Relationship between Grain Yield, Agronomic Traits and Carbon Isotope Discrimination in Durum Wheat Cultivated under Semi-arid climate

In Mediterranean regions, especially around the arid and semi-arid areas, drought is a major abiotic factor that reduces yields in wheat. Identification of reliable criteria in screening for drought tolerance in wheat represents a significant challenge to plant breeders. This study was carried out at two locations (Béni Fouda and Ain Abessa) in Sétif, Algeria. The objectives were to study the performance of durum wheat genotypes (Triticum durum Desf.) in relation to yield and some agronomical traits and the evaluation of carbon isotope discrimination (Δ^sup 13^C) as a selection criterion for drought tolerance. Analysis of variance revealed that grain yield and all measured parameters (excepted for number of spikes per m^sup 2^ and thousand kernels weight) were significant (P < 0.01) affected under locations. Among genotypes, significant differences (P < 0.01) were observed for all traits, excepted for biomass. Under both locations (Béni Fouda and Ain Abessa) gain yield was positively and significantly correlated with earliness, number of spikes per m^sup 2^, number of grain per m^sup 2^, harvest index and Δ^sup 13^C. The results suggested that the selection of early heading genotypes would give high grain yield under rain-fed conditions. Also, grain yield could be effectively increased by maximum genetic expression of number of spikes per m^sup 2^, number of grains per m^sup 2^ and harvest index. Strong correlations between grain yield and carbon isotope discrimination indicate that Δ^sup 13^C can be used as indirect criterion in screening for drought tolerance in semi-arid conditions.