Molecular characterization using SSR markers points to population admixture of genetic variation among introduced Cashew (Anacardium occidentale L.) in Northern Cameroon

Understanding the genetic diversity of cashew ( Anacardium occidentale L.) is crucial for effective conservation and breeding programs. This study aimed to assess the genetic variability of 74 cashew genotypes collected from five provenances across three regions of northern Cameroon using 13 SSR markers. All primers successfully amplified DNA, producing an average of 2.5 polymorphic bands. The SSR markers revealed a low level of polymorphism, with two to three alleles per locus, which is relatively noteworthy for an introduced species.Discriminant Analysis of Principal Components (DAPC) showed that the first two components explained 43.9% of the total variability, allowing clear discrimination of genotypes and revealing structured genetic variation. The genotypes were partitioned into seven clusters. Cluster analysis based on Nei’s genetic distance confirmed these results, highlighting genetic structuring among populations. Genotypes from Ngaoundéré (Ng) were largely assigned to specific clusters, while those from Garoua (Ga) and Yagoua (Ya) were distributed across several clusters, indicating genetic differentiation, structure, and admixture. Most genotypes displayed strong cluster membership (≥ 90%), but a subset showed admixed ancestry, suggesting human-mediated propagation or multiple introduction events of cashew germplasm into northern Cameroon.The observed genetic variation likely reflects the combined influence of environmental factors, local adaptation, and historical cultivation practices. This study provides the first insights into cashew genetic diversity in northern Cameroon, offering a valuable basis for future production, conservation, and breeding efforts.