Using canopy temperature depression to select for yield potential of wheat in heat stressed environments
1997
Reynolds, M.P. | Nagarajan, S. | Razzaque, M.A. | Ageeb, O.A.A. (eds.)
The main objective of the study was to validate the use of canopy temperature depression (CTD) as a rapid early generation screening tool for heat tolerance in wheat. CTD was measured at hot sites in Mexico on F2 derived bulks (BULKS) and on recombinant inbred lines (RILs) derived from the same BULKS, using crosses of parents with different levels of heat tolerance. Results showed (i) CTD measured on BULKS in Mexico were significantly correlated with their average performance at 11 international sites, (ii) CTD was an excellent indicator of which BULKS produced heat tolerant inbred lines evaluated in Mexico, and (iii) CTD measured on RILs were highly significantly correlated with performance in Mexico. These results indicate the robustness of CTD as a selection trait, with potential application at early and intermediate stages of selection. In addition the genetic link between CTD and heat tolerance was demonstrated by showing their association in recombinant inbred lines. Measurements of photosynthesis and leaf conductance on F5 individual plants showed high heritabilities with measurements made on F5 derived F7 sister lines, as well as significant correlations with yield. Results suggest the potential of screening for quantitative traits on individual plants in early generation derived bulks. Genotype by environment interaction in hot wheat growing regions worldwide was tested by growing a set of 60 advanced lines (ALs) selected for heat tolerance in Mexico, at 15 international sites. The results indicate Tlaltizapan to be the best site in Mexico for predicting yields in Bangladesh, NW India, Sudan and Nigeria, and indicated NW India as a good site for heat tolerance screening.
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