Breeding potential of the basmati rice germplasm under water stress condition
Eight parents were selected on the basis of phenotypic and genotypic screening for the development of F1. All the possible combinations were made between the parents excluding reciprocals in diallel mating design. Data were analyzed by using Hayman graphical approach and Griffing’s approach to study the genetics of the parents and their F1 hybrids. Based on the genetic component analysis, both additive and non-additive components appeared which is important in the inheritance of most of the traits. Both additive and dominance type of gene action were found important in inheritance for different traits under study. Most of the traits showed constant gene action in both environments, but the gene action of some traits was affected by the environment. Morphological traits like plant height, productive tillers per plant and 1000 seed weight showed over dominance type of gene action in both environments (control and drought environments), while seeds per panicle and seed length width ratio showed this type of gene action only in drought conditions. The seeds per panicle and length width ratio showed additive type of gene action with partial dominance only in normal irrigation conditions. From Griffing analysis, genotypes CB-17, CB-32 and Basmati-198 were found to be good general combiners for productive tillers per plant, primary branches per panicle and yield per plant, especially under water stress condition. Also, maximum specific combining ability was found in Basmati-198 × CB-17 for productive tillers per plant, Basmati-198 × CB-42 for primary branches per panicle and CB-32 × CB-14 for yield per plant.
Key words: Oryza sativa L., gene action, combining ability, stress, yield traits.