Effect of supplemental irrigation and nitrogen fertilizer on growth indices of two durum wheat cultivars in Kermanshah conditions

In order to investigate the effect of supplemental irrigation and different levels of nitrogen fertilizer on growth indices of two durum wheat cultivars, this experiment was carried out as a randomized complete blocks design as sub-sub plots with three replications at the research farm of Agriculture College of Kermanshah Razi University in 2008-2009 cropping year. Treatments of this experiment included supplemental irrigation as the main factor at four levels and supplemental irrigation during booting, pollination and grain filling), net nitrogen fertilizer as a sub factor at four levels (without fertilizer, 50, 100 and 150 kilogram per hectare) and two durum wheat cultivars (Sardari and Cross Alborz) in sub-plot were placed. The measured traits including total dry matter, leaf area index, relative growth rate, net assimilation rate, crop growth rate, leaf dry matter, grain yield, grain length, grain diameter and peduncle length. The highest and lowest leaf area index was allocated to supplemental irrigation at pollination stages and durum conditions, respectively. With supplemental irrigation at booting stage, the maximum net assimilation rate was obtained, but supplemental irrigation caused the highest relative assimilation rate than control conditions (durum). Treatment of 150 kilogram per hectare produced the higher leaf area index and treatments 50 and 100 kilogram per hectare produced more net assimilation rate and relative growth rate. The highest grain yield was obtained in supplemental irrigation at pollination and booting time with 3622 and 3520 kilogram per hectare, respectively. Applying 50 kilogram per hectare of nitrogen caused the highest grain yield (3350 kilogram per hectare). Cross Alborz wheat cultivar (3378 kilogram per hectare) had more grain yield in comparison with Sardary cultivar (2982 kilogram per hectare). The maximum length and diameter of the grain was obtained with supplemental irrigation at anthesis stage, but the maximum length of pedankol was obtained by irrigation at stage of booting.