New sources of resistance - cacao germplasm evaluation for natural incidence of witches' broom. In: Agrotrópica v. 33 n. 2 p. 91-100, 2021.

Abstract

This study is part of the first ones that came to guide the recurrent selection processes for the association of resistance genes conducted by the Cocoa Research Center, at Ilhéus, Bahia. Two sets of accessions of the Cocoa Germoplasm Collection of this Center were evaluated for natural incidence of witches’ broom, the biggest phytosanitary problem for cacao cultivation in Brazil. For the first set, which consisted of 573 accessions, it was considered the incidence of brooms on pods of up to 10 plants per row, with one or two rows of each accession, in five years of evaluation. For the second, formed by 154 genotypes pre-selected among the accessions introduced in the period with indications of good performance in relation to witches’ broom, it was computed seven removals of vegetative brooms in the canopy, being each accession represented by one to three rows with up to seven plants. For both sets, a large number of genotypes of different origins were observed among the resistant ones, indicating the perspective of the occurrence of different resistance genes and possibilities of genetic gain in associating these different genes.