Floral biology, breeding system and pollination of Pterocarpus marsupium Roxb

Abstract

Pterocarpus marsupium Roxb. is a medicinally important tree species distributed throughout India. In order to provide important information in relation to reproductive success, we investigated floral biology, breeding system and pollination mechanism which will help to conserve the plant. The flowering period in the trees ranged between 20 and 38 days. The bright yellow, showy flowers start to open from 05.30 h and continued upto 06:30 h during which they emit mild fragrance and nectar. Asingle flower produced around 35,180±127.9 pollen grains. After flower opening, different insects represented by Hymenoptera, Lepidoptera and Thysanoptera were found to forage the flowers. Among the flower visitors, bees were found to be the most dominant and effective one. Fruit-set in natural conditions was 32% and 4% through bagging while 12% was observed in netting condition. But in case of controlled pollinations 10%, 24% and 16% fruit set was noticed through autogamy, xenogamy and geitonogamy, respectively. Results from the breeding experiment suggested that, the trees of P. marsupium exhibits mixed breeding system with selfing and outcrossing.