STOMATA DIMENSION AND PHYSIOLOGICAL PARAMETERS IN DURUM WHEAT (TRITICUM DURUM L.) GENOTYPES UNDER RAINFED CONDITION

Heat stress and various precipitation regimes due to global climate change increase the importance of physiological studies in field crops. The relationship between stomatal behaviour and physiological parameters in plants is important in response to drought stress. The experiment was laid out to compare the stomata dimension and physiological parameters of advanced durum wheat genotypes under rainfed conditions. A total of 25 durum wheat genotypes were examined during the 2018-2019 growing cycles in the Edirne location in the Trakia region, Turkiye. The experiment was conducted in a randomized complete block design (RCBD) with four replications. Stoma area, perimeter, width and length were made on samples taken during the heading stage of the flag leaf. Plant height (PH), Chlorophyll content (SPAD), canopy temperature (CT) and normalized difference vegetation index (NDVI) were taken at heading stages. The results of variance analysis showed significant differences (p<0.01) among genotypes for stoma area, perimeters and width. According to stoma dimensions, the widest stomata were determined in G5 and G18 genotypes. Stomata number is an important parameter for drought tolerance and the highest stomata number was determined in G4 and G5 genotypes in the study. These genotypes may be more tolerant to drought due to the high number of stomata. Flag leaf area differed among genotypes. Genotypes G14, G1, G8 and G2 had higher FLA. The chlorophyll content is an important parameter for photosynthesis. The highest chlorophyll content was measured in G25, G23 and G19. Low canopy temperature is important for drought tolerance. The lowest canopy temperature was scaled by genotypes G15 and G9. Genotype G8 had a higher NDVI. It can be stated that these genotypes are more tolerant to drought than others. Different correlations were determined between stoma measurements and physiological parameters. A negative correlation was determined between NDVI and stomatal parameters in genotypes. The significant differences between genotypes showed the importance of stomatal characters for selection in adaptation to different environments. The adaptation of genotypes to different environments is determined by their physiological responses. Significant differences were determined between genotypes in the physiological parameters examined in the study, except for canopy temperature.