Genetic Analysis of Agronomic traits in Rice (Oryza sativa L.)

Inheritance of agronomically important traits was studied by crossing six rice genotypes including Shahpasand, Ahlami Tarom, Gharib, Neda, IR28 and Sepidroud in a 6×6 diallel mating design. The P1, P2, F1 and reciprocal crosses were arranged in a complimentary random block design with three replications. This study was conducted in 2009 at the research farm of Gonbad Kavous University. Nine quantitative traits were recorded for all accessions at each replication: of days to flowering, flag-leaf length to width ratio, plant height, number of panicles, number of primary branches, number of filled grains, panicle exertion length, panicle length and days to maturity. The results showed that there were significant differences among parents and also among crosses in terms of all of the traits studied. Genetically, parameters were significant for all traits (p<0.05) except in a few cases. The analysis of genetic variance was carried out that variation sources were not significant in b1 and c for number of filled grains, in b, b1, b2, b3 and d for flagleaf length, in b1 and b3 for plant length and c and d for panicle number. The average heterosis b1 was not significant for number of filled grains, flag-leaf length and plant height. In terms of traits studied, Ahlami Tarom was the best combinative parent. In many cases, crosses had positive and negative specific combinability, in which one or both of its crosses parent, had general combinability in terms of interested traits, notwithstanding, there were a few exceptional cases.