The Water Relations and Irrigation Requirements of Passion Fruit (Passiflora Edulis Sims): A Review

SUMMARY It is generally accepted that the two forms of Passiflora edulis, the golden and the purple, originated on the edges of tropical rainforests in Brazil. Extensive hybridisation has since taken place between these two forms and their hybrids. The passion fruit (a vine) is now grown throughout the tropics and subtropics. A limited amount of basic, fundamental research has been published on the water relations of passion fruit. Leaf production and expansion are both sensitive to water deficits, while water stress reduces leaf and floral bud initiation. A single axillary flower bud forms at each leaf node of new growth along with a tendril. Flower bud development and fruit set are less sensitive to water stress than leaf initiation. Heavy rain during pollination prevents fertilization. Unevenness in crop distribution during the year is possibly linked to water stress and temperature variation. Potential evapotranspiration rates in Brazil varied between 3.5 mm d−1 and 5.8 mm d−1. The value for the crop coefficient increases from about 0.6 during apical vegetative growth up to about 1.25 during flowering and fruiting. Water productivities still need to be determined. Micro-sprinklers and drip are the most effective ways of applying irrigation water with precision to passion fruit. Opportunities exist for international cooperation in research projects of mutual interest on passion fruit water relations.