Reduced Pollination Efficiency Compromises Some Physicochemical Qualities in Gac (Momordica cochinchinensis Spreng.) Fruit

Gac is valued for the nutritious aril surrounding its seed. When pollinators are limited or when flower sex expression is female-biased, hand pollination is necessary. Here, female flowers were hand pollinated with male flowers or pollen stored for up to 84 days at 4 or −20 °C, and fruit set and some qualities of mature fruit were evaluated. Cool storage reduced pollen viability (germinability and pollen tube length) and compromised fruit set (10–87%) compared with fresh pollen (97%). Fruit weight was also reduced at least by 8%, and oil concentration in aril by 40%. However, the lycopene and β-carotene concentrations in aril were largely uncompromised, and some fruits were of a marketable weight (>1.2 kg) and quality. Cool storage is a low-cost method for the short-term storage of Gac pollen. However, methods for drying pollen to an inactive state need investigation for a storage protocol, and for improvements in fruit set and fruit physicochemical qualities using hand pollination.