Combining ability for yield and component characters in rice (Oryza sativa L.).

A diallel technique was employed in which ten genotypically diverse lines of rice were crossed among themselves in all possible combinations excluding reciprocals. The analysis for combining ability was significant for all the characters which indicated the presence of both additive and non-additive gene actions. The magnitude of mean square due to SCA were smaller than the GCA for the most of the traits indicating the preponderance of additive gene effects for all the character under study, whereas the ratio of the estimates of variances due to GCA to that of SCA indicated the preponderance of non-additive type of gene effects for most of the characters except for kernel length/breadth ratio and protein content. The best general combiners for grain yield per plant were GR-12, IET-20548 and IET-20536, whereas for other yield attributing characters the best general combiners were NVSR-20 and IET-20528. The best specific cross combinations GR-12 x Safed kada, NVSR-20 x IET-20528, Safed kada x Lal kada, IET-20528 x IET-20533 and IET-20548 x IET-20536 showed the highest SCA effect for grain yield per plant. These cross combinations could be utilized for further use in breeding programme for improvement in yield and quality of rice.