Effects of different pollination treatments on the fertilization physiology and fruit production in passion fruit

• Pollination by Chinese bees enhances flower fertilization and subsequent ovary development. • Pollination by Chinese bees significantly improves the yield and quality of the two kinds of passion fruits. • It is feasible for Chinese bees to pollinate passion fruit. Pollination is often used as an example of an ecosystem service, which secures global food production, and pollination by animals, especially insects, improves the most crop output. In this study, we investigated the effects of different pollination treatments, including Chinese bee pollination (P1), artificial self-pollination (P2), artificial within-plant cross-pollination (P3), artificial cross-plant cross-pollination (P4), and spontaneous self-pollination (CK), on the fertilization physiology, fruit set, yield, fruit development and quality in two passion fruit cultivars of Qinmi 9 and Tainong 1 under field conditions, in order to evaluate the effectiveness of Chinese bee pollination and determine the optimal pollination method. As most important result was that both Chinese bee pollination and artificial pollination promoted the germination and growth of pollen tubes, fostered the development of the ovary, and controlled the reduction of ovule numbers. Specifically, P1 increased the fruit set in Qinmi 9 and Tainong 1 with a respective increase of 2.9 and 6.2 times, and also the yield with a respective increase of 2.9 and 15.7 times. Chinese bee pollination also facilitated fruit development, enhanced both external and internal fruit quality, and improved amino acid content. Membership function analysis indicated that Chinese bee pollination is the best pollination treatment for increasing yield and quality in both passion fruit species.