Reproductive assurance through unusual autogamy in the absence of pollinators in Passiflora edulis (passion fruit)

Abstract

Passiflora edulis (passion fruit), a native of Brazil, is widely grown in frost-free areas around the world. In its native habitat and many other areas, the species is self-incompatible and carpenter bees are the effective pollinators. In India, it is cultivated in North East and southern states. In two of the populations of P. edulis F. flavicarpa (yellow passion fruit) in Karnataka, there was good fruit set, although there were no effective pollinators. Studies were carried out on reproductive ecology of yellow passion fruit to understand the mode of fruit set in the absence of pollinators and the breeding system. Although several floral visitors, Apis cerana, Trigona sp. and an ant (Camponotus sp.) visited the flowers, they were all nectar robbers and not the pollinators. There is a unique autonomous self-pollination, involving the movement of anthers and stigmas, during flower opening which provides reproductive assurance to the species even in the absence of pollinators. The populations used in the present study are self-compatible. Thus. the species is able to produce constant fruit set even when population size is small and pollinators are absent; avolution of these features seems to be the main factor for its wide distribution around the world.