Genetic diversity analysis using shoot and root morphological markers in castor (Ricinus communis L.)

The morphological variation and genetic diversity in 15 root and shoot characters was studied in 27 castor accessions sown in an elevated temporary root study structure. Variation in characters accounted to 3.05 to 50.29%. Characters were subjected to Shannon Weaver diversity index (H`) to know the genetic diversity. Eleven traits recorded high H` indicating suitability in breeding programmes. Their regression coefficients indicated positive change for six traits in dependent variable seed yield. Phenotypic correlation studies revealed that seed yield was significantly correlated to root dry weight, root diameter, plant height, node number, effective spike length and 100 seed weight. Principal component analysis (PCA) revealed that PC1, 2 and 3 accounted for 44.52, 15.93 and 10.54% variation. High loadings in the first three PCs were recorded for nine traits viz., root dry weight, shoot dry weight, root length, total root length, root diameter at crown region, SCMR, effective spike length, node number to primary spike. Hence, present studies gains importance in understanding the root related traits and their role in quantifying the genotypes in terms of divergence.