Patent Publication Number: US-5530181-A

Title: Corn inbreds `899` and `901` and corn hybrid `N5220`

Description:
This is a CONTINUATION of application Ser. No. 08/078,876, filed Jun. 16, 1993, now abandoned. 
    
    
     This invention relates to novel corn inbreds, plant parts and tissue of these inbreds, use of the inbreds to produce hybrid corn plants, hybrid corn plants obtained using at least one of said inbreds as a parent and parts and tissue of these hybrid corn plants. 
     The goals and methods of plant breeding particularly with respect to corn (Zea mays) and the use of inbreds in the breeding of hybrids e.g. in pedigree breeding are well known to those skilled in the art. Representative descriptions of techniques and underlying principles can be found for example in U.S. Pat. No. 4,654,466; U.S. Pat. No. 4,731,499; U.S. Pat. No. 5,159,134; R. W. Allard, Principles of Plant Breeding, John Wiley &amp; Sons (1960) and N. F. Jensen, Plant Breeding Methodology, John Wiley &amp; Sons (1988), the substantive content of which in this respect is incorporated herein by reference. 
     One aspect of the invention provides novel corn inbred 899. Inbred Corn Line 899 is a yellow dent corn inbred with superior characteristics and provides an excellent male and/or female parental line in crosses for producing first generation F1 corn hybrids. This inbred is best adapted over the Northern and Central regions of the United States. The inbred can be used to produce hybrids between approximately 100-115 relative maturity based on the Minnesota Relative Maturity Rating System for harvest moisture of grain. This inbred has rapid dry down characteristics which in hybrid combinations produces fast drying hybrids. Because of its excellent seed yield, good seed sizing and excellent pollen shed, 899 is well qualified for use as either a male or female parent in hybrid crosses. 
     The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information. Most of the data in the Variety Description information was collected at Washington, Iowa. However, heat unit to shed and to silk data was collected at Phillips, Nebr., St. Joseph, Ill. and Washington, Iowa. The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant and ear type to ensure homozygosity and phenotypic stability. Seed of the line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in 899. PG,3 
     Inbred corn line 899, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed, using techniques familiar to the agricultural arts. Reproduction can alternatively take place using conventional tissue or cell culture methods. 
     899 may be further characterized by reference to the following objective descriptors. 
     (i) Type: Dent 
     Region Best Adapted: Northern and Central 
     Maturity: Northrup King Maturity Zone 6;=110-115 RM; 
     FAO=500-550 
     US Heat Units=2660-2720 
     Heat Unit Emergence to 50% silk:1464 
     Heat Units=Σ{(Temp max  +Temp min )/2]-50 where Tmax≦86; Tmin≦50 
     Characteristics 
     (ii) Plant 
     Plant height (to tassel tip): 221 cm 
     Ear height (to base of top ear): 81 cm 
     Length of top ear internode: 15 cm 
     Number of tillers: None 
     Number of ears per stalk: Slight two-ear tendency 
     Cytoplasm type: Normal 
     (iii) Leaf: 
     Color: Light Green (HY) 
     Angle from Stalk: 30°-60° 
     Sheath Pubescence: Light (W22) 
     Marginal Waves: Few (WF 9) 
     Longitudinal Creases: Few (OH56A) 
     Width (widest point, ear node leaf): 10 cm 
     Length (Ear node leaf): 75 cm 
     Number of Leaves (mature plants): 14 
     (iv) Tassel 
     Number of lateral branches: 9 
     Branch Angle from central spike: 30°-40° 
     Peduncle Length (top leaf to basal branches) 11 cm 
     Pollen Shed: Heavy (KY21) 
     Anther Color: Purple 
     Glume Color: Green 
     (v) Ear (Husked Ear Data Except When Stated Otherwise) 
     Length: 16 cm 
     Midpoint diameter: 37 mm 
     Weight: 80 gm 
     Kernel Rows: 16 Distinct Straight 
     Silk Color: Pink 
     Husk Color (fresh): Light Green 
     Husk Color (dry): Buff 
     Husk Extension (Harvest stage): Long (beyond ear tip) 
     Husk Leaf: short (&lt;8 cm) 
     Shank Length: 9 cm 
     Shank (No. of internodes): 7 
     Position of Shank (dry husks): Pendent 
     Taper: Average 
     (vi) Kernel (Dried) 
     Size (from ear mid-point) 
     Length: 10 mm 
     Width: 7 mm 
     Thick: 4 mm 
     Shape Grade (% rounds): 20-40% 
     Pericarp Color: Colorless 
     Aleurone Color: Homozygous white 
     Endosperm Color: yellow 
     Endosperm Type: Normal Starch 
     Gm Wt/100 Seeds (unsized): 18 gm 
     (vii) Cob 
     Diameter at mid-point: 22 mm 
     Strength: Strong 
     Color: white 
     (viii) Resistances 
     (a) Disease 
     Northern Leaf Blight: susceptible 
     Southern Leaf Blight: susceptible 
     Others untested 
     (b) Insects 
     Cornborer: susceptible 
     Others untested 
     (ix) Variety most closely resembling 911 
     A further aspect of the invention provides novel corn inbred designated 901. 
     Inbred Corn Line 901 is a yellow dent corn inbred with superior characteristics and is an excellent female and/or an acceptable male parental line in crosses for producing first generation F1 corn hybrids. This inbred is best adapted over the Northern and Central regions of the United States. The inbred can be used to produce hybrids between approximately 105-115 relative maturity based on the Minnesota Relative Maturity Rating System for harvest moisture of grain. Because of its excellent seed yield, good seed sizing and acceptable pollen shed, 901 is not only well qualified for use as a female parent but can also be used as a male parent in hybrid crosses. 
     The inbred has shown uniformity and stability within the limits of environmental influence for all traits described in the Variety Description Information. Most of the data in the Variety Description Information was collected at Washington, Iowa. However, heat unit to shed and to silk data were collected at Phillips, Nebr., St. Joseph, Ill. and Washington, Iowa. The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant and ear type to ensure homozygosity and phenotypic stability. Seed of the line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in 901. 
     Inbred corn line 901, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed, using techniques familiar to the agricultural arts. Reproduction can alternatively take place using conventional tissue or cell culture methods. 
     901 may be further characterized by reference to the following objective descriptors. 
     (i) Type: Dent 
     Region Best Adapted: Northern and Central 
     Maturity: Northrup King Maturity Zone 7; 115-120 RM; 
     FAO=550-600 
     US Heat Units=2720-2800 
     Heat Unit (HU) Emergence to 50% silk:1430 
     Characteristics 
     (ii) Plant 
     Plant height (to tassel tip): 217 cm 
     Ear height (to base of top ear): 56 cm 
     Length of top ear internode: 15 cm 
     Number of tillers: None 
     Number of ears per stalk: Single 
     Cytoplasm type: Normal 
     (iii) Leaf 
     Color: Medium Green (WF9) 
     Angle from Stalk: &lt;30° 
     Sheath Pubescence: Heavy (OH26) 
     Marginal Waves: None (HY) 
     Longitudinal Creases: Absent (OH51) 
     Width (widest point, ear node leaf): 8 cm 
     Length (Ear node leaf): 72 cm 
     Number of Leaves (mature plants): 11 
     (iv) Tassel 
     Number lateral branches: 8 
     Branch Angle from central spike: 30-40° 
     Peduncle Length (top leaf to basal branches) 11 cm 
     Pollen Shed: Heavy (KY21) 
     Anther Color: Salmon 
     Glume Color: Green 
     (v) Ear (Husked Ear Data Except When Stated Otherwise) 
     Length: 12 cm 
     Midpoint diameter: 8 mm 
     Weight: 99 gm 
     Kernel Rows: 16 Distinct Straight 
     Silk Color: Pink 
     Husk Color (fresh): Light Green 
     Husk Color (dry): Buff 
     Husk Extension (Harvest stage): Medium (barely covering ear) 
     Husk Leaf: short (&lt;8 cm) 
     Shank Length: 7 cm 
     Shank (No. of internodes): 7 
     Position of Shank (dry husks): Pendent 
     Taper of Ear: Average taper 
     (vi) Kernel (Dried) 
     Size (from ear mid-point) 
     Length: 12 mm 
     Width: 8 mm 
     Thick: 4 mm 
     Shape Grade (% rounds): 40-60% 
     Pericarp Color: Colorless 
     Aleurone Color: Homozygous white 
     Endosperm Color: yellow 
     Endosperm Type: Normal Starch 
     Gm Wt/100 Seeds (unsized): 33 gm 
     (vii) Cob 
     Diameter at mid-point: 29 mm 
     Strength: Strong 
     Color: red 
     (viii) Resistances 
     (a) Disease 
     Northern Leaf Blight: susceptible 
     Southern Leaf Blight: susceptible 
     Others untested 
     (b) Insects 
     Cornborer: susceptible 
     Others untested 
     (ix) Variety most closely resembling 
     W8304 
     899 and 901 may be propagated conventionally, i.e. by self-pollination or sib-pollination. 
     The invention further relates to use of the 899 and 901 as parents to produce hybrid corn. The choice of the other parent is within the skill of the corn breeder depending particularly on the characteristics and traits desired of the resulting hybrid. Suitable parents may include other inbred lines or lines which are themselves hybrids. 
     899 combines best with inbred lines derived from Iowa Stiff Stalk Synthetic, e.g. B73, B14, B37 and related lines. 
     901 combines best with lines related to C103. 
     899 and 901 combine particularly well with each other. 
     Hybrids created using 899 and/or 901 also form an aspect of the present invention along with methods of producing them. Cross-pollination is accomplished in the usual fashion. It may be desirable to utilize a male-sterile (either cytoplasmic or nuclear) female plant to prevent self-pollination. If the female plant is not male-sterile, then either physical or chemical steps (i.e. detasseling) should be taken to ensure that self-pollination does not occur. Thus, one aspect of this invention is the process of making hybrid seed comprising the steps of crossing a first plant with a second plant, wherein one of the plants is 899 or 901, and obtaining the resultant seed. The hybrid seed so produced may be grown to produce a hybrid plant, which comprises yet another aspect of this invention. 
     An example of such a hybrid is that known as N5220 which has 899 and 901 as its inbred parents. 
     Hybrid N5220 is a 105-110 relative maturity single cross hybrid, characterized by having purple anthers. 
     N5220 may be distinguished from known hybrid S5340 (Northrup King Co., Golden Valley, Minn.) in that N5220 has purple anthers whereas S5340 has yellow anthers and as otherwise set forth hereinafter. 
     N5220 may be further characterized by the following characteristics. 
     
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Type                Single cross                                          
Kernel type         Dent                                                  
Cytoplasm type      Normal                                                
Maturity                                                                  
Northrup King Maturity zone 5; 105-110 RM; FAO = 550-600                  
U.S. heat units = 2580-2650                                               
Preflowering                                                              
Length of first leaf blade                                                
                    Medium                                                
Anthocyanic pigment of seedling                                           
                    Medium                                                
Juvenile plant                                                            
color               Medium green                                          
form                compact                                               
size                Medium                                                
Flowering                                                                 
Number of leaves                                                          
below ear           9                                                     
above ear           7                                                     
Leaf angle from stalk                                                     
                    30-60 degrees                                         
Leaf                                                                      
marginal waves      Few                                                   
longitudinal creases                                                      
                    Few                                                   
color               Medium green                                          
Number of tillers   None                                                  
Plant height to tassel tip                                                
                    267 cm                                                
Length of top ear internode                                               
                    18 cm                                                 
Second internode                                                          
width               28 cm                                                 
length              9 cm                                                  
Anthocyanic pigment of brace roots                                        
                    Weak or absent                                        
Shape of tassel     Loose                                                 
Number of lateral tassel branches                                         
                    15                                                    
Tassel branch angle Greater than 45 degrees                               
Length of largest tassel branch                                           
                    Medium                                                
Anther color        Purple                                                
Heat units to                                                             
50% pollen shed     1287                                                  
50% silk            1296                                                  
Silk                                                                      
color               Green                                                 
length outside of husk                                                    
                    8 cm                                                  
Fresh husk color    Light Green                                           
Ear leaf                                                                  
anthocyanic pigment Weak or none                                          
pubescence          Light                                                 
sheath pubescence   Light or none                                         
length              81 cm                                                 
width               10 cm                                                 
Ear height          97 cm                                                 
Number of                                                                 
nodes               16                                                    
anthocyanic nodes   0                                                     
anthocyanic internodes                                                    
                    1                                                     
nodes with adventitious roots                                             
                    0                                                     
Peduncle length     9 cm                                                  
Central spike length                                                      
                    Medium                                                
Glume                                                                     
color               Green                                                 
band color          Green                                                 
Pollen shed         Medium                                                
% of plants with ear wings                                                
                    14                                                    
Ear wing length     1 cm                                                  
Number of ears per stalk                                                  
                    Single                                                
Maturity                                                                  
Husk                                                                      
extension           Short                                                 
at maturity         Flared                                                
Shank                                                                     
length              13 cm                                                 
internode number    7                                                     
Kernel                                                                    
rows                Distinct                                              
alignment           Slightly curved                                       
row number          16                                                    
Ear weight          205 gm                                                
Kernel                                                                    
100 weight          160 gm                                                
length              13 mm                                                 
width               8 mm                                                  
thickness           4 mm                                                  
% round kernels     Less than 20                                          
Ear                                                                       
position at maturity                                                      
                    Pendent                                               
length              19 cm                                                 
diameter            51 cm                                                 
taper               slight                                                
Cob                                                                       
color               Red                                                   
diameter            26 mm                                                 
strength            Strong                                                
Kernel color                                                              
pericarp            Colorless                                             
aleurone segregation                                                      
                    Homozygous                                            
aleurone            White                                                 
endosperm           Yellow                                                
kernel crown        Light yellow                                          
kernel body (sides) Yellow                                                
Endosperm type      Normal                                                
% of kernels showing purple                                               
                    None                                                  
plumule tip                                                               
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     The invention is intended to cover both inbred and hybrid plants and parts thereof. This includes plant cells either isolated and cultured or in planta, protoplasts, cell tissue and tissue culture, including that from which corn plants fertile or otherwise can be regenerated, calli and clumps, and differentiated forms of plants such as embryos, pollen, stamen, anthers, flowers, kernels, ears, cobs, leaves, stalks, roots, shoots, plantlets, silks, kernels and the like. 
     Methods of cell and tissue culture and regeneration are well known in the art of plant molecular biology cf for example Plant Tissue Culture Manual: Fundamentals and Application Ed. K. Lindsey, Kluwer (1991), incorporated herein by reference. 
     As is well known corn can be put to a wide variety of uses as forage, silage or grain. Grain can be used as livestock and poultry feed and for industrial uses (food, industry, alcoholic beverages) and of course for seed. 
     Feed Uses Swine, Cattle, Poultry 
     Food Industry 
     Kernels, cobs 
     Wet milling to produce and separate germ, hull, gluten and starch. Germ is used to produce corn oil and the germ cake for feed. Starch may be packaged for human consumption or used in food products such as sauces, gravies, puddings, baking powder. Other nonedible uses include textiles, paper, adhesives, cosmetics, explosives, corn binders, laundry purposes, agricultural formulations (also with gluten). 
     Corn starch may also be processed to syrups and sweeteners e.g. corn syrup, high fructose corn syrup, dextrose. 
     Dry milling to produce breakfast foods, brewers grits, cornmeal, hominy grits, corn flour and the like. 
     Fuel in the form of fuel alcohol or ethanol (e.g. as gasohol) 
     Seed 
     Alcoholic beverages 
     Other uses stalks for cellulose e.g. in making paper and construction elements, combustible uses, etc. 
     For a general discussion see periodic reviews of the US Corn Industry produced by and available from the United States Department of Agriculture (USDA), Economic Research Service, Washington, DC 20250. 
     The following Examples illustrate the invention without restricting its scope. 
    
    
     EXAMPLE 1 
     Development of 899 
     Inbred 899 was derived from the commercially available hybrid 3737 by pedigree ear-to-row breeding. 
     Initial self-pollination of the F1 hybrid took place in Washington, Iowa. The resulting F2 plants were self-pollinated in the winter of 1985 in Waimea, Hawaii to produce F2S1 families. A selected plant of one F2S1 family was self-pollinated followed by a further 5 generations of self-pollination to produce inbred 899. 
     Inbred 899 is uniform and stable and appears to be homozygous for all agronomic characteristics. 
     EXAMPLE 2 
     Development of 901 
     901 was derived from crossing inbreds LH119 (Holdens Foundation Seed Co.) and 790 in winter 1984 and backcrossing to 790 followed by simple pedigree ear-to-row breeding for seven generations after the initial backcross. 
     Inbred 901 is uniform and stable and appears to be homozygous for all agronomic characteristics. 
     EXAMPLE 3 
     Development of Hybrid N5220 
     The cross 901×899 is made. 
     EXAMPLE 4 
     Comparative Data 
     N5220 may be compared to S5340 which is a commercially available hybrid. In the table below, Mst stands for percent moisture at harvest; HU Silk stands for number of heat units form plant to 50% silk. 
     
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          Lodging                                                         
Yield       Mst     Stalk  Root  Dropped                                  
Hybrid  Bu/A    %              Ears   HU Silk                             
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1992 Replicated Yield Trial Data: 100-110 RM Markets                      
N5220   165     24.4    4    4     11     1291                            
S5340   159     26.8    6    2     41     1304                            
LSD      7       0.8    3    2      1      21                             
No. of Loc.                                                               
         34     34      32   28    31       6                             
1992 Replicated Yield Trial Data: 105-115 RM Markets                      
NH5220  170     20.6    4    5      1     1296                            
S5340   165     22.0    5    5     12     1290                            
LSD      6       0.5    2    3      0      16                             
No. of Loc.                                                               
         48     48      42   33    35      12                             
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     A deposit of at least 2500 seeds of each inbred 899, 901 and hybrid N5220 has been made available to the public without restriction with the American Type Culture Collection (ATCC) Rockville, Md. 20852 U.S.A. on December 5, 1995 as ATCC deposit no. 97362 for inbred 899; ATCC deposit no. 97363 for inbred 901 and ATCC deposit no. 97364 for hybrid N5220. The seeds deposited with the ATCC are taken from stock maintained by Northrup King Co. since prior to the filling date of this application or any parents thereof. The deposit of each line will be maintained without restriction in the ATCC depository, which is a public depository, 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 becomes nonviable during that period.