Brachiaria germplasm dissimilarity as shown by RAPD markers

Abstract

The main objective of this work was to study the genetic dissimilarity among germplasm accesses of sixBrachiaria 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. Dissimilarityindexes were estimated for all samples analysed, and ranged from 0.262 to 0.907, grouped by UPGMA, and four groups wereclearly distinct. All accesses and cultivars of Brachiaria could be grouped through RAPD markers. Dissimilarity within aspecies was found. The distribution in African species was narrower in B. decumbens and B. ruziziensis showed low levelsof dissimilarity, and naturally widely-spread species showed high dissimilarity levels.

Keywords

• molecular markers
• genetic variability
• DNA
• pasture.