Allelopathic plants: 18. passion fruit (Passiflora spp.)

Passion fruit (Passiflora incarnata and Passiflora edulis) is medicinal plant and widely grown in tropical and subtropical countries for edible fruits and medicines. In bioassay and greenhouse studies, application of plant materials significantly inhibited the germination and growth of indicator plants and major paddy weeds. In field trial, plant materials applied at 1–2 ton ha⁻¹ reduced the initial growth of paddy weeds by 70% and increased rice yield by 30%. The allelopathic properties of plant parts followed as the order: Leaf > stem > root. Numerous chemical substances belonging to alkaloids, phenolics, flavonoids, and volatiles were found in these plants, of which kavain, yagonin, dihydromethysticin and coumarin completely suppressed the barnyardgrass growth at 500 mg L⁻¹. Hence Passion fruit may be used as natural herbicide to reduce the dependency on synthetic herbicides and other agrochemicals.