Authors: Eder Jorge de Oliveira Cláudia Fortes Ferreira Vanderlei da Silva Santos Onildo Nunes de Jesus Gilmara Alvarenga Fachardo Oliveira Maiane Suzarte da Silva
Publish Date: 2014/04/16
Volume: 127, Issue: 6, Pages: 1423-1440
Abstract
The objective of the present work was to evaluate the diversity and genetic structure of the largest cassava germplasm bank in Brazil Complementary methodological approaches such as discriminant analysis of principal components DAPC Bayesian analysis and molecular analysis of variance AMOVA were used to understand the structure and diversity of 1280 accessions genotyped using 402 single nucleotide polymorphism markers The genetic diversity 0327 and the average observed heterozygosity 0322 were high considering the biallelic markers In terms of population the presence of a complex genetic structure was observed indicating the formation of 30 clusters by DAPC and 34 clusters by Bayesian analysis Both methodologies presented difficulties and controversies in terms of the allocation of some accessions to specific clusters However the clusters suggested by the DAPC analysis seemed to be more consistent for presenting higher probability of allocation of the accessions within the clusters Prior information related to breeding patterns and geographic origins of the accessions were not sufficient for providing clear differentiation between the clusters according to the AMOVA analysis In contrast the F ST was maximized when considering the clusters suggested by the Bayesian and DAPC analyses The high frequency of germplasm exchange between producers and the subsequent alteration of the name of the same material may be one of the causes of the low association between genetic diversity and geographic origin The results of this study may benefit cassava germplasm conservation programs and contribute to the maximization of genetic gains in breeding programsThe authors would like to thank Empresa Brasileira de Pesquisa Agropecuária Embrapa for the financial support The authors gratefully acknowledge the support through fellowships from the Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPqWe declare that the experiments comply with the current Brazilian laws in which they were performed In addition we declare that the authors do not have any competing financial interests including funding support employment and personal financial interests
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