Triple test cross progenies arising from F2 of three crosses, namely, C164 x EB1556 BG25 x NP21 and BH15 x RD103, were used for investigating their interactions with macro- and micro-environments for number of days to heading, plant height, number of tillers per plant, ear length, number of grains per ear, 100-grain weight and yield per plant in barley. The analysis indicated, in general, that the additive component of genetic variance was more sensitive to macro-environment than non-additive components. In order to have a more precise estimate of this component, an experiment repeated over a larger number of locations and years would be desirable. The ‘j and l’type of epistasis showed sensitivity equal to the dominance components in response to the change of soil conditions. Covariances between family means and variances were used to detect the interactions of genetic components with the micro-environmental differences. The additive and the dominance components showed sensitivity to microenvironmental changes and were not differentially affected by the adverse soil condition compared with normal soil. The additive gene effects were relatively more sensitive, indicating the probable superiority of heterozygotes over the corresponding homozygotes with regard to stability.

Amongst the three populations, the population resulting from BH15 x RD103 was found to be most sensitive. Although the genotype x environment interaction for a character was population-specific, number of grains per ear and yield per plant were invariably the most sensitive.