead of four. Two locations were in central Iowa, and the other was in central Indiana. The following traits were measured on each plot. Each is considered an agronomic trait important in corn breeding. TRAIT ABBREVIATION DESCRIPTION Adjusted Yield BUACR Field weight adjusted to 15.5% moisture expressed as bushels per acre. Plant Yield PLNTYLD Field weight divided by the number of plants per plot. Plant Height PLTHT From ground to tip of tassel. Ear Height EARHT From ground to top ear node. • 29- GDU Shed GDUSHD Accumulated heat units to the day that 40% of plants in a plot were shedding pollen. GDU Silk GDUSLK Accumulated heat units to the day that 50% of plants in a plot had silks emerged at least one inch. Grain Moisture MST Percent moisture in grain. Root Lodging RTLDG Number of plants per plot leaning from vertical more than 30". Stalk Lodging STKLDG Number of plants with stalks broken below the ear at harvest. Stay green STAGRN Relative amount of green leaf tissue remaining at physiological maturity. The data from plots of F3 topcrosses and F4 bulks were made available for statistical analyses in October 1987. Data were collected on the progenies rather than the original, individual F2 plants because of the well-established principle that the heritability of these complex traits is very low when measured on a single plant basis. Each trait is probably governed by more than one gene, and expression is affected by environmental conditions. Thus, by testing F3 topcrosses and F4 bulks, in replicated trials, a more accurate measure of phenotype was obtained. These measures a phenotype of F3 and F4 progeny were considered accurate estimates of the phenotype of each 112 F2 plants from which they were derived. EXAMPLE 2 Identification of Informative Probes Maize DNA Isolations Total DNA can be isolated from various maize tissues (leaves, seedlings, etc.) by any one of several standard methods (for example see Maniatis et al .. Molecular Cloning. A Laboratory Manual (1982); Dillon et al . , Recombinant DNA Methodology (John Wiley & Sons 1985). -30- Southern Hybridization Agarose gel electrophoresis of restriction enzyme- generated fragments of maize DNA, transfer of the DNA to nylon membranes, and hybridization with a radioactively labeled probe can be done by any of several standard methods (for example, see Maniatis et al . , Molecular Cloning, A Laboratory Manual). Identification of Informative DNA Probes Total DNA from the maize inbred B73 was purified and digested to completion with the restriction enzyme Pst I and electrophoresed on an agarose gel. Fragments from the size classes 600-1,000 base pairs (bp), 1,000-1,500 bp, 1,500-2,000 bp, and 2,000-2,500 bp were ligated into one of several E. coli vectors at the Pst I site and transformed into one of several laboratory strains of E. coli using standard conditions (for example, see Maniatis et al . , Molecular Cloning, A Laboratory Manual). Colonies containing plasmids with single inserts were identified by plas id minipreps and agarose gel electrophoresis. Plasmid DNA from each previously characterized colony was purified, digested to completion with Pst I, and the two fragments (maize DNA insert and cloning vector) separated by agarose gel electrophoresis. Isolated maize insert DNA, still in the agarose plug, was radioactively labeled with P 32 by either nick translation or random priming. Southern hybridization was done using labeled maize insert DNA as probe and total cell DNA from various maize inbreds digested to completion with one or more restriction enzymes as target. After washing the membrane to remove any nonhybridized probe, the membranes were subjected to autoradiography. Probes were selected for further consideration if (1) 1-3 autoradiographic bands were observed for at least one restriction enzyme, and (2) band patterns were different between at least two maize inbreds. -31 - EXAMPLE 3 Determination of Linkage Among RFLP Marker Loci Individual probes were hybridized to DNAs prepared from each of the 112 F2 plants described above. Each plant was scored for its allelic composition at the locus defined by the probe. Scores were A (only band(s) contributed by B73 present), B (only band(s) contributed by Mol7 present) or H (bands from both parents present). A genetic linkage map was constructed from these data by using the algorithms described by Lander et al . (1987), supra. These genetic linkage groups were assigned to chromosome arms by (1) using as probes DNA sequences whose location was known, and/or (2) using as markers isozyme loci whose location was known. EXAMPLE 4 Determination of Correlations between Phenotypic Expression of Traits and Specific Probes Assessment of the Quality of Quantitative Trait Data Obtained in the Field and Determination of Quantitative Trait Data to Group for Investigation Linkages between RFLP Marker Loci and Quantitative Trait Loci Analysis of variance due to environments, genotypes, and genotype by environment interactions were determined for all quantitative traits. A maximum/minimum test for heterogeneity of variances among locations was used to make sure that data from all locations had similar variability. Data from traits which showed significant variability among genotypes and were highly heritable (> 0.65) were kept for analyses of associations with RFLP marker loci. Because all traits showed some genotype by environment interactions, it was decided to investigate relationships between probes and quantitative traits by location. Linear and Non-linear Relationships between Quantitative Traits and RFLP Marker Loci Were Used to Detect Linkages between Marker Loci and Quantitative Trait Loci (QTLs). Data from each test were analyzed using a two-factor analysis of variance for each pair-wise combination of quantitative trait and marker locus; where factors were the marker locus and environment. Data from traits which showed no significant locus by environment interactions, as judged by an F-test, were investigated across environments. Data from traits which showed significant locus by environment interactions were investigated by environment. An F-test was used to determine if significant variability in the expression of a trait was associated with differences in genotypes of a RFLP marker locus. The marker locus is considered linked to a QTL if there is a significant F-value for the variability at the marker locus and either the linear or non-linear orthogonal contrasts associated with the marker. Based upon the above criteria, loci involved in the expression of grain moisture, adjusted yield, stalk lodging, root lodging, plant height, ear height, plant yield, GDU shed, GDU silk, and stay green in F3 top crosses (TC) and F4 bulk tests (PS) are found to be linked with the indicated mapped probes (Table 3). The numbers in each TC or PS column give the percent of the total variation for that trait expressed in the population associated with a particular RFLP locus. Only values significant at the 0.05 level are shown. CM refers to spacing between the probes in centi-Morgans. Having now fully described the invention, it will be understood that the same can be carried out within a broad and equivalent range of probes, conditions, enzymes, detection techniques, and the like without affecting the spirit or scope of the invention or of any embodiment herein.

Claims: -33- WHAT IS CLAIMED IS: 1. A method of determining a correlation between a phenotypic trait in maize and a restriction fragment length polymorphism comprising: (a) digesting genomic DNA from a maize plant with a restriction endonuclease that produces a restriction fragment length polymorphism digestion pattern that is associated with said trait; (b) separating the fragments obtained from said digestion in step (a); (c) detecting said restriction fragment length polymorphism with a hybridization probe containing sequence information capable of hybridizing to and identifying said RFLP, thereby generating a restriction pattern; and (d) correlating the presence or absence of said RFLP in said digest with the respective presence or absence of said trait. 2. The method of claim 1 wherein said trait is selected from the group consisting of adjusted yield, plant yield, plant height, ear height, GDU shed, GDU silk, grain moisture, root lodging, stalk lodging, and stay green. 3. The method of claim 1 wherein said maize plant is maize inbred B73 or maize inbred Mol7. 4. The method of claim 1 wherein said maize plant is a cross between B73 and Mol7. 5. The method of claim 1 wherein said hybridization probe is a genomic DNA probe made from maize inbred B73 DNA digested with restriction endonuclease PST I. 6. A method for identifying and mapping quantitative trait loci (QTL) for a phenotypic trait in maize plant B73, Mol7 or a cross thereof by analyzing the chromosomes of said plants for DNA polymorphisms and linkage to said trait comprising: (a) digesting genomic DNA from a maize plant with a restriction endonuclease that produces a restriction fragment length polymorphism digestion pattern that is associated with said trait; (b) separating the fragments obtained from said digestion in step (a); (c) detecting said restriction fragment length polymorphism with a hybridization probe containing sequence information capable of hybridizing to and identifying said RFLP, thereby generating a restriction pattern; and (d) correlating the presence or absence of said RFLP in said digest with the respective presence or absence of said trait wherein said phenotypic trait is selected from the group consisting of adjusted yield, plant yield, plant height, ear height, GDU shed, GDU silk, grain moisture, root lodging, stalk lodging, and stay green. 7. A restriction fragment length polymorphism probe that can detect a polymorphism in one or more maize plants wherein said polymorphism is linked to a phenotypic trait selected from the group consisting of adjusted yield, plant yield, plant height, ear height, GDU shed, GDU silk, grain moisture, root lodging, stalk lodging, and stay green. 8. The probe of claim 7 wherein said maize plant is inbred maize B73, Mol7 or a cross thereof. 9. A method for identifying individual corn plants which have the desired genotype at at least one selected genetic marker locus associated with a desired trait, comprising the steps of constructing a preferred RFLP profile for each selected genetic marker associated with the desired trait; -35- determining the RFLP profiles of individual plants in a segregating population of plants versus the selected genetic markers; and selecting individual plants which have RFLP profiles which most closely match the preferred RFLP profile. 10. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with yield in bushels per acre, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL5.59, BNL6.20, UMC042, PI020608, UMC043, PI020622, PI0612, PI01524, PI01518, PI020589, PI0105, SHI, and PI01513; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 11. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with plant yield, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PIO20537, PI020518, BNL8.29, PI020557, BNL6.20, UMC043, PI020622, PI01524, PI01518, PI020589, PI020523, PI020569, PI0105, SHI, PI020626, PI020646, and PI01513; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s) ; and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 12. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with the weight of 100 kernels, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020603, PI020689, PI020654, BNL5.59, PI020682, PI020674, PI020575, PI020644, BNL8.23, PI067, UMC065, UMC021, UMC110, PI020714, PI0105, PI020554, BNL14.28, UMC057, BNL10.13, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 13. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with statistically transformed dropped ear count, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI0205, PI02017, PI020558, PI020508, UMC066, UMC019, PI01518, PI020531, PI020527, PI020528, PI067, BNL8.39, and PI020593; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 14. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus -37- associated in inbred performance with cold test germination, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC034, BNL8.33, PI01017, PI067, UMC065, UMC021, PI020569, PI01537, PI020708, PI020684, PI020746, UMC116, BNL8.32, BNL8.39, SHI, PI065, GLU1, and PI020646; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 15. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with soak test germination, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020518, PI020511, PI020509, BNL8.33, PI020569, PI020708, PI020746, BNL9.11, PI02052, and GLU1; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 16. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with early stand count, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC061, PI020713, PI020725, PI020597, UMC042, BNL7.65, BNL8.33, PI01016, and PI065; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 17. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with ear circumferenc, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020603, PI020640, BNL6.20, PI020508, BNL5.37-, BNL10.24, UMC999, PI020726, UMC031, BNL5.46, PI020597, UMC042, UMC019, BNL7.65, UMC015, PI02071, PI01025, PI020608, PI020622, PI0612, PI01524, PI01518, PI020589, PI020531, PI02026P, PI067, PI020595, PI020599, PI020569, PI01537, PI020708, PI020746, UMC116, BNL10.39, UMC120, PI0105, UMC081, and PI065; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 18. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with ear diameter, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020508, PI020508, BNL5.37-, BNL10.24, UMC999, PI020726, UMC031, PI02071, PI01025, PI020622, PI0612, PI01518, PI020595, PI020599, PI020569, PI01537, PI020708, PI020746, BNL8.39, and UMC081; -39- determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 19. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with ear length, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020557, PI020726, BNL15.45, UMC015, PI02071, PI020854, UMC062, BNL8.39, PI02020, PI01040, and PI020554; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 20. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with cob circumference, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, BNL8.29, PI020557, BNL6.20, BNL5.37-, UMC999, PI01080, PI020726, UMC031, BNL5.46, PI020597, BNL15.45, UMC042, UMC066, UMC019, BNL7.65, UMC015, PI02071, PI01025, PI020608, UMC043, PI020622, PI0612, PI01524, PI01518, PI020589, PI020531, PI02026P, UMC065, UMC081, and PI065; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and -40- selecting individual plants which have RFLP profiles which most closely match the preferred profile. 21. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with cob diameter, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, PI020713, PI020725, UMC031, BNL5.46, PI020597, BNL15.45, UMC042, UMC066, UMC019, ' BNL7.65, UMC015, PI02071, PI01025, PI020608, UMC043, PI020622, PI0612, PI01524, PI01518, PI020589, PI020531, PI02026P, UMC065, UMC021, UMC046, UMC062, MDH2, PI020599, BNL8.44, UMC081, PI065, GLU1, and PI020646; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 22. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with bare tip, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, PI020644, PI020661, PI02017, BNL10.24, BNL15.45, UMC042, UMC066, PI01025, PI0612, PI01524, PI01518, PI020589, PI020531, PI02026P, PI020854, UMC065, PI020569, PI020708, UMC116, BNL10.39, UMC012, WX1, PI02052, UMC081, CSS1, and PI020554; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and -41 - selecting individual p lants which have RFLP profiles which most closely match the preferred profile. 23. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with kernel row length, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020518, BNL8.29, PI020557, PI020726, UMC015, PI02071, PI01524, PI020523, PI020527, UMC065, UMC062, UMC116, PI01040, and SHI; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 24. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with kernel depth, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020603, PI020640, PI020661, PI01012, PIO2017, E8, PI020622, UMC021, PI020569, PI01537, PI020708, UMC110, and BNL8.39; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 25. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus -42- associated in inbred performance with kernels per kernel row, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, UMC061, BNL6.20, E8, PI020713, PI020725, UMC031, UMC043, PI020622, PI0612, PI01524, PI01518, PI020589, UMC065, PI01014, UMC062, BNL10.39, UMC081, CSS1, PI020554, and PI020626; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 26. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with number of kernel rows per ear, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020690, UMC999, PI020726, UMC031, BNL5.46, PI020597, UMC042, UMC019, BNL7.65, UMC015, PI02071, PI01025, PI020608, PI0612, PI01524, PI01518, PI020589, PI020531, PI020566, PI02026P, PI02045, UMC065, UMC046, PI020569, PI01537, PI020708, PI020684, PI020746, UMC116, UMC110, BNL8.32, BNL8.44, PI0105, UMC057, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 27. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus -43- associated in inbred performance with kernel width, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, UMC023, PI020726, UMC015, PI02071, PI020608, PI0612, PI01524, PI020589, PI020531, PI020566, PI02026P, PI02045, UMC065, PI020569, PI01537, PI020708, PI020684, PIO20746, UMC116, UMC110, BNL8.32, BNL8.44, UMC012, UMC057, BNL10.13, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 28. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with percent moisture at harvest, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC094, PI020537, PI020603, PI020689, PI020640, PI020575, PI02044, PI020661, PI020518, BNL8.29, PI020557, UMC061, UMC043, PI020622, PI020531, UMC021, PI01016, BNL8.32, PI020593, BNL10.39, PI065, PI01513, UMC057, BNL10.13, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 29. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with the ratio of yield in bushels per acre to percent moisture at harvest, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, BNL5.59, UMC061, BNL6.20, BNL6.16, UMC042, BNL7.65, PI020608, UMC043, PI020622, PI0612, PI01524, PI01518, PI020589, PI020527, PI0105, SHI, PI020646, and PI01513; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 30. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with GDU shed, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, UMC034, PI01012, PI0205, BNL5.37-, BNL5.37-, BNL10.24, PI020713, PI020725, BNL5.46, UMC042, UMC066, PI020854, BNL13.05, BNL9.11, UMC012, WX1, PI02052, UMC081, CSS1, PI020554, BNL8.17, BNL7.21B, GLU1, PI020646, PI01513, PI01033, UMC057, and BNL10.13; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 31. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with GDU silk, comprising the steps of -45- constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020690, PI020537, PI020640, BNL10.24, PI020713, PI020725, BNL5.46, UMC042, UMC066, PI01524, PI020854, BNL13.05, UMC012, PI0105, SHI, WX1, PI02052, UMC081, CSS1, PI020554, BNL8.17, GLU1, PI020646, PI01513, and BNL10.13; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 32. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with stay green, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, PI020654, BNL5.59, PI020682, PI020674, PI020575, PI020644, PI02044, PI020661, PI020557, UMC034, BNL6.16, PI01518, PI020531, PI020566, PI020527, BNL8.39, BNL8.44, PIO2020, WX1, BNL8.17, UMC057, BNL10.13, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 33. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with plant height, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, UMC034, PI01012, PI0205, PI020576, PI020508, BNL5.37-, BNL5.37-, BNL10.24, PI020713, PI020725, PI020728, BNL10.39, UMC120, UMC012, WX1, PI02052, UMC081, PI020554, PI020626, PI02075, GLU1, and PI020646; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 34. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with ear height, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, PI02044, UMC034, PI01012, PI0205, PI020576, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, BNL6.16, PI020521, UMC999, PI020713, PI020725, BNL6.29, PI020728, BNL10.39, UMC120, UMC012, WX1, PI02052, UMC081, PI020554, and UMC057; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 35. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with European corn borer second brood tolerance, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL5.59, PI020644, PI0205, BNL6.20, E8, BNL6.16, PI020597, BNL15.45, UMC042, PI020608, PI0612, PI02045, UMC065, MDH2, PI020595, PI020599, PI020569, PI01537, PI020708, UMC110, BNL10.39, UMC120, and PI0105; -47- determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 36. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with root lodging, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC094, PI020537, PI020603, PI020689, PI020640, PI020518, PI020576, PI020511, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL10.24, PI020713, PI020725, UMC031, UMC066, UMC019, UMC065, MDH2, PI020595, and UMC081; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 37. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with statistically transformed root lodging score, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, PI020654, PI020644, PI020518, PI020576, PI020511, PI020558, PI020509, PI020508, PIO20508, BNL5.37-, BNL5.37-, BNL10.24, UMC019, BNL6.29, UMC065, PI020581, and UMC081; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 38. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with stalk lodging, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL6.20, PI020597, MDH2, PI020595, PI020599, PI020728, UMC012, PI0105, PI02075, and UMC057; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 39. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in inbred performance with statistically transformed stalk lodging score, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020682, PI020661, PI020668, AMP1, BNL6.20, UMC042, PI067, PI020595, PI020599, BNL13.05, PI0105, SHI, and BNL3.04; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 40. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus -49- associated in inbred performance with grain quality, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL5.59, PI020575, PI020644, PI02044, PI020661, AMP1, PI020557, UMC061, PI01012, PI0205, PI02017, E8, PI020509, PI02071, PI01025, BNL8.33, PI020569, PI01537, PI020708, PI020684, PI020746, UMC116, UMC110, BNL8.32, BNL8.39, PI020593, PIO1033, UMC057, and BNL10.13; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 41. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with yield in bushels per acre, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL6.20, PI020576, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, BNL6.16, BNL7.65, UMC015, PI02071, PI020589, PI020569, PI01537, PI020708, PI020684, PI020746, UMC116, UMC110, BNL8.32, BNL8.39, PI020593, and PI020714; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 42. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with % Moisture, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, BNL12.06, UMC061, UMC034, PI01012, PI0205, PI02017, BNL6.20, PI020569, PI01537, UMC116, BNL8.32, BNL10.39, UMC120, PI020714, UMC012, PI02052, PI020646, and PI01513; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 43. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Bulk Density, adjusted, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020518, PI01012, PI0205, PI02017, BNL6.20, PI020511, PI020558, PI020509, PI020508, PI020508, BNL7.65, UMC015, PI02071, PI01025, PI0612, PI01524, PI020589, PI02045, PI020569, PI01537, PI020708, PI020684, PI020746, UMC116, UMC110, BNL8.32, SHI, WX1, PI02052, UMC081, CSS1, PI020626, PI02075, BNL3.04, PI065, GLU1, PI020646, and PI01033; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 44. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Yield to % moisture ratio, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, PI020518, BNL8.29, UMC061, -51 - UMC034, PI01012, PI020576, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, BNL6.16, UMC066, UMC019, BNL7.65, PI02071, BNL8.33, UMC043, PI020622, PI0612, PI01524, PI020589, and PI02026P; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 45. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with GDU Shed, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI01012, PI0205, PI02017, PI020576, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, PI020521, PI01533, UMC999, PI020713, PI020725, BNL5.46, PI0612, PI01524, PI020589, BNL13.05, PI01040, BNL10.39, UMC120, PI020714, UMC012, WX1, PI02052, UMC081, PI020554, and BNL10.13; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 46. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Stay green, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020690, PI02017, BNL6.20, BNL5.37-, BNL10.24, UMC046, MDH2, PI020595, PI020599, PI020569, PI01537, PI020684, UMC116, BNL8.32, BNL10.39, UMC120, PI020714, UMC012, SHI, and BNL3.04; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 47. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Dropped Ears, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL10.39, UMC081, BNL7.21B, and BNL10.13; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 48. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Dropped Ears, Statistically transformed, comprising the steps of constructing a preferred RFLP profile with respect to the genetic marker PI020690; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the genetic marker; and selecting individual plants which have RFLP profiles which most closely match the preferred profile. -53- 49. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Ear height, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020640, UMC034, PI020576, PI020511, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, PI020521, PI01533, PI020713, PI020725, BNL8.33, PI020569, BNL8.32, BNL8.39, PI020593, BNL10.39, UMC120, PI020714, UMC012, WX1, UMC081, PI020646, and PI01513; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 50. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Plant height, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020690, PI020668, PI020518, PI020576, PI020511, PI020558, PI020509, PI020508, PI020508, BNL5.37-, BNL5.37-, BNL10.24, BNL6.16, PI020521, PI01533, UMC999, PI01080, BNL8.33, PI01040, BNL10.39, UMC120, UMC012, PI065, GLUl, PI020646, PI01513, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 51. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Grain quality, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from BNL12.06, BNL8.29, BNL6.20, UMC999, BNL6.29, PI020528, PI020599, and BNL14.28; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s) . and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 52. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with European Corn Borer Second Brood Tolerance, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI02017, PI020576, PI020509, PI020508, BNL5.37-, PI020569, PI01537, PI020708, UMC116, BNL8.39, PI020593, BNL10.39, UMCI20, PI020626, and PI02075; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual .plants which have RFLP profiles which most closely match the preferred profile. 53. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Root lodging, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC094, PI020511, BNL5.37-, BNL5.37-, -55- BNL10.24, BNL6.16, UMC999, BNL8.23, BNL6.29, PI020527, PI020528, PI020854, PI02045, PI067, UMC065, MDH2, PI020595, UMC012, PI020562, and PI020646; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 54. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Root lodging, statistically transformed, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from UMC094, PI020576, PI020511, BNL5.37-, BNL5.37-, BNL10.24, UMC999, UMC019, BNL6.29, PI020527, PI020528, PI020854, PI02045, PI067, UMC065, MDH2, PI020595, UMC012, and PI020562; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 55. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Stalk lodging, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020622, PI01537, BNL14.28, PI020562, UMC057, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile. 56. A method according to Claim 9 for identifying individual corn plants which have the desired genotype at a genetic marker locus associated in hybrid performance with Stalk lodging, statistically transformed, comprising the steps of constructing a preferred RFLP profile with respect to one or more genetic markers selected from PI020537, PI01012, PI0205, E8, PI020558, PI020597, PI020622, PI0612, PI01524, UMC065, PI01537, UMC110, PI020626, PI02075, PI020646, PI015I3, UMC057, BNL10.13, and UMC044; determining the RFLP profiles of individual corn plants in a segregating population of corn plants with respect to the selected genetic marker(s); and selecting individual plants which have RFLP profiles which most closely match the preferred profile.

Inventors: ALBERTSEN MARC CHRISTIAN, BEAVIS WILLIAM DALE, FINCHER ROBERT REID, GRANT DAVID, KUHN WILLIAM EDWARD, SMITH JOHN STEPHEN CHARLES, SMITH OSCAR SAMUEL JR, ALBERTSEN, MARC, CHRISTIAN, BEAVIS, WILLIAM, DALE, FINCHER, ROBERT, REID, GRANT, DAVID, KUHN, WILLIAM, EDWARD, SMITH, JOHN, STEPHEN, CHARLES, SMITH, OSCAR, SAMUEL, JR.
Applicants: PIONEER HI BRED INT, PIONEER HI-BRED INTERNATIONAL, INC.
Application year: 1989
Main classification: C12N15
IPC codes: A01H1, C12Q1