M.P.HaqueShravan Kumar Singh2024-06-282024-06-281997https://krishikosh.egranth.ac.in/handle/1/5810211104Ten genotypes of rice (Oryza sativa L.) namely Birsa Dhan 104, Birsa Dhan 106, Birsal Dhan 105, RAU-1004-105, Dhan103, Birsa Dhan 201, Rasi, IR-36, Birsa Dhan 202 and Rajendra Dhan 202 were crossed in a diallel fashion excluding reciprocals. The forty-five crosses and ten parents were grown in a complete block design during kharif season of 1995 irrigated condition. The data recorded on characters viz., days to panicle emergence, fourteen plants randomized under. normal quantitative height, total number of leaves per plant, flag leaf area, total number of tillers per plant, number of ear-bearing tillers per plant, length, number of grains per panicle, spikelet fertility, panicle. grain yield per panicle, 1000-grain weight, biological yield per plant, grain yield per plant and harvest index were analyzed to find out the estimates of variability, heritability (broad sense), genetic advance, heterosis (over mid-parent combining ability.. and better parent) and combining ability. The analysis of variance revealed highly significant differences among the genotypes for except grain yield per panicle. Almost This all indicated genetic differences among all the genotypes (10) the characters the parents F₁'s) for all the characters under this investigation. Grain yield per plant, grain yield per panicle and biological yield per plant showed considerable genetic coefficient of variation. High estimates of heritability (broad sense together with moderately high genetic advance was observed for the characters, spikelet fertility and biological yield per plant. Most of the crosses manifested positive heterosis over mid-parent and better parent for grain yield per plant. Maximum heterosis to the extent of 138.44 and 131.68 per cent was observed over mid-parent and better parent respectively. The best cross combination showing significant heterosis over the better parent was RAU-4000-105 X IR-36 (131.68 %). Crosses showing heterosis for grain yield were not heterotic for all the characters. The combining ability studies indicated that both additive and non-additive genetic components were involved in deter mining the expression of the characters studied but non-additive type of gene action predominanted in all these characters. Similarly, presence of over dominance was revealed in all the characters. Birsa Dhan 105 was found to exhibit maximum general combining ability for grain yield per plant, which also showed good general combining ability for biological yield per plant, harvest index and flag leaf area.EnglishThesis