بررسي ميزان تحمل به خشكي لاينها و ارقام گندم مناطق سرد كشور

Study on drought tolerance of bread wheat cultivars in cold regions of Iran

Drought tolerance levels in some wheat cultivars received the uniform cold region wheat yield trial (URWYT-C) across the country were studied using a strip-plot based on randomized complete block design with 3 replications fort years (1998-2000) in Torogh Agricultural Research Station Mashhad, Iran.The main plots (Horizontal factor) were assigned to 3 levels of irrigation :10-day irrigation (Al ), 20-day irrigation (A2) and 30-day irrigation (A3) intervals. The sub-plots (Vertical factor) were assigned to 20 lines or cultivars of winter and facultative bread wheats set up for URWYT cold Regions (C-75: 1-20). The amount of seed and inorganic fertilizers applied as recommended in region. During the growth stages, major agronomic, morphological and physiological traits were recorded. Irrigation requirement was supplied by using a drop irrigation system. Irrigation, treatments were carried out on the basis of the difference between soil moisture before irrigation and its water content at field capacity. Based on the results of combined years analysis, the effect of irrigation levels on grain yield, biological yield, number of spike per m2, harvest index and 1000 kernel weight, were significant (P<0.05). With increasing water stress (long period between two irrigation) these parameters were decreased. There was a significant difference among cultivars for number of kernel per spike, harvest index, peduncle length, plant height, days to heading and maturity. In A2 treatment, water use efficiency for water productivity; was higher than other two treatments. In Al treatment, grain yield, biological yield and number of spike per m^ of C-75-6, C-75-10 and C-75-16 lines were higher than the others. In A2 and A3 treatments (slight and severe water stress, respectively) ,grain yield, number of spike per m^2, harvest index and water productivity of C-75-14 and C-75-9 lines were high. Moreover, they had good flexibility in normal and stress conditions (slow stressing).The studied lines had an acceptable drought tolerance index and were moderately early mature.