Investigate of physiological and morphological parameters that can be utilization in the determination of heat stress tolerance in durum wheats (Triticum durum Desf.)

The Southeastern Anatolia Region, despite having a suitable ecology for durum wheat, has experienced significant losses in the yield and quality due to various stress factors. One of these stress factors is high temperature stress and it causes serious losses during grain filling.In this study, some physiological and morphological parameters, which can be easily and quickly measured, were examined in durum wheat breeding for resistance to heat stress. To this and, thirteen of durum wheat genotypes including landraces were used. Trial were conducted in irrigated conditions according to randomized blocks split plots experimental design with 3 replications as a normal and a late planting time at the GAP International Agricultural Research and Training Center trial field. Drought stress was eliminated with irrigation and heat stress was formed with late sowing.In the stressful conditions formed with late sowing, the grain yield, biological yield, thousand kernel weight and spike number per unit area decreased and the grain filling period shortened. According to heat sensitivity index (HSI), calculated over grain yield, Fırat-93 and Diyarbakir-81 has become tolerant with values between 0-0.5; Ç-1252, Fuatbey-2000, Özberk, Sarıçanak-98, Şahinbey, Zühre has become moderately tolerant with HIS values between 0.5-1 and Svevo, Şölen, Omrabi, Sorgül, Bağacak has become sensitive with values greater than 1.Physiological properties of canopy temperature (CT) and chlorophyll content (SPAD) was measured at the heading, flowering and milk stage. While canopy temperature (CT) was related with SHI in only heading in the stressful conditions it was unrelated with grain yield in both planting times. All of the SPAD measurements were related with grain yield in the normal planting, but it was only significant heading SPAD measurement in the late planting. Waxiness and leaf erectness can be used as a powerful selection criterions to improve stable and heat tolerant wheat genotypes due to their relations with grain yield at both conditions.