Characterization of Heat‐ and Drought‐Stress Tolerance in High‐Yielding Spring Wheat

Abstract

ABSTRACTUnpredictable temperature and rainfall patterns have increased global concerns about sustaining current levels of wheat (Triticum aestivum L.) production. Although many international breeding programs are focused on developing high‐temperature and drought‐stress tolerant wheat varieties, changing weather patterns has increased the need to develop widely adaptable wheat varieties. Research was conducted to identify the potential resilience of spring wheat lines to heat and drought stresses and to define phenotypic and physiological traits that are associated with stress adaptation. A trial consisting of 28 newly developed spring wheat lines and two checks was tested under optimal, heat‐, and drought‐stress conditions for 2 yr in Ciudad Obregon, Mexico. Phenotypic and physiological data was recorded in all environments. While a 50% reduction in mean grain yield was observed due to heat and drought stress, two distinct groups of stress‐adapted lines were identified. In the first group, the wheat lines performed well in either heat‐ or drought‐stress environment, and in the second group there were lines that produced high yields in optimal conditions and maintained higher yields under high temperature and drought stresses, with a yield advantage of 7 to 8% above the check varieties in the trial. Of the traits studied, grain weight per tiller (GWT) had significant influence in stress adaptation. Although heat‐ and drought‐stress tolerance may involve different mechanisms, the results of this study show that it is possible to develop high‐yielding heat‐ and drought‐tolerant wheat varieties.