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.
Highlights
Rice is one of the world's most important food crops
Cross combinations 2 and 22 showed well over 70% higher standard heterosis (SH) compared to all standard checks in Yala season
BgCMS4A could be considered as the best tester
Summary
Rice is one of the world's most important food crops. More than half of the world's population, especially in South and Southeast Asia, depends on rice for calories and proteins. The population growth rate in Asia is relatively higher than the rate of increase in average rice yield (Dawe, 2007). By the year 2025, about 758 million tons of rough rice which is 70% more than current production will be needed to meet the growing demand in future. Development of high yielding varieties having multiple resistances to biotic and a- biotic stresses is important to cater to the present and future changing environment. Hybrid rice technology, formulated in China, assures the rice farmers with an increased yield over improved conventional varieties by 15 to 20% and is one of the options to enhance the productivity (Tran, 2002) and income. Hybrid rice area is rapidly increasing outside China as well as China released
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