Submitted to: Acta Horticulturae
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2000
Publication Date: 10/6/2000
Citation: Levi, A., Thomas, C.E., Keinath, A.P., Wehner, T.C. 2000. Estimation of genetic diversity among citrullus accessions using rapd markers. Acta Horticulturae. 510:385-390.
Technical Abstract: Genetic relatedness was estimated among 42 U.S. Plant Introduction (PI) accessions of the genus Citrullus, 37 PIs of which are reported to have disease resistance, and five watermelon cultivars, using 30 RAPD primers. These primers produced 662 RAPD markers that could be scored with high confidence. Based on these markers, genetic similarity coefficients were calculated and a dendrogram was constructed using the unweighted pair-group method with arithmatic average (UPGMA). The analysis delineated three major clusters. The first cluster consisted of a group of five watermelon cultivars, a group of C. lanatus var. lanatus accessions, and a group of C. lanatus var. lanatus accessions that contained some C. lanatus var. citroides genes. The second cluster consisted of the C. lanatus var. citroides accessions, while the third cluster consisted of 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 that closely related Citrullus PIs may have resistances to the same diseases. Thus, molecular markers may be a useful tool in the development of core collections of Citrullus PIs with resistance to diseases.