Genotype × Environment Interaction For Protein Content and Grain Weight in 2-Row and 6-Row Barleys

A set of 24 elite barley varieties, comprising thirteen 2-row and eleven 6-row types were evaluated under two sowing dates and two nitrogen levels over a period of two years for protein per cent and 100-grain weight. Delayed sowing and application of nitrogen increased per cent protein consistently. Delayed sowing decreased the mean grain weight in both the seasons, whereas, application of N decreased it in one year only. The variety × nitrogen interaction was significant for per cent protein in both years and for 100 grain weight in one year. The variety × sowing date interaction was significant for 100-grain weight in one year. The second order interactions were not significant. Regression analysis over the environments suggested that both linear and non-linear components were significant. However, linear component for protein and non-linear for grain weight made major contributions to V xE interactions. For protein per cent, the relationship between mean level and linear response differed in 2-row and 6-row groups. in the 2-row group, varieties with higher protein per cent were less responsive whereas such an association was absent in 6-row group. There was no significant unfavourable association between protein content and grain weight in both 2-row and 6-row groups for both mean level and linear response. K 1012, DL 150 and Notch-2 had consistently high protein per cent in different environments and varieties K 1012, DL 150 (2-row types) and DL 219 (6-row) had higher grain weight and protein content per grain.