Correlation of morphological and physiological traits at early stages with curcumin accumulation in diverse turmeric genotypes

Abstract

Turmeric (Curcuma longa L.) is a globally significant rhizomatous perennial spice crop valued for its rhizomes, which contain 1-6% curcuminoids with curcumin as the principal bioactive compound. These curcuminoids exhibit potent anti-inflammatory, antioxidant, antimicrobial, anticancer, and hepatoprotective properties, making turmeric an important crop in medicinal, nutraceutical, cosmetic, and food industries. This study evaluated 21 turmeric genotypes to investigate the relationships among morphological traits, leaf chlorophyll content (SPAD), and curcumin concentration, aiming to aid precision breeding for enhanced turmeric quality. Plant height, leaf length and width, petiole length, tiller and leaf numbers, and SPAD chlorophyll readings were recorded. Curcumin content was estimated using solvent extraction and spectrophotometric analysis. Phenotypic correlation analysis revealed significant positive associations among morphological traits and between these traits and curcumin content. Leaf number and SPAD chlorophyll content showed strong positive correlations with curcumin concentration, indicating that vigorous vegetative growth and enhanced photosynthetic efficiency favour curcumin biosynthesis. The considerable variation among genotypes highlights the genetic potential for selection. Integrating morphological and physiological markers such as SPAD readings offers a rapid, non-destructive tool to screen turmeric genotypes for curcumin content, facilitating targeted breeding programs and turmeric quality improvement.