Assessment of the genetic diversity of onion cultivars (Allium cepa, Amaryllidaceae) collected in southern Benin

Onion is one of the widely consumed vegetables in most food preparations. The present study aims to evaluate the genetic diversity of onion cultivars in southern Benin in ۲۰۲۳. DNA isolation of the fourteen (۱۴) morphotypes collected was carried out using the CTAB protocol and amplified by PCR using five RAPD markers. The observed polymorphism rate was ۱۰۰%. A total of ۳۵ alleles were scored with an average of ۷ per locus. The Polymorphism Information Content (PIC) of loci varies from ۰.۷۳۴ to ۰.۸۰۶ with an average of ۰.۷۸۴. The loci OPA۰۸ (Na = ۸ alleles, PIC = ۰.۸۰۶) was the most polymorphic and the most discriminating. OPB۰۸ (Na = ۶ alleles, PIC = ۰.۷۳۴) was the least polymorphic and the discriminating loci. The rate of rare alleles was Ra = ۳۱.۴۲%. The lowest genetic distance (D = ۰.۰۹) was observed between PVOV and PVAL but the highest (D = ۰.۹۴) was between FPAL and BQOV genotypes. The dendrogram classified the morphotypes into four genetic groups with a dissimilarity coefficient of ۴۰% confirmed by the Principal Coordinate Analysis. These results are globally significant for the definition of strategies for the improvement, conservation and sustainable use of onion genetic resources in Benin.

Keywords:

Allium cepa , Genetic differentiation , RAPD marker , Genetic group , Benin