Genetic diversity of cacao accessions selected for resistance to witches’ broom based on RAPD markers
Fábio G. Faleiro, Uilson V. Lopes2, Milton M. Yamada1, Gilson R.P. Melo, Wilson R. Monteiro, José L. Pires, José B. Rocha2, Rita C.S. Bahia, Luana M.C. Gomes, Ioná S. Araújo and Alessandra S.G. Faleiro
To increase the genetic diversity sources of resistance to witches’ broom disease, 59 cacao trees of commercial plantations of the State of Bahia, Brazil, were selected and cloned. The diversity of these clones was evaluated with RAPD markers. Their pedigree was investigated by comparison to traditional resistance sources used as parents for most hybrid mixtures cultivated in the State. One hundred and six RAPD bands were obtained, 85.8% of which were polymorphic. Genetic distances among the clones varied from 0.04 to 0.41. The MDS plot showed large genetic variability among clones. Analyses based on rare markers inherent to Scavina-6 and Scavina-12 clones, which represent important resistance sources, showed a close relationship of these sources to most accessions. However, some accessions did not present any of the rare Scavina markers, suggesting potentially different alleles, which could contribute to broaden the gene pool of breeding programs for resistance to witches’ broom.