Study on relationship between yield and yield components of wheat under normal irrigation and drought stress conditions by path analysis method

To investigate the relationship between yield and its components in wheat under non stress and drought stress conditions an experiment was conducted in on Agricultural Research Station at Bahonar University of Kerman. Experimental trial was split-plot (non-stress and drought stress as main plots and 15 cultivars as sub plots) in randomized complete block design with three replications. The measured traits were relative water content، yield and its components (number of spikes per m2، number of grain per spike and 1000 grain weight)، biological yield and harvest index. The results showed that the effects of drought and cultivar were significant on all traits، and drought stress decreases all traits. Correlation coefficients between grain yield and harvest index under both conditions was positive and highly significant. Correlations of harvest index with the number of spikes per m2، number of grains per spike and 1000 grain weight under drought stress، were significant. However، under non-stress condition was non significant. Correlation between 1000 grain weight and grain number per spike was significant under drought stress and was not significant under non-stress conditions. Under drought stress and non stress conditions، the correlation between 10 grain weight and grain yield was positive and significant. Correlation coefficient between grain yield and relative water content under non-stress condition was not significant; however under stress condition was significant. Based on path analysis، under stress and non stress conditions، harvest index had the highest and positive direct effect on grain yield. Under non-stress condition number of spike per m2 and under stress condition number of grains per spike had the highest direct effect. The number of spikes per m2 via by the number of grains per spike had the highest indirect negative effect under non-stress condition. Under stress condition، the 1000 grain weight by harvest index had the highest indirect negative effects.