Phenotypic diversity and clustering of germplasm accessions of cashew for utilization and conservation

To promote the better utilization of genetic resources of cashew, 91 accessions maintained at Cashew Research Station, Madakkathara were assessed for 38 phenotypic traits. Frequencies of the phenotypic classes of each character were calculated. The Shannon diversity index (H′) was used to estimate the magnitude of diversity. Polymorphism was high for tree habit (0.96), tree height (0.89), branching pattern (0.89), colour (0.80), ridges (0.93), apex (0.95), cavity (0.90) and weight (0.84) of cashew apple, attachment of nut to apple (0.85), fanks of nut (0.95) and cotyledonary grooves (0.99). The cluster analysis using the squared Euclidean distance method classifed the accessions into 13 clusters at a 55 per cent similarity level. More than 50 per cent of the accessions were high yielding with moderate quality kernels. Grouping of the genotypes into agronomic groups revealed the existence of highly prolifc accessions with high quality kernels that can be exploited for crop improvement programmes.