Genetic Diversity Among some Cucurbits Species Determined by Random Amplified Polymorphic DNA RAPD Marker

Abstract

RAPD markers were used to determine the genetic relationships and evaluating similarity among some cucurbits species. Thirteen RAPD primers were used to amplify DNA extracted from the leaves of 10 cucurbit species using CTAB method. A total of 227 bands were amplified of which 225 showed polymorphism among the 10 species. PCR-RAPD analysis showed a number of differences in the size and number of bands among the species, which means that there are genetical differences among the studied cucurbit species. Based on these markers, genetic similarity coefficients were calculated and a dendrogram was constructed. The dendrogram analysis delineated three major clusters. The first cluster consisted of one group which comprised <i>Cucurbita moschata</i> and <i>C. pepo</i> at a level of 38.6 % genetic similarity. The second cluster consisted of four groups: Group I comprised <i>Luffa aegyptiaca </i>at a level of 20.6 % genetic similarity. Group II comprised the closely related species <i>Cucumis melo</i> var. <i>reticullatus</i> and <i>C. melo</i> var. <i>flexuosus</i> at a level of 62 % genetic similarity. Group III consisted of <i>Cucumis sativus</i> with about 37.8 % genetic similarity to group II. Group IV consisted of <i>Ctenolepis cerasiformis</i> at a level of 26.6 % genetic similarity. The third cluster consisted of two groups. Group I comprised <i>Citrullus lanatus</i> and <i>Colocyny</i><i>t</i><i>his vulgaris</i> at a level of 36.2 % genetic similarity. Group II consisted of <i>Coccinia grandis</i> at the level of 19.4 % genetic similarity. The three clusters were similar to each other at a level of 15% genetic similarity. Genetic similarity ranged between 15% and 62 %. This study demonstrates that RAPD markers are useful in assessing genetic diversity among cucurbits.