CULTIVAR CORNER Yukon Gem OVERVIEW Parentage: Brodick x Yukon Gold Developer: Northwest Potato Variety Development Program Plant Variety Protection: PVP issued in 2007. Strengths: Yukon Gem is a better-yielding, disease-resistant Yukon Gold type. MORPHOLOGICAL CHARACTERISTICS Plant: Yukon Gem is a mid-season selection with PVY and late blight resistance. Tubers: Round-oblong, yellow flesh with higher yield potential than Yukon Gold. Its low to medium tuber set yields an optimal size profile. AGRONOMIC CHARACTERISTICS Maturity: Mid-season maturing. Tubers: Yukon Gem produces round-oblong tubers with a slightly russet-like yellow skin. Tuber yield and size distribution is better than Yukon Gold. Yield Potential: High Specific Gravity: Yukon Gem has a moderately low specific gravity. Culinary Quality: Excellent with tubers exhibiting no after-cooking darkening. Diseases/Physiological Disorders: Yukon Gem is resistant to PVY and late blight, as well as tuber malformation and most internal and external defects. Incentives for Production: Resistance to diseases make Yukon Gem an excellent organic alternative for fresh, fry and chip production. MANAGEMENT Fertility: In Idaho, a total of 240 pounds of nitrogen (N) per acre gave the best U.S. No. 1 yield response with a 500 cwt/acre yield. Yukon Gem requires about 10% less nitrogen fertilizer than Russet Burbank per unit of yield produced. Excessive N can lower and quality and prolong maturation. Higher N can also lower specific gravity. Metribuzin resistance for Yukon Gem is good at normal application rates. Planting: Cut seed to 2.5- to 3-ounce size. Optimal plant spacing for commercial production on 36-inch rows inSoutheast Idaho is 8 to 10 inches; 11- to 13-inch seed piece spacing should be used for an increased proportion of large tubers. Plant 5 to 6 inches deep. Storage: Store just as you would Yukon Gold. Seed Production and Availability: Check www.pvmi.org for a full list of seed growers. Spudman * May/June 2021 35http://www.pvmi.org