Studies on effects of terminal heat stress on yield stability, grain iron and zinc contents in wheat (Triticum aestivum L.)

Considering global warming as a major constraint of yield and quality, the present study accessed the impact of terminal heat stress on wheat yield stability and grain Fe and Zn content in wheat. Twenty-three wheat genotypes of CGIAR Research Program (CRP) and two check varieties, PBW343 and HD2967 were evaluated for grain yield stability and the Fe and Zn content under heat stress conditions at terminal stage. Stability measures indicated CRP7, CRP8, CRP33, CRP46, and CRP48 to be the most stable genotypes. Grain iron (Fe) and zinc (Zn) content showed a high degree of variation. Under normal sown conditions the Fe content varied from 20.47 ppm (HD2967) to 76.07 ppm (CRP7) while the Zn content varied from 25.17 ppm (HD2967) to 65.6 ppm (CRP48). Under the stress, variation in the Fe content was observed from 10.17 ppm (PBW343) to 43.93 ppm (CRP54) whereas the Zn content variation ranged from 20.33 ppm (CRP30) to 55.13 ppm (CRP48). The overall average content of Fe was reduced by 31.98 % and Zn by 5.91% under the heat stress indicating grain Fe content to be highly vulnerable to the terminal heat stress than the Zn content.