EVOLUTIONARY RELATIONSHIPS BETWEEN AND WITHIN THE HIGHLAND PAPAYAS (GENUS VASCONCELLEA) AND THE COMMON PAPAYA (CARICA PAPAYA)

Being less known than the common papaya, but offering a variety of tasty fruits and great economical potential for breeding programmes, highland papayas (Vasconcellea spp.) are generally considered as under-utilized Andean crops. In the course of ethnobotanical surveys, an undescribed morphological variability among and within species of the genus Vasconcellea was observed, and identification of some of the taxa appeared to be hard or sometimes impossible. This high amount of diversity is probably partly caused by the intercompatibility between several species leading to the production of hybrids, spontaneously occurring in areas where species distributions overlap. Several recent molecular studies have focused on unraveling the taxonomy and the complicated evolutionary relationships between Vasconcellea spp. By using different molecular marker techniques and DNA sequence analyses, these studies provided new information about the genetic diversity and evolution of Vasconcellea in comparison with Carica papaya and other related genera. This review illustrates the utility of molecular marker techniques and sequence analyses to resolve taxonomic questions in Caricaceae. In general, the evolution of Vasconcellea has been shown to involve both recent speciation and reticulation.