EFFECTS OF DIFFERENT WATER REGIMES ON POTATO CULTIVARS IN ARDEBIL REGION

Sufficient water supply is very important in potato production. It is very necessary to study different potato cultivars’ tolerance to water deficit stress and determine the potato water consumption in Ardebil water deficit region. An experiment was conducted in split plot on based of RCBD in 3 replications and two years. Main-plots treatments were irrigation at 40%, 60% and 80% plant water deficit. Agria, Arinda and Nevita were the sub-plots treatments. Combined analysis of variance showed that there were significant differences between cultivars and year effect on tuber per plant (TPP), main stem number (MSN) and diameter (MSD). significant also. Irrigation effect on tuber weight per plant (TWP), MSD, tuber number (TN) and weight (TW) which less than 35mm were significant. But tuber yield (TY) difference between irrigation levels for majority of attributes was not significant but for TW 35-55 mm and >55 mm was significant. Cultivars × Irrigation interaction on tuber yield was significant at 5%. Arinda in mild to high stress showed yield decreasing less than other cultivars. It showed a good tolerance to water deficit. There was a high potential TWP in control and severe stress in Arinda. Yield decrease in Arinda in mild and severe stress to control was 18.88% and 29.37% respectively. In mild and severe stress Agria had the least yield damage among cultivars (8 and 27%). Correlation between yield (TY) with TWP and MSD was significantly positive. Evaluation of cultivars by water deficit tolerance index showed that Agria was beyond the other cultivars. Yield (TY) in severe and mild stress and non-stress conditions had positive relation with MP, GMP, STI, K1STI and K2STI and negative with TOL and SSI. Stability of cultivars was evaluated by these parameters. Finlay and Wilkinson showed Arinda; Environmental Variance Coefficient showed Agria; Eberhart and Russell, Shukla; Within Location Variance and Within Location Coefficient of Variation showed Nevita as high stable cultivars. Nonetheless, Agria had more performance in all environmental conditions.