Análise molecular de germoplasma de melancia com base em marcadores microssatélites

Abstract

The objectives of this work were to establish allelic patterns and to estimate genetic distances in 17 watermelon cultivars and one accession of Citrullus colocynthis, based on microsatellite marker, in order to generate a reference database to support the plant variety protection, as well as to guide improvement programs and genetic resources of this species. For visualization of the genetic similarity, the dendrogram UPGMA generated by the matrix of distances of the coefficient of Jacquard was used, based on 32 alleles of ten microsatellite loci. The total DNA was extracted by the CTAB 2x method, and PCR products were analyzed in denaturing polyacrylamide 6% gels, stained with silver nitrate. The number of base pairs was estimated by the method of inverse mobility, based on known size products regression. Among the 36 tested microsatellites primers only ten presented polymorphic amplification of easy interpretation. The cultivars presented a similarity coefficient between 34 and 100%, which reflected the high genetic variability. The 32 alleles were not enough to distinguish all 17 watermelon cultivars, with “Sugar Baby” and “Omaru Yamato”; “Charleston Gray” and “Sunshade”, “Crimson Sweet” and “Nova Crimson” presenting a 100% of similarity. Two groups were observed at the cut point of 0.42 of similarity, with Citrullus colocynthis, positioned as an out group. One watermelon group was formed predominately by cultivars derived from Crimson and another group formed by cultivars of different types as “Sugar Baby”, “Charleston Gray” and “Pérola”.