Abstract:
The new potato variety Solanum tuberosum is a cross of a Lemhi and a ND450-3Russ. It was first grown at the Langdon Experiment Station, North Dakota. The new variety produces tubers that are long, smooth, and uniform with shallow eyes and dark brown skin that are suitable for fresh market. The variety is resistant to hollow heart and appears to be well adapted to the soils of the Mid-Western United States.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a new and distinct variety of potato Solanum tuberosum which was discovered by me growing at the Langdon Experiment Station, North Dakota. 
     2. Prior Art 
     The new potato variety was produced from a cross made by me in the North Dakota State University horticulture greenhouse, Fargo, N. Dak., with a seedling tuber also produced in the North Dakota State University horticulture greenhouse. The new variety, ND1538-1Russ resulted from a cross between a Lemhi and a ND450-3Russ. 
     University colleagues, breeders and seedsmen who have seen this potato do not recognize this selection as anything that they have previously selected or evaluated. The potato variety has been classified as a cross of a Lemhi and ND450-3Russet. Selection and initial evaluation was done as set out above. Evaluations were done at the Langdon Experiment Station, North Dakota, and horticulture greenhouse of the North Dakota State University. Testing in variety trials at North Dakota State University began in 1986 and commercial trials were initiated in Grand Forks, N. Dak. in 1988. 
     BRIEF SUMMARY OF THE INVENTION 
     The plants of the new variety of potato hereinafter referred to as ND1538-1Russ are medium to slightly large in size and are somewhat upright. The stems are green and are purple near the base of the plants. The leaves are medium in size and are green to dark green in color. The flowers are light lavender to white. The base of the corolla is purple in color. The flowers are male and female fertile, however flowering in general is quite scant. 
     The tubers of ND1538-1Russ are oblong to quite long and have a fairly heavy russet skin. Shape can vary depending on the soil they are produced in. The tuber eyes are shallow with purple sprouts. After several months of storage a reddish tinge can be seen in the skin of the tubers. Yields of ND1538-1Russ at two locations in North Dakota for two years showed this variety to be much higher than standard russet variety, Russet Burbank, but comparable to NorKing Russet and slightly lower than Norgold Russet and Russet Norkotah. 
     ND1538-1Russ exhibits very little internal or external defects especially hollow heart. Hollow heart is an internal defect that makes a hollow center in the tuber. This defect cannot be detected unless the tuber is cut or is run through an X-ray machine that shows the hollow center. Hollow heart generally occurs after a tuber of a susceptible variety is exposed to rapid growth as occurs from excessive moisture following a dry period. Several varieties especially some of the russet varieties are very susceptible to hollow heart. In tests during a 3-year period ND1538-1Russ only showed from six (6) to two (2) percent hollow heart while Norgold Russet and several other russet type varieties showed from forty-nine (49) to twelve (12) percent hollow heart when grown in similar conditions. ND1538-1Russ appeared to be very resistant to hollow heart. 
     When evaluated for culinary qualities, ND1538-1Russ expressed excellent boiling and baking qualities. The flesh of ND1538-1Russ following cooking is especially white and attractive. ND1538-1Russ is comparable to Russet Burbank when tested for french fry qualities. Total solids are comparable to Norgold Russet but higher than Russet Burbank and Russet Norkotah. ND1538-1Russ has been increased by indexed disease-free tubers and by tissue culture. All increase of ND1538-1Russ has been done by foundation seed growers in North Dakota and Montana. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows as true as is reasonably possible, a plant and leaf type of ND1538-1Russ grown at Grand Forks, N. Dak.; 
     FIG. 2, shows as true as is reasonably possible, a flower of ND1538-1Russ, the corolla of which should be understood to be purplish; 
     FIG. 3, shows as true as is reasonably possible, tubers of ND1538-1Russ grown at 1988 commercial trials at Grand Forks, N. Dak.; and 
     FIG. 4, shows as true as reasonably possible, a Norgold Russet tuber infected with hollow heart cut longitudinally, bottom row; 
     FIG. 5 is a mechanical drawing which shows the coloration of the plant by cross hatching; and, 
     FIG. 6 is a flow chart which shows the pedigree of the plant of this invention through 5 generations. The arrows in the chart indicate the parents of the plant from which the arrow is drawn. 
    
    
     DETAILED DESCRIPTION 
     The following is a detailed description of the new variety of potato Solanum tuberosum, hereinafter referred to as ND1583-1Russ. Color terminology as set out herein is to be accorded its ordinary dictionary significance except where otherwise indicated. The tubers and plants described were grown at Casselton and Grand Forks, N. Dak. 
     Plant, as shown best in FIGS. 1 and 2: Medium to quite large, somewhat upright. 
     Stems: Green pigmented, purplish near base of the plant. 
     Wings: Medium in size reaching 1/2 or more of the entire way or distance to the next node. 
     Nodes: Not prominent. 
     Leaves: Medium in size compared to Russet Burbank and Russet Norkotah, but small compared to NorKing Russet and Norchip. Green to dark green, moderately pubescent. Open when young, open from maturity to senescence. 
     Terminal Leaflets: Elliptical; apex acuminate; base lobed to auriculate; asymmetrical; length 64 mm±0.105, width 37.0 mm=0.055, L-W 17.3±0.013. 
     Primary Leaflets: Ovate; apex acuminate; asymmetrical; 3 to 4 pairs. Length 64.0 mm±1.22, width 36.9±0.66, length to width 17.3±0.11. 
     Secondary Leaflets: Common. 
     Tertiary Leaflets: Common. Supernumerary secondary leaflets on petiole of secondary leaflets, common. 
     Midriffs and Petioles: Light green; sparsely pigmented; slightly pubescent. 
     Flowers: Sparse 
     Buds: Off-white or greenish white to light lavender. 
     Calyx: Long straight green pubescent, 18.32 mm. 
     Corolla: Large; light lavender to white; green midrib. 
     Anthers: Orange pollen abundant and of good quality. 
     Style: Curved. 
     Stigma: Roughly globose; multilobed and green. 
     Tubers (as shown best in FIG. 3): Oblong to quite long; a 25 tuber sample was measured and found to have a mean length of 112 mm., a mean width of 63.9 mm, and a mean thickness of 55.0 mm. 
     Indices: Width to length 0.51; thickness to length 0.56; thickness to width 0.59; average number of tubers per plant 6-10. 
     Skin: Dark brown; fairly heavy russeted. 
     Eyes: Shallow; well distributed and fairly numerous. 
     Flesh: Very white. 
     Sprouts: White with purple tip. 
     Maturity: Medium; later than Russet Norkotah but much earlier than Russet Burbank. 
     Characteristics: Tubers are usually smooth and quite uniform, however ND1538-1Russ is not as smooth and uniform as Russet Norkotah. Off-shape tubers have been observed. After storage a reddish blush can be observed on the apical end of tubers. Very few external or internal defects have been observed, however ND1538-1Russ is almost free of the defect hollow heart. 
     Uses: Because of ND1538-1Russ&#39;s hollow heart resistance, FIG. 4 shows a hollow heart infected Norgold Russet, it is accordingly a variety that can be grown and marketed as a count carton variety in the Red River Valley of North Dakota and Minnesota or other areas where hollow heart is a problem. This variety with its white flesh makes a very good variety for both mashing and baking, and can be used for french fries. 
     Yields: Two year tests at two locations in North Dakota have shown ND1538-1Russ to produce as good a yield as test plantings of NorKing Russet, and produced a higher yield than Russet Burbank. In the two year trials both Norgold Russet and Russet Norkotah had slightly greater yields than the tested ND1538-1Russ. 
     Disease Resistance: ND1538-1Russ expresses both plant and tuber symptoms when infected with bacterial ring rot. 
     A germ plasma of ND1538-1Russ, Solanum tuberosum to be deposited with the American Type Culture Collection (ATCC), Rockville, Md., accorded an Accession Number (ATCC) 75857C, deposited Aug. 10, 1994, which deposit is made under the conditions of the Budapest Treaty that provide that: 
     (a) during the pendency of this application access to the invention will be afforded to the Commissioner upon request; 
     (b) all restrictions upon available to the public will be revokable removed upon granting of a patent on this application; 
     (c) the deposit will be maintained in a public depository for a period of thirty (30) years, or five (5) years after the last request, or for the effective life of a patent issued on this application, whichever is longer; and (d) the deposit will be replaced should it become inviable. 
     A complete pedigree of ND1538-1Russ follows: 
     Identification of the Potato Varieties in the Parentage of ND1538-1Russ 
     1. Lemhi Russet--Named in Idaho in 1981. 155 acres grown for certification in the United States and Canada in 1988. 
     2. Pioneer--Named in Nebraska in 1963. No certified acres grown. Probably extinct. 
     3. Norgold Russet--Named in North Dakota in 1964. 1632 acres grown in the United States and Canada for certification in 1988. Was replaced by Russet Norkotah. 
     4. Advanced Selections: 
     
         ______________________________________ND450-3RussA63126-8Wash. 330ND9852-lRussMinn. 113-1-45Neb. 225.43-1A589-65ND89l7-7RussWash. 245A180-24A36-1; andA6673-4Russare all advanced selections that probably have beendropped from the breeding program or only maintained.They have not, and most probably will not, becomevarieties.______________________________________ Legend for above advanced selections: ND = North Dakota; A = Idaho USDA; Wash. = Washington; Minn. = Minnesota; Neb. = Nebraska. 
    
     TABLES 
     Herein are included Tables I, II, and III that detail ND1538-1Russ characteristics for, respectively: U.S. No. 1 yield and percent U.S. No. 1 in 1987 and 1988; percent total solids, 1987 and 1988, and percent hollow heart by weight, 1986-1988 for two locations in North Dakota. 
     
                                           TABLE I__________________________________________________________________________U.S. No. 1 Yield and Percent U.S. No. 1 (Grand Forks and Park River, ND1987-1988).    1987            1988    Grand Forks            Park River                    Grand Forks                            Park River                                    Average    Cwt %   Cwt %   Cwt %   Cwt %   Cwt %    U.S.        U.S.            U.S.                U.S.                    U.S.                        U.S.                            U.S.                                U.S.                                    U.S.                                        U.S.    No. 1        No. 1            No. 1                No. 1                    No. 1                        No. 1                            No. 1                                No. 1                                    No. 1                                        No. 1__________________________________________________________________________ND1538-1Russ    247 63  165 86  128 80  176 86  179 79NorKing Russet    225 83  192 90  143 73  155 79  179 82Norgold Russet    240 82  273 86  81  67  178 73  193 79Russet Burbank     92 53  156 54  24  26   33 22   77 38Russet Norkotah    261 87  232 95  85  77  178 80  189 86__________________________________________________________________________ 
    
     
                       TABLE II______________________________________Percent Total Solids(Grand Forks and Park River, ND 1987-1988).     1987      1988     Grand Park    Grand   Park     Forks River   Forks   River Average______________________________________ND1538-1Russ       19.4%   19.0%   18.0% 22.7% 19.7%NorKing Russet       19.9%   20.9%   20.9% 22.0% 21.0%Norgold Russet       19.4%   20.1%   16.9% 20.9% 19.8%Russet Burbank       19.4%   18.8%   18.6% 19.0% 19.0%Russet Norkotah       19.4%   19.7%   17.5% 20.9% 19.4%______________________________________ 
    
     
                       TABLE III______________________________________Percent hollow heart by weight in potatotubers 2 inches and larger in clonesunder test for resistance to hollow heart.Clone         1986   1987     1988 Average______________________________________Norgold Russet         36%    28%      0%   21%Russet Burbank         12%     2%      0%    5%Russet Norkotah         32%    19%      0%   17%NorKing Russet         33%    26%ND1113-10Russ 49%    17%      0%   22%ND67l-4Russ   34%    15%Krantz        14%    15%ND1538-lRuss   6%     2%      0%    3%ND2l4l-4Russ                  0%ND2008-2                      0%ND2224-5R                     0%LSD (0.05)    10%     8%______________________________________ 
    
     Hereinabove has been set out a new variety of potato, Solanum tuberosum, identified as ND1538-1Russ including its physical characteristics and qualities. It should, however, be understood that the present disclosure is made by way of example only and that variations are possible within the scope of this disclosure without departing from the subject matter coming within the scope of the following claims, and a reasonable equivalency thereof, which claims I regard as my invention.