Genetic analysis of yield in a six-row and two-row varietal cross in barley–I. Genetics of yield and its primary components¹

Studies were conducted on the inheritance of quantitative characters in a barley cross, C138-2 (6-rowed) × E.B. 410 (2-rowed). A number of non-segregating (P₁, P₂ and F₁) and segregating generations (F₂, F₃, B₁, B₂, during 1961–62 and F₂, F₃, F₄, B₁, B₂, B₁₁, B₁₂, B₂₁, B₂₂ during 1962–63) were grown in randomised complete block design. Non-epistatic and epistatic models were fitted to the generation means to estimate the additive (d),dominance (h), additive × additive (i), additive × dominance (j) and dominance × dominance (l) gene effects in respect of the yield and three of its primary components, viz., tillers per plant, grains per ear and 100-grain weight. Inferences were also drawn with regard to the linkage relationship of the genes.

Considerable additive effects were observed for yield per plant and number of grains per ear while these effects appeared to be unimportant for number of tillers per plant and 100-grain weight. More than one non-additive effect was found important for each of the four characters studied in each of the years. Linkage was found to cause disturbance in the estimate of these components in all the cases. Genes controlling these characters were found to be in a dispersed or partially-dispersed phase. It was concluded that improvement in yield and number of grains per ear could be brought about by the exploitation of additive effects of the genes. This could be achieved by intermating selected individuals in the segregating generations. The present material appeared to be unsatisfactory for improvement in respect of 100-grain weight and number of tillers per plant.

The non-additive effects were found to be more variable over the seasons as compared to additive effects. More than one seasons’ data are therefore necessary for arriving at a valid interpretation of the various gene effects.