Heterosis and combining ability studies under artificial epiphytotic condition for yield and its related traits in Indian mustard

Abstract

The performance of Indian mustard genotypes for eleven morpho-physiological traits was assessed. Genotypes (lines) having white rust resistance viz., BioYSR, Donskaja, Heera and Basanti, were crossed with genotypes (testers) having high per se performance for yield viz., Varuna, Kranti, RH749 and Giriraj in the line × tester fashion. The analysis of variance revealed significant mean sum of squares due to crosses for all traits. All traits, except area under disease progression curve and daysto 50% flowering, showed both, additive and a predominance of non-additive gene action. Results suggested that heterosis breeding would lead to good result. All traits had lower levels of narrow sense heritability, as well. Predominance of non-additive gene action coupled with low heritability suggested that, selection should be practised once plant reach sufficient levels of homozygosity. Single seed descent method with large F2 and diallel selective mating design would be preferable for obtaining superior pure lines. Additionally, all lines showed significant desirable general combining ability for disease resistance. Varuna × BioYSR was the only cross that showed significant heterosis for yield over national check, Kranti. It also revealed significant heterobeltiosis for: seeds per siliqua, number of primary branches, days to 50% flowering, AUDPC and days to maturity. This potential hybrid can be deployed with the help of cytoplasmic-genetic male sterility, or it can be utilised to obtain superior purelines through conventional breeding methods.