Genotype × environment interaction on grain yield and yield components in bread wheat

Genotype by environment (Location) interaction (GEI) is essential for identifying environment-specific and widely adapted genotypes of wheat. The experiment was carried out across five locations (Shyampur and Godagari under Rajshahi district, Nachole at Chapainawabganj, Sapahar at Naogaon and Lalpur at Natore district in north-west Bangladesh) to assess GEI effects on grain yield and its components and to identify high yielding and stable genotypes of wheat for grain yield in the year of 2020-21. Combined analyses of variance for G and GEI were significant for almost all traits. Significant GEI suggested that the performance of genotypes was not consistent across locations, revealing strong influence of environments on the expression of phenotype for all traits. Average over five locations, genotypes G84 (3647 kg ha-1) and G76 (3576 kg ha-1) exhibited maximum values for grain yield and also produced similar tillers m-2 (SPM) and grains spike-1 (GPS) where difference between them was statistically insignificant thus appeared as leading genotypes for yield and production traits. Again, the genotypes G84 and G76 produced statistically insignificant maximum yield in all locations indicating that they are high yielding and wide adapted genotypes. The genotype G80 produced insignificant yield and other yield traits with G76 and G84 across the locations indicating its wide adaptability. However, G26, G69 and G77 with higher grain yield in Shyampur, G53 and G59 in Godagari ,G20 in Lalpur, G3 in Nachole and G8 in Sapahar proved their specific adaptability in particular locations. Among locations, Shyampur and Godagari were identified as highly productive locations in terms of grain yield and positive environmental index. Correlation analysis showed that grain yield had strong positive association with spikes m-2 (r = 0.92**), grains spike-1 (r = 0.72**) and TGW (r = 0.89**). On the basis of mean grain yield and higher positive phenotypic index for SPM, GPS, TGW and GY, G76, the genotypes G84,G76 and G80 were found as high yielding genotypes and thus could be recommended as important breeding materials in upcoming specific breeding program for drought prone north-west part of Bangladesh.