Strawberry Pollination Basics
Strawberry flower morphology and seed set
Strawberry flowers have both male and female parts on each bloom. The male parts include the pollen carrying portion of the flower (highlighted in blue) and pollinators must come into contact with this area to collect pollen grains. The female parts of the flower (highlighted in pink) must individually receive pollen grains to attain complete pollination.
Lack of complete pollination in each pistil (female flower part) can result in smaller or misshapen berries, meaning reduced yield of marketable fruit.
The actual berry forms from each pistil developing into an individual “seed’ that is actually an individual fruit, called an achene. The fleshy red part of the strawberry is rather an enlarged receptacle that holds the achenes (Poling, 2012).
As seen in the photo below, there are many ways for pollen to be transferred within the flower and unlike some crops, strawberries are self-fertile. However, maximum yields are possible with a combination of self-pollination (pink), wind (blue), and insects (green).Although flowers are capable of self-pollinating, each pistil must receive pollination, and studies have shown that self-pollination and wind-blown pollen are often not sufficient to completely pollinate a flower. Only about 60-70% of maximum pollination results from these vectors alone, and open pollination with the aid of insects is necessary for the greatest yield. Insect pollination can also improve strawberry quality and shape, meaning that berries last longer and look fuller!
- Klatt, B. K., Holzschuh, A., Westphal, C., Clough, Y., Smit, I., Pawelzik, E., & Tscharntke, T. (2014). Bee pollination improves crop quality, shelf life and commercial value. R. Soc. B, 281.
- Wietzke, A., Westphal, C., Kraft, M., Gras, P., Tscharntke, T., Pawelzik, E., & Smit, I. (2016). Pollination as a key factor for strawberry fruit physiology and quality. Berichte Aus Dem Julius Kühn-Institut, 183, 49–50.
- Zebrowska, J. (1998). Influence of pollination modes on yield components in strawberry (Fragaria x ananassa Duch.). Plant Breeding, 117(3), 255–260.
(Written by Jeremy Slone, August 2016)