Exploring grain amaranth germplasm potential as a source of breeding nutritious leafy greens: insights from nutritional profiling, genetic and multivariate analysis

Grain amaranth (Amaranthus hypochondriacus) is a nutri-dense pseudocereal with dual-purpose potential as both grain and leafy vegetable. The exploration of grain amaranth types as leafy green could be useful in diversifying food systems, cropping systems and enhancing amaranth germplasm resources. The systematic nutritional profiling and multivariate analysis of grain amaranth leaves is limited, constraining targeted breeding efforts to improve nutritional quality. To establish its breeding potential for nutritious leafy greens, underscoring the compositional diversity of mineral nutrients and heavy metals accumulation in grain amaranth germplasm is vital. Plants were grown in an augmented randomized block design, and nutrient profiling was performed using digestion-based methods and microwave plasma atomic emission spectroscopy (MP-AES). Significant genetic variations were observed for essential mineral nutrients and heavy metals concentrations. Exotic accession EC519523 exhibited superior N and P content, while indigenous collections IC42356 and IC47434 showed promise for K-related nutritional quality. Vegetable checks, Arka Neelachal Bainishi and Arka Neelachal Ruchitha, along with grain type accessions, displayed potential for Fe and Mn biofortification. Notably, the comparative analysis of heavy metals with corresponding FAO/WHO permissible limits depicted significant genotypic variations where several accessions remained within limits, while the mean Cd and Pb values exceeded the referenced permissible thresholds. These findings indicated that suitability for consumption should therefore be considered genotype-dependent rather than universally safe. Multivariate analyses revealed five principal components explaining > 80% of the total variation, while cluster analysis grouped accessions into five nutritional clusters. These results enabled the scope of selecting ideal parents from diverse clusters for escalating breeding for nutritional and food security. Strong correlations between macro- and micronutrients indicated shared uptake pathways. These findings highlighted the scope of developing Amaranthus hypochondriacus cultivars with dual-purpose value and offered the opportunities for diet diversification, biofortification, and sustainable food security. The results necessitated the need of further multi-location experiments to fetch a better understanding of breeding nutritious cultivars having level of heavy metals within permissible limits, and underscoring the trade-offs between leaf and grain yield in grain amaranths.