Brachiaria germplasm dissimilarity as shown by RAPD markers
Ana Claudia Ambiel, Nelson Barbosa Machado Neto, Luciana Machado Guaberto, and Talita Marques Vanderlei
The main objective of this work was to study the genetic dissimilarity among germplasm accesses of six Brachiaria species and to compare the most important cultivars through the use of RAPD markers with the studied material. DNA was extracted from seeds of five different accesses of B. decumbens, B. ruziziensis, B. nigropedata, B. humidicola, B. jubata and B. brizantha from the EMBRAPA – CNPGC, 12 commercial cultivars, and two accesses each of P. maximum and B. arrecta. From 120 primers tested, 10 polymorphic were selected, amplifying a total of 114 polymorphic bands. Dissimilarity indexes were estimated for all samples analysed, and ranged from 0.262 to 0.907, grouped by UPGMA, and four groups were clearly distinct. All accesses and cultivars of Brachiaria could be grouped through RAPD markers. Dissimilarity within a species was found. The distribution in African species was narrower in B. decumbens and B. ruziziensis showed low levels of dissimilarity, and naturally widely-spread species showed high dissimilarity levels.