Antioxidant potential and molecular diversity of passion fruit genotypes from Northeast India

Passion fruit (Passiflora spp.) is a nutritionally rich fruit crop, and exhibits wider variability among the germplasm in terms of genetic, morphological and nutritional traits. In spite of such potential, the biochemical and genetic diversity from Northeast India remains poorly characterized. This study evaluated antioxidant potential and molecular diversity in 29 genotypes of Northeast India. Considerable variation in antioxidant-related compounds was observed among the genotypes. Total phenolic content ranged from 114.04 to 842.01 mg GAE 100 g⁻¹, flavonoid content from 74.12 to 321.11 mg 100 g⁻¹, and ascorbic acid from 92.62 to 261.21 mg 100 g⁻¹. Carotenoid concentration varied between 0.60 and 6.11 mg 100 g⁻¹, while vitamin A ranged from 0.22 to 0.57 mg 100 g⁻¹. Antioxidant activity also varied widely, ranging from 56.95% to 96.49%, indicating substantial nutritional variability among the genotypes. Molecular diversity analysis using 19 polymorphic SSR markers generated 105 alleles, with 3 to 10 alleles per locus and a mean of 5.53 alleles. Genetic diversity indices revealed high variability with expected heterozygosity of 0.70 and polymorphic information content of 0.70, while observed heterozygosity remained relatively low (0.10). Bayesian population structure analysis grouped the genotypes into three genetic populations (K = 3), broadly corresponding to geographic origin. Analysis of molecular variance indicated that 91% of genetic variation occurred within populations and 9% among populations. Integrated biochemical and molecular analyses reveal genetically diverse, nutritionally superior genotypes valuable for conservation and future breeding studies.