Abstract:
An inbred corn line, designated NP 2045, is disclosed. The invention relates to the seeds of inbred corn line NP 2045, to the plants of inbred corn line NP 2045 and to methods for producing a corn plant produced by crossing inbred line NP 2045 with itself or with another corn plant. The invention further relates to hybrid corn seeds and plants produced by crossing inbred line NP 2045 with another corn line.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a new and distinctive corn inbred line designated NP 2045 and to hybrids made by using NP 2045 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, agronomically 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 parent, inbred germplasm. These traits may include maximization of yield, resistance to disease and insects, tolerance to drought, heat and other environmental stresses. These traits are governed by a complex genetic system that makes selection and breeding of an inbred line challenging. 
     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 first generation (F1) progeny; double cross hybrids, produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F1 hybrids are crossed again (A×B)×(C×D); or three-way cross hybrids produced from crossing a single cross (A×B) to a third inbred line 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. However, while many of the techniques and methods are known, breeder care and expertise must be used in the selection of breeding material for resulting yield increase and superior agronomic traits. Reference is made particularly to Corn and Corn Improvement, Third Edition, ed. G. F. Sprague and J. W. Dudley, American Society of Agronomy Monograph No. 18, particularly chapters 8 and 9, the substantive content of which is hereby incorporated by reference. 
     SUMMARY OF THE INVENTION 
     According to the invention, there is provided a novel inbred corn line, designated NP 2045. This invention thus relates to the seeds of inbred corn line NP 2045, to the plants of inbred corn line NP 2045 and to methods of producing a corn plant comprising the crossing of inbred line NP 2045 with itself or another corn line. 
     This invention further relates to hybrid corn seed produced by crossing the inbred line NP 2045 with another corn inbred line. More specifically the invention extends to hybrid corn seed produced by planting in pollinating proximity seeds of inbred corn line NP 2045 and a second inbred line having a genotype different from NP 2045; cultivating corn plants resulting from said planting until time of flowering; emasculating the flowers of plants of one of the inbred lines; allowing cross pollination to occur between the inbred lines; and harvesting seeds produced on the plants of the inbred line. The hybrid plants grown from the seed produced as stated above. 
     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. 
     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 Rating System. 
     MST=Harvest Moisture. The moisture is the actual percentage moisture of the grain at harvest. 
     YLD=Yield; bushels per acre. The actual yield of the grain at harvest (bu/a) adjusted to approximately 15.5% moisture. ##EQU1## 
     HUS=Heat units from emergence to 50% of plants in silk. 
     HU to pollen=Heat units from emergence to 50% of plants in pollen. 
     HU to pollen shed=Heat units from 10% to 90% pollen shed. 
     GRLS=Grey Leaf Spot. 
     BClFl=(A×B)×B or A. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Inbred corn line NP 2045 is a yellow dent inbred line with superior characteristics and is best suited as a male in crosses for production of first generation (F1) corn hybrids. NP 2045 is best adapted to the North central part of the United States. NP 2045 can be used to produce hybrids from approximately 110-120 PRM days based on the Minnesota Relative Maturity Rating System for harvest of grain. Inbred line NP 2045 has demonstrated good combining ability with families derived from Iowa Stiff Stalk, for example B73 and related lines LH119, LH132, W8304 (PVP Certificate No. 8800032) and Northrup King inbred line NP894. 
     Inbred corn line NP 2045 was derived from the crossing LH82, Holdens Foundation Seed, to Northrup King Co. Proprietary line NP J8606 (PVP Certificate No. 8900226). LH82×NPJ8606 was backcrossed to NPJ8606. Self-pollinations and selections were then practiced within the above BC1F1 hybrid cross for seven generations in the development of NP 2045. During the development of the line, crosses of segregating families were made to inbred testers to evaluate combining ability. Inbred line NP 2045 can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollination or sub-pollination conditions with adequate isolation and then harvesting the resulting seed. No variant traits have been observed or are expected in NP 2045. 
     The inbred fine has been evaluated at numerous research stations including stations across the Northern United States Corn Belt and Canada. Inbred line NP 2045 has shown uniformity and stability for all discernible characteristics as described in the following variety description. The description is based on data collected primarily at Washington, Iowa; Webster City, Iowa; and Napoleon, Ohio on 6 (six) replication in 1995. In interpreting the color designations herein, reference is made to the Munsell Glossy Book of Color, a standard color reference to describe all color choices. 
     
                       TABLE 1______________________________________VARIETY DESCRIPTION INFORMATION FOR INBRED LINENP 2045, Mo17 and NP 899 -UNITED STATES GEOGRAPHICAL AREAS           NP 2045                  Mo17     NP 899______________________________________Type:             Dent     Dent     DentRegion Best Adapted:             North    Northern North             central  and      Central                      CentralA.  Maturity:    HU to Silk (HUS): 1361     1510   1408                 (63 days)                          (68 days)                                 (65 days)    HU to pollen:     1367     1408   1426                 (63 days)                          (64 days)                                 (65 days)    HU to pollen shed:                 91       98     96                 (3.3 days)                          (3.7 days)                                 (3.7 days)B.  Plant Characteristics:    Plant height (to tassel tip) (cm):                 196      226.7  227.1    Length to top ear internode                 14.5     15.6   16.4    (cm):    Ear height (to base of top ear                 59.6     82.2   80.4    internode) (cm):    Number of tillers:                 0        0      0    Number of ears per stalk:                 1        1      1    Cytoplasm type:   Normal   Normal Normal    Anthocyanin of brace roots:                 Faint    Faint  AbsentC.  Leaf:    Color:            Medium   Medium Medium                 green    green  green                 (7.5GY-  (7.5GY-                                 (7.5GY-                 4/2)     4/2)   4/4)    Leaf angle (from 2nd leaf above                 16°                          33.5°                                 32.5°    ear at anthesis to stalk above    leaf)    Number of leaves- above top ear                 5.3      4.8    5.2    (mature plants):    Marginal waves:   7        6      4.8    (Scale: 1 = none to 9 = many):    Width (widest point of                 9        9.4    9.4    ear node leaf) (cm):    Sheath Pubescence:                 2        0      4.7    (Scale 0 = none to 9 = many):    Longitudinal creases:                 5        5      5    (Scale: 1 = none to 9 = heavy):    Length (ear node leaf) (cm):                 74.1     66.2   67.2D.  Tassel:    Number of primary lateral                 7.3      5.5    11.2    branches:    Branch angle from central spike:                 33.7°                          54.7°                                 49.2°    Pollen shed:      7        5.8    7.7    () = male sterile to 9 = heavy):    Anther color:     Yellow   Green- Purple                          Yellow                 (5Y-7/6) (2.5GY-                                 (5RP-3/4)                          8/6)    Glume color:      Light    Light  Green                 Green    Green                 (5GY-    (5GY-5/6)                                 (7.5GY-                 6/6)            5/6)    Bar glumes:       Absent   Absent Absent    Tassel length (from top leaf                 28.9     36.3   33.3    collar to tassel tip):E.  Ear (Husked ear data except    where stated otherwise):    Length (cm):      12.9     18.6   15.5    Weight (gm):      112.7    120.4  90.7    Midpoint diameter (mm):                 39.1     36.4   36.7    Kernel rows:      15.6     10.6   14.8                 Distinct Distinct                                 Distinct    Row alignment     Straight Straight                                 Straight    Silk color (3 days after                 Green-   Green- Pink    emergence):       yellow   yellow                 (2.5GY-  (2.5GY-                                 (2.5R-7/6)                 8/6)     8/6)    Husk extension (length of the                 Medium   Medium Medium    husk past the ear tip at maturity:                 &lt;8 cm    &lt;8 cm  &lt;8 cm    Taper of ear:     Slight   Slight Average    Husk color (fresh)                 Medium-  Medium-                                 Medium    25 days after 50% silking:                 green    green  green    Husk color (dry)  Buff     Buff   Buff    65 days after 50% silking:                 (2.5Y-8/4)                          (2.5Y-8/4)                                 (2.5Y-8/4)    Shank length (cm):                 10.8     11.9   7.9F.  Kernel (Dried):    Size (from ear mid-point):    Length (mm):      10.6     10.5   10.1    Width (mm):       7.4      8.8    7.4    Thickness (mm):   4.6      4.9    4.8    Shape grade (% of kernels that                 65.2     48.7   57.8    do not pass through a 13/64    slotted screen):    Aleurone color:   Homo-    Homo-  Homo-                 zygous   zygous zygous                 Bronze   Bronze Yellow-                                 orange    Endosperm color:  Yellow-  Yellow-                                 Yellow-                 orange   orange orange                 (7.5YR-  (7.5YR-                                 (7.5YR-                 5/8)     6/10)  6/10)    Endosperm type:   Normal   Normal Normal                 starch   starch starch    Gm weight/100 seeds (unsized):                 23.0     29.1   19.4G.  Cob:    Diameter at mid-point (mm):                 22.3     19.2   19.0    Color:            Red      Light red                                 White                 (10R-4/6)                          (10R-6/6)H.  Agronomic Traits:    Stay Green: (At 65 days after                 5.3      3      2    anthesis), Scale 1 = worst to    9 = excellent):    Kg/ha Yield on Inbred per se                 4663     4585   3876    (At 12-13% grain moisture)I.  Disease Resistance:    Northern corn leaf blight:                 7        8      5    Exserohilum turcicum    Grey leaf spot:   7        7      5    Cercospora zea-maydis    Southern leaf blight:                 4        6      3    Bipolaris maydis:J.  Insect Resistance:    European Corn Borer    (Ostrinia nubilialis)    1st generation    5        7      6    2nd generation    6        5      2______________________________________ 
    
     The above disease and insect resistance description is based on a scale of 1-9; wherein 1-3 is considered susceptible, 4-5 intermediate, 6-7 resistant and 8-9 highly resistant. 
     With respect to publicly available inbred lines, NP 2045 most closely resembles Mo17. However, these lines differ in a number of characteristics. The lines differ in plant height, ear height, ear length and number of kernel rows. While NP 2045 is shorter than Mo17 and has lower ear height, it has more kernel rows compared to Mo17. Other characteristics between NP 2045 and Mo17 are summarized in Table 1. 
     NP 2045 most closely resembles Northrup King inbred line NP 899 (PVP Certificate No. 9400106) in terms of usage and maturity. Line NP 899 is claimed in U.S. Pat. No. 5,530,181 and has ATCC accession No. 97362. However, the following quantitative traits are statistically differentiating (TABLE 2). 
     
                       TABLE 2______________________________________                          Sample StandardCharacteristic        NP 2045  NP 899   Size   Deviation______________________________________1. Plant Height (cm):        196.0    227.1    30     2.742. Ear Height (cm):         59.6     80.4    30     5.843. Anther Color:        Yellow   Purple        (5Y-7/6) (5RP-3/4)______________________________________ 
    
     These data were taken from Washington, Iowa; Webster City, Iowa; and Napoleon, Ohio on 6 replications in 1995. 
     In addition to phenotypic observations, the genotype of a plant can also be examined. There are many techniques available for the analysis, comparison and characterization of plant genotype and these include isozyme electrophoresis, restriction fragment length polymorphism (RFLPs), randomly amplified polymorphic DNAs (RAPDs) sequence characterized amplified regions (SCARs) and amplified fragment length polymorphisms (AFLPs). While many of the techniques are used, RFLPs have the advantage of revealing an exceptionally high degree of allelic variation in corn. Moreover, there are a tremendous number of markers available to use. Reference is made to Mumm and Dudley, A classification of 148 U.S. Maize Inbreds: I Cluster Analysis Based on RFLP&#39;s, Crop Sci., 34:842-851 (1994), and Lee, M &#34;Inbred Lines of Maize and Their Molecular Markers&#34; The Maize Handbook (Springer-Verlag, New York, Inc. 1994 which are hereby incorporated by reference. 
     Both inbred lines NP 2045 and Mo17 were subject to various RFLP probes and the results indicate that the two inbreds have 55 out of 107 loci with different alleles. Additional RFLP relationship data indicates that NP 2045 is different from NP 899. 
     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 2045. However, both first and second parent corn plant can come from the inbred corn line NP 2045. Therefore, any methods using NP 2045 are part of this invention including self-pollination, backcross-pollination, hybrid breeding and crosses to produce germplasm 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 may be taken to ensure that self-pollination does not occur. 
     Any plants produced using inbred corn line NP 2045 as a parent are within the scope of this invention including any plant produced by the use of cells, protoplasts or tissue from NP 2045. 
     Specifically, NP 2045 produces hybrids that are competitive yielding, have good stalk strength, stay green ratings and Grey Leaf Spot resistance. 
     The techniques used to obtain the corn hybrid seeds and plants of this invention 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, tassels are removed from all plants of the female parent by hand, machine or other means. Natural cross-pollination is allowed to occur. Ears from the female plants are harvested to obtain novel F1 hybrid corn seeds of the present invention. F1 hybrid corn plants of the invention are obtained by planting seeds harvested from the female plant. 
     An example of a competitive yielding hybrid of this invention is that produced by the cross Northrup King Co. Inbred line NP 894×NP 2045 The hybrid produced from NP 894×NP 2045 is a 115 Minnesota Relative Maturity (RM) single cross hybrid. This hybrid most closely resembles the commercially available Northrup King Co. hybrid N6223, N6822 and N6330. 
     The hybrid produced by the cross NP 894×NP 2045 has significantly better Grey Leaf Spot resistance compared to N6223 and Pioneer (P) 3489 (Table 3). Table 3 also shows data for NP 894×NP 2045 compared to N6822, N6330 and Pioneer (P) 3394. NP 894×NP 2045 is also significantly higher for yield and Grey Leaf Spot resistance compared to N6330, N6822 and P3394. 
     
                       TABLE 3______________________________________Combined Location and Year Performance Data(1995, 1996; 72 environments; 110-120 RM Markets)Hybrid       YLD (bu/a)  MST (%)  GRLS______________________________________NP 894 × NP 2045        156.1       19.8     3.3N6223        152.8       18.0     6.0N6330        149.3       18.8     5.6N6822        150.7       19.3     6.6P3394        151.4       18.4     7.5P3489        154.3       18.6     5.1Trials with data:        72          72       9LSD          4.3         0.3      0.9______________________________________ GRLS = Grey Leaf Spot, a rating to 1 = best resistance, 9 = most susceptible. 
    
     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. In this context, the invention also includes a corn plant regenerated from any NP 2045 corn cell, protoplast and tissue mentioned above and having the same genotype as NP 2045. 
     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 of inbred NP 2045, has been made unrestrictedly available to the public via the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA. The deposit corresponds to ATCC Deposit No. 209450, ATCC and was made on Nov. 12, 1997. The seeds are from stock maintained by Northrup King since prior to filing this application or any parents thereof. The deposit of inbred corn line NP 2045 will be maintained in the ATCC depository, which is a public depositary, for a period of 30 years, or 5 years after the most recent request, or for the effective life of the patent, whichever, is longer, and will be replaced if it ever becomes nonviable during that period. Additionally, with respect to Plant Variety Protection Certificates received and applied for, Applicant does not waive any infringement of its rights granted under this patent or under the Plant Variety Protection Act (7 U.S.C. 2312 et seq.).