The Role of Male Flowers and Bearing Status on Pollen Germination in Olive (Olea europaea L.)

Olive is an andromonoecious plant producing both male and perfect flowers. This study was performed to determine the pollen germination percentage and growth rate of male and perfect flowers of Zard and Roghani cultivars in ۲۰۱۵ at the Tarom olive research station. Three trees from each cultivar (On and Off bearing) were selected. Pollen was collected from male and perfect flowers on the flowering shoots at flower opening stage. These anthers insert the capped glasses. Pollens were incubated in a modified medium that contained ۰.۸% agar, ۱۰% sucrose, and ۱۰۰-ppm boric acid. Pollens were spread using a modified medium, separately collected pollens of male and perfect flowers were spread on Petri dishes containing the medium, and then transferred into the incubator for germination at ۲۵°C. After six hours of incubation, the number of germinated pollen grains was enumerated and recorded. The Zard olive cultivar had a higher pollen germination percentage (۳۹.۹۵%) than the Roghani olive cultivar (۲۹.۸%). In both cultivars, the male flowers exhibited a pollen germination rate of ۴۸.۰۱%, whereas the perfect flowers demonstrated a lower germination rate of ۲۱.۷۳%. Moreover, the germination rate of perfect flowers was significantly greater in the Zard cultivar (۳۵.۲%), in contrast to the Roghani cultivar (۲۰.۷%). In both cultivars, the pollen germination rate was ۳۹.۴۸% in the Off-season trees, surpassing the germination rate of ۳۶.۳۸% observed in the On-season trees. Moreover, the Zard cultivar exhibited a significantly higher germination rate of ۴۱.۱۳%, compared to a germination rate of ۳۸.۲۷% found in pollen from the Off-season of the Roghani cultivar. The overall results showed that male flowers of olive trees play an important role in the fertility and fruit set of perfect flowers.

کلیدواژه ها:

Andromonoecious ، germination percentage ، Olive ، Perfect flower ، Zard cultivar