Genetic diversity of elephant grass ( Cenchrus purpureus   [Schumach.] Morrone) for energetic production based on quantitative and multi-category traits

Elephant grass (Cenchrus purpureus (Schumach.) Morrone) has been used as an alternative source of energy. It is widely cultivated in Brazil, however it needs genotypes adapted to different ecosystems of the country. The knowledge of genetic diversity allows the identification of genotypes that can be used in breeding programs. Thus, this study aimed to evaluate the diversity among 85 genotypes of elephant grass by Tocher’s clustering method and by the unweighted pair group method with arithmetic averages (UPGMA), using quantitative and multi-category traits in 2 yr of evaluations. The experiment was implemented in the State Center for Research on Bioenergy and Waste Use at Pesagro-Rio, located in Campos dos Goytacazes, Río de Janeiro, Brazil. Eighty-five elephant grass genotypes donated by the Active Elephant Grass Germplasm Bank of Embrapa Dairy Cattle, in Coronel Pacheco, Minas Gerais, Brazil, were included in the experiment. The experimental design was arranged as randomized blocks, with two replicates. Based on the quantitative traits, the 85 genotypes analyzed belonged to 17 groups according to Tocher’s optimization method and to 13 groups when analyzed by UPGMA. For the qualitative traits, however, the genotypes formed 10 groups for both methods. Therefore, the multivariate technique indicated genetic divergences among the genotypes and allowed the formation of similarity groups by Tocher’s optimization and UPGMA methods for both the quantitative and qualitative traits.