Differential Adaptation of CIMMYT Bread Wheat to Global High Temperature Environments

Abstract

and lowland Bolivia and Paraguay) and lowland dry areas (e.g., central and peninsular India, Nigeria and A good understanding of the target environment and the extent of Sudan). The most important disease constraints are Helgenotype ϫ environment (G ϫ E) interaction is essential for all cereal breeding programs. Differential adaptation of bread wheat (Triticum minthosporium Leaf Blight (HLB) caused by Bipolaris aestivum L.) to various heat-stressed environments around the world sorokiniana (Sacc.) Shoemaker and leaf rust caused was analyzed by cumulative cluster analysis of locations and genotypes by Puccinia triticina Eriks. ϭ P. recondita Roberge ex in 9 yr of CIMMYT's High Temperature Wheat Yield Trial (HTWYT). Desmaz. f. sp. tritici (Eriks. & E. Henn.) D.M. Hender-The grouping pattern of yield-testing environments could largely be son (Dubin and van Ginkel, 1990). HLB is mostly conexplained by the temperature at different growth stages and relative fined to the humid tropical areas, whereas leaf rust is humidity at booting. A clear distinction was observed between sites important to all areas (Dubin and Rajaram 1996). Adwith heat stress and more temperate locations, and the heat-stressed vanced breeding lines targeted for heat-stressed areas environments could be grouped into sites experiencing high temperaare annually distributed to international cooperators ture throughout the season and sites with more specific terminal heat through the HTWYT. stress. In addition, dry and humid heat-stressed locations tended to differentiate. The ability of individual locations to predict yield in Crop environments can be characterized in terms of different heat-stressed environments was studied by the shifted multi-the way they influence the relative performance or rank plicative model (SHMM) site clustering method, and identified locaof genotypes. One useful method for this purpose is tions like Tandojam (Pakistan), which associated well with both heatthe SHMM, which identifies subsets of locations with stressed and temperate environments. The good ability of the January minimal internal crossover interaction (Cornelius et al., planting date in Ciudad Obregon (Mexico) to predict yield perfor-1992; Crossa et al., 1993). However, this method requires mance in many heat-stressed environments was also confirmed. Genobalanced data sets where the same locations and genotypes grouped according to their relative performance in different types are repeated over years. To analyze multienvironlocations, and specific adaptation to the various types of heat-stressed ment trials where the composition of genotypes changes environments was apparent. However, a subset of genotypes was idenfrom year to year, DeLacy et al. (1996b) developed a tified that showed stable, and high yield across all types of environments, both heat-stressed and temperate.

Crops that feed the world 10. Past successes and future challenges to the role played by wheat in global food security

“…For example, analysis of CIMMYT international nursery data shows clear and steady progress in the performance of both bread and durum wheat under drought stress (Ammar et al 2008;Braun et al 2010). In addition, analysis of germplasm released by CIMMYT for hot, irrigated environments shows significant progress, with many of the lines that perform well at the hottest sites also expressing good yield potential under more temperate conditions (Lillemo et al 2005), an important consideration given typical year-to-year variation in temperature. Recent effort has focused on breeding for earlier maturing cultivars that escape terminal heat stress and encompass resistance to diseases associated with warm humid environments (Joshi et al 2011) as well as the highly virulent stem rust strains of the Ug99 lineage.…”

Spot blotch and terminal heat stress tolerance in south Asian spring wheat genotypes

“…Diversity for heat stress tolerance is well established (Al-Khatib and Paulsen, 1990;Reynolds, 1994;Lillemo et al, 2005). Spot blotch tolerance is not well known, and researchers have paid less attention to tolerance than to resistance.…”

Physiological Interventions in Breeding for Adaptation to Abiotic Stress

“…More recent and comprehensive analysis (Reynolds et al 1998). Cluster analysis was based on cross-over interaction of genotypes as described by Vargas et al (1998) using CIMMYT international nursery yield data indicated that main genotype clusters correspond to three main types of environment, viz., temperate, continuous heat stress and terminal heat stress, and confirmed relative humidity as an important factor determining G×E within some of these clusters (Lillemo et al 2005).…”