Water use efficiency and water productivity in potato genotypes under water stress conditions

In order to identify sensitivity of different potato genotypes to water stress, a research was carried out as a factorial experiment in a randomized complete block design with three replications in Karaj in 2014 and 2015. Potato genotypes at eleven levels (Agria, Caesar, Savalan, Sante, Marfona, Milva, Picasso, Hermes, Jelli, 397081-1, 397069-2) and irrigation treatments in two levels (stress and control) are conducted. Tape irrigation was done normally and in the early stages of tuber production, watering for stress plots was disconnected and control plots were irrigated in a normal way, after reaching to ninety percent of the soil moisture deficit, irrigation was done again until the soil moisture reached field capacity and irrigation was done normally up to the end of growing season. Combined analysis of data for two years showed a reduction of biological yield, healthy tuber fresh weight, marketable healthy tuber fresh weight, LAIM, dry weight of LAIM, evapotranspiration and water usage in genotypes under the stress compared to the control. WP based on fresh weight of healthy tubers and fresh weight of marketable healthy tubers reduced or showed a tendency to reduction in most of genotypes under the stress. WUE based on the healthy tuber yield and marketable healthy tuber yield decreased under the water stress compared to the control in all genotypes except for 397069-2. The most amount of WP based on fresh weight of the marketable healthy yield was observed in 397069-2, respectively (5.41) and (5) kg/m3 in two years under the stress. Based on results of this experiment, doing of additional researches in order to achieve suitable potato genotypes for planting in actual deficit water conditions of our country according to diversity of planting season, place, climate, quality of seed potato, experts and etc. are recommended.