Dr. V. P. ChovatiaL. G. Vanpariya2017-03-282017-03-282004-09http://krishikosh.egranth.ac.in/handle/1/5810006346Heterosis, combining ability and gene action in bread wheat (Triticum aestivum L.) were studied under timely sown condition using line X tester (10 lines X 4 testers) design at Wheat Research Station, Junagadh Agricultural University, Junagadh, during Rabi 2002. Observations were recorded on five randomly selected plants per treatment in each replication for grain yield per plant, days to heading, plant height, effective tillers per plant, length of main spike, spikelets per spike, peduncle length of main spike, days to maturity, number of grains per spike, 100-grain weight, grain yield per spike and harvest index. Analysis of variance revealed significant differences among all the parents as well as crosses for all the characters studied. Variances due to parents Vs hybrids were also significant for all the characters except for plant height and 100-grain weight. The magnitude of heterosis was higher for grain yield per plant, effective tillers per plant, length of main spike, spikelets per spike, number of grains per spike, grain yield per spike and harvest index, moderate for peduncle length of main spike and 100-grain weight and lower for days to heading, plant height and days to maturity. The crosses K-8565 X Lok-1, PBW-316 X Lok-1, DL-803-3 X GW-173, CPAN-1933 X Lok-1, DL-803-3 X GW-190, GW-326 X GW-190, GW-273 X GW-190, GW-326 X Lok-1, K-8565 X GW-190, WexBbinia X GW-496 and GW-326 X GW-496 exhibited exploitable heterosis for grain yield and its components. Variances due to females, males and females X males were significant for all the characters except for grain yield per spike and harvest index, when tested against error mean squares. Mean squares due to females and males were significant for days to heading, plant height, length of main spike, spikelets per spike and peduncle length when tested against females X males interaction mean squares; while mean squares due to females and males were non-significant for grain yield per plant, number of tillers per plant, days to maturity and number of grains per spike, and only females and only males were significant for grain yield per spike and 100-grain weight, respectively. These indicated the involvement of additive as well as non-additive type of gene actions in the inheritance of these characters. The ratio (2sca / 2gca) suggested preponderance of non-additive gene action for grain yield per plant, number of effective tillers per plant, days to maturity, number of grains per spike, 100-grain weight, grain yield per spike and harvest index, and additive gene action for rest of the characters. The best general combiners for various characters were DL-803-3 and PBW-316 for grain yield per plant, GW-326 for days to heading, CPAN-1933 for plant height, DL-803-3 for effective tillers per plant, GW-190 for length of main spike and spikelets per spike, CPAN-1933 for peduncle length of main spike, GW-326 for days to maturity, WexBbinia for number of grains per spike, Lok-1 for 100-grain weight and K-8565 for grain yield per spike. The best combinations were WexBbinia X GW-173 for grain yield per plant and effective tillers per plant, DWR-202 X GW-173 for days to heading, DL-803-3 X GW-173 for plant height, K-8565 X Lok-1 for length of main spike, spikelets per spike and grain yield per plant, K-8565 X GW-190 for peduncle length of main spike, DL-803-3 X GW-190 for days to maturity, GW-326 X GW-496 for number of grains per spike and harvest index and PBW-316 X Lok-1 for 100-grain weight. On the basis of combining ability and heterosis, the parents viz., K-8565, CPAN-1933, GW-326, WexBbinia, GW-190 and Lok-1 and hybrids viz., K-8565 X Lok-1 and WexBbinia X GW-173 found to offered the best possibilities of their further exploitation for developing the high yielding varieties of bread wheat. The present study revealed that both additive and non-additive components were important for inheritance of different characters, hence reciprocal recurrent selection would be the most appropriate breeding methodology, which can exploit both additive and non-additive gene actions so that designed genes could be fixed.enBotanyLINE X TESTER ANALYSIS IN BREAD WHEAT (Triticum aestivum L. em. Thell.)Thesis