Combining ability analysis and gene action for yield and yield related traits in rice (Oryza sativa L.) under saline conditions

Abstract

Salinity is a major abiotic constrain faced by farmers in most rice cultivating areas of the world and improving grain yield in rice is the most important breeding objective. Twenty seven hybrids were generated in a line x tester mating design and were evaluated with their parents in a Randomized Complete Block Design at the Fadama site of the Federal University of Agriculture, Abeokuta (FUNAAB) during the 2014/2015 and 2015/2016 cropping season. Analysis of variance revealed a highly significant difference (P<0.01) among testers and lines for all traits except panicle length and a number of effective tillers per plant, respectively. Variances of Specific Combining Ability (SCA) were higher in magnitude than the corresponding General Combining Ability (GCA). The lines FARO 60 (P 7 ), OG300315 (P 10 ), NERICA L53 (P 4 ) including a tester ITA 212 (P 1 ) were the best general combiners for yield per plant. POKKALI (P 3 ) was the best general combiner for reduced vegetative growth and ITA 212 (P 1 ) and ITA 222 (P 2 ) were the best general combiners for plant height. The best specific combiner for yield per plant was P 1 x P 4 . P 3 x P 11 was the best specific combiner for reduced duration characters and P 2 x P 7 was the best specific combiner for plant height.\xa0 Estimates of narrow sense heritability (0.00 – 0.03) for all the traits under study were low which indicated preponderance of non-additive gene action governing these traits. Therefore, inter-mating among selected segregants followed by recombination breeding in an advanced generation might be advocated for improvement of the studied traits under salinity.