Relationships between Grain Yield and Yield Components in Bread Wheat under Different Water Availability (Dryland and Supplemental Irrigation Conditions)

Path and correlation analysis were executed to investigate the relationships between grain yield and other important yield components in bread wheat (Triticum aestivum L.) genotypes during two years (2009-2011) under supplemental irrigation and dryland conditions. Field experiments were performed in a randomized complete block design with four replications. Grain yield showed positive correlation with plant height and test weight under supplemental irrigation condition. The similar results were also revealed between grain yield and plant height, spike length, days to maturity, agronomic score and test weight in dryland environment. The grain yield of bread wheat in dryland condition depended on the effect of plant height, days to maturity, agronomic score and 1000 kernel weight, whereas in supplemental irrigation was mainly related to plant height, spike length, 1000 kernel weight and test weight. The influence of 1000 kernel weight on grain yield in both environments seems to cause from the fact that grain yield in wheat is frequently the sink limited, and for this reason, the 1000 kernel weight has been reported as a promising trait for increasing grain yield in wheat under different conditions. The nearly equal value of correlation and path coefficients of plant height and grain yield showed plant height had positive and direct effect on grain yield, in both conditions and suggesting a criteria trait for improving of grain yield. The results showed that genotype 12 (CS/TH.SC//3*PVN/3/MIRLO/BUC/4/MILAN/5/ TILHI) is a high yielding potential genotype in moisture limited conditions.