Genetic diversity of common bean accessions in the germplasm bank of the Instituto Agronômico (IAC)

Abstract

The genetic divergence among 993 accessions of common bean (Phaseolus vulgaris L.) in the germplasm bank of the Instituto Agronômico IAC (agronomical Institute in Campinas, state of São Paulo) was evaluated in an analysis using 23 qualitative and quantitative agromorphological/ morphological and agronomic descriptors. Multivariate analyses such as the Euclidean distance, principal component analysis and Tocher’s cluster method were used to quantify the divergence among the accessions. The joint use of the analyses allowed the identification of 45 groups of which the first five absorbed 88.28% of all accessions. Among the 23 evaluated descriptors, the principal component analysis allowed the discarding of five that were redundant and/or little variable and the eight first principal components were necessary to explain 70% of the total variation. The multivariate methods proved efficient when used in germplasm collections, optimizing the descriptor set and establishing an orientation for future crossings in the common bean improvement program of the IAC.