BC Fruit Grower Perspective: Arctic® apples and cross-pollination

We are very pleased to have esteemed agricultural scientist and orchardist Dr. David Lane share his thoughts on Arctic® apples as a guest blogger for www.arcticapples.com. You may recall that we also shared Dr. Lane’s letter to the Canadian Food Inspection Agency (CFIA) in early July and we hope to have him share his expertise on a variety of topics relating to Arctic apples again soon. For this entry, Dr. Lane provides his opinion on cross-pollination concerns:

As was outlined in my submission to the Canadian Food Inspection Agency, Arctic® apples are a tremendously valuable and innovative solution to a blatant barrier to apple consumption: enzymatic browning. Furthermore, they absolutely do not present any unusual environmental risks, including to neighbouring apple orchards. Dr. David Lane

Domestic cultivated apples were introduced to North America hundreds of years ago and have interacted with the native crab apple species without any harmful effects to speak of. Much in the same way, Arctic trees and their apples respond to weather, plant pests, etc. just as conventional trees do, so have no more propensity to threaten existing varieties than any other cultivar.

Cutting right to the point, cross-pollination should not be a concern. Even if it did occur only some of the seeds (which aren’t used or consumed anyway) would contain any Arctic material. None of the resulting fruit would contain any Arctic material. But for those who would still like the additional re-assurance that cross-pollination will not transpire in any case, the answer lies in bee behavior.

Okanagan Specialty Fruits has done their due diligence in this matter through their collaboration with mathematical modeling specialists which resulted in the publication of two scientific papers in very high ranking journals. These papers describe, in mathematical terms, the flow of pollen in apple orchards in such a way that contour maps illustrating pollen gene flow from source (high-quality area) to sink (low-quality area) can be generated. 

Bee with apple blossoms

At the Arctic apple field trials, 37,000 individual seeds were tested for a marker gene, collected at distances up to 200 meters from the Arctic trees in two different years. This data was used to develop equations for bee travel and pollen distribution in orchards (based on diffusion) including a provision to allow for ‘scout’ bees that travel further than the average foraging bee. The model explains the effects of different sizes of pollen source and sink blocks, and factors such as the effects of buffer rows between blocks. 

Most interesting to me is that bees can pollinate (with very low frequency) at up to a kilometer or two but only if there is no competing pollen from another source – a trap plant scenario. On the other hand, pollen from a small source (a circle one meter on diameter) in the midst of a very large sink results in pollen gene flow detectable at only 0.3 meters. This is because of the overwhelming competition from the massive sink pollen population.

The model, other research papers on pollination and commercial experience indicate pollen gene flow to be undetectable in all but the most unusual circumstances, certainly so if conditions such as barrier rows are applied. It is interesting to note that one contaminated apple seed in a million is the equivalent of one seed in 200 bins of apple – in practical terms, undetectable.

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