Heat stability of winter wheat depends on cultivars, timing and protective methods

Heat stress negatively affects wheat production in many regions of the world. At present, sensitivity to heat stress remains one of the least understood aspects of wheat genetics and breeding, and measures for preventing heat stress are understudied. In this study, we used three cultivars of winter wheat (GY2018, SL02-1 and SY20) to evaluate the effect of heat stress at different days after anthesis (DAA) on yield and quality. Heat stability of the cultivars were analyzed and evaluated for the effects of two kinds of regulators on wheat under heat stress conditions. Heat treatment at 7 DAA led to the most substantial reduction in yield while GY2018 had the best heat stability with respect to yield, and demonstrated the most positive effects on several quality traits including protein content, sedimentation volume and glutenin and gliadin contents. Heat treatment at 14 DAA had the least reduction in yield, while SY20 had the best heat stability with respect to yield and heat treatment had minimal effects on quality. Heat treatment at 21 DAA had only a limited effect on yield, while SL02-1 had the best heat stability with respect to yield, but it showed the most negative effects on quality. Stable time at 14 DAA and protein content at 21 DAA can be used as indicators for detecting the stability of quality under heat stress. Among the three studied cultivars, SY20 was the most sensitive to heat stress with the stable time decreasing from 26.4 to 9.1 min, a higher sedimentation volume at 7 DAA, and a lower γ-gliadin content which increased 2.4-fold under high-temperature treatment. The addition of various regulators had different effects: potassium dihydrogen phosphate (KDP) was more protective of yield with heat stress at 7 DAA, while Duntianbao (DTB) had better effects on quality with heat stress at 21 DAA.