Combining ability for grain yield and its components in rice

Abstract

A 8x8- diallej cross without reciprocals, involving "Kataribhog" and "Bashmati 370" (aromatic varieties) was done to determine the general combining ability (GCA) and the specific combining ability (SCA) of eight morpho-agroclimatic characters. The GCA and SCA variances were significantly different, but the SCA variances were always lower than the GCA variances in all the characters, indicating additive gene effects in the inheritance of these traits. The local variety "Harinandi", was a good general combiner for yield and its components, viz. panicle per plant, panicle length, spikelet per panicle, and reduction of spikelet sterility. On the other hand, "Bashmati 370" showed a poor GCA for yield and its component characters except the panicle length. The variety "Kataribhogh" had also poor GCA for yield but it was a good combiner for spikelet number per panicle, panicle length, reduced growth duration. A cross between good general combiners (goodxgood) showed a good specific cross for plant height, growth duration, and spikelet sterility. The predominance of good specific crosses were found in goodxpoor and poorxpoor combiners for yield per plant, spikelet per panicle, panicle length , panicle per plant, and 1000- grain weight, indicating an ovcrdominance and epistatic gene actions for these traits.