Study of combining ability and gene action of cooking quality traits in rice (Oryza sativa L.) using line × tester analysis

The relative proportion of additive and non-additive genetic variances in a population can be used as a tool to study inheritance of traits. This research was an attempt to estimate the combining ability and action of genes associated with the cooking quality of rice. Four lines (restorer) and three testers (male sterile line) were crossed to obtain twelve F1 hybrids in a line × tester fashion at Rice Research Institute of Amol, Iran in 2010. In the 2011growing season, parents and hybrids were laid out in a randomized complete block design with five replications. After harvesting, seeds were characterized for amylose content (AC), gelatinization temperature (GT) and gel consistency (GC). In the present study, the analysis of variance for general combining ability (GCA) and specific combining ability (SCA) were significant for the traits with the exception of SCA variance for GT. The GCA effect was larger than the SCA effect for GT while the AC and GC had larger SCA. These results along with calculation of predictability factor revealed that traits AC and GC were governed by genes with dominance action while additive gene action was more important in the genetic control of GT.