Linked digenic epistasis in the inheritance of tillering and yielding ability in a cross of wheat

Abstract

The nature of genetic variation in an intervarietal cross ('WG 377' × 'Sonalika') of bread wheat (Triticum aestivum L. em Thell.) was determined for grain yield and tillers per plant by analyzing 21 generation means and 36 family variances. For both traits, duplicate epistasis of linked loci in the pairs and gene dispersion was observed through the analysis of 21 generation means. The analysis of generation variances further suggested repulsion phase linkages for the gene pairs. The additive genetic component was significant for both traits in each of the analyses. Prevalence of gene dispersion suggested the possibility of high transgressive segregation. However, the task of exploiting additive genetic variation would be difficult because of duplicate epistasis and repulsion phase linkages. Considering these results a breeding procedure like biparental mating among a large number of superior F2 plants which encourages crossing-over is suggested.Key words: Triticum, linked epistasis, quantitative traits, additive effects, tillering.