Morpho-biochemical and molecular characterization of accessions with unique traits as potential genetic stocks for cashew improvement

Cashew is a tree of great commercial importance. The demand for cashew nuts and by-products is increasing. An increase in cashew production is possible through genetic enhancement by effective utilization of germplasm. However, the utility of cashew germplasm in the breeding programme is limited by the lack of reliable data on germplasm characterizations. In this research study, we identified 11 germplasm accessions with unique traits through a genebank survey and evaluated them for morphological and biochemical characteristics and genetic diversity. Morphological characterization revealed significant variations, and high variability was observed for qualitative characteristics like nut stylar region width, cashew apple shape, and color. The morphometric traits such as the cashew nut, kernel, and cashew apple dimensions and weights also showed great variability. The correlation analysis showed that the nut weight had strong correlations with traits like kernel weight (r = 0.95) and shell thickness (r = 0.95). Biochemical analysis for cashew nut shell liquid (CNSL), kernel oil, and cashew apple juice content and TSS showed significant variations in the tested accessions. Correlations were observed between CNSL content and shell thickness. Further, genetic diversity analysis of accessions using nine genic simple sequence repeats (SSRs) detected a sum of 64 alleles, and the accessions were divided into three major clusters by the neighbor-joining method. This study confirms that the identified accessions are genetically diverse and are promising candidates for varietal development. The correlations between characters indicated the scope for simultaneous selections for the strongly correlated characters with economic importance.