Multivariate Assessment of Curcuminoid Content, Leaf Oil Yield, and Rhizome Productivity in Curcuma longa Accessions from Northeast India

Curcuma longa L. (turmeric) is a versatile crop of significant culinary and medicinal value. In the present study, 152 accessions were evaluated to assess morphological diversity for two years (2022–2023 and 2023–2024) at the CSIR NEIST experimental farm, Jorhat. All studied traits exhibited significant variation (p ≤ 0.001), indicating substantial genetic variability among the genotypes. The genetic coefficient of variation (GCV) ranged from 3.46 to 63.06, while the phenotypic coefficient of variation (PCV) ranged from 5.08 to 63.15, reflecting a wide spectrum of variability. Most traits plant height (PH), number of tillers/plant (NOT), number of leaves/plant (NOL), leaf length (LL), leaf width (LW), initial rhizome weight (IRW), rhizome yield per plot (RY)) demonstrated moderate to high heritability (33.64–99.74) and high genetic advance as a percentage of the mean (129.75), except for days to maturity. Correlation analysis revealed strong associations among traits where leaf essential oil yield showed the highest positive correlation with curcuminoid content (r = 0.54 and r = 0.53) at the genotypic and phenotypic levels, respectively, and the rhizome yield per plot showed significant and positive correlation with most of the characters (PH, NOT, NOL, LL, LW, IRW), where plant height (r = 0.37) and initial rhizome weight (r = 0.30) were found to have the highest significant correlation both genotypically and phenotypically, respectively. Path coefficient analysis indicated that plant height (1.66) and days to maturity (0.37) had a direct positive effect on rhizome yield, whereas plant height (0.40) had a negative direct effect on curcuminoid content. This suggests the potential for developing dwarf genotypes with a higher curcuminoid concentration. Using Mahalanobis D² statistics, 16 distinct clusters were identified, and principal component analysis (PCA) revealed 10 principal components contributing to the observed variability (69.03%). This is the first comprehensive report incorporating correlation and path analysis for traits such as leaf essential oil yield, curcuminoid content, and rhizome yield per plot together across such a large number of C. longa accessions from Northeast India. These findings provide valuable insights into the genetic diversity, breeding strategies, and conservation efforts for turmeric.