Genetic Analysis of Grain Yield and Milling Quality Characters of Two Line Rice Hybrids

The experiment was laid out at Agricultural College and Research Institute, Madurai, Tamil Nadu. India and the materials for this study consisted of three TGMS lines viz., TS 29, TS 6 and GD 98013 and 11 testers viz., ADT 39, ADT 41, Pusa Basmathi 1, Basmathi 370, Improved White ponni, AD 98028, GEB 24, ADT 43, ADT 45, Taroari Basmathi and Jeeraga samba. Crossing was done according to clipping and churning method in L X T fashion. Based on the nature of combing ability inferred from line x tester analysis, three cross combinations viz, TS 29 / ADT 41, TS 29 / Pusa Basmathi 1 and TS 29 / Basmathi 370 were selected for generation mean analysis study. The scaling tests indicated the presence of epitasis for all the characters and there fore six parameters model was followed to estimate the various gene action. The scales A and C are negatively significant in all the crossed viz., TS 29 / ADT 41, TS 29 / Pusa Basmathi 1 and TS 29 / Basmathi 370 for grains per panicle and hundred grains weight. The scale B is negatively non significant for grains per panicle and hundred grains weight in all the three crosses. The crosses TS 29 / ADT 41, TS 29 / Pusa Basmathi 1 and TS 29 / Basmathi 370 showed positively significant A and C scales for grain yield. The mean effect m was significantly positive and greater than all other effects in all the three crosses viz., TS 29 / ADT 41, TS 29 / Pusa Basmathi 1 and TS 29 / Basmathi 370 for productive tillers, hundred grain weights, graim yield, hulling per cent, milling per cent and head rice recovery. A significant additive x dominance (j) effect was recorded in TS 29 / Pusa Basmathi 1 and TS 29 / Basmathi 370 crosses for grain yied and hulling per cent A significant additive x dominance (j) was observed in TS 29 / ADT 41 cross (panicle length and milling per cent). The (h) and (l) effects took opposite signs in all the three crosses indicating the involvement of duplicate dominant epistatic kinds of interaction for productive tillers, hundred grains weight, grain yield, hulling per cent, milling per cent and head rice recovery. In general , both additive and non-additive gene effects appear to all eight characters studied. Therefore, improvement of these traits appears to beset with difficulties as simple selection techniques will not be able to fix superior lines in the early segregating generations. Postponement of selection of superior lines to later generations in pedigree breeding will be effective.