Differential Adaptation of CIMMYT Bread Wheat to Global High Temperature Environments

Abstract

A good understanding of the target environment and the extent of genotype × environment (G × E) interaction is essential for all cereal breeding programs. Differential adaptation of bread wheat (Triticum aestivum L.) to various heat‐stressed environments around the world was analyzed by cumulative cluster analysis of locations and genotypes in 9 yr of CIMMYT's High Temperature Wheat Yield Trial (HTWYT). The grouping pattern of yield‐testing environments could largely be explained by the temperature at different growth stages and relative humidity at booting. A clear distinction was observed between sites with heat stress and more temperate locations, and the heat‐stressed environments could be grouped into sites experiencing high temperature throughout the season and sites with more specific terminal heat stress. In addition, dry and humid heat‐stressed locations tended to differentiate. The ability of individual locations to predict yield in different heat‐stressed environments was studied by the shifted multiplicative model (SHMM) site clustering method, and identified locations like Tandojam (Pakistan), which associated well with both heat‐stressed and temperate environments. The good ability of the January planting date in Ciudad Obregon (Mexico) to predict yield performance in many heat‐stressed environments was also confirmed. Genotypes grouped according to their relative performance in different locations, and specific adaptation to the various types of heat‐stressed environments was apparent. However, a subset of genotypes was identified that showed stable, and high yield across all types of environments, both heat‐stressed and temperate.