Résumé
Phytophthora megakarya is an aggressive and destructive pathogen that causes black pod disease of cacao in West and Central Africa. We examined genetic diversity and population structure of P. megakarya using genomic data from 165 isolates collected from cacao in Africa. We used genotyping by sequencing of 150 isolates and published whole genome sequences of 15 isolates to call 2,644 high quality SNPs relative to reference genome Pm1/GH34. Isolates could be assigned to one of two major clades. One clade contained isolates from Nigeria and Ghana and the other clade contained isolates collected in all regions. To examine the virulence of isolates, a diverse panel of 300 cacao clones from the International Cacao Germplasm Collection at CATIE, Costa Rica were phenotyped using excised pods shipped to the University of Florida. Genomic and phenotypic data will be used together to improve phenotypic predictions of pathogen virulence and host resistance.