Diversidade genética e caracterização morfoagronômica da mamoneira

Abstract

One of the great current challenges of the agricultural research is the production of improved castor bean cultivars with genetic stability, high quality and high-yielding potential. The genetic divergence is one of the most important parameters evaluated by plant breeders in the early phase of a genetic improvement program. Owing to this, the objective of the present work was to determine the genetic diversity through the characterization and estimation of the genotypic, phenotypic and environmental correlation among traits of castor bean accessions. The experiment in a randomized blocks design, with fifteen treatments and three replicates, was established in Lavras, MG, Brazil. The data were submitted to the variance analysis, the genetic distances being obtained among the accessions and on the basis of these distances, clustering analysis and correlations among these accessions for determination of the genetic divergence were performed. According to the clustering by utilizing Tocher´s methods, there was the formation of three distinct clusters for the qualitative data. In relation to the clustering for the hierarchic method of nearest neighbor, there was the formation of four clusters, the crosses among superior accessions belonging to different clusters being recommended. But in relation to the quantitative data, there was the formation of four groups, that is, both in Tocher´s method and in the hierarchical method of the nearest neighbor. For correlations, it was found that there was positive phenotypic and environmental correlation among the variables, supplying important information to the establishment of a plan the variable, supplying important information the establishment of a genetic improvement plan of castor bean from the evaluated accessions.