Principal component analysis for evaluating genetic diversity in turmeric (Curcuma longa L.) accessions

Abstract

Turmeric (Curcuma longa L.) is one of the most important spice crops in India and is widely cultivated in the north-eastern region of the country, which represents a rich reservoir of genetic diversity. The current study was undertaken to assess the genetic diversity among turmeric accessions and to determine the contribution of rhizome yield and its associated traits to the overall genetic divergence using principal component analysis (PCA). A total of forty turmeric accessions were evaluated for yield and related morphological traits under field conditions. Principal component analysis revealed that two principal components had eigenvalues greater than one, indicating that these components accounted for a substantial proportion of the variability among the studied traits. The first 3 principal components (PC1, PC2 and PC3) explained 45.73, 6.77 and 6.05% of the total variation, respectively, collectively accounting for 58.66% of the overall variability. Traits viz., plant height, leaf length, leaf breadth, total number of leaves, yield per plant, number of mother rhizomes, weight of mother rhizomes, number of primary fingers and curcumin content showed positive contributions in PC1, PC2 and PC3, indicating their significant role in genetic divergence among the accessions. Among these traits, plant height exhibited the highest contribution towards total divergence (69.62%) in the ranked contribution analysis. The results indicate that these key traits are major contributors to variability and can be effectively utilised as selection criteria in genetic improvement programs aimed at improving yield and quality in turmeric.