ISOLATION AND CHARACTERIZATION OF MAINTAINERS AND RESTORERS FROM INTER SUB- SPECIFIC (indica xjaponica) DERIVATIVE LINES OF RICE

Abstract

The study was conducted at the experimental farm of Sher-e-Bangla Agricultural University, Dhaka-1207, during Kharif 2006, Rabi 2006-2007 and kharif 2007 seasons with the objective of identification of potential restorers and maintainers from indica/japonica derivative lines and conversion of selected maintainers possessing desirable plant type into CMS lines. To achieve the objectives, 65 test cross combinations including one wild abortive cytoplasmic male sterile (CMS) lines and 46 pollen parents were used as material of the study. The aspects of the study were development of source nursery and test cross nursery, estimation of pollen fertility, identification of potential restorers and potential maintainers. The study showed that of all the pollen parents in 65 success test crosses, 14 were restorers (21.54%), 27 were partial restorer (41.54%), 14 were partial maintainers (21 .54%) and 10 were maintainers (15.38%). Out of 14 restorer lines, 11 were selected on the basis of crop uniformity and all types of observation were recorded only from uniform lines. Based on scale of different characters a combined score was computed and on the basis of pooled approach of ranking, five restorers having the rank I to Ill will be used for production of experimental hybrid in next season. The 10 lines identified as maintainers were further subjected to screening based on various morphological characters favouring out-crossing, increased seed production, good grain quality as well as high level of heterosis. Following various scoring parameters and overall rankings four maintainer lines identified which were chosen for conversion into new CMS lines in the next crop season.