Abstract
Twenty five hybrid combinations were produced using five CMS lines (BgCMS4A, IR68902A, IR70369A, IR68902A, IR78354A) and five restorers R147(IR72998-93-3-3-2R), R156(IR73885-1-4-3-2-1-10R), R317(IR183325-66-2-1-NPT), R160(IR75282-58-1-2-3), SN290 10-2071 following Line x Tester mating design. Twenty five cross combinations, ten parents and three standard checks namelyBg300, Bg 357 and Bg379-2 were field evaluated in Maha2014/2015 and Yala 2015 at Rice Research and Development Institute, Batalagoda to find out the better parents having high general combining ability (GCA) and, good hybrid combinations having high specific combining ability (SCA). BgCMS4A was identified as the best tester for the grain yield and has also shown significantly higher SCA for Y/P in one of the cross combinations. Number of plants per hill (P/H) has highly contributed to achieve high grain yield of BgCMS4A. IR78354A also could be considered as a comparatively better tester as it has recorded significantly higher SCA for Y/P and P/H in one of the cross combinations. IR70369A also was a tester that showed significantly higher GCA for TGW in both seasons. The crosses 22(IR78354A/IR73885-1-4- 3-2-1-10R) and 2(BgCMS4A/IR73885-1-4-3-2-1-10R) were identified as the best cross combinations to be used as hybrids in the low country intermediate zone.