Phenotypic and genetic characterization of date palm cultivars resistant to bayoud disease

Taqerbucht cultivars of date palm are well known by their natural resistance against devastating fungus Bayoud disease. In order to know, if these accessions have the same genetic and morphological profile or each of them constitutes a separate cultivar, we carried out a morphological and molecular characterization and we compared four Taqerbucht (Tq.) date palm cultivars from the southwestern region of Algeria: Tq.hamra cultivar (red fruits), Tq. safra cultivar (yellow fruits), Tq.beïda (white fruits) and Tq.kahla cultivar (black fruits). Seventy one phenotypic characteristics, including 33 quantitative and 38 qualitative traits, have been selected for comparison. Principal component analysis (PCA) and multi-component clustering were used to analyze and compare the data. The results suggest that the four cultivars can be classified into distinct groups. One group contains one cultivar, the Tq.kahla and another group contains the three other cultivars (Tq.safra, Tq.beïda and Tq. hamra). Based on phylogenetic analyses and sequence comparisons, the cultivar Tq. kahla seems to be divergent from the cultivar Tq.hamra, whereas the two cultivars Tq.Safra and Tq.beïda are close to each other. Using 16 Simple Sequence Repeat (SSR) genetic markers to analyze genetic diversity among the cultivars, we found that 13 markers were detectable in 31 allele's loci, and the number of alleles per locus varied from 1–4 with an average of 2.38 alleles per locus. Expected heterozygosity (He) values ranged from 0.375–0.500 and observed heterozygosity (Ho) values from 0.750–1.000