Estimation of Gene Action and Combining Ability Analysis for Yield and Drought Tolerant Traits in Hybrid Rice (Oryza sativa L.)under Aerobic Condition

摘要

Information on yield and drought tolerant potential of the genotypes is more important in the crop improvement programme, to evolve hybrids suitable for rainfed situation under aerobic cultivation. Combining ability analysis for yield and drought tolerant traits was carried out in rice through line x tester analysis of 30 hybrids developed by crossing three CMS (Cytoplasmic Male Sterile) lines, ten testers (aerobic cultures and upland genotype) along with parents and checks. The 30 hybrids along with13 parents and one standard check were grown in a randomized block design with two replications and were evaluated for yield and drought tolerant traits under aerobic condition. The experiments were conducted at research farm, Department of Plant Breeding and Genetics, Tamil Nadu Agricultural University, Madurai during rabi 2011-12. Observations were recorded on 15 yield attributes drought tolerant characters and single plant yield for all the parents and hybrids. Predominance of non-additive gene action was recorded for days to 50% flowering, number of productive tillers per plant, panicle length, number of grains per panicle, spikelet fertility, 100-grain weight, relative water content, root length, root dry weight, root: shoot ratio, harvest indexand single plant yield, while additive gene action was predominant for plant height, proline content and chlorophyll stability index. Among the parents, IR 58025 A, MAS 946 -1, CB 87 R, and BI 33 were found to be general combiners for majority of the traits including drought tolerance and yield characters. The hybrids IR 58025 A x CB 87 R, IR 68897 A x MAS 946 -1, IR 68897 A x IR 65912 R and IR 58025 A x MAS 26 were specific combiners for most of the yield contributing and drought tolerant traits including single plant yield.