The Genetical Evaluation of Quantitative Traits in Rice (Oryza sativa L.) by Generation Mean Analysis

In order to study mode of gene action in rice for the traits related to yield، four varieties of rice were investigated. Direct and reciprocal crosses have been done between parents Sang-Tarrom and Gerdeh، IR229 and IRRI2 and their back crosses. The F1 and BC seeds were grown in 2006 and F1 plants were selfed for obtaining F2 seeds. Therefore، 10 different populations (generations) including P1، P2، F1، RF1، BC1، RBC1، BC2، RBC2، F2 and RF2 were planted in a randomized complete block design with three replications. The Additive×Dominance model was significant for the traits in both crosses (except number of panicle length trait in Sang-e-Tarrom×Gerdeh cross). The join scaling test indicated that the inheritance of traits related to yield was described by Additive×Dominance components، non-allelic interactions mainly Additive×Additive and Additive×Dominance and duplicate epistasis. Estimated of narrow and broad-sense heritability for two crosses was 0. 56 to 0. 98 and 0. 03 to 2. 68 respectively. More than one major gene group appeared to be involved for the expression of 1000-grain weight and plant height while the remaining traits showed the presence of at least one major group of genes for controlling their inheritance.