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Is it Congo or British Columbia Blue?

Actually, they are one and the same according to recent DNA fingerprinting.


November 14, 2007
By Rosalie I. Tennison

28aIf you grow blue-fleshed potatoes to sell to the fresh market and a customer
requests British Columbia Blue but you grow Congo, you can safely sell Congo
assuring the buyer they are getting the same great potato. Recent genetic research
at the Potato Research Centre in Fredericton, New Brunswick, proved that some
of the blue varieties currently preserved at the Potato Gene Resources Repository
have the same genetic fingerprint.

Blue potatoes have the same rich history as their white or yellow-fleshed relatives.
They were used to dye clothing in ancient civilizations and they have travelled
around the world with immigrants and explorers. Grown primarily for personal
use for many years, the blue potato is starting to make inroads at gourmet markets
and tony restaurants. Potato Gene Resources has 12 blue varieties in its repository
and speculation about their genetic makeup led to some DNA testing in 2003.
Research scientist, Dr. X. Li performed the tests and, based on the current
DNA tests that are available today, he determined that Congo, British Columbia
Blue, McIntosh Black, River John Blue, Sharon's Blue and Nova Scotia Blue are
genetically the same potato.

There could be several reasons why there are so many names for the same variety.
Cultural and regional differences may hold the clue to why this has occurred,
suggests Dr. Richard Tarn, a potato breeder and the curator of the repository.
"One hundred years ago people might have renamed potatoes to suit their
area or their needs," he says.

Folks who moved west from Nova Scotia may have taken seed for their favourite
blue potato, Nova Scotia Blue, with them but once they got settled and gave
seed to their neighbours, the name may have changed to British Columbia Blue.
Perhaps the giver of the seed was named Sharon and thereafter the receiver referred
to the potato as 'Sharon's Blue'. Over time and repeated sharing of seed, the
new names stuck. Other criteria for naming potatoes was by shape, as in 'Fingerling'
or 'Lumpers' or even to recognize the plant, as in 'Green Mountain'.

Tarn suggests marketing may have had a lot to do with renaming potatoes which,
in some cases, had cultural overtones. For example, some older varieties of
white potatoes, especially during the economic depression of the 1930s, were
called 'Money Make' and 'Forty Fold'. Renaming an old variety to make it appear
like a new one, or giving a less popular variety the name of a popular one,
to boost sales was a common practice in the early years of the last century.

"I don't know how these names would hold up in advertising," comments
Tarn. He adds that neither Money Make or Forty Fold are in the repository, so
unless growers of heritage varieties have seed, the validity of the names cannot
be tested!

Finally, in 1919 in the United Kingdom, a committee was struck to address the
issue of using synonyms to describe the same variety. This led to the creation
of the certification process that prevents use of synonyms among officially
registered cultivars. However, that has not prevented marketers today from 'branding'
varieties to suit their needs. In a recent case, a company licensed the use
of a popular variety which has been given a new name or 'label' to make it appealing
to dieters following a low carbohydrate regimen. Essentially, growers will produce
the variety under its original name and if it is sold to the 'low-carb' market,
it will appear in store bins under its new name. Even as Tarn and his colleagues
try to identify groups of potatoes as virtually the same, marketers are creating
the next generation of synonymous potato varieties.

Where does this leave the many varieties of blue potatoes? Tarn says all the
varieties will continue to be maintained at the repository. Even though they
are within the limits of current scientific technology and appear to be the
same, scientific advances in the future may prove them to be different. "We
have to preserve the differences, if they exist," he explains.

While blue potatoes may be the showiest and the most colourfully named varieties,
they are not an isolated case. Tarn and his colleagues already know there are
similarities between some white-fleshed varieties, identifying potential similarities
within the fingerling or banana group of varieties. But, the genetic testing
takes time and it could be years before similar varieties in the repository
are tested and identified as 'synonyms'.

The good news in this research is that blue potatoes are gaining some notice
in the media and, ultimately, the marketplace. Tarn says work is just beginning
on proving the extra nutritional value of blue-fleshed potatoes in the area
of their antioxidant properties. Blueberries have been touted as the antioxidant
source of choice, but the dark blue flesh of Congo and its relatives also offer
the same antioxidant value. Potatoes offer a more economical source for these
disease-reducing nutrients and, since they can be stored more easily for longer
periods, they offer a long-term solution for people seeking to increase their
antioxidant intake.

Again, the work of the repository has proven its value. Not only has it preserved
the blue varieties for future health-conscious generations, it has also proved
the quirkiness of early potato growers, who identified their potato varieties
by where they lived or where the seed came from. Thanks to DNA fingerprinting,
we now know that a blue potato by any other name is likely Congo. -30-