Analysis of chlorophyll fluorescence parameters as predictors of biomass accumulation and tolerance to heat and drought stress of wheat (Triticum aestivum) plants

Agricultural technologies aimed at increasing yields require the development of highly productive and stress-tolerant cultivars. Phenotyping can significantly accelerate breeding; however, no reliable markers have been identified to select the most promising cultivars at an early stage. In this work, we determined the light-induced dynamic of chlorophyll fluorescence (ChlF) parameters in young seedlings of 10 wheat (Triticum aestivum L.) cultivars and evaluated potency of these parameters as predictors of biomass accumulation and stress tolerance. Dry matter accumulation positively correlated with the effective quantum efficiency of photosystem II (Phi(PSIIef)) and negatively correlated with the half-time of Phi(PSIIef) reaching (t(1/2)(Phi(PSIIef))). There was a highly significant correlation between t(1/2)(Phi(PSIIef)) and dry matter accumulation with increasing prediction period. Short-term heating and drought caused an inhibition of biomass accumulation and photosynthetic activity depending on the stressor intensity. The positive correlation between the Phi(PSII) dark level (Phi(PSIId)) in young seedlings and tolerance to a rapidly increasing short-term stressor (heating) was shown. In the case of a long-term stressor (drought), we revealed a strong negative relationship between tolerance and the level of non-photochemical fluorescence quenching (NPQ). In general, the results show the potency of the ChlF parameters of young seedlings as predictors of biomass accumulation and stress tolerance.