The study of potato genotypes (Solanum tubersum L.) tolerance to water deficit stress

Potato is one of the susceptible crops to drought. This research was carried out as a split factorial experiment in a randomized complete block design with three replications in Karaj in 2014. Potato genotypes at 11 levels (Agria, Caesar, Savalan, Sante, Marfona, Milva, Picasso, Hermes, Jelli, 397081-1, 397069-2), irrigation treatment in two levels (stress and control) and samplings in two stages (after stress and recovery) were considered. Irrigation was done as drip and conventional systems and in the stage of tuber production, watering for stress treatment was stopped and control treatment was irrigated normally. After getting to ninety percent of the soil moisture deficit, irrigation restarted until the soil moisture reached to the field capacity and normally continued up to the end of growing season. The results showed that there were significant differences among genotypes, the irrigation levels and the stages of measurement for large and small diameters of the tubers, number of tubers and healthy tubers, the tuber smaller than 35 and larger than 55 mm, dry and fresh weight of the healthy tubers per plant. However, number of tubers between 35-55 mm was, significantly different for the genotypes and irrigation levels. The most changes were observed in the tuber number smaller than 35 mm, dry and fresh weight of the healthy tubers. In addition, in this research, genotypes were categorized in 4 groupes according to the estimated drought tolerance and sensitivity indices.