Phytochemical profiling and antioxidative potential of yardlong bean landraces of North-East India

Vegetable legumes supply a substantial amount of proteins, micronutrients, and health-assisting phytochemicals with lesser anti-nutritional inhibitions. Yardlong bean ( Vigna unguiculata subsp. sesquipedalis ) which belongs to the leguminaceae family, a nutrient enriched crop in North Eastern region of India, often falls shorter in this context as the landraces differ widely in assimilate partitioning and secondary metabolites. The present investigation focuses on the gap investigating thirty landraces of the crop collected from different states of North-East India to verify whether genetically influenced biochemical variations can be exploited to identify lines with the addition of dense nutrition with lower levels of phytate, tannins, and trypsin inhibitors by amalgamation of comprehensive biochemical profiling with correlation analysis and principal component analysis, the present investigation extends beyond single-trait comparisons and enables resolution of coordinated metabolic modules. It was observed that the 30 accessions of yardlong bean landraces possessed significant biochemical diversity with regard to the nutritional, phytochemical and antinutritional characteristics. The accessions CHFYB-7 and CHFYB-2 stood out as excellent nutritional and antioxidant genotypes, whereas CHFYB-5 and CHFYB-15 were observed to have high amounts of vitamin A and vitamin C, respectively. CHFYB-15 was also seen to have low trypsin inhibitor activity. Positive correlations, PCA and GT biplots indicated strong positive correlation between various nutritional characteristics and negative correlations among some traits with G2 having positive and healthy combinations of various biochemical characteristics. The overall ranking of the landraces as regards their nutritional qualities was found to be CHFYB-7 > CHFYB-11 > CHFYB-15 > CHFYB-2 > CHFYB-25. Clustering of the genotypes resulted in two groups with Cluster I including seven landraces exhibiting relatively healthier biochemical compositions, while Cluster II included twenty-three landraces exhibiting greater biochemical diversity. The Z-score heatmap supported this grouping and identified biochemical differences among the genotypes. The selection index placed G7, G11, G15, G2, and G25 in the top five list, whereas G28 was the least ranked. The landraces CHFYB-7 and CHFYB-2 were found to be superior in total soluble protein, carbohydrates, phenols, flavonoids, and antioxidant activity, whereas vitamin A and vitamin C content was highest in CHFYB-5 and CHFYB-15, respectively. Based on overall ranking, landraces as CHFYB-7 > CHFYB-11 > CHFYB-15 > CHFYB-2 > CHFYB-25 are highly recommended, it is clear from these results that the North-East Indian yardlong bean landraces contain valuable ideotypes that can help achieve both nutritional quality and digestibility through breeding programs.