COMBINING ABILITY ANALYSIS OF THE PHOTO-THERMOSENSETIVE GENIC MALE STERILITY LINES (PTGMS) OF JAPONICA RICE.

Combining ability and genetic parameters analysis for agronomic, yield and its component characters were carried out in rice through line x tester analysis of 20 hybrid rice combinations developed by crossing four Photo-Thermosensitive Genic Male Sterility (PTGMS) lines (females) with five male lines / varieties along with parents and check. The 20 hybrids with nine parents were grown in a randomized complete block design with three replications. The experiments were conducted at RRTC in 2010 and 2011growing seasons. Data analysis of variance for combining ability revealed a significant differences among PTGMS lines for plant height, panicle length, panicle weight and filled grains panicle-1, indicating the importance of additive genetic variance in the inheritance of these characters. The mean squares due to female PTGMS lines were found non-significant for days to heading, tillers plant-1, spikelet fertility%, 100-grain weight and grain yield characters, indicating the prevalence of non-additive genetic variance and suggesting the importance of heterosis breeding for improvement of rice. An overall appraised of GCA effects revealed that among females; PTGMS-80 and PTGMS-51 had a good general combiners for most characters. Among PTGMS and the tester lines, PTGMS-80 and the tester line JRL-252 had favorable genes for grain yield and the most of desirable characters under study. The hybrid combinations PTGMS-80 x JRL-252 followed by PTGMS-51 x Giza 177 were the best specific hybrid combinations which have significant values for grain yield with desirable characters.