Multivariate analysis of seed mineral composition in lablab bean (Lablab purpureus L.) germplasm

This study assessed seed mineral composition in lablab bean ( Lablab purpureus L.), an underutilized legume with potential to combat micronutrient malnutrition, focusing on key micronutrients (Fe, Zn, Cu, Mn) and macronutrients (P, K). Seed samples were oven-dried, finely ground and subjected to di-acid (HNO₃:HClO₄, 9:4) wet digestion following standard protocols to ensure complete oxidation of organic matter and release of mineral elements. The digested extracts were diluted to a known volume and used for analysis. Micronutrients were determined using an Atomic Absorption Spectrophotometer (AAS), while phosphorus and potassium were estimated using a spectrophotometer and flame photometer, respectively. Wide differences were observed, with Fe ranging from 71.95 mg/kg (IC-285148) to 212 mg/kg (IC-556845) and Zn from 34.3 mg/kg (IC-413709) to 76.5 mg/kg (EC-454159). Copper content varied between 8.6 mg/kg (IC-285148) and 35.3 mg/kg (EC-454159), while Mn ranged from 14.25 to 28.5 mg/kg. Among macronutrients, P content spanned 0.352% (IC-556765) to 0.505% (IC-586963) and K from 0.942% (IC-285115) to 1.761% (Pusa Garima). High coefficients of variation for Cu (37.79%) and Fe (28.87%) reflected considerable diversity. Correlation analysis showed significant positive associations of Fe with P (r = 0.465) and Zn with Cu (r = 0.550, p < 0.01), while negative associations such as K with Zn (r = -0.250) suggested nutrient trade-offs. Principal component analysis (PCA) explained 79.29% of the total variance, with PC1 (34.55%) capturing co-variation of Fe, Zn, Cu, and P, and PC2 (26.57%) defined by Mn and K. Hierarchical cluster analysis (HCA) classified the accessions into five groups, highlighting IC-556845, EC-454159, IC-856772, RCPD-16, IC-285115, and IC-586963 as mineral-rich lines. These results are important because they provide a scientific basis for utilizing lablab bean as a sustainable source of essential dietary minerals. The identified lines represent valuable resources for breeding and biofortification programs aimed at addressing widespread Fe- and Zn-deficiency malnutrition in developing regions. • Substantial genetic diversity recorded in lablab bean seed mineral content. • Fe ranged 71.95–212 ppm and Zn 34.3–76.5 ppm across evaluated genotypes. • IC-556845 (Fe-rich) and EC-454159 (Zn-rich) emerged as key donor lines. • PCA revealed Fe–Zn–Cu–P as major enrichment axis, distinct from Mn–K. • Mineral-rich genotypes identified for targeted biofortification breeding.