RUSSET NORKOTAH
Description
Tuber Shape Oblong to Long
Eyes Shallow evenly distributed eyes
Skin Smooth medium russet
Flesh White
Plant Small to medium sized upright vine with white flowers

Russet Norkotah is a early-maturing potato released in 1987 by North Dakota State University(APJ 65:597-604, 1988). It is primarily a fresh market potato with good boiling and bakingqualities. It is widely adapted to the western U.S. and performs especially well in the SLV.

Plant/roots Plant is fast emerging with a medium, slightly upright vine and white flowers; it has adeterminate growth habit with a shallow, concentrated root system; it is very susceptible to haildamage with little or no re-growth of vines.

Tubers are white flesh, long to slightly oblong with medium to heavy russeted skin. Eyes areshallow, numerous and well distributed; medium specific gravity (1.085). Although not consideredsuitable as a processing potato, it will fry directly from the field.

Yield potential 450 to 500 cwt. range with a high percentage of No. l's.

GROWING SEASON MANAGEMENT

Pre-planting considerations Tubers have a medium dormancy. Whole or cut seed is acceptable. However, cut seed often is preferred since the increased stem number helps prevent oversizing oftubers late in the season. Closer seed spacing also will help control tuber size. Avoid prolongedwarming (usually no more than 60 F for two weeks) to minimize excessive sprouting andphysiological aging. Pre-cutting seed a month or more before planting also can add physiologicalaging. Avoid planting seed in cool soils; delayed emergence can aggravate rhizoctonia stemcankering and result in poor fertilizer uptake. Plant this cultivar 4 to 6 inches deep in a broadwellshaped hill to control late season greening.

Fertility (soil test basis; lbs/acre)

Apply total fertilizer in the following range: N(210-230#), P(l20-200#), K(O-40#). Performancein alkali soils is poor. Pre-plant N applications (110- 140#) are critical for early vine growthnecessary to support maximum yields; high N rates do not delay tuberization. Sprinkler applied Nshould be in the 90 to 100# range at a rate of 25# per application.

Irrigation Irrigation interval at the maximum ET is 2.5 days. Drought tolerance is poor;significant yield reduction occurs if plants are moisture stressed. Adequate irrigation applied atshort intervals coupled with high early season fertility will help this cultivar develop necessaryvine growth prior to tuberization. After tuberization, vine growth often slows dramatically. Subsequent rapid tuber bulking and early vine senescence results in minimum late season waterrequirements. Growers should strive to avoid late season overwatering since it creates idealconditions for expression of many diseases such as blackleg or leak.

Pest control

Weeds Competes poorly against weeds, but is not sensitive to any major herbicides. InsectsStandard insect control measures generally are effective but time and rotate insecticides properlybecause of high aphid preference and virus spread.

Fungicides Three to five fungicide applications may be necessary to control foliar early blight.

Tuberization/bulking Tuber set is light to medium, high in the hill. Greening may be a problemwithout good hill management. Tuber bulking occurs in a short interval during early to mid-season at an extremely rapid rate. Russet Norkotah is moderately resistant to blackspot andresistant to growth cracks, second growth and hollow heart.

Vine Kill Average days from planting to vine kill are 95 to 110. Vine killing usually is notrequired.

However, if senescence is not complete, vines are killed easily; adequate skin set occurs in 12 to

21 days. Tubers can become large late in the season, so close monitoring is necessary after early

August.

STORAGE MANAGEMENT

Russet Norkotah generally has few storage problems, but leak, blackleg and silver scurf canbecome serious. This cultivar is not considered a long-term storage potato. It should bemarketed by mid-March because tuber dehydration can result in pressure bruises and blackspotdevelopment.

DISEASE REACTION

Potato early dying caused by Verticillium dahliae is a problem in some years, but can be easilyconfused with natural vine senescence. Soil-borne disease problems such as leak and silver scurfalso can be serious.

Bacterial Ring Rot symptom expression is erratic and difficult to see under most circumstances. Symptoms are mild and tend to appear only after vines begin senescing (90 + days after planting). Reaction to PVY infection is mild to latent. Infected plants are difficult to detect early in thegrowing season, but usually express mild symptoms that become somewhat more detectable asthe plants age. Infected plants tend to die by mid-season with potentially significant yield losseswhen PVY incidence is high.

Toxic-seedpiece-decay syndrome is characterized by severe plant wilting just prior to tuberization,when the plants are switching from seedpiece nutrition to their root system. Plants appear windburned with dehydrated leaf margins in the upper canopy. A light brown, jelly-type rottedmass is all that is left of the seedpiece and brown streaks may be visible in the lower stem. Normally the plant recovers within a couple of weeks. This problem may be present when earlyseason wet conditions are linked with warm weather.

Field Storage
Foliar early blight: Susceptible Tuber early blight Moderate
Verticillium wilt: Susceptible Bacterial soft rot Susceptible
Blackleg Susceptible Fusarium dry rot Susceptible
Seedpiece decay Susceptible Leak (Pythium) Susceptible
Leafroll virus Susceptible Pink rot (Phytophthora) Susceptible
Leafroll Net necrosis Susceptible Silver scurf Susceptible
PVY, PVX Susceptible Rhizoctonia scurf Moderate
Bacterial ring rot Susceptible
Common Scab Moderately Resistant

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.