Multivariate Analysis of Cashew (Anacardium occidentale L.) Germplasm in Nigeria

Multivariate analyses were carried out on fifty-nine germplasm accessions of cashew derived from both local and exotic populations established at the research plots of Cocoa Research Institute of Nigeria (CRIN), Ibadan, southwestern Nigeria, to assess the extent of variability and pattern of genetic diversity among these cashew populations. Data collected on 36 quantitative and 33 qualitative plant characters were subjected to taximetric tools of Euclidean distance of complete linkage (furthest neighbour) and principal component analysis (PCA). The multivariate analyses tentatively grouped the selections into four distinct morphogenetically diverse clusters. The groupings appear to be a function of origin, eco-geographical distribution, genetic and/or agronomic affinity of the selections. Brazilian populations distinctly clustered together in two major groups while local clones and Indian selections dominated the other two major clusters with each group having its unique fruiting and tree growth habits. The clustering pattern at sub-cluster levels clearly reflects affinity of each genetic population. The principal component analysis and the potency indices showed that fruit characters are the most discriminating parameters for delineating cashew at the varietal level.