Knowledge about the extent of variability and the association among traits are of a high value for any breeding efforts. The objective of this investigation is to evaluate the agro-morphological traits in a set of durum wheat genotypes under supplemental irrigation and dry land conditions. Results showed that principal component (PC) analysis had grouped the measured traits into four main components that altogether accounted for 77% of the total variation under non-stressed condition and 87% under water-stressed condition. With regard to the first four PCs, peduncle length, agronomic score, grain yield, vigority, test weight, days to physiological maturity and thousand kernel weight have shown to be the most important variables affecting the performance of durum wheat under non-stressed condition. In the first four PCs at the water- stressed condition, agronomic score, grain yield, vigority, days to physiological maturity, test weight and peduncle length have been shown to be the important variables under water-stressed condition. The results of factor analysis relatively confirmed the results of PC analysis. Our findings indicated that a selection strategy should take into consideration of agronomic score and days to physiological maturity under non-stressed condition while plant height and spike length under water-stressed condition. Therefore, the above-mentioned traits could be used as indirect selection criteria for genetic improvement of grain yield in durum wheat, especially in early generations of breeding programmes

Drought stress is the most important factor restricting crop production in the majority of agricultural fields in the world. Durum wheat is generally grown in arid and semi-arid areas and drought often causes serious problems in its production. Fourteen durum wheat genotypes were evaluated under semi-arid Mediterranean climatic conditions in two non-stressed and water-stressed conditions. Data on fourteen agronomic traits are presented to assess the phenotypic diversity and to investigate the relationships between grain yield and other important yield components in durum wheat. The coefficient of variation (CV) for all the genotypes ranged from 0.71% to 17.62% in non-stressed environment and ranged from 1.38% to 23.70% in water-stressed environment. Clustering based on durum wheat genotypes separated the measured traits into three main groups under non-stressed environment. Peduncle length, agronomic score and plant height were the most related traits with grain yield. Such clustering in water-stressed environment indicated that growth vigor, thousand kernel weight, test weight or hectoliter and agronomic score were the most associated traits with grain yield. Cluster analysis assigned the durum wheat genotypes to at least two major groups in non-stressed conditions and three major groups in water-stressed conditions. Therefore, it seems that for improving grain yield performance in nonstressed conditions, genotypes G1, G3, G4, G6, G8 and G13 and in water-stressed conditions, genotypes G3, G8, G10 and G14 are good candidates. Finally, for improving grain yield performance in both humidity conditions, genotypes G3 and G8 can be used.