Anil KumarRoy, Amitava2021-01-232021-01-232020-09https://krishikosh.egranth.ac.in/handle/1/5810160518The present investigation was carried out to study genetic variability parameters, combining ability, gene action, and heterosis utilizing line x tester mating design during Rabi season of 2018-19 and 2019-20, at Norman E. Borlaug Crop Research Centre, G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand). The experimental material consisted of eleven lines viz., K 1402, QLD 75, QLD 65, WH 1182, HPBW 01, NW 6036, QBP 12-11, SOKOLL, NAC/TH.AC//3*PVN/3/MIRLO/BUC/4/2*PASTOR/5/…, PRL/2*PASTOR*2//FH6-1-7/3/ KINGBIRD#1//…, VORB/4/D67.2/PARANA66.270 crossed with three testers viz. HD 3237, PBW 725 and HI 1621 in line X tester mating design to produce 33 F1s. These 33 F1s, along with the 14 parents and two standard checks viz., UP 2855 and HD 2967 were planted in randomized block design with three replications during Rabi season of 2019-20 and observations were recorded on thirteen traits viz., days to 75% heading, days to maturity, number of productive tillers per plant, plant height, peduncle length, spike length, number of spikelets per spike, number of grains per spike, grain weight per spike, 1000 grain weight, biological yield per plant, grain yield per plant and harvest index. The results revealed that there were significant differences observed among all the genotypes indicating the presence of considerable amount of genetic variability, as mean squares for all the characters were observed to be highly significant. The parental line PRL/2*PASTOR*2//FH6-1-7/3/KINGBIRD#1//… was identified as a good general combiner for maximum number of the characters viz., days to 75% heading, days to maturity, spike length and peduncle length, followed by QLD 75 for grain yield per plant and grain weight per spike and QLD 65 for number of tillers per plant and biological yield per plant. The cross combination VORB/4/D67.2/PARANA66.270 x PBW 725 was observed as a good specific combiner for days to 75% heading, days to maturity and plant height. The hybrid NAC/TH.AC//3*PVN/3/MIRLO/BUC/4/2*PASTOR/5/… x HD 3237 was recognized as the superior specific combiner for grain yield per plant and biological yield per plant, whereas, F1, VORB/4/D67.2/PARANA 66.270 x HI 1621 was a better specific combiner for 1000 grain weight and peduncle length and QLD 75 x HI 1621 was a good specific combiner for harvest index and number of grains per spike. The variance ratio between general and specific combining ability was observed to be less than one, indicating the prevalence of non additive gene actions for most of the traits. Among the crosses, F1, VORB/4/D67.2/PARANA66.270 x PBW 725 was observed as the best heterotic combination for days to 75% heading and days to maturity, whereas, F1, QLD 75 x HI 1621 exhibited maximum heterosis for grain weight per spike and harvest index. The hybrids SOKOLL X HD 3237 and QLD 65 x HI 1621 were the superior heterotic combinations for 1000 grain weight and number of tillers per plant, respectively. The most promising heterotic cross combination with high per se performance for the trait grain yield per plant was SOKOLL x HI 1621 followed by QBP 12-11 X HI 1621, NAC/TH.AC//3*PVN/3/MIRLO/BUC/4/2*PASTOR/ 5/… x HD 3237, PRL/2*PASTOR*2//FH6-1-7/3/KINGBIRD#1//… x HI 1621 and SOKOLL x HD 3237. It is advocated that, good combiner genotypes could be used in crossing programme and the crosses having significant sca effects can be utilized for getting transgressive segregants. So, from above investigation, we can select best lines and crosses for further use in the future breeding programmes.EnglishThesis