Surveying the relations among traits affecting seed yield in sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.)

To determine the most important traits influencing seed yield of sesame, 18 lines were evaluated in a randomized block design with three replicates in two years during the 2013 and 2014 growing seasons. Following a combined analysis of variance, multivariate statistical analyses such as simple correlation coefficients, factor analysis, stepwise analysis, path analysis, and cluster analysis were administered on combined means. The correlation coefficient analysis showed a significant negative correlation between seed yield and number of capsules per plant and number of seeds per capsule. Correlation between germination period and seed yield was positive and significant at 5% probability level. Factor analysis divided the 14 measured variables into five factors. In the stepwise regression analysis for seed yield as the independent variable, four traits including number of capsules per plant, first capsule height, number of seeds per capsule, and stem length to first capsule were entered into the regression model in four steps with r² =0.72. The regression coefficient of number of capsules per plant, number of seeds per capsule, and stem length to first capsule were negative and the regression coefficient of the first capsule height was positive and significant at the 5% probability level. The path coefficient analysis based on seed yield as a dependent variable implicated that the number of seeds per capsule had the highest negative direct effect on seed yield. The highest negative indirect effect on seed yield was related to the number of capsules per plant through the number of seeds per capsule. Cluster analysis using Ward’s method divided 18 investigated lines into five clusters.