Influence of cross-pollination on the development of parthenocarpic olive (Olea europaea) fruits (shotberries)

摘要

The impact of three different pollination treatments (self-, cross-, free-) on the degree of shotberry (seedless fruit) formation of the olive tree cultivars (cvs) Koroneiki, Kalamata, Mastoidis and Amigdalolia was studied for three consecutive years. Controlled crosses were made for the cross-pollination treatments, while for the free pollination treatment flowers were allowed to receive pollen from more than 40 cultivars present in the field. Significant differences were recorded between treatments, cultivars and years. The lowest degree of shotberry formation was observed in free-pollinated trees while the highest was in self-pollinated trees of all cultivars. Low air temperature incidents during the flowering period increased shotberry formation. Cultivars Koroneiki and Mastoidis were reciprocally the most effective pollinator varieties in reducing shotberries. Cultivar Koroneiki could be considered as the most suitable pollinator to reduce shotberries in Kalamata. When cv. Amigdalolia was cross-pollinated by cvs Koroneiki and Mastoidis the degree of shotberry formation was lower when compared to cross-pollination by cv. Kalamata.