Evaluation of yield and yield components of wheat varieties under supplemental irrigation levels

Among abiotic stresses, drought stress is one of the main factors, which limits plant growth in arid and semi-arid regions. Large parts of cultivated wheat in Iran are subjected to such weather conditions, which decrease in precipitation and its inappropriate distribution limits grain yield. A field split plots experiment based on randomized complete blocks design was conducted to evaluate of wheat yield and yield components variation under different supplemental irrigation treatments. The main plots were supplemental irrigation in three levels no irrigation (I0), irrigation at heading (I1), and irrigation at heading and early grain filling stages (I2). Subplots treatments included five different wheat varieties (Azar 2, Rijjaw, Sardari, Sirvan and Homa). Results showed that yield increase in two irrigation treatments were 51, 38, 38, 50 and 63 percent for Azar 2, Rijjaw, Sardari, Sirvan, and Homa cultivars, respectively. The rates of yield increase in I1 than I0 treatments were 16.3, 10.7, 52.5, 28.9, and 30.2 percent in Azar 2, Rijjaw, Sardari, Sirvan and Homa cultivars, respectively. The results showed that application of one stage irrigation in Sardari could increase grain yield above 50 percent rather than I0 treatment.