Determination of the tolerance of physiological, morphological, and yield parameters of landrace durum wheat (Triticum durum Desf.) to high-temperature stress

In the South-eastern Anatolia Region, where the climate is favorable to cultivation for durum wheat, there have been notable reductions in both yield and quality due to biotic and abiotic stress factors in the region. Primary one of these stresses is high-temperature stress. High-temperature stress, specifically during the late flowering stage and early grain filling stage, results in substantial reductions in both crop yield and quality. In this study, several practical, easily and rapidly quantifiable physiological, morphological, and yield-related parameters that may be used in durum wheat improvement programs in the region for high-temperature stress tolerance were investigated. Ninety landrace durum genotypes and 4 standard cultivars were used. The study was carried out at GAP (South-eastern Anatolia Project) International Agricultural Research and Training Centre in an air conditioning room according to an augmented design under optimum conditions and stressful conditions where high-temperature stress was created. Compared to optimum conditions, there were reductions in flag leaf greening time by 20%, days to maturity by 7%, spike length by 10%, peduncle length by 18%, grain filling time by 23%, number of spikelets on the spike by 12%, number of grains on the spike by 39%, and thousand-kernel weight by 33%, while grain filling rate increased under high-temperature stress conditions. The genotypes 82, 83, 87, 88, 99, and 103 and the standard varieties Artuklu and Sümerli prevailed in both optimum and stress conditions. The fact that leaf erectness, flag leaf greening time, grain filling time, and leaf chlorophyll content among morphological and physiological characteristics had a significant correlation with yield components under both conditions indicates that these characteristics can be used as selection criteria for tolerance to stressful conditions in the region.