Prepared by Susie Thompson, Ph.D. and Robert D. Davidson, Ph.D., Department of Horticulture & Landscape Architecture, San Luis Valley Research Center, Colorado State University.
This profile was developed for production in the San Luis Valley. While some guidelines may be appropriate regardless of growing area, fine-tuning for specific production locales is recommended.
Fremont Russet is a medium yielding, medium-late maturing, fresh market russet cultivar. Tubers are oblong to long, with medium specific gravity. Due to excellent late-season storage capabilities, Fremont is suitable to fill the Centennial Russet niche as a late storage potato. It performs well in rocky soils. Release is pending by the Colorado Agricultural Experiment Station. Fremont Russet was tested as CO85026-4 and is the result of a cross between Century Russet x WNC630-2. Plant variety protection will be pursued.
Plants/roots: Emergence is uniform, with a medium-sized vine, similar to Century Russet in color and vine architecture. Flowers are white. It has a determinate growth habit and a moderate to shallow root system.
Tubers: Tubers are oblong to long, with a dark, medium-heavy russet skin. Eyes are shallow and most prevalent on the apical end. Tuber flesh is white. Specific gravity is medium (1.084 avg.).
Yield potential: Yield potential is medium (+350 cwt./acre).
Pre-planting considerations: Tubers have medium dormancy. Whole or cut seed is acceptable. A seed spacing of 12-inches may optimize total yield and desired tuber size for the commercial market. Wider plant spacing often increases tuber yield, however due to rough and misshapen tubers, more culls are produced.
Fertility: Apply total fertilizer in the following range N(140-150#), P(80-190#), K (0-100#). Fertility needs are very minimal compared to many other major russet cultivars. Pre-plant N applications should be in the range of 50-70#. Timing of tuberization is affected by N applications. Tuberization does not seem to be delayed, however tubers tend to grow extremely rapidly and misshapen in the process. Spoon-feed remaining N at the rate of 7-10# per application (do not exceed 20# per application).
Irrigation: Interval at the maximum ET is 3 days. Drought tolerance is moderate. Enlarged lenticels have been noted when water applications were excessive, particularly late in the season.
Weeds: Fremont Russet is resistant to metribuzin (Sencor, Lexone) applications.
Insects: Standard insect control measures generally are effective but timing and rotation of appropriate control is important.
Vine Kill: Average days from planting to vine kill are 115 to 120. Vine killing is required most years. Adequate skin set occurs within 14 days.
Fremont Russet is an excellent long-term storage cultivar.
Overall, disease problems are minimal. Bacterial ring rot foliar expression is adequate with typical symptoms and occurs at or slightly past 90 days after planting.
Foliar early blight Susceptible
Verticillium wilt Unknown
Seedpiece decay Susceptible
Leafroll virus Susceptible
Leafroll net necrosis Unknown
Common scab Unknown
Powdery scab Unknown
Bacterial ring rot Susceptible
Tuber early blight Moderately Resistant to Resistant
Bacterial soft rot Susceptible
Fusarium dry rot Susceptible
Pythium leak Unknown
Pink rot (Phytophthora) Unknown
Silver scurf Moderately Resistant
Rhizoctonia scurf Unknown
Disease reaction ratings = susceptible, moderately susceptible, moderate, moderately resistant and resistant.