Abstract
Irrigation is an integral part of potato production in the Pacific Northwest. When the region comes under pressure from water limiting situations, alternative irrigation methods should be evaluated to determine cultivar reaction, economic return, and water use efficiency. A two-year study was conducted in Aberdeen, Idaho, USA, to examine the effects of deficit irrigation on three readily grown potato cultivars; Clearwater Russet, Teton Russet, Russet Burbank, and a soon to be released breeding line, A12305-2adg. These cultivars were grown in a split-plot randomized complete block design under four deficit irrigation treatments based on evapotranspiration (ET). The irrigation treatments were 50% ET, 75% ET, 100% ET, and 125% ET, initiated 60 days after planting and continued until vine kill. The ET replenishment treatments had minimal effects on tuber yield, size profile, bruise incidence, and fry color across both years. Growth cracks, second growth and hollow heart were present but were not significantly impacted by irrigation treatments. A12305-2adg and Clearwater Russet showed a decline in specific gravity with increased irrigation. Russet Burbank and Teton Russet specific gravity were not affected. A12305-2adg had the highest yield at 75% ET, while Clearwater Russet demonstrated the highest water use efficiency at 83% ET. The lack of major impacts from deficit irrigation on yield and quality indicates that further research should focus on irrigation recommendations for specific cultivars.