NEW CMS SOURCES WITH STABLE MALE STERILITY AND BETTER OUTCROSSING TRAIT IN RICE (0. SATIVA L.)

Abstract

Six CMS lines possessing different cyto-sterility sources from O. rufipogon and O. nivara were evaluated for pollen and spikelet sterility characters in advanced back cross generations (BCs-BCs). All CMS lines showed 100 per cent spikelet sterility but the pollen stainability varied depending on the CMS source. The lines viz., RPMS 1~1, 1-2, 1.3, 1-4 and RPMS 2 possessing cyto-sterility source from O. rufipogon and O. nivara respectively were found to have gametophytic type of male sterility and RPMS 4 possessing g"nivara source was found to exhibit sporophytic male sterility system. The maintenarti::e of complete male sterility with restorers of WA system indicate the diversified nature of new male sterility sources. The field evaluation of these new CMS lines along with CMS lines belonging to wild abortive (WA), O. perennis (IR 64A) and MS 577A sources, carried out during khari! 1994 and rabi 1994-95 seasons demonstrated that in addition to stable male sterility the new CMS lines possessed very good panicle and· stigma exsertion rate and high rate of outcrossing which will goa long way in maximising the seed yield in hybrid rice seed production plots. The efforts are on to identify effective restorers for the new CMS sources. Reduction in the cost of hybrid seed and the nuclear and cytoplasmic diversification of hybrids will help in large scale adoption and sustenance of hybrid rice technology in India respectively, in the years ahead.