Evaluation of genetic similarity between accessions of Pityrocarpa moniliformis (angico-de-bezerro) using RAPD markers.

Pityrocarpa moniliformis (Benth.) Luckow and Jobson, commonly known as angico-de-bezerro, is a forage legume that occurs naturally in the Caatinga of northeastern Brazil. This fast growing, vigorous, melliferous tree is well adapted to arid terrains and its branches and leaves possess high nutritional value. However, the scarcity of information regarding genetic variability within the species limits its possible exploitation as an animal forage. The aim of the study was to evaluate the genetic similarities of ten accessions of P. moniliformis available in the active germplasm collection of Embrapa Meio-Norte, using the RAPD markers to select those most suitable for cultivation and/or plant breeding. Polymerase chain reaction using ten selected RAPD primers generated 110 amplified loci, 106 (96.4%) of which were polymorphic. Primers A10 and M06 produced the largest number of polymorphic loci (18 and 13 bands, respectively), while primers B18 and K15 generated the smallest number (7 bands each). The dendrogram, constructed using the Jaccard coefficients and considering a cut-off point of 0.41 allowed the separation of the ten accessions into four genotypic groups. The highest genetic similarity coefficient (0.56) was observed between group I accessions BGFAB6 and BGFAB9 and BGFAB 7 and BGFAB 8, while the lowest coefficient (0.11) was observed between accessions BGFAB3 (group IV) and BGFAB10 (group III). The results revealed that genetic variability is present in the accessions of P. moniliformis.