The effective pollination period of the olive cultivar 'Arbequina' (Olea europaea L.) in a non-traditional production region

In non-traditional production regions, olive cultivation is facing challenges sometimes associated with poor fruit set. That is the case of Uruguay, where olive cultivation has reached 7000-planted hectares; however, yields are low and irregular. Uruguay has a temperate climate with particular characteristics that differentiate it from the Mediterranean basin. It presents greater annual rainfall, reaching up to 1600 mm, high relative humidity and high interannual variability in the rainfall and thermal regime. We hypothesized that these environmental conditions may affect the reproductive biology of olive trees, reduce their Effective Pollination Period (EPP) and limit fruit set. For this reason, we determined the EPP for 'Arbequina', the main olive cultivar in Uruguay, by two methodologies: sequential pollination of flowers of different ages, and analysis of its components (stigmatic receptivity, ovule viability, and pollen tube growth). We determined the EPP to be of at least 7 days with both methods. Stigmatic receptivity, assessed by the ability to support pollen adhesion and germination, was maintained for at least 20 days after anthesis. More than 50% of the evaluated flowers maintained at least one viable ovule 23 days after anthesis, and pollen tubes required between two and three days to reach an ovule. No differences in pollen tube growth were found in relation to the age of the pistil. Our results indicate that a short EPP is not behind the low yields of 'Arbequina' in Uruguay. (c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

Olive cultivation in Uruguay faces challenges due to poor fruit set, potentially caused by environmental factors. This study determined the Effective Pollination Period (EPP) of the main olive cultivar in Uruguay, 'Arbequina', to be at least 7 days. The research also found that stigmatic receptivity can be maintained for at least 20 days, and over 50% of evaluated flowers still have viable ovules 23 days after anthesis. Pollen tubes required two to three days to reach the ovules, with no differences observed based on pistil age. The study suggests that the low yields of 'Arbequina' in Uruguay are not attributed to a short EPP.