Vol. 17 No. 2
Combining ability and heterosis studies for grain yield in rice (Oryza sativa L.)
Author(s): Y.C. MOHAN, L. KRISHNA, T.V. SINGH, Ch. DAMODAR RAJU, T.K. BABU, N.R.G. VARMA AND M.V. RAMANA
Abstract: Thirty six F1s along with the parents (B and R lines) and standard checks viz., RNR 15048 and PA 6444 were evaluated for grain yield and related yield attributing traits to assess combining ability and heterotic estimates in rice. The analysis of variance divulges that for parents, hybrids and parent vs hybrids were highly significant in all the traits barring spikelet fertility for parents, effective bearing tillers and number of grains per panicle for crosses. Predictability ratio and average degree of dominance values derived from gca and sca variances clearly mention that all the traits studied except effective bearing tillers were under control of genes having additive effects. The gca effects revealed that among the lines, RNR 17441, TP 29631 and TP 30011 whereas in testers, CMS 59A were recognized as good general combiner with respect to grain yield and spikelet fertility. Similarly, the hybrids CMS 11A × CB 12593,CMS 59A × RNR 25843,CMS 23A × TP 29631, CMS 23A × IR 11A 334 and CMS 59A × RNR 25842 were found to be good specific combiner for grain yield. Significant positive standard heterosis over variety and hybrid check was recorded in seven and six hybrids, respectively. Overall data disclose that hybrids viz., CMS 59A × RNR 25842, CMS 59A × RNR 25843 and CMS 23A × TP 29631 were identified as superior based on their sca, heterosis estimates and their parental gca effects besides good per se performance.
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