Study of Correlation and Path Coefficient Analysis of Agronomic Traits and Grain Yield for Aegilops cylindrica Accessions under Non-stress and Drought Stress Conditions in Ilam

In order to study the relationships between grain yield and its components of Aegilops cylindrica, 48 accessions of this plant species was studied in an experimental augmented design based on randomized complete block designwith4 replications under normal and drought stress conditions in the Agricultural Research Station of Ilam University. The results of correlation analysis between the traits in both normal and stress conditions suggested that spike yield per plant, biological yield per plant and straw weight per plant had the highest correlation with the grain yield per plant. The results of regression analysis showed that the spike yield per plant, number of grains per spike, 1000 grain weight, single spike weight and spike length in normal conditions and spike yield per plant, single spike weight and 1000 grain weight in stress condition were entered into regression model. 96.3 and 95.3 percent of the total of variance of the regression was expressed in normal and stress conditions, respectively. Also, path analysis confirmed the effects of these traits on grain yield. In both irrigated and drought conditions, spike yield per plant had the greatest positive direct effect on grain yield. The results showed that in breeding programs aimed at increasing grain yield in populations of Aegilops cylindrica, selection is better to be done through the more spike yield in both normal and drought conditions.