Effect of pollination on seed set of Origanum syriacum under semiarid Mediterranean conditions

Abstract

This study was aimed at identifying the potential different insect visitors of Origanum syriacum flowers and at evaluating their role in seed set in Syrian Oregano grown under its native semiarid Mediterranean conditions. Three treatments were imposed on O. syriacum plants before flowering: 1) Plants were left uncovered to permit insect visiting, 2) plants were covered and hand pollinated with pollen from flowers of other plants, and 3) plants were covered (control). The results showed that 21 bee species were identified visiting O. syriacum flowers, of which 8 species were recorded for the first time in Jordan. Supplementary pollination produced a higher significant number of seeds and seed set than other pollination treatments that led us to conclude that O. syriacum flowers are affected by pollen shortage under natural conditions. Wind plays little or no role in its pollination process. There is low seed yield production and seed set by O. syriacum under natural conditions in Jordan. The number of bee colonies as well as the wild bees must be enhanced in the area to improve their value in O. syriacum flower pollination.