Effectiveness of Pollinator Insects in Increasing Fruit Formation of Pummelo (Citrus maxima (Burm.) Merr.)

Pummelo (Citrus maxima (Burm.) Merr.) is a type of plant which have commercial value, and at least 24 cultivars are spread across various regions in Indonesia. Some cultivars have self-incompatibility (SI) mechanisms as genetic barriers to fertilization, but this can be reduced through cross-pollination by insects. Therefore, this study aims to measure the effectiveness of wild pollinator insects, as well as human and bee pollinations in pummelo. A total of six treatments were set up, namely closed pollination or control, open treatment, human pollination using pollen from the same tree (geitonogamy) or different trees (xenogamy), as well as supplementation colony of honey bee (Apis cerana), and stingless bee (Tetragonula laeviceps). The highest increase of pummelo fruit formation was found in human-pollination (xenogamy), followed by A. cerana, T. laeviceps, open treatment, and geitonogamy pollination with 63%, 54%, 48%, 41%, and 14%, respectively. Based on the results, bees (A. cerana, T. laeviceps, Ceratina sp., Xylocopa confusa, X. latipes), fly (syrphid species), as well as butterflies (Papilio demoleus, Catopsilia pyranthe, and C. pomona) are potential pollinating agents of pummelo