First study of Genetic diversity in watermelon (Citrulluslanatus) germplasm collected from Southern Tunisia using RAPD markers

The genetic diversity in local Tunisian watermelon (Citrullus lanatus) was studied using RAPD markers. Eight watermelon cultivars originating from south of Tunisia and belong to four populations were analysed and compared to two commercial varieties (Giza and Sugar-baby) widely produced in this area. Five of nine RAPD primers generated a total of 86 reproducible bands, 85 of which were polymorphic (98.4%). Cluster analysis of the accessions considered in this study employing RAPD data indicated that commercial varieties are significantly different of all the local cultivars. The relationships among the local cultivars (four populations) showed that Medenine population and the most genotypes of Benguerdane population were grouped together and significantly different from Kebili population. The AMOVA showed significant differentiation between populations (27%). In addition, the data showed clusters according to some fruit characteristics such as fruit shape and fruit weight. This proved that RAPD markers are useful for germplasm discrimination as well as for investigation of patterns of variation in watermelon.