Global climate change poses a significant threat to wheat (Triticum aestivum L.) production due to rising temperatures. This study aimed to investigate the impact of high temperatures on wheat yield, thousand kernel weight (TKW), colour, and protein composition to inform breeding strategies for heat tolerance. Two field experiments were conducted: one at three locations in Australia (Horsham, (Vic) Narrabri, (NSW) and Merredin, (W.A.)) in 2019, involving two wheat varieties (Berkut (high-heat-tolerant) and Sokoll (medium-heat-tolerant)) sown at normal (TOS1) and late (TOS2) sowing times; and a second experiment at Narrabri in 2019 and 2020, involving three wheat varieties (Cobra (heat-sensitive), Flanker (high-heat-tolerant) and Suntop (medium-heat-tolerant)) sown at normal (TOS1) and late (TOS2) sowing times. There were reductions in yield and TKW under high temperatures (p < 0.05), particularly in late sowing conditions. The glutenin/gliadin ratio decreased, affecting dough strength and elasticity, especially at Merredin. Heat-tolerant varieties like Flanker and Suntop maintained protein quality, with an increase in the glutenin/gliadin ratio, under high temperature. These findings highlight the necessity for breeding heat-tolerant wheat varieties that can sustain both yield and quality. Future research should focus on genetic traits for heat tolerance, advanced molecular techniques, and interdisciplinary approaches to ensure sustainable wheat production in a changing climate.

Cotton, as a globally important economic crop, has high nitrogen (N) demand but low N uptake and N utilization efficiency (NUE). Optimizing N input by improving NUE represents a critical challenge for sustainable cotton production. We applied six N levels (0, 0.04, 0.4, 1, 4, 8 mM Ca(NO3)2, designated as N0, N0.04, N0.4, N1, N4, and N8, respectively) to examine their effects on morphology, biomass, nutrient absorption, and NUE at four treatment durations. Results showed that seedling growth and nutrient accumulation initially increased and subsequently decreased with increasing N levels. The optimal N ranges for seedling growth at 7, 14, 21 and 28 d were 0.4, 0.4–1, 1–4 and 4–8 mM Ca(NO3)2, respectively. Under optimal N, seedlings achieved maximum accumulations of N, P, K, and Ca (55.8, 8.8, 64.9, and 26.2 mg/plant at 28 d, respectively), while maintaining consistent N:P:K:Ca ratios of approximately 1:0.2:1.2:0.5 across seedling stage. Under low N, nutrients were preferentially allocated to roots, promoting root growth. NUE exhibited positive correlations with root traits and nutrient proportion, whereas shoot traits showed positive associations with nutrient accumulation and shoot nutrient proportion. These findings provide a theoretical basis for scientific fertilization, and establish a theoretical foundation for understanding the physiological mechanisms of efficient N use in cotton.