RUSSET NUGGET

Description
Tuber Shape Oblong
Eyes Shallow evenly distributed eyes
Skin Smooth medium russet
Flesh White
Plant Large sized upright vine with many white flowers

Russet Nugget is a late-maturing fresh market/processing potato released in 1988 by ColoradoState University (APJ 69:331-336, 1 992). It ranks high in all taste tests. Levels of Vitamin Calso are high (35.0 mg/l 00g, fresh weight basis).

Plant/root Plants emerge quickly and produce a vine that is large and erect with abundant whiteflowers and an indeterminate growth habit. A deep spreading root system helps provide adequatewater and nutrient uptake for the large vines. Hail damage generally is minimal.

Tubers have creamy white flesh and are oblong with a light russet skin. Eyes are shallow andwell distributed; tubers consistently have high specific gravity (1 . 1 00).

Yield potential 400 to 450 cwt. range with a high percentage of No. l's.

GROWING SEASON MANAGEMENT

Pre-planting considerations Tubers have a medium dormancy; either single drop or cut seed isacceptable. Germination tends to be uniform, regardless of eye location on the tuber. Adequatewarming of seed prior iseven to 1 0 days at 65 F) to planting is essential to obtain uniform emergence. Plant this cultivar 2 to 4 inches deep.

Fertility (soil test basis; lbs/acre)

Apply total fertilizer in the following range: N(l20-140#), P(80-190#), K(0-100#). Performance in alkaline soils is excellent. Pre-plant incorporated N should be 60 to 80#. Early season N applications as well as excess N may result in delayed tuberization and bulking. In addition, high levels of fertility may act to lengthen stolons within the hill creating conditions which favor the development of internal purple or pink pigmentation in the tuber. Sprinkler applied N should be 60# applied at a rate of 20# per application, no later than mid-August. During periods of rapidgrowth, this cultivar may express a physiologically induced mosaic pattern in the leaves.

Irrigation Irrigation interval at the maximum ET is 3 to 3.5 days. Drought tolerance is excellent. Overly abundant water, late in the growing season, coupled with excessive nitrogen, on soils with relatively high salt content, can result in alligator hide on the tubers.

Pest Control

Weeds Competition against weeds is excellent with no major herbicide sensitivities known. Insects Standard insect control measures generally are effective, but must be applied in a timely manner. Psyllid injury is common in this cultivar. In addition, the abundance of flowers mayattract large numbers of insects.

Fungicides Control of foliar early blight usually is accomplished with one fungicide application,but, sometimes none are required.

Tuber/bulking Tubers set in the middle of the hill and spread throughout by the end of the season. Under proper fertility, rapid bulking occurs relatively late. Tubers are resistant to hollow heart,second growth, blackspot and shatter bruise.

Vine kill Average days from planting to vine kill are 120 +. Vine killing is required. Excessive N can delay maturity making this operation much more difficult. However, once mature, vine killing is readily accomplished. Adequate skin set occurs within 14 to 21 days.

STORAGE MANAGEMENT

Russet Nugget stores well with few problems and sprouting is negligible.

DISEASE REACTION

Overall disease problems are minimal. Bacterial ring rot foliar symptom expression is somewhatmild and occurs within 90 days after planting. Excessive N, applied early, may inhibit typicalleafroll symptoms. There is a relatively short "optimum time" available for roguing leafroll infected plants from seed fields due to early rapid foliage growth and profuse flowering. If tubers remain in the soil for an extended time after skin set and prior to harvest Rhizoctonia black scurfmay be severe.

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

Disease reaction ratings susceptible, moderately susceptible, moderate, moderately resistant andresistant,