Study of genetic structure in quantitative and qualitative traits in rice lines and varieties

In order to evaluate gene action and narrow heritability for quantitative and qualitative traits in rice, six crosses were conducted among improved and traditional rice varieties in 2004. The F1 generations and parents were planted and then first and second back cross were done in 2005.Also F1 generations were selfed to obtained F2 generation seeds. The experiment was done with 6 treatments including 7 parents and their F1 and F2 generations for each cross, with three replications on rice Research Institute of Iran (Rasht) in 2006. In this study 10 quantitative and qualitative traits were measured and evaluated.The results obtained from analysis of variance indicated that mean squares in generation were significant for all traits except for brown rice length and shape in Neamat / Alikazemi and brown rice width and shape in Kadous / Hasansaraei. Therefore generations mean analyses (Mater & Jinks method) were performed for significant traits. The results showed that in most of crosses both additive or dominance gene effects were controlled the traits such as panicle length, fertile tiller per plant, fill grain per panicle, grain yield per plant. Also in some of these crosses the effecte of additive×additive and dominance×dominance were significant. The estimation of narrowsense heritability (NH) for traits based on the means indicated the highest NS for grain shape(59.94%).The NH for fill grain per panicle was highest one (52.82%) among agronomic traits. The cooking quality traits such as amylose content and gelatinization temperature had NS 30.93 and 28.09 respectively. In crossess that the aditive and aditive×aditive gene effects were significant, the selection of suitable line with desirable trait in segregation generation could be successful. Because the traits were controlled by aditive genes could be transfer to progenies. While the traits were controlled by dominant and dominant × dominant genes could not be transfer to progenies.Therefore these traits could be used on hybrid rice breeding program.