REDUCED OVULE LONGEVITY INCREASES CROSS-POLLINATION RESPONSE IN OLIVE

Olive is partially self-incompatible.
Self-incompatibility in olive expresses as slower pollen tube growth that provokes a lower level of fertilization.
Such self-incompatibility reaction often leads to a reduction on fruit set, but the magnitude and significance of yield losses vary among years and zones even for the same cultivar.
Orchard management that reduces Effective Pollination Period and specially ovule longevity would cause that differential response.
With the objective of relating cross-pollination response and ovule longevity we have evaluated initial and final fruit set under self- and cross-pollination and computed the Index of Self-Incompatibility (ISI) for both periods on irrigated and non-irrigated orchards of ‘Picual’. For initial fruit set, ISI ranked from 0.08 to 0.29 for non-irrigated and irrigated orchards respectively, while for final fruit set, values fluctuated between 0.07 and 0.21. Ovule longevity was limited to 6-9 days after anthesis (d.a.a.) for unwatered trees and extended beyond 12 days for watered ones.
Self-fertilization occurred about ten d.a.a. and cross-fertilization between 4 and 10 d.a.a.
Stigma receptivity surpassed 12 days with scarce differences between rainfed and watered orchards.
Analysis of Effective Pollination Period pointed out the critical role of ovule longevity and suggests that greater cross-pollination response (lower ISI) under non-irrigation can be related with shorter ovule longevity.
Our results emphasize the advantages of pollination designs in rainfed groves of the most important olive oil cultivar in Spain.

IV International Symposium on Olive Growing

A. Quero, V. Pinillos, J. Cuevas

olive, Ola europaea, Picual, Self-incompatibility, Index of Self- Incompatibility (ISI), Effective Pollination Period (EPP).

https://doi.org/10.17660/ActaHortic.2002.586.97