Effects of high temperature during anthesis and grain filling on physiological characteristics of winter wheat cultivars

Abstract Due to climate change, multiple heat events are expected to be an additional limiting factor that will adversely affect wheat production. The study aimed to analyze the physiological response to heat stress in four winter wheat cultivars at different physiological stages under greenhouse conditions during 2019. The net photosynthetic rate, stomatal conductance, chlorophyll index, maximum quantum efficiency of photosystem II, fructose, glucose and sucrose content, grain yield per plant, grain weight and number of grains per plant were analyzed in wheat cultivars under short periods of heat stress at anthesis and mid‐grain filling, and combined stress at anthesis and mid‐grain filling. The results of the study indicated that heat stress modified the photosynthesis‐related and grain yield–related traits. Moreover, heat stress caused a decrease of sucrose content, while fructose and glucose content increased. Heat stress had more pronounced effects on the photosynthetic parameters and grain yield during grain filling than during anthesis. A significant variation observed among cultivar responses to the negative impact of heat stress highlighted the fact that cultivars Pobeda and Gladius were more tolerant than Renesansa and Simonida. Different cultivar reactions to heat stress during anthesis and grain filling indicated the need to conduct further studies with wheat cultivars of different origin in order to identify additional sources of tolerance.