Study of flower biology and pollen tube growth of mature olive tree cv. 'Zard'

Olive (Olea europaea L.) is one of the valuable fruit trees due to its desirable olive oil and table olive. To facilitate olive orchard management decisions is essential to have knowledge on flower biology and physiology of fruit set of each planted cultivar. In order to achieve these objectives this experiment was conducted to explore flower biology and pollen tube growth of 'Zard' cultivar under the environmental condition of Roodbar, Iran. In addition effective pollination period (EPP) for 'Zard' cultivar was monitored. For the study of flower biology two sets of inflorescence samples (60 inflorescence each) were taken for further evaluation. In additions in order to evaluate pollen tube growth in the style ovary of 'Zard' cultivar, four branches of this cultivar were pollinated using pollen from 'Zard' and 'Roghani Roodbar' cultivars after flower emasculation. Pollinated flowers were sampled in time intervals by 24, 48, 72, 96 and 120 hours after pollination. For further study of pollen tube growth using fluorescence microscopy. Results of the study on flower biology of 'Zard' cultivar indicated that 32.81 percent of its flowers are complete. In addition, results from pollen tube growth study showed that pollen tube of both cultivars ('Zard' and 'Roghani Roodbar') reached the style base of 'Zard' cultivar 48 hours after pollination, although 72 hours were needed for reaching pollen tube growth into the ovule. Note that there were not any significant differences in pollen tube growth among pollen of 'Zard' and 'Roghani Roodbar' in the style of 'Zard' cultivar. Also the best performance in terms of better fruit set and development on 'Zard' cultivar was achieved if pollination occurred 1 to 4 day days after emasculation, so this period should be considered as effective pollination period (EPP) for this cultivar. Under the condition of this study it is concluded that olive cv. 'Zard' has a good fruiting and yield potential.