Evaluation of irrigation regimes on yield and yield components In different cultivars of wheat (Triticum aestivum L.)

In order to investigation of the effects of irrigation regimes on yield and yield components and some physiological parameters on different genotypes wheat and lines under field conditions on experiment was conducted. The experiment was conducted as a split-plot in base of randomized complete block design on four replications in agricultural research center of Islamic Azad University Of Karaj on 2007. First factor was consisted of 4 different irrigation regimes including a control treatment (T1), irrigation after 60 and 75 percent of soil moisture depletion during from the start of flowering to ripening (T2 and T3, respectively) and non irrigation from start of flowering to ripening (T4) at four wheat cultivars consist of Pishtaz (V1), Shiraz (V2), Bahar(V3) and Chamran (V4) and a line including WS-82-9(V5). The determined parameters were yield, its components, biological yield, harvest index, height of plant, length of peduncle and spike. The results showed that yield and its components, biological yield, harvest index, height of plant and length of peduncle were reduced significantly by stress and length of spike wasn’t sensitive to that. So that the highest and lowest yields were obtained in control and T4 respectively, T2 and T3 treatments were shoed 12.5 and 23 yield reduction percentages in compare to control. Among the cultivars and lines, Pishtaz(V1) and Shira (V2) had the highest and lowest biological yield respectively. Results showed that non irrigation from start of flowering to ripen caused the most reduce yield.