Variation and Relationships among Agronomic Traits in Durum Wheat [Triticum turgidum (L.) Thell. ssp. turgidum conv. durum (Desf.) MacKey] under South Mediterranean Growth Conditions: Stepwise and Path Analyses

Relationships among agronomic traits and grain yield were investigated in 56 genotypes of durum wheat (Triticum durum Desf.). The results indicated the presence of sufficient variability nearly for all measured traits. Heritability and expected genetic gain varied among traits. Aboveground biomass, harvest index, and spike number were the most grain yield-influencing traits. Early genotypes showed above-average grain and biological yields, spike number, and lower canopy temperature. Assessed genotypes were clustered into three groups which differed mainly for biological, economical, straw, and grain yields, on the one hand, and plant height, chlorophyll content, and canopy temperature, on the other hand. Selection for direct use from clusters carrying best combinations of yield-related traits and crosses to be made between genotypes belonging to contrasted clusters were suggested to generate more variability. Selection preferentially for spike number, biological yield, harvest index, and canopy temperature to accumulate favorable alleles in the selected entries for future uses is suggested.