Multivariate analysis from maturase K (matK) gene-based markers and morphological indices in Indian cashew

Abstract

The patterns and extent of genetic variation among 56 cashew germplasm with respect to 32 qualitative and 33 quantitative traits were evaluated for two successive years in the present study. Additionally, maturase K gene-based genetic diversity among those breeding materials was also assessed. The cashew hybrids were developed from five crosses (local parent × 2/9 Dicherla; H-2/15 × red hazari; WBDC-V × JGM-1; BLA-39-4 × H-2/15 and H-2/15 × yellow hazari) involving eight parents of Indian cashew. Different genotype groups (parents and their hybrids) showed significant variation in both the years of assessment based on quantitative characters. The highest Shannon–Weaver diversity (H′) was obtained for the colour of the young leaf (0.96), possibly indicating differential exposure to sunlight, mixing of various pigments and another set of chemicals such as phenolics, carotenoids, etc. in trees. From correlation studies, canopy spread, tree spread, nuts/m2 and nuts/panicle were found to be significantly and positively correlated with nut yield. In the year 2021, nuts/m2, area and tree height were the significant explanatory variables that explained 80% of the variation in the yield, whereas in 2022, nuts/m2, tree area, nuts/panicle, kernel weight, shell thickness, inflorescence breadth and sex ratio explained 86% of the variation. Principal component analysis indicated that the genotypes under study are diverse enough to be exploited for the future cashew improvement programmes.