Cultivar Corner: Rocky Mountain Russets are attractive tubers with high yield potential
Rocky Mountain Russet, a Colorado State University cultivar, are attractive tubers with high yield potential and resistance to many common potato plant diseases.
Name: Rocky Mountain Russet (CO05068-1RU)
Parentage: AWN86514-2 x CO98009-3RU
Developer: Colorado State University
Plant Variety Protection: Applied for in 2021
Strengths: High yield potential; high percentage of U.S. No. 1 tubers; attractive, smooth tubers, few tuber defects; disease resistance; fresh market and processing potential.
Weaknesses: Susceptible to the herbicide metribuzin and some susceptibility to common scab.
Plant: Medium-large plant with white flowers.
Tubers: Oblong-long with a russet skin and white flesh.
Maturity: Medium to medium-late
Yield Potential: High and a high percentage of U.S. No. 1 tubers.
Specific Gravity: High
Diseases/Physiological Disorders: Resistant to PVY, Verticillium wilt, foliar early blight, and tuber soft rot. While susceptible to other primary potato diseases, Rocky Mountain Russet has not exhibited any serious disease susceptibilities.
Incentives for Production: High yield potential; high percentage of U.S. No. 1 tubers; disease resistance; fresh market and processing potential. Tubers are resistant to hollow heart, second growth, growth crack, blackspot bruise and shatter bruise.
Fertility: Rocky Mountain Russet is very efficient in N utilization. Caution should be taken to avoid applying too much nitrogen to assure timely vine maturity and skin set after desiccation. Excessive nitrogen can also impact storage quality.
The following fertility program is recommended for short growing season areas:
The applied N rate should be between 160-170 lbs of N/acre. However, total available N (residual soil N + irrigation water N + applied N) should not exceed 200-220 lbs N/acre for optimum yield and tuber quality for commercial production. For seed production, applied N rate should be between 120-140 lbs of N/acre. However, total available N should not exceed 150-160 lbs N/acre. These recommendations do not include nitrogen mineralization from the previous crop stubble and from soil organic matter.
Apply about 40% of the required seasonal N pre-plant or at planting. The remaining seasonal N should be applied in split applications beginning at early tuber formation. Nitrogen fertilizer application should be completed early in the growing season for tuber growth and tuber maturation. For fresh market production, N fertilizer application should be completed by July 30 in the San Luis Valley.
The sufficiency level for petiole nitrate N concentration during the growing season should range from 25,000 to 26,000 ppm at tuber initiation, 23,000 to 24,000 ppm during tuber bulking, and between 20,000 to 21,000 ppm at tuber maturity.
Planting: If cutting seed, pre-cut seed to a size of 2.5 to 3.0 ounces and allow to suberize before planting. To obtain maximum marketable size tubers, seed tubers should be planted at in-row spacing of 14 inches, with a row spacing of 34 inches.
Seed Availability: Limited amounts of seed available from the San Luis Valley Research Center and Colorado certified seed potato growers.