Genetic Analysis of Cold Tolerance at Seedling Phase in Rice

Genetic analysis of components of cold tolerance at seedling phase was studied using four different criteria viz., reduction in height, root length, seedling weight and yellowing of leaf. The tolerance was estimated as the difference in the expression of a component character under normal and stress conditions. Relatively higher estimates of variance due to sca in comparison to gca in F₁ generation suggested a major role for nonadditive gene action in the expression of the trait. In respect of leaf yellowing, however, additive and additive x additive type of gene action seemed to play a predominant role. Also the study helped identify the best general combiners and the best cross combinations which varied with the component of cold tolerance.