Rio Grande Russet (AC 89536-5)

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

Rio Grande Russet is a medium-maturing fresh market potato yet to be released by Colorado State University. It has a very high yield potential with a high percentage of U.S. #1's. Tubers are very smooth and have an attractive appearance. The large plant has ruffled leaves and produces well on low nitrogen inputs. The variety is resistant to PVY, PLRV and other diseases.

Plant/root Plants emerge quickly and produce a vine that is large and erect with abundant lavander flowers. A deep spreading root system helps provide adequate water and nutrient uptake for the large vines. Hail damage generally is minimal.

Tubers have white flesh and are oblong to long with a light russet skin. Eyes are shallow and well distributed. A high percentage of tubers have an attractive long-type shape.

Yield potential 500 to 550 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 is acceptable. Germination tends to be uniform, regardless of eye location on the tuber. Adequate warming of seed prior seven to 10 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(l40-160#), P(80-190#), K(0-100#). Performance in alkaline soils is good. Pre-plant incorporated N should be 60 to 100#. Excessive N applications may result in delayed tuberization and bulking and an excessively large plant. Sprinkler applied N should be 40 - 80# applied at a rate of 20# per application, no later than august.

Irrigation Irrigation interval at the maximum ET is 2.5 to 3 days. Drought tolerance is excellent early in the season, but late season during tuber bulking be sure to keep them wet or pointly stem ends may result..

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.

Fungicides Control of foliar early blight usually is accomplished with one fungicide application, Early blight tolerance is good.

Tuber/bulking Tubers set in the middle of the hill and spread throughout by the end of the season. Tubers can set deep. Plant sets an average of 9 to 10 tubers/plant. Tuber bulking occurs evenly thoughout the later part of the season.. Tubers are resistant to hollow heart, secondary growth, and growth cracks. Tubers are sensitive to shatter bruise so care should be taken during harvest.

Vine kill Average days from planting to vine kill are 100 - 110. Vine killing is required. Excessive N can delay maturity making this operation much more difficult. However, once mature, vine killing is readily accomplished. Good skin set occurs within 14 to 21 days.

STORAGE MANAGEMENT

Rio Grande Russet stores well with few problems and sprouting is negligible.

DISEASE REACTION

Overall disease problems are minimal. Bacterial ring rot foliar symptom expression is some what mild and occurs within 90 days after planting.

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

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