Abstract:
According to the invention there is provided an inbred corn line, designated NP 982. The invention thus relates to the seeds of inbred corn line NP 982, to the plants of inbred corn line NP 982 and to methods for producing a corn plant produced by crossing inbred line NP 982 with itself or with another corn plant. The invention further relates to hybrid corn seeds and plants produced by crossing inbred line NP 982 with another corn line. Particularly the invention provides a novel hybrid corn plant, designated N7590 produced by crossing inbred NP 982 with another Northrup King proprietary inbred corn line.

Description:
This is a CONTINUATION of application Ser. No. 08/543,240, filed on Oct. 13, 1995 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to the field of corn breeding. More specifically the invention is related to a new and distinctive corn inbred line designated NP 982 and to hybrids made by using NP 982 as a parent. 
     Corn (Zea mays) is a valuable and important field crop. Thus, plant breeders are continually developing new and superior corn inbred lines for production of high yielding, agronomicly sound hybrids. The goal of the plant breeder is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These traits may include maximized yield, resistance to disease and insects, tolerance to drought, heat and other environmental stresses, and better agronomic quality. 
     Corn hybrid development requires the development of homozygous inbred lines, the crossing of these lines, and the subsequent evaluation of those crosses. Pedigree, backcross, and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs combine the genetic backgrounds from two or more inbred lines or various other genetic sources into breeding pools from which new inbred lines are developed by self pollination and selection of desired phenotypes. The new inbred lines are crossed with other inbred lines, and hybrids from these crosses are evaluated to determine which have commercial potential. 
     Once the inbred parents that give a superior hybrid are identified, the hybrid seed can be reproduced indefinitely as long as inbred parent homogeneity is maintained. Corn hybrids may be either single cross hybrids, produced when two inbred lines are crossed to produce the F 1  progeny; or double cross hybrids, produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F 1  hybrids are crossed again (A×B)×(C×D); or three way cross hybrids produced by crossing a single cross (A×B) to a third inbred (C). Numerous references are available on the topic of corn breeding and hybrid seed corn production; those skilled in the art of corn breeding and production are well aware of techniques and methods for the development of inbred corn lines and corn hybrids. Reference is made particularly to Corn and Corn Improvement, Third Edition, eds. G. F. Sprague and J. W. Dudley, American Society of Agronomy Monograph No. 18, particularly chapters 8 and 9 the substantive contents of which is hereby incorporated by reference. 
     SUMMARY OF THE INVENTION 
     The invention provides a novel inbred corn line 982, designated NP 982. This invention thus relates to the seeds of inbred corn line NP 982, to the plants of inbred corn line NP 982 and to methods of producing a corn plant produced by the crossing of inbred line NP 982 with itself or another corn line. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line NP 982 with another corn inbred line, and particularly to the hybrid designated N7590. 
     DEFINITIONS 
     In the description and examples that follow a number of terms are used; therefore, to provide a clear and consistent understanding of the specification and claims the following definitions are provided. 
     RK=Round Kernels: the percentage of kernels that do not pass through a 13/64 slotted screen. 
     HE=Husk Extension: the length (cm) of the husk past the ear tip at maturity. 
     LL=Leaf Length: the length of the ear leaf measured in cm. 
     NN=Node Number: the number of nodes of the entire plant. 
     PLT HT=Plant Height. The measure of the height of the plant from the ground to the tip of the tassel in cm. 
     DE=Dropped Ears. The number of ears that have fallen from the plant over all observations. 
     EAR HT=Ear Height. The measure from the ground to the top developed ear node attachment measured in cm. 
     PRM=Predicted Relative Maturity. This trait is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and is referred to as the Minnesota Relative Maturity Rating System. 
     MST=Harvest Moisture. The moisture is the actual percentage moisture of the grain at harvest. 
     STK (BR)=The percentage of plants broken below the ear at harvest. 
     YLD=Yield; bushels per acre. The actual yield of the grain at harvest (bu/a) adjusted to 15.5% moisture. 
     RT=Number of plants lodged (leaning from vertical but not broken). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Inbred corn line NP 982 is a yellow dent inbred line with superior characteristics and is best suited as a male in crosses for production of first generation F 1  corn hybrids. NP 982 is best adapted to the Central Cornbelt Area of the United States, and can be used to produce hybrids from approximately 112 to 120 days relative maturity based on the Minnesota Relative Maturity Rating System for harvest of grain. The timing between pollen shed and silking is highly synchronous in inbred NP 982. Additionally, NP 982 has demonstrated good specific combining ability with families derived from Iowa Stiff Stalk, for example, B73, B37, B14 and related lines. 
     Inbred corn line NP 982 was developed from the F 1  population (LH123×J8503) by self-pollination and simple pedigreed ear-to-row breeding. Parent LH123 is a well known Holden&#39;s Foundation Seed Co. inbred line, and parent J8503 is a Northrup King Co. line derived by selfing within the F 1  of Pioneer Brand P3382. Self-pollination and selection were practiced within the above F 1  cross for seven generations in the development of NP 982. During the development of the line, crosses of segregating families were made to inbred testers to evaluate combining ability. Inbred line NP 982 can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollination or sib-pollination conditions with adequate isolation and then harvesting the resulting seed. No variant traits have been observed or are expected in NP 982. 
     Inbred line NP 982 has been evaluated at numerous research stations across the United States Corn Belt. The line is uniform and stable for all discernible characteristics as described in the following Variety Description, Table 1. The description is based on data collected primarily at Phillips, Nebraska and St. Joseph, Illinois on a maximum of 4 replications and or 10 subsamples. In interpreting the color designation herein, reference is made to the Munsell Glossy Book of Color, a standard color reference. 
     
                       TABLE 1______________________________________VARIETY DESCRIPTION INFORMATIONFOR INBRED LINE NP 982Type: Dent Region Best Adapted: Central Corn Belt (US)______________________________________A.     Maturity:  Heat Units Silk (HUS): 1516. ##STR1##B.     Plant Characteristics:  Plant height (to tassel tip): 225 cm  Length to top ear internode: 16.4 cm  Ear height (to base of top ear internode): 72.7 cm  Number of tillers: none  Number of ears per stalk: 2.1  Cytoplasm type: normalC.     Leaf:  Color: medium green (Munsell code 5GY4/4)  Angle from stalk (upper half): 19 degrees  Number of leaves (mature plants) above top of the ear: 6  Marginal waves: few  Width (widest point of ear node leaf): 8.3 cm  Sheath Pubescence: few  Longitudinal creases: few  Length (ear node leaf, &#34;LL&#34;): 80.5 cmD.     Tassel:  Number of lateral branches: 3.5  Branch angle from central spike: 30 degrees  Pollen shed: medium  Anther color: green-yellow  Glume color: green-yellowE.     Ear (Husked ear data except where stated otherwise):  Length: 15.6 cm  Weight: 109.7 gm  Midpoint diameter: 37.7 mm  Kernel rows: 14  Silk color: green-yellow  Husk extension: medium  Taper of ear: average  Husk color (fresh): medium green  Husk color (dry): tan  Shank length: 6.7 cmF.     Kernel (Dried):  Size (from ear mid-point):   Length: 10.2 mm   Width: 8.3 mm   Thickness: 4.0 mm  Shape grade (% rounds): 44%  Pericarp color: colorless  Aleurone color: colorless  Endosperm color: yellow  Endosperm type: normal starch  Gm weight/100 seeds (unsized): 24.3G.     Cob:  Diameter at mid-point: 22 mm  Strength: strong  Color: light red (Munsell Code 5YR5/6)H.     Disease Resistance and Insect Resistance:  Preliminary data suggest  Northern leaf blight: tolerant  Southern corn leaf blight: tolerant  European corn borer: susceptible  Gray Leaf spot: tolerantJ.     Variety Most Closely Resembling:  Character  Inbred  Maturity   Mo17  Usage      Mo17______________________________________ 
    
     Inbred Mo17 is a well known and available corn line. Inbred corn line NP 982 may be distinguished from Mol 7 and other inbred lines by characteristics described in Table 2. 
     
                       TABLE 2______________________________________1994 Variety Comparison Data ofInbred Line NP 982Variety/Line   Silk HU  Pollen HU Plant Ht. (cm)                                Ear Ht. (cm)______________________________________NP 982  1542     1508      241       65Mo17    1582     1476      220       83NP 8304 1572     1546      228       86B73     1513     1502      235       97B68     1628     1567      227       89# Reps   10       10        8         8LSD (0.5)    43       41        18       12cv %      3        3        7        12______________________________________ 
    
     This invention is also directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant, wherein the first or second corn plant is a corn plant of the inbred line NP 982. However, both first and second parent corn plant can come from the inbred corn line NP 982. Therefore any methods using NP 982 are part of this invention including self-pollination, backcross-pollination, hybrid breeding and crosses to populations. It may be desirable to use a male-sterile (either cytoplasmic or nuclear) female parent to prevent self-pollination. If the female is not male-sterile, then either physical or chemical steps should be taken to ensure that self-pollination does not occur. Any plants produced using inbred corn line NP 982 as a parent are within the scope of this invention including any plant produced by the use of cells, protoplasts or tissue from NP 982. 
     An example of a hybrid produced by crossing inbred line NP 982 is hybrid N7590. This hybrid has NP 982 as a male parent and Northrup King inbred line NP 8304 as a female parent. Inbred NP 8304 (also known as W8304) has PVP Certificate No. 8800032 which is hereby incorporated by reference. The techniques used to obtain the corn hybrid seeds and plants are conventional in the seed industry and are well known to those skilled in the art. The two parent lines are planted in pollinating proximity to each other in alternating sets of rows; however, any convenient planting pattern that allows for the free transfer of pollen is acceptable. The plants of both inbred lines are allowed to grow until the time of flowering. At flowering, the tassels are removed from all plants of the female parent. Natural cross-pollination is allowed to occur. Only the ears from the female plants, NP 8304, are harvested to obtain novel F 1  hybrid corn seeds N7590 of the present invention. The F 1  hybrid corn plants of the invention are obtained by planting the seeds of N7590 at the next proper growing season. The techniques used to obtain the corn hybrid seeds and plants are conventional in the seed industry and are well known to those skilled in the art. 
     N7590 is a 115 relative maturity (RM) single cross hybrid. N7590 most closely resembles Northrup King Co. hybrid N7992. N7992 is a Northrup King Co. hybrid sold in the Southern Corn Belt and Southeast U.S. N7590 is distinguished from known hybrid N7992 in that N7590 is substantially higher yielding than N7992; N7590 silks about 60 HU sooner than N7992, with comparable plant and lower ear height. N7590 has been compared with various hybrids, and in Table 3 some of these results are indicated. 
     
                       TABLE 3______________________________________Combined Location and Year Performance Data(1993-1994: Corn Belt Locations Nebraska to Ohio) YLD    MST    STK   RT   HUS  PLT HT Ear Ht.                                            DEHybrid (bu/a) %      %     %    GDD  (cm)   (cm)  #______________________________________P3394 159    18.9   4     2    1425 260    117   21N6330 151    19     5     1    1407 253    108   23P3245 156    20.4   5     1    1470 269    112   15N7448 155    20.7   4     2    1449 274    112   37N7590 170    20.8   4     1    1422 275    112   23PX9540 156    21.4   5     1    1440 261    117   28N7707 162    22     3     1    1436 268    104   16N7992 163    22.6   3     2    1485 281    129   25N7989 146    23.1   5     2    1536 269    123   33LSD    5     0.4    1     1     17   5      4     0C.V    10    5.3OBS    83    83     65    51    14   30     30   52______________________________________ 
    
     N7590 may be further described by characteristics listed in Table 4. 
     
                       TABLE 4______________________________________VARIETY DESCRIPTION INFORMATION FOR HYBRID N7590        Region Best Adapted: Central Corn BeltType: Dent   (Northrup King Maturity Zone 7)______________________________________A.       Maturity:    Relative Maturity (RM): 112-116 days    U.S. Heat Units = 2770    FAO = 550-600    Cytoplasm Type; normalB.       Preflowering:    Length of first leaf blade: long    Anthocyanic pigment of seedling: medium    Juvenile plant:     color: medium green     form: planofil     size: mediumC.       Flowering    Number of leaves: 15     below ear: 8     above ear: 7    Leaf angle from stalk: 30-60 degrees    Leaf:     marginal waves: few     longitudinal creases: none     color: dark    Number of tillers: None    Plant height to tassel tip: 281 cm    Length of top ear internode: 17 cm    Second internode:     width: 24 mm     length: 9 cm    Anthocyanic pigment of brace roots: medium    Shape of tassel: loose    Number of lateral tassel branches: 6    Tassel branch angle: 30-45 degrees from vertical    Length of largest tassel branch: medium    Anther color: yellow    Heat units to:     50% pollen shed: 1424     50% silk: 1420    Silk:     color: green     length outside of husk: 11 cm    Fresh husk color: light green    Ear leaf:     anthocyanic pigment: medium     pubescence: medium     sheath pubescence: light or none     length: 100 cm     width: 9.5 cm    Ear height: 103 cm    Number of:     nodes: 12     anthocyanic nodes: 10     anthocyanic internodes: 2     nodes with adventitious roots: 2    Peduncle length: 14 cm    Central spike length: medium    Glume:     color: green     band color: green    Pollen shed: medium    % of plants with ear wings: 57    Ear wing length: 11 cm    Number of ears per stalk: (1.3)D.       Maturity    Husk:     extension: medium     at maturity (HE): medium    Shank:     length: 6.8 cm     internode number: 7    Kernel:     rows: distinct     alignment: straight     row number: 16    Ear weight: 229 gm    Kernel:     100 weight: 28.5 gm     length: 12.5 mm     width: 7.5 mm     thickness: 3.7 mm     % round kernels (RK): 32.5    Ear:     position at maturity: upright     length: 17.3 cm     diameter: 46.3 mm     taper: average    Cob:     color: red     diameter: 28.3 mm     strength: strong    Kernel color:     pericarp: colorless     aleurone segregation: homozygous     aleurone: tan     endosperm: yellow     kernel crown: light yellow     kernel body (sides): yellow    Endosperm type: normal    % of kernels showing purple plumule tip: none______________________________________ 
    
     As used herein the term plant includes plant cells, plant protoplasts, plant cell tissue cultures including that from which corn plants fertile or otherwise can be regenerated, plant calli and plant cell clumps, and differentiated forms of plants such as, but not limited to embryos, pollen, stamen, anthers, flowers, kernels, ears, cobs, leaves, stalks, roots, shoots, plantlets, silks and kernels. 
     Methods of cell and tissue culture and regeneration are well known in the art and described for example in &#34;Plant Tissue Culture Manual: Fundamentals and Application&#34;, Ed. K. Lindsey, Kluwer (1991) and in Green and Rhodes, &#34;Plant Regeneration in Tissue Culture of Maize&#34;, Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va., 1982, pp. 367-372), which are hereby incorporated by reference. 
     As is well known, corn can be put to a wide variety of uses not only as livestock feed but also for human consumption of corn kernels and as a raw material in industry. Both grain and non-grain portions of the plant are used as a livestock feed for swine, cattle and poultry. In the food industry corn is used in wet and dry milling. In wet milling there is the separation of the germ, hull gluten and starch. Germ is used to produce corn oil and germ cake for feed. Corn starch may be packaged for human consumption or used in food products such as sauces, gravies, puddings, sweeteners, syrups, and baking powder. Other nonedible uses include textiles, paper, adhesives, cosmetics, explosives, corn binders, laundry purposes and agricultural formulations. Dry milling is used to produce breakfast foods, grits, cornmeal and corn flour. Other uses of corn include fuel, in the form of fuel alcohol or ethanol; seed; alcoholic beverages and construction. 
     DEPOSIT INFORMATION 
     Deposits of at least 2500 seeds each of inbred NP 982, NP 8304 and hybrid N7590 have been made unrestrictedly available to the public via the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA. The deposit corresponds to ATCC Deposit Nos. 209453, 209540, and 209507, respectively. The seeds deposited with the ATCC are taken from stock maintained by Northrup King since prior to filing this application. This deposit of Inbred Corn Line NP 982, Inbred Corn Line NP 8304 and Hybrid N7590 will be maintained without restriction in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years from the most recent request, or for the enforceable life of the patent, whichever is longer and will be replaced if they become nonviable during that period.