Pattern analysis of international sorghum multi-environment trials for grain-yield adaptation

 Pattern analysis, which consists of joint and complementary use of classification and ordination techniques, was applied to grain-yield data of 12 sorghum genotypes in 25 environments to identify the grouping of genotypes and environments. The 12 genotypes represented a wide geographical origin, different genetic diversity, and three photoperiod-sensitive classes. The 25 environments represented a super population of widely different environments covering latitudes from 20°S to 45°N. The knowledge of environmental and genotype grouping helped reveal several patterns of genotype×environment (GE) interaction. The existence of two mega-environments – African and Asian – was indicated. Within these mega-environments, several subgroups were further discernible. The Asian-type subgroups of environments tended to be closer to one another, suggesting that they discriminated genotypes similarly. By contrast, the African-type sub-groups of environments were more divergent. Differential genotype adaptation patterns existed in the two mega-environments. The repeatability of the GE patterns seen in this multi-environmental trial, however, needs to be established over time. Received: 4 April 1997 / Accepted: 6 October 1997