Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2000
Publication Date: 7/2/2000
Citation: Levi, A., Thomas, C.E., Keinath, A.P., Wehner, T.C. 2000. Estimation of genetic diversity among citrullus accessions using rapd markers. Hortscience. 35:491.
Technical Abstract: Genetic relatedness was estimated among forty-six watermelon (Citrullus lanatus) cultivars, and among 42 U.S. Plant Introduction (PI) accessions of the genus Citrullus (37 PIs of which are reported to have disease resistance), using 30 RAPD primers. Based on RAPD data, genetic similarity coefficients were calculated and dendrograms were constructed using the unweighted pair-group method with arithmetic average (UPGMA). The dendrogram for cultivars showed that they all were contained in one major cluster and differentiated at the level of 93-99% genetic similarity. The dendrogram for the PIs delineated three major clusters. The first cluster contained the C. lanatus var. lanatus accessions, while the second cluster contained the C. lanatus var. citroides accessions. The third cluster contained the C. colocynthis accessions. The two C. lanatus clusters differentiated from each other and from the C. colocynthis cluster at the level of 58.8% and 38.9% genetic similarity. The results in this study indicate a low genetic variation among watermelon cultivars and emphasize the need to expand the genetic base of cultivated watermelon. The results also indicate that Citrullus PIs with resistances to the same diseases may be closely related. Thus, molecular markers can be a useful tool in the development of core collections of Citrullus PIs with resistance to diseases.