The goal of this research was to study the mechanism of pollination in the yellow passion fruit and to identify natural pollinators of importance. The study was carried out in 2010-2011 in the Palestina (Caldas) to 1050 masl, by performing five treatments of pollination: natural (P.N), hand pollination (P.M.D), spontaneous and assisted self-pollination (A.P, A.P.E.) and geitonogamy/autogamy (G) in 48 accessions of yellow passion fruit. The results showed significative differences between treatments, the highest percentage of set fruit (88%) was observed during P.N carried by bumblebees from genus Xylocopa spp, followed by P.M.D. (60%). In contrast self-pollination treatments (A.P.E, A.P, G) achieved only a 3% set fruit. Likewise, the P.N showed the highest fruit weight average (203 g), and the highest flesh to seed ratio (47%), followed closely by P.M.D (187.5 g and 44.7%, respectively). The activity and effectiveness of pollinators showed a correlation with the maximum daytime temperature (r=0.69), solar irradiance (r=0.56) and relative humidity (r=0.64). However, the highest percentage of fruiting was achieved when the first two environmental variables decreased simultaneously below 26°C and three hours per day less.
Keywords: plant/pollinator relationship, Xylocopa spp, tropical fruit, carpenter bee.