JIA-2018-09

1983 TAO Zhi-qiang et al. Journal of Integrative Agriculture 2018, 17(9): 1979–1990 were significant at P <0.01 or P <0.05; however, the effect of year and the interaction effect of year, cultivar, temperature, and zinc fertilizer were not significant (Table 1). Zinc fertilizer had the largest contribution to total variation of grain yield and grain weight, followed by temperature, cultivar, cultivar×zinc fertilizer, temperature×zinc fertilizer, cultivar×temperature, and cultivar×temperature×zinc fertilizer (Table 2). Zinc fertilizer had a significant effect on grain yield and grain weight in wheat under HTS. Comparisons between the Zn0 treatment under HTS and the Zn0 treatment grown at ambient temperature of their respective cultivars in both experimental years revealed reductions in grain yield by about 26% in GY2018 and 13% in ZM8. Grain weight was reduced by about 14% in GY2018 and 15% in ZM8. In contrast, in Zn15, Zn30, and Zn45 treatments under HTS compared to their respective zinc treatment levels that were not under HTS, grain yield was reduced by 6.7–12.1% and grain weight by 8.0–13.9% in GY2018 in both years. For ZM8, the same treatment comparisons were reduced by 3.8–9.6% in yield and 5.4–11.8% in weight in both years (Figs. 1 and 2). 3.2. Effects of zinc fertilizer and high temperature stress on NR activity HTS reduced NR activity in both cultivars; whereas, zinc Table 1 Results of the ANOVA of effects of cultivar (C), temperature (T), zinc fertilizer (Zn), and year (Y) on wheat grain yield, grain weight, nitrate reductase activity (NR), glutamine synthetase activity (GS), grain protein content, grain protein yield, and contents of albumin, globulin, gliadin, and glutenin in 2016 and 2017 Source Grain yield Grain weight NR GS Grain protein content Grain protein yield Albumin Globulin Gliadin Glutenin C ** ** ** ** ** ** ** ** ** ** T ** ** ** ** ** ** ** ** * ** Zn ** ** ** ns ** ** ** ** ** ** Y ns ns ns ns ns ns ns ns ns ns C×T ** ** ** ** ** ns ** ** ns ** C×Zn ** ** ** ns ** ** ** ** ** ** C×Y ns ns ns ns ns ns ns ns ns ns T×Zn ** ** ** ns ** ** ** ** ns ** T×Y ns ns ns ns ns ns ns ns ns ns Zn×Y ns ns ns ns ns ns ns ns ns ns C×T×Zn ** * ** ns ** ** ** ** ns ** C×T×Y ns ns ns ns ns ns ns ns ns ns C×Zn×Y ns ns ns ns ns ns ns ns ns ns T×Zn×Y ns ns ns ns ns ns ns ns ns ns C×T×Zn×Y ns ns ns ns ns ns ns ns ns ns * and ** , significance at P ≤0.05 and P ≤0.01, respectively; ns, not significant. Table 2 Results of factor contribution analysis (Eta 2 ) of cultivar (C), temperature (T), zinc fertilizer (Zn), and year (Y) on wheat grain yield, grain weight, nitrate reductase activity (NR), glutamine synthetase activity (GS), grain protein content, grain protein yield, and contents of albumin, globulin, gliadin, and glutenin in 2016 and 2017 Source Grain yield Grain weight NR GS Grain protein content Grain protein yield Albumin Globulin Gliadin Glutenin C 0.886 0.814 0.414 0.868 0.820 0.620 0.993 0.981 0.913 0.996 T 0.945 0.914 0.917 0.913 0.824 0.805 0.081 0.807 0.663 0.679 Zn 0.966 0.948 0.980 0.138 0.981 0.973 0.700 0.887 0.739 0.829 Y 0.024 0.007 0.014 0 0 0 0.011 0.001 0.000 0.001 C×T 0.368 0 .001 0.198 0.366 0.286 0.010 0 0.216 0.160 0.143 C×Zn 0.856 0.654 0.330 0.049 0.927 0.814 0.185 0.544 0.434 0.387 C×Y 0 .007 0.002 0.002 0 0 0 0.002 0 0.002 0 T×Zn 0.756 0.351 0.608 0.017 0.266 0.386 0.058 0.319 0.022 0.275 T×Y 0.002 0.001 0.000 0 0 0 0.002 0 0 0.001 Zn×Y 0.004 0.005 0.008 0 0.001 0 0.004 0.011 0.008 0.004 C×T×Zn 0.320 0.134 0.338 0.030 0.189 0.169 0.030 0.473 0.167 0.333 C×T×Y 0.019 0 0.005 0 0 0 0 0.005 0 0.001 C×Zn×Y 0.004 0.007 0.006 0 0.004 0 0.004 0.004 0.009 0.010 T×Zn×Y 0.015 0.001 0.002 0 0.009 0 0.004 0.020 0.003 0.002 C×T×Zn×Y 0.017 0.003 0.002 0 0.006 0 0.004 0.021 0.004 0.004