Effect of different amount of irrigation water on yield and water use efficiency of various wheat cultivars in Gorgan

In the water-limited areas, the great challenge of the agricultural sector is more production from less water that it can be achieved by increasing water productivity. A field study was conducted to compare various cultivars of wheat to water using line source sprinkler irrigation at Gorgan Research Station in 2005-2006. The effect of variable water supply on yield and WUE of six wheat cultivars were determined. Four locations with distance from the laterals were monitored all of the irrigations. Four irrigation treatments (W1, W2, W3 and W4) were provided by the reduction of irrigation water with distance from the line source. The experiment used a strip plot design to examine the effect of fixed irrigation rates on six cultivars (C1=Tajan, C2=N-80-6, C3=N-80-7, C4=N-80-19, C5=N-81-18, C6=Desconcido) with four replications. Each irrigation treatment of each strip was divided into six cultivars treatments, along the length of the laterals. Result indicated that the grain yield was affected by irrigation treatment and genotypes. Due to suitable rainfall during the growing season, soil moisture depletion was high in deficit irrigation treatment (W4) as compared to W1 treatment. Generally, the WUE was increased with decreasing applied water under supplementary irrigation. The optimum amount of water to achieve maximum WUE was a range of 290 to 320 mm in the above-mentioned cultivars. The highest and the lowest WUE was related to C5 (1.48 kg m^-3) and C1 (1.3 kg m^-3) respectively. The optimum yield to achieve the highest WUE was found between 4100 kg ha^-1 (in C1 cultivar) up to 4900 kg ha^-1 (in C3 cultivar).