WO1994012016A1

WO1994012016A1 - Improved inbred corn lines

Info

Publication number: WO1994012016A1
Application number: PCT/US1993/006977
Authority: WO
Inventors: John A. Schillinger; Donald L. Bockelman; Richard D. Muckler; David W. Peters
Original assignee: The Upjohn Company
Priority date: 1992-11-24
Filing date: 1993-07-26
Publication date: 1994-06-09
Also published as: MX9307306A; AU4688493A

Abstract

Provided are novel inbred corn lines, designated 3087, 5720, 6022 and 7054. This invention also provides the seeds of inbred corn lines 3087, 5720, 6022 and 7054, plants of inbred corn lines 3087, 5720, 6022 and 7054, methods involving crossing of inbred 3087, 5720, 6022 and 7054 with other inbred lines to produce commercial F1 hybrids, and to methods of crossing inbred 3087, 5720, 6022 and 7054 with other plants to produce breeding populations for developing new inbred lines.

Description

IMPROVED INBRED CORN LINES FIELD OF INVENTION This invention is in the field of corn breeding, specifically relating to an inbred corn line designated 3087, 5720, 6022 and 7054.

BACKGROUND OF THE INVENTION The goal of corn breeding is to produce a hybrid which has outstanding agronomic features for a number of traits. The most important trait is typically the grain yield expressed in weight or volume of grain produced per unit area of harvest, e.g., tons/hectare. Several secondary traits, many of which indirectly affect yield, are also important. These traits may include resistance to disease and insects, resistance to lodging, tolerance to heat and drought, length of time to maturity, and quality traits. Any new hybrid developed by breeding techniques must have improvement in enough of these traits to provide a grower an advantage over previously released hybrids. The breeding and development of new commercial hybrids involves the use of 2 essential techniques: self-pollination and cross-pollination. For self-pollination, the pollen from one plant is placed on the silks of the same plant. For cross-pollination, pollen from one plant is placed on the silks of another plant When self-pollination is practiced over a series of several generations, the resulting plants become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. Plants at this stage in development are called inbred lines and can be maintained by continued self-pollination.

A cross between two homozygous, inbred lines produces a uniform population of plants referred to as Fl hybrids. Fl is defined as the first filial generation resulting from a cross. While these hybrids are genetically uniform, they are typically heterozygous for many gene loci. A cross of 2 plants that are not inbred will also produce Fl plants with many heterozygous loci; however, the hybrid plants resulting from this cross will not be genetically uniform.

During the self pollination process, inbreeding occurs and the vigor of the lines decrease. The vigor, which is manifested in many ways including increased vegetative growth and increased yield, is restored when two unrelated inbred lines are crossed to produce the Fl hybrid seed. It is important that lines used as parents in commercial Fl hybrids be inbred (true breeding) and unrelated. The inbred nature ensures the uniformity of the hybrid, which is essential for mechanical harvesting and it allows the reproduction of the same hybrid year after year. The unrelatedness of the inbred lines maximizes the vigor that result in the Fl hybrids. Hybrids between closely related lines are not as vigorous as from unrelated lines. A single-cross hybrid is produced when two inbred lines are crossed to produce the Fl progeny. A double-cross hybrid is produced from four inbred lines crossed in pairs (AxB and CxD) and then the two Fl hybrids are crossed again (AxB)x(CxD). Double cross hybrids are not as genetically uniform as single-cross hybrids; however, they can be uniform enough to be acceptable for mechanical harvest procedures used today.

The development of commercial corn hybrids requires: 1) the development of homozygous inbred lines, 2) the crossing of these inbred lines to form hybrids, and 3) the evaluation of these hybrids.

The development of inbred lines most commonly utilizes the pedigree method of breeding. The initial step involves the development of a source population. The source population may consist of an Fl hybrid, or it may consist of a group of plants resulting from cross pollination of several lines. Lines to be included in die source population are selected so that desirable traits from different parental lines will be combined together into the daughter population. This daughter population is self-pollinated several generations, with the best plants selected during each generation of inbreeding. As the lines become more inbred, the genes included in the source population will recombine in new combinations giving a series of new inbred lines, some having desirable traits from different parents involved in the source population.

These new inbred lines are then crossed to other, unrelated inbred lines to produce Fl hybrids which are evaluated in multiple locations for commercial potential. The best Fl hybrids are identified and the inbred lines used to make these Fl hybrids are then increased for commercial production.

Backcrossing can also be used to improve an inbred line. Backcrossing transfers a specific desirable trait from one inbred or source to an inbred that lacks a trait(s). This can be accomplished for example by first crossing a superior inbred (A) (recurrent parent) to a donor inbred (non-recurrent), which carries the appropriate gene(s) for the trait in question. The progeny of this cross is then mated back to the superior recurrent parent (A) followed by selection in the resultant progeny for the desired trait to be transferred from the non-recurrent parent. After several backcross generations, the progeny will contain the new trait in the superior background of the recurrent parent.

Other breeding methods for developing inbred lines include recurrent selection and various modifications of the pedigree method.

While the ultimate goal is to identify superior hybrids, this must be achieved by identifying superior inbred lines as parents of the hybrids.

SUMMARY OF THE INVENTION According to the invention, there is provided novel inbred corn lines including corn lines 3087, 5720, 6022 and 7054. This invention thus also provides die seeds, plants, and plant parts of inbred corn lines 3087, 5720, 6022 and 7054. This invention further provides methods involving crossing of inbred corn lines 3087, 5720, 6022 and 7054 with each other as well as with other inbred lines to produce commercial Fl hybrids, and to methods of crossing inbred corn lines 3087, 5720, 6022 and 7054 with other plants to produce breeding populations for developing new inbred lines. DEFINITIONS

In the description of die invention, several terms will be used. The following definitions are given to provide a clear understanding of the specific claims:

Relative maturity is the predicted maturity of hybrids developed from the inbred of the invention and is based on the harvest moisture of the grain at maturity, relative to a set of standard checks.

Yield or YLD is the yield in tons/hectare (tons/ha) of grain at harvest adjusted to 15.5% moisture.

Moisture or MOIS is the actual moisture of the grain at harvest represented as a percent weight of water/weight of grain x 100. Y:MO is a statistic calculated by dividing die yield (in tons ha) by the moisture (MOIS), multiplied by 100. This statistic expresses yield as a function of moisture. Hybrids which yield high, within its maturity class, will score high with this statistic.

Growing Degree Units or GDU is the number of growing degree units needed for an inbred line or hybrid to reach a certain stage of development. GDU is another method for measuring maturity. Growing degree units are calculated by the Barger Method, where the heat units for a 24 hour period are: GDU = (Max + Min)/2 - 50, and d e highest maximum value used is 86 F and the lowest minimum used is 50 F.

Stalk lodging or STL is a rating which evaluates the ability of plants to resist stalk breakage. The range in the rating is between 1 and 9. Hybrids scored as 1 have no or few lodged plants (when the stalk breaks or bends below die ear) whereas a rating of 9 indicates tiiat many plants are lodged. The data are given as the mean percentage of the experiments in which the hybrid was grown.

Root lodging or RTL is a rating which evaluates the ability of plants to resist root lodging. The range in the rating is between 1 and 9. Hybrids scored as 1 have no root lodged plants while those scored as 9 have a large percentage of plants which are root lodged. The percentage of root lodged plants is measured at harvest. Plants are considered root lodged when the stalk leans more than 30 degrees from the vertical axis. The data are given as the mean percentage of the experiments in which the hybrid was grown.

Central corn belt or CCB is a measure of the number of days it takes hybrid corn to grow to maturity in the mid-north to northern regions of the US corn belt.

Stay green or SGR is a measure of plant health near the time of black layer formation (physiological maturity). The range in this rating is also between 1 and 9 witii low scores indicating better late-season plant health. The data is given as a mean rating for the experiments in which the hybrid was grown.

Field score or FSC is a measure of plant integrity and visual appeal at harvest. The range in this rating is between 1 and 9 with low scores indicating better plant integrity and appearance.

Test weight/hectoliter weight or HLWT is a measure of the density of the grain. It is the weight of the grain in kilograms for a given volume (hectoliter) adjusted for percent moisture. Data is given as a mean weight of the experiments in which the hybrid was grown. Plant height or PHT is the height of the hybrid or inbred (in centimeters) from the ground to die tip of die tassel. The data is given as the mean height of the experiments in which the inbred or hybrid was grown.

Ear height or EHT is die height of the ear of hybrid or inbred plants (in centimeters) from the ground to die ear node attachment. The data is given as the mean height of the experiment in which the inbred or hybrid was grown.

Restriction Fragment Length Polymorphism or RFLP is a molecular approach for characterizing the genetic makeup of different lines of com. The data generated from RFLP is presented in molecular weights (MW) of bands identified when DNA from an inbred is cut by a particular enzyme, separated electrophoretically, and hybridized with a particular DNA probe. The molecular weight units are in kilobase pairs, and die DNA probes are publicly available.

DETAILED DESCRIPTION OF THE INVENTION The inbred com lines 3087, 5720, 6022 and 7054 of die present invention are a yellow dent com witii superior characteristics and are excellent parental lines in crosses for producing hybrid com. Inbred 3087 was selected from a source population made by crossing a number of inbred lines related to Mol7 and Oh43 with the inbred LH123. Standard pedigree ear-row selection for acceptable agronomic types was performed tiiroughout the generations of self pollination. Test crosses witii unrelated inbred lines were made and evaluated over multiple locations. One subline within this population had good hybrid performance and appeared acceptable as a male parent. This subline was crossed with several non-related inbred lines from the stiff stalk family and were evaluated throughout the central US cornbelt. This inbred had very good testcross performance witii a number of unrelated inbred lines.

The inbred 3087 produces hybrids which are well adapted to central latitudes of the US co belt, producing hybrids witii relative maturity of 100-110 days CCB. Inbred 3087 has good pollen shed and tiius serves as a good male parent.

The inbred 3087 has shown uniformity and stability for all traits as described in d e following variety description information (Table 1). It has been self-pollinated and ear-rowed a sufficient number of generations witii careful attention paid to uniformity of plant type to ensure genetic homozygosity and phenotypic stability. No variant traits are expected in 3087. Table 1 shows the morphological and otiier characteristics of inbred 3087. The data in Table 2 shows die relative hybrid performance of 3087 compared to a number of inbred lines which are currendy used as males in hybrid production. These inbred lines are either Asgrow proprietary or those from a seed stock company from which Asgrow has a license. The comparisons of 3087 with the other inbred lines was conducted on two testers as indicated in Table 2. In all instances, the 3087 hybrids yielded more man the other parents, with an overall advantage of 0.5 tons/hectare. The 3087 hybrids also were 0.2% drier at harvest, on die average, giving a Y:MO ratio advantage of 3.4. The stay green, stalk lodging, root lodging, and field score, ratings were all comparable. 3087 also produced hybrids that are taller with slightly higher ear placement..

An RFLP profile of inbred 3087 is listed in Table 3. As far as is known, this pattern is unique from those of all other inbreds available.

Inbred seeds of 3087 have been placed on deposit pursuant to the terms of the Budapest Treaty at the American Type Culture Collection (ATCC), Rockville, MD, 20852, under deposit accession number 75337 on 2 November, 1992. A Plant Variety Protection Certificate has also been applied for with the United States Department of Agriculture. Inbred 5720 was selected from a source population developed by crossing a public inbred line developed at University of Illinois with an inbred line related to Mo 17, a popular inbred line developed at University of Missouri. Standard pedigree ear-row selection for acceptable agronomic types was performed tiiroughout the generations of self pollination. Test crosses with unrelated inbred lines were made and evaluated over multiple locations. One subline within this population had good hybrid performance and appeared acceptable as a male parent. This subline was crossed witii several non-related inbred lines from d e stiff stalk family and were evaluated throughout the central US combelt with an emphasis in eastern environments. This inbred had very good testcross performance with a number of unrelated inbred lines. The inbred 5720 produces hybrids which are well adapted to die eastern half of the US com belt, producing hybrids with relative maturity of 107-116 days CCB. Inbred 5720 has good pollen shed and tiius serves as a good male parent.

The inbred 5720 has shown uniformity and stability for all traits as described in the following variety description information (Table 4). It has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure genetic homozygosity and phenotypic stability. No variant traits are expected in 5720. Table 4 shows the morphological and otfier characteristics of inbred 5720.

The data in Table 5 shows die relative hybrid performance of 5720 compared to two other Mo 17 type inbred lines currently marketed by a Foundation Seed Stock Company. The comparisons of 5720 with the other inbred lines was conducted with 3 testers as indicated in Table 5. On the average, the 5720 hybrids yielded better than the other parents, with an overall advantage of .1 tons/hectare. The yield advantage was most pronounced when die test was grown in d e southeastern quadrant of die com belt, where com diseases are typically present in high amounts. This advantage is reflective of the high degree of resistance this inbred contributes to its hybrids (Table 4). Hybrids involving 5720 have harvest moistures very similar to other hybrids involving Mo 17. The excellent health of 5720 hybrids is reflected in the favorable scores for stay green, stalk lodging, root lodging, and field score. 5720 showed very distinct advantages in all of these categories (lower ratings are better than high ratings).

An RFLP profile of inbred 5720 is listed in Table 6. As far as is known, this pattern is unique from those of all other inbreds available. Inbred seeds of 5720 have been placed on deposit pursuant to the terms of the Budapest

Treaty at the American Type Culture Collection (ATCC), Rockville, MD, 20852, under deposit accession number 75339 on 2 November, 1992. A Plant Variety Protection Certificate has also been applied for witii the United States Department of Agriculture.

Inbred 6022 was selected from a cross between two lines from the stiff stalk synthetic family available to Asgrow. Standard pedigree ear-row selection for acceptable agronomic types was performed tiiroughout the generations of self pollination. Test crosses with unrelated inbred lines were made and evaluated over multiple locations. One subline within this population had good hybrid performance and appeared acceptable as a female parent. This subline was crossed with several non-related inbred lines and were evaluated tiiroughout the central to northern US combelL This inbred had good testcross performance with a number of unrelated inbred lines and excellent testcross performance with one specific tester.

The inbred 6022 produces hybrids which are well adapted to mid-north to northern regions of the US com belt, producing hybrids witii relative maturity of 100-105 days CCB. Inbred 6022 has good seed yield per se and excellent seed quality and tiius serves as a good female parent.

The inbred 6022 has shown uniformity and stability for all traits as described in the following variety description information (Table 7). It has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure genetic homozygosity and phenotypic stability. No variant traits are expected in 6022. Table 7 shows the morphological and other characteristics of inbred 6022.

The data in Table 8 shows die relative hybrid performance of 6022 compared to a number of stiff stalk inbred lines. These inbred lines are either Asgrow proprietary lines presently involved in commercial hybrids or those from a Foundation seed stock company from which Asgrow has a license. The comparisons of 6022 witii the other stiff stalk inbred lines was conducted on 2 testers as indicated in Table 8. In all instances, the 6022 hybrids yielded more man the other stiff stalk parents, with an overall advantage of 0.4 T/ha. This yield advantage was maintained even though the 6022 hybrids were on the average, 1.6% drier, giving a Y:MO ratio advantage of 7.4. The stay green ratings were a bit less favorable (higher rating) that the other stiff stalks. For stalk lodging, root lodging, and field score, 6022 produced hybrids which were comparable to the other stiff stalk hybrids. 6022 also produced hybrids that are taller with high ear placement.

An RFLP profile of inbred 6022 is listed in Table 9. As far is known, this pattern is unique from those of all other inbreds available.

Inbred seeds of 6022 have been placed on deposit pursuant to the terms of the Budapest Treaty at the American Type Culture Collection (ATCC), Rockville, MD, 20852, under deposit accession number 75336 on 2 November, 1992. A Plant Variety Protection Certificate has also been applied for witii the United States Department of Agriculture.

Inbred 7054 was selected from a cross between two lines from the stiff stalk synthetic family available to Asgrow. Standard pedigree ear-row selection for acceptable agronomic types was performed throughout the generations of self pollination. Test crosses with unrelated inbred lines were made and evaluated over multiple locations. One subline within this population had good hybrid performance and appeared acceptable as a female parent. This subline was crossed witii several non-related inbred lines and were evaluated throughout the central US combelt. This inbred had very good testcross performance with a number of unrelated inbred lines.

The inbred 7054 produces hybrids which are well adapted to central and north central regions of the US com belt, producing hybrids with relative maturity of 100-110 days CCB. Inbred 7054 has good seed yield per se and excellent seed quality and thus serves as a good female parent.

The inbred 7054 has shown uniformity and stability for all traits as described in the following variety description information (Table 10). It has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure genetic homozygosity and phenotypic stability. No variant traits are expected in 7054. Table 10 shows the morphological and other characteristics of inbred 7054.

The data in Table 11 shows die relative hybrid performance of 7054 compared to a popular stiff stalk inbred line from a Foundation Seed Stock Company. This stiff stalk inbred line is from the same family as 7054, being derived from B73, a popular inbred line developed at Iowa State University. The comparisons of 7054 with die Foundation inbred was conducted on 2 testers as indicated in Table 11. In both instances, the 7054 hybrids yielded more than the other B73 parent, with an overall advantage of 0.3 T./ha. In addition, die 7054 hybrids were on the average, 0.2% drier which gives a Y:MO ratio advantage of 2.5. This Y:MO advantage was apparent in a number of other comparisons involving other B73 inbreds and several different tester inbreds. In most of the other traits, 7054 produced hybrids which were comparable to the other B73 hybrids.

An RFLP profile of inbred 7054 is listed in Table 12. As far as is known, this pattern is unique from those of all other inbreds available.

Inbred seeds of 7054 have been placed on deposit pursuant to the terms of the Budapest Treaty at the American Type Culture Collection (ATCC), Rockville, MD, 20852, under deposit accession number 75338 on 2 November, 1992. A Plant Variety Protection Certificate has also been applied for witii the United States Department of Agriculture.

This invention is also directed to metiiods for producing a com plant by crossing a first parent com plant with a second parent com plant wherein the first or second parent com plant is an inbred com plant selected from the group consisting of the lines 3087, 5720, 6022 and 7054. Further, botii first and second parent com plants may be from each respective inbred line. Thus any metiiods using the inbred com lines of the present invention are part of the invention: self pollination, backcrosses, hybrid breeding and crosses to populations. Any plants produced using inbred co lines 3087, 5720, 6022 or 7054 or a combination thereof as a parent are within the scope of this invention. Advantageously, die inbred com lines are used in crosses with other com varieties to produce first generation (Fl) com hybrid seed.

As used herein, the term "plant" includes plant cells, plant protoplasts, plant cell or tissue culture from which co plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as pollen, flower, kernels, ears, cobs, leaves, husks, stalks, and the like.

Tissue culture of com is described in European Patent Application, publication number 160,390. Com tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize," Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982), at 367-372. Thus, another aspect of this invention is to provide for cells which upon growth and differentiation produce the inbred 3087, 5720, 6022 and 7054.

Altiiough the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, one skilled in the art will appreciate that certain changes and modifications may be practiced within the scope of the invention, without departing from the true scope of the invention. In die foregoing specification the entire contents of all cited references are incoiporated by reference. TABLE 1 Moφhological and other characteristics of Inbred 3087:

A. MATURITY

-Relative Maturity: Predicted maturities of hybrids 100-110 day CCB -Heat units to silk: 1460 GDU

B. PLANT CHARACTERISTICS

-Plant height (to tassel tip): 203 cm -Length of top ear intemode: 11 cm -Number of ears/stalk: 1

-Ear height (to base of top ear): 70 cm -Number of tillers: Absent -Cytoplasmic type: Normal

C. LEAF

-Color: Dark green

-Angle from stalk: 45 degrees

-Marginal waves: few

-Number of leaves (mature plant): 12 -Sheath pubescence: light

-Longitudinal creases: absent

-Length (ear node leaf): 62 cm

-Width 6.0 cm

D. TASSEL

-Number of lateral branches: 4-5

-Branch angle from central spike: > 45 degrees

-Pollen shed (High, medium, low): light

-Peduncle length (top leaf to basal branch): 14 cm -Anther color: pale green

-Glume color: green TABLE 1 (continued - Inbred 3087)

E. EAR (husked ear unless otherwise stated)

-Length: 20 cm

-Weight: 95 g -Midpoint diameter: 40 mm

-Silk color: pale green

-Husk extension (at harvest stage): medium (barely covering ear)

-Husk leaf length: short < 8 cm

-Taper of ear (ear shape):straight, cylindrical -Kernel row number: 10-12

-Husk color (fresh): light green

-Husk color (dry): buff

-Shank length: 9 cm

-Shank no. of intemodes: 4

F. KERNEL (size from midpoint of dried ear).

-Length: 10 mm

-Width: 7 mm

-Thick: 5 mm -Shape grade (%rounds): 60-80 %

-Pericaφ color: colorless

-Aleurone color: colorless

-Endosperm color: yellow

-Endosperm type: dent-medium hard texture -Gm Wt/100 seeds (unsized): 30 g

G. COB

-Diameter at midpoint: 2.5 cm -Strength: strong -Color: white TABLE 2 DATA OF HYBRIDS OF INBRED 3087

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT Tester 1/

3087 10.29 17.83 59.33 3.00 1.22 5.40 4.77 73.80 97.48 251.5

Tester 1/

ASGL3 9.81 18.80 53.62 3.40 .85 4.48 4.74 73.75 99.58 246.5

STD ERROR

OF DIFF. .161 .177 1.003 .521 .198 .372 .173 .383 1.396 1.375

PROBABILITY NO DIFF. .01 .00 .00 .44 .08 .04 .84 .88 .15 .00

NUMBER OF

REPLICATIONS 93 93 93 84 54 27 78 72 60 60

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT

Tester 1/

3087 10.29 17.83 59.33 3.00 1.22 5.40 4.77 73.80 97.48 251.5

Tester 1/

FSSL4 9.68 18.11 54.42 2.55 .91 6.18 5.22 73.62 83.52 218.9

STD ERROR OF DIFF. .185 .166 1.259 .378 .154 .389 .118 .399 2.022 3.267

PROBABILITY

NO DIFF. .00 .11 .00 .24 .06 .08 .00 .65 .00 .00 NUMBER OF

REPLICATIONS 93 93 93 84 54 27 78 72 60 60 TABLE 2 (continued - Inbred 3087)

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT Tester 2/

3087 9.21 18.24 51.60 3.63 1.31 5.08 5.61 75.61 97.31 258.9

Tester 2/

FSSL4 9.17 17.36 53.41 3.48 1.19 6.00 5.84 74.76 84.44 221.7

STD ERROR

OF DIFF. .219 .351 1.422 .578 .151 .300 .191 .407 1.849 3.244

PROBABILITY NO DIFF. .86 .02 .22 .80 .46 .03 .25 .05 .00 .00

NUMBER OF

REPLICATIONS 46 46 46 42 26 12 44 38 36 36

Enzymes: H=Hind III, El=EcoRl, E5=EcoR5 TABLE 4 Moφhological and other characteristics of inbred 5720:

A. MATURITY

-Relative Maturity: Predicted maturities of hybrids 107-116 day CCB -Heat units to shedding: 1554 GDU

-Heat units to silk: 1596 GDU -Amoimt of replication supporting above data: 16 reps over 2 years.

B. PLANT CHARACTERISTICS -Plant height (to tassel tip): 220 cm

-Length of top ear intemode: 17 cm

-Number of ears/stalk: 1

-Ear height (to base of top ear): 83 cm

-Number of tillers: Absent -Cytoplasmic type: Normal

C. LEAF

-Color: Light green

-Angle from stalk: 20-45 degrees -Marginal waves: Few marginal waves and moderate in degree

-Number of leaves (mature plant): 12

-Sheath pubescence: light

-Longitudinal creases: Few and not pronounced

-Length (ear node leaf): 80 cm -Width: 9 cm

D. TASSEL

-Number of lateral branches: 6-10 -Branch angle from central spike: 30 degrees -Pollen shed (High, medium, low): medium

-Peduncle length (top leaf to basal branch): 3-5 cm -Anther color: light green -Glume color: light green TABLE 4 (continued - Inbred 5720) AR (husked ear unless otherwise stated)

-Lengtii: 14 cm

-Weight: 68 g -Midpoint diameter: 35 cm

-Silk color: light green

-Husk extension (at harvest stage): long 8-10 cm

-Husk leaf length: short <8cm

-Taper of ear (ear shape):slightly tapered -Kernel row number: 12

-Husk color (fresh): light green

-Husk color (dry): buff

-Shank length: 18 cm

-Shank no. of intemodes: 7

TABLE 4 (continued - Inbred 5720)

F. KERNEL (size from midpoint of dried ear).

-Lengtii: 12 mm -Width: 8 mm -Thick: 5 mm

-Shape grade: 10.0% small rounds

37.7% medium rounds 9.8% large rounds 1.4% small flats 16.8% medium flats

24.2% large flats -Pericaφ color: colorless -Aleurone color: colorless -Endosperm color: yellow -Endosperm type: dent-medium soft texture

-Gm Wt 100 seeds (unsized): 27 g

G. COB

-Diameter at midpoint: 23 mm -Strength: weak

-Color: red

H. DISEASES

-Resistant to northern com leaf blight race 1, Setosphaeria turcica (Luttrell) Leonard and Suggs. Homozygous for Htl gene.

-Resistant to northem com leaf blight race 2, Setosphaeria turcica (Luttrell) Leonard and Suggs. Rated 2.5 on 1 (res.) to 9 (susc.) scale, in 2 reps data over two years.

-Resistant to southern com leaf blight race 0, Cochliobolus heterostrophus (Srechs.) Drechs.

Rated 3.5 on a 1 to 9 scale, for 2 reps of data over two years.

-Resistant to gray leaf spot, Cercospora zeae-maydis Tehon and Daniels. Rated 2.9 on a 2 to 9 scale, for 4 reps of data over two years. TABLE 4 (continued - Inbred 5720) -Resistant to Stewart's bacterial blight, Erwinia sterartii (Smith) Dye. Rated 1.4 on a 1 to 9 scale, for 3 reps of data over two years.

-Resistant to Goss's bacterial blight, Clavibacter michiganense subsp. nebraskense (Schuster et.al.) Davis et. al. Rated 1.0 on a 1 to 9 scale, for 1 rep of data in one year.

SECTS

Hybrids involving 5720 have shown excellent tolerance to second brood of European com borer, as measured by visual integrity of the stalk at harvest.

TABLE 5

DATA OF HYBRIDS OF INBRED 5720

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT

Tester 1/

5720 9.76 17.40 57.44 3.03 1.08 3.92 4.14 76.74 91.78 258.1 Tester 1/

FSSL3 9.53 17.29 56.21 4.88 1.73 5.83 5.89 74.84 104.9 254.1

STD ERROR

OF DIFF. .182 .207 1.138 .963 .523 .154 .241 .503 2.030 2.134

PROBABILITY

NO DIFF. .22 .63 .29 .07 .24 .00 .00 .00 .00 .08

NUMBER OF REPLICATIONS 46 46 46 42 26 12 44 38 36 36

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT

Tester 2/

5720 9.86 18.63 54.93 3.47 .86 2.80 3.51 76.32 96.89 263.6

Tester 2/

FSSL3 9.99 19.31 53.91 3.58 1.05 4.00 4.32 75.78 106.6 268.7

STD ERROR OF DIFF. .195 .169 1.025 .425 .090 .279 .234 .307 2.270 2.907

PROBABILITY

NO DIFF. .52 .00 .33 .79 .06 .00 .00 .09 .00 .10 NUMBER OF

REPLICATIONS 72 72 72 56 28 40 48 54 28 28 TABLE 5 (continued - Inbred 5720)

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT Tester 3/

5720 9.12 17.65 52.97 2.99 1.00 3.17 4.14 75.96 101.4 263.8

Tester 3/

ASGL4 9.11 17.92 51.88 6.02 1.92 4.75 5.64 76.86 105.3 265.3

STD ERROR

OF DIFF. .184 .231 1.192 1.029 .396 .417 .174 .457 1.962 2.166

PROBABILITY NO DIFF. .97 .27 .37 .01 .04 .01 .00 .06 .06 .52

NUMBER OF

REPLICATIONS 46 46 46 42 26 12 44 38 36 36

TABLE 6 Inbred 5720 RFLP Characterization

nzymes: H=Hind III, El=EcoRl, E5=EcoR5 TABLE 7 Moφhological and other characteristics of inbred 6022:

A. MATURITY

-Relative Maturity: Predicted maturities of hybrids 100-110 day CCB -Heat units to shedding: 1450 GDU

-Heat units to silk: 1478 GDU

B. PLANT CHARACTERISTICS

-Plant height (to tassel tip): 198 cm -Length of top ear intemode: 75 cm

-Number of ears/stalk: Slight 2 eared tendency

-Ear height (to base of top ear): 70 cm

-Number of tillers: Absent

-Cytoplasmic type: Normal

C. LEAF

-Color: Green

-Angle from stalk: 45 degrees

-Marginal waves: few -Number of leaves (mature plant): 16

-Sheath pubescence: medium

-Longitudinal creases: few

-Length (ear node leaf): 74 cm

-Width: 79 mm

D. TASSEL

-Number of lateral branches: 5 -Branch angle from central spike: Semi-erect -Pollen shed (High, medium, low): medium -Peduncle length (top leaf to basal branch): 5 cm

-Anther color: light puφle -Glume color: green TABLE 7 (continued - Inbred 6022)

E. EAR (husked ear unless otherwise stated)

-Length: 16.3 cm -Weight: 110 g -Midpoint diameter: 3.75 cm

-Silk color: light green

-Husk extension (at harvest stage): medium (barely covering the ear) -Husk leaf length: medium 8-15 cm -Taper of ear (ear shape):straight, cylindrical -Kernel row number: 12-14

-Husk color (fresh): light green -Husk color (dry): buff

F. KERNEL (size from midpoint of dried ear). -Length: 10 mm

-Widtii: 9 mm -Thick: 5 mm

-Shape grade (%rounds): 20A0 % -Pericaφ color: clear -Aleurone color: white

-Endosperm color: yellow -Endosperm type: dent/normal -Gm Wt/100 seeds (unsized): 25 g

G. COB

-Diameter at midpoint: 2.5 cm -Strength: strong -Color: red TABLE 8 Data of Hybrids of Inbred 6022 YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT 6022/

TESTER 1 9.68 16.14 61.17 3.01 .96 6.48 5.63 74.12 91.20 223.4

FSSL2/

TESTER 9.55 18.56 52.20 2.75 .83 5.78 5.07 74.62 80.80 220.4

STD ERROR

OF DIFF. .127 .153 1.011 .406 .081 .399 .157 .486 1.685 1.748

PROBABILITY NO DIFF. .31 .00 .00 .53 .13 .12 .00 .31 .00 .10

NUMBER OF

REPLICATIONS 93 93 93 84 54 27 78 72 60 60

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT

6022/

TESTER 1 9.68 16.14 61.17 3.01 .96 6.48 5.63 74.12 91.20 223.4 ASGL1/

TESTER 1 8.99 17.46 52.18 3.42 .97 6.59 5.48 74.62 80.10 208.9

STD ERROR

OF DIFF. .142 .133 1.024 .316 .062 .310 .139 .329 1.420 2.755

PROBABILITY

NO DEFF. .00 .00 .00 .21 .91 .73 .29 .14 .00 .00

NUMBER OF REPLICATIONS 93 93 93 84 54 27 78 72 60 60 TABLE 8 (continued - Inbred 6022)

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT 6022/

TESTER 2 9.39 16.98 56.47 3.72 2.50 6.00 5.75 74.75 1 18.9 278.2

ASGL2/

TESTER 2 9.11 17.92 51.88 6.02 1.92 4.75 5.64 76.86 105.3 265.3

STD ERROR

OF DIFF. .160 .185 1.284 .936 .434 .382 .186 .361 1.703 2.003

PROBABILITY NO DIFF. .09 .00 .00 .02 .21 .02 .55 .00 .00 .00

NUMBER OF

REPLICATIONS 46 46 46 42 26 12 44 38 36 36

TABLE 9 Inbred 6022 RFLP Characterization

Probe/enzyme Fragment MW(s) in kilo base pairs

Enzymes: H=Hind III, El=EcoRl, E5=EcoR5 TABLE 10 Moφhological and other characteristics inbred 7054:

A. MATURITY

-Relative Maturity: Predicted maturities of hybrids 100-1 10 day CCB -Heat units to shedding: 1450 GDU

-Heat units to silk: 1465 GDU -Amount of replication supporting above data: 2 years, 8 sites (16 reps).

B. PLANT CHARACTERISTICS -Plant height (to tassel tip): 200 cm

-Length of top ear intemode: 12 cm

-Number of ears/stalk: 1

-Ear height (to base of top ear): 80 cm

-Number of tillers: Few -Cytoplasmic type: Normal

C. LEAF

-Color: Dark green

-Angle from stalk: 30 degrees -Marginal waves: None

-Number of leaves (mature plant): 12

-Sheath pubescence: light

-Longitudinal creases: absent

-Length (ear node leaf): 72 cm -Width: 83 mm

D. TASSEL

-Number of lateral branches: 5-6 -Branch angle from central spike: 30-40 degrees -Pollen shed (High, medium, low): medium

-Peduncle lengtii (top leaf to basal branch): 12 cm

-Anther color: pink

-Glume color: puφle and green TABLE 10 (continued - Inbred 7054)

E. EAR (husked ear unless otherwise stated)

-Length: 15 cm

-Weight: 85 g -Midpoint diameter: 4.25 cm

-Silk color: light green

-Husk extension (at harvest stage): short (barely covering ear)

-Husk leaf length: short (<8cm)

-Taper of ear (ear shape):straight, cylindrical -Kernel row number: 14-16

-Husk color (fresh): medium green

-Husk color (dry): buff

-Shank length: 7cm

-Shank no. of intemodes: 6

F. KERNEL (size from midpoint of dried ear).

-Lengtii: 10 mm

-Width: 8 mm

-Thick: 4 mm -Shape grade (%rounds): 20-40 %

-Pericaφ color: clear

-Aleurone color: white

-Endosperm color: yellow

-Endosperm type: dent/normal -Gm Wt/100 seeds (unsized): 25 g

G. COB

-Diameter at midpoint: 2.6 cm -Strength: strong -Color: red TABLE 10 (continued - Inbred 7054) ISEASES

-Southern com leaf blight: Moderately resistant for a stiff stalk line

- overall rating: susceptible. -Northern com leaf blight: Moderately susceptible

-Gray leaf spot: Susceptible

-Stewart's wilt: Moderately resistant for a stiff stalk line

- overall rating: susceptible.

TABLE 11 DATA OF HYBRIDS OF INBRED 7054

YLD MOIS Y.MO STL RTL SGR FSC HLWT EHT PHT

7054/ TESTER 1 10.64 18.83 59.26 1.94 .86 6.00 4.70 72.30 97.18 250.6

FSSL1/

TESTER 1 10.27 19.46 55.37 2.70 1.00 4.75 4.73 72.78 96.93 256.2 STD ERROR

OF DIFF. .129 .154 .563 .497 .092 .250 .215 .358 1.348 2.131

PROBABILITY

NO DIFF. .01 .00 .00 .14 .17 .13 .88 .20 .86 .02

NUMBER OF

REPLICATIONS 40 40 40 36 14 4 30 34 28 28

YLD MOIS Y:MO STL RTL SGR FSC HLWT EHT PHT

7054/

TESTER 2 9.57 19.62 50.14 2.38 1.09 3.23 3.75 74.30 98.79 254.5

FSSL1/

TESTER 2 9.19 19.40 48.84 2.06 .87 3.29 3.72 75.83 94.02 258.2

STD ERROR OF DIFF. .125 .164 .789 .348 .108 .203 .171 .473 1.189 1.566

PROBABILITY

NO DIFF. .01 .18 .11 .38 .06 .75 .88 .00 .00 .03 NUMBER OF

REPLICATIONS 93 93 93 84 54 27 78 72 60 60

Claims

CLAIMS I claim:

1. An inbred com line selected from the group consisting of the inbred co lines designated 3087, 5720, 6022 and 7054.

2. A plant or plants of the inbred com lines of claim 1.

3. Pollen of the plant of claim 2.

4. Seed or seeds of the inbred com line selected from the group consisting of the inbred com lines designated 3087, 5720, 6022 and 7054 of claim 1.

5. An inbred com plant having the phenotypic, physiological and moφhologic characteristics of an inbred com line selected from the group consisting of the inbred com lines designated 3087, 5720, 6022 and 7054.

6. A method for producing a co plant comprising crossing a first parent com plant witii a second parent com plant wherein said first or second parent com plant is selected from the group consisting of the inbred com plants designated 3087, 5720, 6022 and 7054 or mixtures thereof.

7. The method of claim 6, wherein the first and second parent com plants are both from the inbred com line designated 3087.

8. The method of claim 6, wherein the first and second parent com plants are both from the inbred com line designated 5720.

9. The method of claim 6, wherein the first and second parent com plants are both from the inbred com line designated 6022.

10. The metiiod of claim 6, wherein the first and second parent com plants are both from die inbred com line designated 7054.

11. A first generation (Fl) hybrid com plant produced by crossing a first inbred female com plant with a second inbred male com plant, wherein the first or second parent com plant is the inbred com plant having the designation 3087.

12. The hybrid com plant of claim 11, wherein the inbred co plant having the designation 3087 is the female parent.

13. The hybrid com plant of claim 11, wherein the inbred com plant having the designation 3087 is the male parent.

14. A first generation (Fl) hybrid com plant produced by crossing a first inbred female com plant with a second inbred male com plant, wherein the first or second parent com plant is the inbred com plant having the designation 5720.

15. The hybrid com plant of claim 14, wherein the inbred com plant having the designation 5720 is the female parent.

16. The hybrid com plant of claim 14, wherein the inbred com plant having the designation 5720 is the male parent.

17. A first generation (Fl) hybrid com plant produced by crossing a first inbred female com plant with a second inbred male com plant, wherein the first or second parent com plant is the inbred com plant having the designation 6022.

18. The hybrid com plant of claim 17, wherein the inbred com plant having the designation 6022 is the female parent.

19. The hybrid com plant of claim 17, wherein the inbred com plant having the designation 6022 is the male parent.

20. A first generation (Fl) hybrid com plant produced by crossing a first inbred female com plant with a second inbred male com plant, wherein the first or second parent com plant is the inbred com plant having the designation 7054.

21. The hybrid com plant of claim 20, wherein the inbred com plant having the designation 7054 is the female parent.

22. The hybrid com plant of claim 20, wherein the inbred com plant having d e designation 7054 is the male parent.

23. A method for producing first generation (Fl) hybrid com seed comprising crossing a first inbred parent com plant with a second inbred parent com plant, wherein the first or second parent com plant is the inbred co plant having die designation 3087, to produce first generation (Fl) hybrid com seed.

24. A first generation (Fl) hybrid com plant produced by growing the hybrid com seed of claim 23.

25. A method for producing first generation (Fl) hybrid com seed comprising crossing a first inbred parent com plant with a second inbred parent com plant, wherein the first or second parent com plant is the inbred com plant having the designation 5720, to produce first generation (Fl) hybrid com seed.

26. A first generation (Fl) hybrid com plant produced by growing the hybrid com seed of claim 25.

27. A method for producing first generation (Fl) hybrid com seed comprising crossing a first inbred parent com plant with a second inbred parent co plant, wherein the first or second parent com plant is the inbred com plant having the designation 6022, to produce first generation (Fl) hybrid com seed.

28. A first generation (Fl) hybrid com plant produced by growing the hybrid com seed of claim 27.

29. A method for producing first generation (Fl) hybrid com seed comprising crossing a first inbred parent com plant with a second inbred parent com plant, wherein the first or second parent co plant is the inbred com plant having the designation 7054, to produce first generation (Fl) hybrid com seed.

30. A first generation (Fl) hybrid com plant produced by growing the hybrid com seed of claim 29.

31. An inbred com plant having an RFLP profile characteristic of an inbred co line selected from the group consisting of the inbred com lines designated 3087, 5720, 6022 and 7054.

32. An inbred com plant with an RFLP profile characteristic of the inbred com line designated 5720.

33. An inbred com plant with an RFLP profile characteristic of the inbred com line designated 6022.

34. An inbred com plant with an RFLP profile characteristic of the inbred com line designated 7054.