02435naa a2200169 a 450000100080000000500110000800800410001910000160006024501060007626000090018252019480019165000140213965300280215370000200218170000190220177300450222012797392025-02-28       1976    bl uuuu     u00u1 u    #d1 aBYTH, D. E.  aTwo-way pattern analysis of a large data set to evaluate genotypic adaptation.h[electronic resource]  c1976  aA 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. The cultivar and environment groupings were superimposed on the original data matrix, reducing it to a 100 cell 10 x 10 matrix of group means. The efficiency of the reduction process was measured by comparing the variation retained in the reduced matrix with the total variation available in the original data matrix. Further study of the information retained by the 10 x 10 matrix was made by plotting cultivar group yields and cultivar group interaction effects against an environment group index. The reduction process achieved a size reduction of 97 per cent with the loss of only 18 per cent of the total variation available in the original unreduced matrix. Partitioning was used to identify the nature of this loss. However, the information retained in the reduced matrix maintained the integrity of the cultivar group yield response patterns and allowed comparison of cultivars on a group basis across the environmental range. This reduced greatly the complexity of analysis of cultivar performance and interaction patterns, and simplified the identification and specification of differences in response among cultivars.  aGenótipo  aAdaptação genotípica1 aEISEMANN, R. L.1 aLACY, I. H. de  tHereditygv. 37, n. 2, p. 215-230, 1976.