Heat stress tolerance of wheat (Triticum aestivum L.) at different developmental stages

Abstract

The objective of this study was to analyse the effect of heat stress on morphological and physiological traits of 12 wheat cultivars (10 cultivars from Serbia, cv. Gladius as a heat tolerant and cv. Paragon as aheat susceptible check) at flowering and grain filling stages. The experiment was conducted at the Aarhus University in Denmark using Dynapheno phenotyping facilities. Four sets of the cultivars with five replications were denoted as control treatment plants (T1), heatstressed plants at the flowering stage (T2), heat-stressed plants at the grain filling stage (T 3) and heat-stressed plants at the both stages (T4). The following measurements were performed on flag leaves one day before heat stress started and on the first, the third, the fifth and the seventh day of heat stress: chlorophyll content using SPAD chlorophyll meter, photosynthetic parameters using MiniPAM II photosynthesis yield analyzer and leaf temperature with infrared thermometer. Four cultivars were subjected to further CIRAS-2 measurements, as well as carbohydrate and chlorophyil analysis. All measured values significantly decreased after the third, fifth and seventh day after heat stress at flowering, heat stress at grain filling and especially after the double stress. The heat stress affected more severely the wheat cultivars during grain filling stage in comparison to the stress during flowing time, while the combined stress at both stages was the most detrimental. The results enabled identification of the genotypes with promising level of heat tolerance, which could be used in breeding process for further improvement of heat tolerance in wheat.