Identification of usable maintainers and restorers for new CMS lines of rice (O. sativa L.)

The success of hybrid rice technology depends on the extent of heterosis realized and the grain quality of rice. Seven new CMS lines developed at Zonal Agricultural Research Station, Mandya through backcross breeding were evaluated along with two checks CRMS31A and CRMS 32A for their morphological and floral traits besides aroma during kharif 2008. All the CMS lines evaluated exhibited complete pollen sterility and spikelet sterility. KCMS 29A recorded the higher stigma exsertion (30.31%) and natural outcrossing (19.76%). KCMS 31A had the longest style (1.26 mm) and stigma (1.20 mm) while the angle between stigma lobes was wider ( 65.48 (φ)) in KCMS 37A which also had the best panicle exsertion (79.28%). All the nine CMS lines had no aroma. Based on morphological and floral traits CMS lines KCMS 29A, KCMS 31A and KCMS 37A were better compared to the checks CRMS 31A and CRMS 32A. To identify usable maintainers and restorers for these CMS lines eleven testers were crossed with all the nine CMS lines in a line x tester fashion. Based on the percent spikelet fertility in hybrids, 60 showed restorer reaction and eight had maintainer reaction while the rest 31 showed partial maintainer / restorer reaction. Among the testers MSN-20-13, MSN-62, MSN-63, MSN-64 and MSN 68 were identified as good maintainers while KMR-3, KMR-4, MSN-67 and MSN-69 as good restorers.