Floral Biology and Pollination of Ampalaya (Momordica charantia L.)

Floral traits such as anthesis, anther dehiscence, pollen morphology and viability, and pollination of ampalaya or bitter gourd ( Momordica charantia L.) were observed from November 2006 to March 2007 at the Central Experimental Station, University of the Philippines Los Banos. Insect pollinators were identified and the fruit and seed sets in insect-pollinated and hand-pollinated plants were compared. Flowering of M. charantia started 38 + 3.5 d after planting with the development of male flowers earlier than the female flowers. The ratio of male to female flower was 19:1. Flowers started to open at about 0300 h, and were fully opened at 0530-1200 h. A successfully pollinated female flower started to set fruit after 2-5 d. Unpollinated flowers dried up completely after 5 d. The pollinator species were honey bees ( Apis mellifera and Apis cerana ), stingless bees ( Trigona spp.) and Halictus spp. The foraging period synchronized with anthesis, and peaked at 0700-0800 h. Fruit set in insect-pollinated (78%) and hand-pollinated (80%) flowers did not significantly vary. Likewise, there was no significant difference in fruit weight, length, diameter and number of seeds between both methods. Flowers that were not visited by pollinators did not set fruit. Key Words: honey bee, Momordica charantia , pollination, stingless bees