INHERITANCE OF HIGH TEMPERATURE TOLERANCE AND SOME RELATED TRAITS IN RICE

A study was carried out at the Agronomy Department, Faculty of Agriculture, Kafr El-Sheikh University and the Rice Research and Training Center, Field Crop Research Institute, during 2013, 2014 and 2015 seasons to study the inheritance of heat stress tolerance and some traits in rice crosses. The six populations; P1, P2, F1, F2, BC1 and BC2 of each of the three studied crosses were evaluated in the New Valley research field under heat stresses
using randomized complete block design (RCBD) with three replications. The results indicated the presence of non-allelic interaction for all studied traits in all crosses. The gene action of the studied traits indicated that additive,
dominance and epistemic genetic components was important for the expression of the traits studied. The results showed considerable amount of dominance effect for days to 50% heading, plant height, total stigma length,
anther length, 100-grain weight and grain yield/ plant indicating that selection for these traits should be postponed to the later generations until homozygosity is achieved. Also, the relative importance of additive × dominance effects varied within traits and crosses under heat conditions. Among the epistatic components, the dominance × dominance was greater in magnitudes than additive × additive and additive × dominance in most of the studied traits. Positive heterotic effects relative to the mid-parent and betterparent were found for most of the studied traits under both conditions.