Understanding pollination processes in avocado (Persea americana) orchards

D.E. Pattemore, L.E. Evans, H.M. McBrydie, A. Dag, B.G. Howlett, B. Cutting, R.M. Goodwin
Avocado (Persea americana) is an important tree crop globally, and the fruit have high nutritional value. Fruit-set percentages in avocado are typically less than 0.3%, while hand-pollination often achieves about 5% fruit set. This suggests that fruit set could be limited byinsufficient pollination. We investigated pollination processes in avocado orchards in Australia and New Zealand in order to understand whether poor pollination was limiting avocado production. We recorded no pollen deposited on more than 80% of all female flowers. While receptive female flowers were visited multiple times by potential pollinating insects, few of them carried more than 100 pollen grains (e.g., just 6% of flower-visiting honey bees, Apis mellifera). Honey bees, bumble bees (Bombus spp.) and flies caught off either polleniser male-phase flowers or 'Hass' female-phase flowers carried different amounts of avocado pollen grains, suggesting that differences in behavior between pollinator species may affect the rate of pollen movement between pollenisers and 'Hass' flowers. Improving the rate of pollen movement between cultivars and deposition in avocado orchards is critical to ensure that pollination does not limit fruit production. Our research demonstrates the importance of understanding key metrics of pollination, and provides a template for monitoring and managing pollination in avocado orchards globally.
Pattemore, D.E., Evans, L.E., McBrydie, H.M., Dag, A., Howlett, B.G., Cutting, B. and Goodwin, R.M. (2020). Understanding pollination processes in avocado (Persea americana) orchards. Acta Hortic. 1299, 317-328
DOI: 10.17660/ActaHortic.2020.1299.48
flower, pollinator, fertilisation, honey bee, Apis mellifera, bumble bee, fruit set

Acta Horticulturae