Floral biology of Grewia flavescens Juss.: an underutilized crop

Grewia flavescens is a fruit species found throughout semi-arid and sub-humid parts of the world including India. In contemporary era, emphasis on food supply, market value and medicinal utility of underutilized crops made this fruit species suitable for commercial cultivation. The present study was the first attempt made to study the floral biology of G. flavescens. Anthesis was noticed between 1130 and 1300 h whereas, between 1200 and 1230 h its peak anthesis was observed. Pollen dehiscence occurred 1–2 h prior to anthesis. The maximum pollen viability of 80.34 ± 5.16 per cent  with 1% acetocarmine was observed at the time of anthesis and it was coincided with the stigmatic receptivity. After 2 h of anthesis, receptivity of stigma was found maximum and the peak nectar production was between 0 and 2 h after flower opening. A total of 21 flower visitors were recorded, of which Megachile species was more abundant compared to Apis, Xylocopa species and other minor flower visitors. The absence of insect pollination reduce the fruit set 21% from 82% under open pollination. Delayed selfing was observed as a safety mechanism in this species.