Two-way pattern analysis of a large data set to evaluate genotypic adaptation

A method for the analysis of genotype x environment interaction in large data sets is presented and applied to yield data for 49 wheat cultivars grown in each of 63 international environments. Pattern analysis using numerical classification defined separately groups of cultivars and groups of environments, based on similarities in yield performance. The group structure for cultivars was interpreted in terms of similarities and differences in cultivar mean yield and/or cultivar yield response patterns across environments. In addition, the cultivar groups reflected differences in genetical and selectional origin. Environment groups largely reflected differences in the average mean yield of the set of cultivars, but some groups showed differences in response patterns related to differential rust incidence