RESISTANT COCOA GENOTYPES SELECTED AGAINST PHYTOPHTHORAMEGAKARYA IN THE RECIPROCAL RECURRENT SELECTION PROGRAM

Black pod rot of cacao caused by stramenopiles of the genus Phytophthora can lead to up to 60% yield losses in endemic regions of Cote dIvoire. To reduce the field incidence of this disease, genetic control emerges as an alternative solution capable of providing resistant varieties to farmers.This study was conducted on 93 cocoa genotypes and three reference controls with Variables sensitivities. The inoculation technique used was that described by Nyasse, and the strain utilized was a highly aggressive isolate of P. megakarya. The Blaha scale was applied to assign infection scores to each leaf disk.The results of hierarchical cluster analysis on principal components (HCPC), followed by Correspondence Factor Analysis (CFA), revealed that the genotypes were divided into five homogeneous groups based on infection score frequencies. Twenty-eight genotypes in cluster 1 were classified as highly resistant to P. megakarya. Twenty other genotypes belonging to cluster 2 were classified as resistant to the pathogen. These genotypes will be used as progenitors in the genetic improvement program to create and disseminate resistant descendants against this phytopathogen.