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EVALUATION AND DEVELOPMENT OF MAINTAINER GENE POOL IN RICE FOR DEVELOPMENT OF IMPROVED HYBRIDS

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(EVALUATION AND DEVELOPMENT OF MAINTAINER GENE POOL IN RICE FOR DEVELOPMENT OF IMPROVED HYBRIDS)

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2007
SUDHEER KUMAR, S
ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
D8110;

The present investigation was carried out during Kharif 2006 and Rabi 2007 to morphologically characterize maintainer lines, to analyze variance for different characters and to analyze combining ability and study heterosis and heterobeltiosis of the different characters of ten selected maintainer lines and their 45 direct hybrids. The experiment was conducted at the Directorate of Rice Research, Rajendranagar, Hyderabad. During the Kharif season, the selection of superior maintainer lines from a maintainer collection available at the Directorate was made and the crosses were made among the selected ten lines in half diallel fashion. The evaluation of F1s with parental lines was taken up during the Rabi 2007 season in a randomized block design with three replications. Observations were recorded for fifteen characters viz. days to 50% flowering, plant height, panicle exsertion, spikelet opening, stigma exsertion, number of productive tillers, culms strength, panicle length, number of filled grains, filled grain %, grain yield, 1000-grain weight, leaf senescence, grain type and phenotypic acceptability. The gca/sca variance for all the characters studied was less than one indicating that they are predominantly governed by non-additive gene actions. However, grains length and breadth ratio and days to 50 % flowering showed the least magnitude of the predominance of non-additive gene actions while panicle exertion rate, stigma exertion rate and filled grains per panicle showed the highest magnitude of the non-additive gene action. From the gca effects IR68897B was good general combiner for six characters viz. plant height, productive tillers plant-1, panicle length, filled grains panicle-1, yield plant-1 and 1000-seed weight. The parental lines APMS6B, IR79128B and IR79156B were good general combiners for three characters each. From the specific combining ability results IR68897B x IR79156B was good specific combiner for seven characters viz. days to 50 % flowering, stigma exsertion %, productive tillers per plant, panicle length, filled grains panicle-1, filled grain % and grain yield plant-1. For heterosis over mid parent APMS6B x PMS17B was good heterotic combination for 7 characters viz. days to 50 % flowering, plant height, productive tillers plant-1, panicle length, filled grains panicle-1, filled grain % and grain yield plant-1. For heterobeltiosis DRR2B x IR67684B was good heterotic combination for 6 characters viz. plant height, panicle exsertion %, stigma exsertion, panicle length, filled grains panicle-1 and grain yield plant-1. According to overall studies based on specific combining ability, heterosis and heterobeltiosis the following five crosses viz. IR58025B x IR79156B, IR68897B x IR79156B, IR68897B x IR69628B, APMS6B x PMS17B and DRR2B x IR67684B could be given consideration for selection of desirable maintainers from F2 generation onwards. This study provided information as well as the material for improvement of maintainer line gene pool in rice for development of improved hybrids

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