Combining ability for yield and physical characters in rice

Combining ability for ten quantitative and physical characters in rice was studied through Line × Tester analysis involving eight lines and four testers. The mean squares of variance for Line × Tester interaction was significant for all the characters except grain length and grain breadth. The combining ability analysis revealed non-additive gene action governing the characters viz., days to first flower, plant height, panicles plant-1, grain yield plant-1 and grain L/B ratio. Predominance of GCA variance was recorded for days to first flower, plant height, grains panicle-1 and grain yield plant-1. Among the parents, the lines AD 95137, AD 95157 and MDU 5 and testers ADT 36, ADT 43 and IR 50 were good combiners for grain yield and most of the yield component characters studied. Hence, crosses involving these parents were identified as suitable for recombination breeding.