Genetic variability in cultivated cacao populations in Bahia, Brazil, detected by isozymes and RAPD markers/
Milton M. Yamada; Fábio G. Faleiro; Uilson V. Lopes; Rita C. Bahia; José L. Pires; Luana M.C. Gomes and Gilson R.P. Melo
The objective of this work was to study genetic variability in accessions from the CEPLAC cacao germplasm collection, which constituted the parents of hybrids recommended by CEPLAC, to infer about the diversity of cacao plantations in Bahia. The 21 clones or accessions utilized were SIC, SIAL (local selections) groups and ICS, IMC, PA, SCA, TSA and UF groups (foreign selections). Molecular markers used were isozymes (MDH, IDH, and DIA enzyme systems) and RAPD (105 RAPD loci of 11 primers). Genetic similarities among accessions were determined by the NTSYS statistical package. A similarity matrix based on Dice´s coefficient was calculated, and a dendrogram using unweighed pair-group method with arithmetic average (UPGMA) clustering was constructed. The accessions were classified into 7 groups. Four accessions (SIC 19, IMC 67, ICS 6 and ICS 8) did not cluster in any group. Other accessions formed small groups such as SCA 6, SCA 12, PA 30, PA 150 and ICS 1. The larger group was formed by 12 accessions, including SIC, SIAL, UF and TSA 644. Results indicate that the genetic base in Bahia plantations was quite narrow before using the recommended hybrids by CEPLAC. However, with the planting of hybrids, both the genetic variability and the chances of success from selection increased.