“COMBINING ABILITY AND HETEROSIS STUDIES FOR GRAIN YIELD AND ITS COMPONENTS IN RICE (Oryza sativa L.)”
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Date
2008
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
A study entitled “Combining ability and heterosis studies for grain yield and its components in rice (Oryza sativa L)” was conducted during kharif 2006, on Research Farm, Department of Plant Breeding and Genetics, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh to asses the variability, for various yield and related traits, to identify the maintainers and restorers for CMS lines under study and to estimate the GCA of parents and SCA of hybrids, to assess the magnitude of heterosis. The experimental material included 3 CMS lines viz., CRMS 31A,CRMS 32A and IR 58025A and eleven testers viz., WAR 120-1-5-6-2B-B-3, RPHR 203-3, R 1130-102-3-88-1, IR 68830-NDR-1-1, CR 780-1937, R 1241-1856-1-1, R 304-34,R 1216-6, Chinikapoor, OR1898-18RAU 729-12-44 and WAR 89-4-A9-1-B-B-B-2 and thirty three hybrids generated in line x tester pattern. These hybrids and parents were raised in Randomized Complete Block Design (RCBD) with two replications. The data obtained were subjected to line x tester analysis. Combining ability analysis and heterosis was worked out for characters days to 50% flowering, plant height, tillers per plant, productive tillers per plant, panicle length, flag leaf angle, second leaf angle, third leaf angle, leaf area, pollen fertility (%), spikelet fertility (%), harvest index and seed yield per plant. The analysis of variance revealed the predominance of non-additive gene action for the all characters under study, which suggested possibility of utilizing them to develop commercial hybrids. Among the CMS lines studied, only one line, IR 58025A was found to be the good general combiner and among testers RPHR 203-3 and OR 1898-18RAU 729-12-44 were found to be superior general combiners for yield and attributing characters. The hybrids IR 58025A/OR 1898-18RAU 729-12-44 followed by CRMS 31A/IR 68830-NDR-1-1, IR 58025A/ R 304-34, CRMS 32A/R 1130-102-3-88-1 and CRMS 31A/RPHR 203-3 were identified as a good combinations on the bases of SCA effects for yield and several attributes under study. Four hybrids viz., IR 58025A/OR 1898-18RAU 729-12-44, IR 58025A/R 304-34, CRMS 31A/RPHR 203-3 and IR 58025A/ Chinikapoor, were recorded to have significant heterosis for yield and attributing characters for two levels of heterosis. These F1s were derived
from parents having high, average and low GCA effects. These promising hybrids offer greater scope for further exploitation of hybrid vigour commercially. Based on the pollen fertility (%) and spikelet fertility (%), ten genotypes were identified as potential restorers. Among these two genotypes viz., RPHR 2033 and R 1216-6 have been identified as potential restorers for all three lines (CRMS 31A, CRMS 32A and IR 58025A). Among remaining, WAR 120-1-5-6-2B-B-3, CR 780-1937 and Chinikapoor were considered as potential restorers for CRMS 31A and IR 58025A. IR 68830-NDR-1-1 for CRMS 32A and R 1130-1023-88-1, OR 1898-18RAU 729-12-44 and WAR 89-4-A9-1-B-B-B-2 found to be good restorers for CRMS 32A. The study also concluded that the frequency of potential restorers is much higher than the maintainers in the material under study.
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131 p.