Estimation of Heritability of Agronomic Traits of Sesame (Sesamum indicum L.) under Non-Stress and Drought Stress Conditions using Diallel Analysis

To estimate general combining ability (GCA), specific combining ability (SCA) and genes action in sesame, a 7×7 diallel cross was conducted using randomized complete block design with three replications under non-stress and stress conditions in 2005 and 2006 in research field of faculty of agriculture of Birjand university. Analysis of variance showed significant differences between genotypes. Griffing analysis showed that significant GCA for all traits in non-stress and stress conditions. SCA was significant for all traits, except plant height, height to first capsule and number of capsule, in non-stress conditions. In stress conditions, SCA was also significant for all traits, except plant height, auxiliary branch number and number of capsule plant-1. Hayman analysis of variance showed that additive genetic variance was significant for all traits in both conditions. The dominant genetic variance was significant for all traits, except plant height and height to first capsule, in non-stress conditions. It was also significant for all traits, except plant height, in stress conditions. Inheritance of yield and related traits was relatively high in both conditions. Broad sense heritability varied from 0.51 (plant height) to 0.99 (several traits), and narrow sense heritability varied from 0.27 (harvest index) to 0.99 (number of capsule) in both conditions. The highest (29.2%) and lowest (-9.47%) heterosis relative to mid-parent observed for grain yield in non-stress and harvest index in stress conditions, respectively. The estimated heterosis relative to superior parent was positive (0.03%) only for capsule length in non-stress conditions.