RANGER RUSSET

Ranger Russet is a medium- to late-maturing fresh market/processing potato jointly released in 1991 by the USDA and the University of Idaho (AP 69:483-488, 1 992).

Plants/roots Fast emerging with a medium-large upright spreading vine and red-purple flowers; indeterminate growth habit; moderate, spreading root system.

Tubers are white fleshed, long and slightly flattened with a medium russet skin; eyes are numerous, medium to deep and well distributed; high specific gravity (1.095) with a rapid development of solids early in the season; reducing sugars are low at harvest and throughout the storage season resulting in very light french fries; high Vitamin C content (27.9mg/100g fresh weight basis).

Yield potential 400 to 500 cwt. range.

GROWING SEASON MANAGEMENT

Pre-planting considerations Tubers have medium dormancy; either single drop or cut seed is acceptable. Avoid excessive warming (longer than two weeks at more than 60 F) of seed prior to planting since excessive sprout length and physiological age may reduce stands and yields. Tends to produce oversize tubers, closer seed spacing may help optimize yield and tuber size. Plant this cultivar 2 to 4 inches deep with good hill cover.

Fertility (based on soil test; lbs./acre)

Apply total fertilizer in the following range: N(l70-180#), P(120 190#), K(0 -60#). Performance in alkaline soils is good. Pre-plant incorporated N should be 70 to 90#. Early season N applications do not adversely affect the timing of tuberization; may be helpful in encouraging early vine growth. Sprinkler applied N should be 90 to 1 00# at a rate of 20# per application. End applications within one month of estimated vine kill to promote plant maturity.

Irrigation

Irrigation interval at the maximum ET is three days. Drought tolerance is good. Monitor soil moisture carefully. Early season moisture stress will result in long, misshapen tubers. Tuber dehydration from late season water stress will increase blackspot susceptibility at harvest.

Pest control

Weeds Competition against weeds is good. Ranger Russet is not sensitive to any of the major herbicides.

Insects Standard insect control measures generally are effective.

Fungicides Control of foliar early blight usually requires two to four fungicide applications.

Tuberization/bulking

Tuber set is light and occurs in the middle of the hill; occurs early and bulking proceeds at a moderate rate until late in the season. Resistant to hollow heart, moderately resistant to growth cracks and second growth, but susceptible to blackspot.

Vine kill

Average days from planting to vine kill are at least 120. Vine killing is required in most years; it can be difficult if vine immaturity persists until the end of the growing season. Adequate skin set occurs within 1 4 to 21 days. Oversized tubers can be a problem. Carefully monitor size after mid-August.



STORAGE MANAGEMENT

Ranger Russet stores well; long-term storage with few sprouting problems can be achieved if storage temperatures are kept cool (38 F to 40 F). Blackspot can be a problem when long-term storage is required; especially when potatoes are stored at temperatures necessary for processing.

DISEASE REACTION

Overall disease problems are relatively minimal. Typical bacterial ring rot foliar symptoms occurs within 90 days after planting. Leafroll virus symptom expression also is adequate. PVY expression is severe, resulting in stunted necrotic plants that die by mid season. This cultivar is extremely susceptible to Columbia root knot nematode and the corky ring spot virus.

Field

Foliar early blight Moderately Susceptible

Verticillium wilt Moderate

Blackleg Moderately Susceptible

Seedpiece decay Moderately Susceptible

Leafroll virus Susceptible

Leafroll Net necrosis Moderately Resistant

PVY Moderately Resistant

PVX Immune

Common Scab Susceptible

Bacterial ring rot Susceptible

Storage

Tuber early blight Moderately Resistant

Bacterial soft rot Moderately Susceptible

Fusarium dry rot Moderately Resistant

Leak (Pythium) Unknown

Pink rot (Phytophthora) Unknown

Silver scurf Unknown

Rhizoctonia scurf Moderately Susceptible



Disease reaction ratings susceptible, moderately susceptible, moderate, moderately resistant and resistant.

Note: This information should only be used as a guide. Adjustments for local conditions must always be made.