effect of irrigation intervals on yield of wheat lines and cultivars

in order to study of drought tolerance levels in some wheat lines and cultivars based on uniform regional wheat yield trial (urwyt-m-75) an experiment was carried out using a strip plot design based on complete block design with 3 replications for two years (1998-2000) in torogh agricultural research station (mashhad, iran). the main plots (horizontal factor) were 3 levels of irrigation: 10, 20 and 30 days irrigation interval. for irrigation were used on drip irrigation system. the sub plots (vertical factor) were 20 lines or cultivars of spring bread wheat set up for urwyt (m-75-1-20). sowing date, the amount of seed and fertilizer were as normal rates in region. for measuring of water requirement and irrigation, were used on drip irrigation system. for each irrigation, measured the soil moisture before that. the results showed that when irrigation interval was 10 days, the lines yield of m-75-8, m-75-6, m-75-2 and m-75-16 were higher than other lines. when the irrigation interval was 20 days, the lines of m-75-2, m-75-14, m-75-16 and m-75-12 produced the highest. in 30 days irrigation interval, the lines of m-75-15, m-75-4, m-75-2 and m-75-14 had maximum yields. as summery, m-75-2 line was better than other because indicated good flexibility and water use efficiency, in normal and stress condition.