Physiological traits for evaluating heat‐tolerance of Australian spring wheat cultivars at elevated CO₂

Abstract

High temperatures and increasing CO2 concentrations are a major threat to global wheat (Triticum aestivum L.) production, demanding the development of heat‐tolerant wheat cultivars. Plant physiological traits are potential surrogates for evaluating genetic variation for crop stress tolerance. This research evaluated 23 Australian wheat cultivars and two breeding lines for heat‐tolerance by characterising the associated physiological traits. The interactive effects of heat‐stress and elevated CO2 were studied under controlled greenhouse conditions and delayed sowing in the field with exposure to higher temperature. Physiological changes, pollen viability and grain yield were assessed. A significant correlation was observed between physiological and agronomical traits under high temperature at 35°C and elevated CO2 at 800 µl L−1, providing evidence of adaptation to high temperatures in some genotypes. Variation in stomatal conductance, transpiration rate, canopy temperature, leaf chlorophyll and photosynthesis were associated with maintenance of pollen viability and grain yield at high temperatures. Of the genotypes assessed, seven were classified as heat tolerant at both ambient and elevated CO2 and nine were heat susceptible while the remainder showed a variable response to CO2 at high temperatures. Field data confirmed the heat responses of the most heat‐tolerant and susceptible genotypes. The heat tolerant genotypes identified are candidates for further breeding and selection to improve adaptation to a changing climate.

Phenotyping wild potatoes (Solanum Sect. Petota) for photosynthesis associated traits under heat stress.

“…These ndings also agrees with the ndings of (Berry and Bjorkman, 1980) who reported that transpiration is temperature dependent. This behavior is also in agreement with (Ullah et al, 2020;Bokshi et al, 2022), who observed an increase in transpiration rate under HS in tomato genotypes. Overall, S. chacoense recorded a decrease in transpiration rate, which shows the intraspecies differences between genotypes in transpiration may be due to their differences in morphology.…”

Traits Related to Heat Stress in Phaseolus Species

“…According to the results of their works on faba bean (Vicia faba L.), Bishop, Potts [43] reported some explanation of the reduction of yield as a result of the long exposure of the plants to the heat stress. They stated that flowers were the most affected part of the plant under heat stress conditions, due to reduced pollen viability and germinability in many crop plants [44][45][46][47][48][49]. Many researchers demonstrated that although the male and female reproductive organs of the common bean were the most sensitive to heat stress, the male organs suffered more damage [20,50].…”

UAV-Based Multi-Temporal Thermal Imaging to Evaluate Wheat Drought Resistance in Different Deficit Irrigation Regimes

“…In contrast, the transpiration water of the crops was sufficient in W2 due to the irrigation during the flowering stage, and thus canopy temperature differences among varieties were small [75,84]. Recent studies also highlighted that no significant or weak correlation between canopy temperature and physiological traits, e.g., leaf chlorophyll content, LAI and Pn, under normal or mild water stress [85][86][87]. In this study, these results suggest that canopy temperature alone could not reflect the physiological changes of crops well under mild water stress.…”