The heat stress restricts the yield and quality parameters of durum wheat. The objective of this study was to examine some physiological and morphological parameters, which can be easily and quickly measured and resistance to heat stress in durum wheat breeding program. The study was conducted by using a total of 13 of durum wheat genotypes. Trials were conducted in irrigated conditions according to randomised complete blocks design with split plots and 3 replications as normal and late planting time. Drought stress was eliminated with irrigation and heat stress was formed with late planting time. According to heat susceptibility index (HSI), calculated over grain yield, Firat-93, Diyarbakir-81 and Sariçanak-98 varieties showed tolerant/medium tolerant. Low canopy temperature (CT), leaf erectness and waxiness were related with heat tolerance. Although SPAD readings did not relate heat tolerance, it can be used to select the genotypes which have high yield potential. Moreover, the GGE biplot indicated that PCA 1 and PCA 2 axes (principal component) were significant as P < 0.01 and supplied to 76.29% of the complete GT (Genotype × Trait) interaction. When the parameters were analysed for genotypes, four different groups were formed, in which grain filling speed (GFS) formed the first group, chlorophyll content (SPAD), waxiness (WXN), flag leaf steepness (FLS), grain yield (GY) formed the second group, canopy temperature depression (CTD) formed the third group and grain filing duration (GFD) formed in the fourth group. The traits, which located in same group, related to each other. On the other hand, GGE biplot showed that planting times took place in different mega-environments and some cultivars were related with normal planting time, while some others genotypes were related with late planting time. Statistical results indicated that GGE biplot are informative techniques to compare varieties with planting time and traits to discover general stability, adaptation pattern for practical recommendations
