Genetic and morphological diversity of okra (Abelmoschus esculentus [L.] Moench.) genotypes and their possible relationships, with particular reference to Greek landraces

Abstract

Despite its high economic value in many countries (especially in developing regions of the tropics and sub-tropics), okra has received little attention with respect to its source of origin and genetic diversity, particularly at the molecular level. Phenotypic description (morphology, pod characteristics and seed germination) and AFLP (amplified fragment length polymorphism) analysis were performed on Greek and international genotypes. Whereas morphological descriptors did not separate the accessions according to their geographical origin, AFLP analysis revealed a low level (12%) of polymorphism and distinct geographical groupings. Greek germplasm separated into three distinct groups with no overlap between them on the basis of molecular markers. A higher degree of genetic heterogeneity was found (UPGMA analysis) among the accessions of the Boyiatiou group than in the Pylaias group, whereas the occurrence of some common phylogenetic characteristics made separation on the basis of morphology alone difficult. The results from AFLP markers indicate that Greek germplasm constitutes a significant pool of variation with respect to morphological parameters, pod characteristics and seed germinability. Moreover, differences in seed germination among phenotypes may relate to their geographical origin (mainland or islands).