PATTERN-ANALYSIS OF INTERNATIONAL SORGHUM MULTI-ENVIRONMENT TRIALS FOR GRAIN-YIELD ADAPTATION

Pattern analysis, which consists of joint and complementary use of cla ssification and ordination techniques, was applied to grain-yield data of 12 sorghum genotypes in 25 environments to identify the grouping o f genotypes and environments. The 12 genotypes represented a wide geog raphical origin, different genetic diversity, and three photoperiod-se nsitive classes. The 25 environments represented a super population of widely different environments covering latitudes from 20 degrees S to 45 degrees N. The knowledge of environmental and genotype grouping he lped reveal several patterns of genotype x environment (CE) interactio n. The existence of two mega-environments - African and Asian - was in dicated. Within these mega-environments, several subgroups were furthe r discernible. The Asian-type subgroups of environments tended to be c loser to one another, suggesting that they discriminated genotypes sim ilarly. By contrast, the African-type sub-groups of environments were more divergent. Differential genotype adaptation patterns existed in t he two mega-environments. The repeatability of the GE patterns seen in this multi-environmental trial, however, needs to be established over time.