Accessions from the Watermelon Germplasm Bank collected in three different regions of the state of Bahia were characterized using morphological and molecular descriptors. The cultivar Crimson Sweet was added to the group as a check genotype. The field trial was carried out at the Experimental Station of Embrapa, Petrolina-PE. Uni- and multivariate analyses were performed. Samples of five to eight individuals from each of the 43 accessions were analyzed by RAPD technique, using six primers. Jaccard mean similarity coefficients among accessions and grouping by Tocher method were estimated. There were significant differences among accessions for all descriptors, except for the number of fruits per plant. Eight morphological descriptors (length of the main stem and fruit stripe pattern, soluble solid content, shape, weight, external color, and rind thickness at the flower scar and at the distal region) retained 79% of the variation observed among accessions. When the multivariate analysis was performed including cultivar Crimson Sweet, only two groups were formed: a group with solely the cultivar itself, and another with all the other accessions. When the cultivar Crimson Sweet was not included, the multivariate analysis showed nine groups of accessions, with a single group containing 69% of the accessions. Sixty-four RAPD markers were identified, out of which 31 were polymorphic. When accessions were grouped based on this molecular information, 28 groups were formed, 24 of them with a single accession. None of the groups with more than one accession contained individuals with the same geographical origin. RAPD markers revealed expressive polymorphism in several accessions, which is a good indication that such class of markers could be used in the characterization of accessions in watermelon germplasm banks.
Citrullus lanatus; morphological descriptors; molecular markers; RAPD; germplasm
