Exploring Genetic Variations Among Palestinian Watermelon (Citrullus lanatus) Germplasm Using RAPD Molecular Markers

Characterizing the various genotypes of watermelons (Citrullus lanatus) is an important step to manage effectively the use of genotype resources. The aim of this work is to determine the level of genetic diversity among different landraces of Palestinian watermelon using RAPD molecular markers. For this, 14 RAPD primers were used to amplify the DNA extracted from 8 watermelon landraces. The banding pattern from RAPD analysis was scored visually for each primer and the data matrix was developed for UPGMA-based cluster analysis. Using the Nei and Li distance coefficients, cluster analysis was performed. Marker index and polymorphic information content as well as resolving power was calculated for all the markers. Twelve RAPD markers produced various banding patterns and revealed polymorphic bands of which 52 (94.6%) bands were polymorphic and 3 (0.035%) were monomorphic. The highest percentage of polymorphic markers was 100% and the lowest was 60%. The genotypes were mainly divided into two clusters based on the dendrogram derived from RAPD data. Cluster-I, which has two sub-clusters, included seven genotypes, sub-cluster-I.a contained only two genotypes (UB-199–11 and UB-510–20), and sub-cluster-I.b included two groups containing in which genotypes UB-402–19 and UB-578–21-2 represented in group 1 and genotypes UB-307–18-2, UB-377–19, and UB-578–21-1 represented in group 2. Cluster-II contained only one genotype accession (UB-307–18-1). Based on 12 RAPD, the similarity coefficients of Watermelon genotypes ranged from 0.31 to 0.82.