Estimation of general combining ability, specific combining ability and heterosis among selected rice (Oryza sativa L.) genotypes

Rice is the most important cereal crop and is primary source of calorie for Nepalese. Though, few rice varieties have been released for cultivation among farmers, most of them are low yielding so are not preferred by the farmers. So, broadening the genetic base of rice is an important intervention that can be done to increase productivity. Thus, an experiment was conducted to estimate general combining ability, specific combining ability, and heterosis from three sets of crosses to find out best parents and their cross combinations. The set1 consists 2 lines and 4 testers, set2 consists 3 lines and 2 testers and set3 consists 2 lines and 2 testers respectively. Each set of parents were crossed in line X tester mating design with two replications to produce 18 F1. The analyzed data showed that all genotypic values were significant and showed maximum variations among the traits. When fertile grain number was considered Sukhadhan-2 was best parents and cross of Manjushree 2 X Samba Mahsuri Sub-1 and Himali X Taichung-176 were the best cross and for panicle length IR775- 39-80-2- 2-2 was obtained as best parent and the best cross was Khumal 8 X Sugandha- 2. Maximum heterosis was observed in Khumal 8 X Sukhadhan-2 for fertile grain number and Khumal -4 X Sugandha-2 for panicle length. Therefore, best parents could be utilized for creating best lines through hybridization and best cross combinations would work as best lines for further selection and evaluation. These lines might work as promising varieties for Nepal.