Tuffelrud

Research card canon

Blue Congo

Also Blå Kongo, Blue Kongo, Congo, Purple Congo, Blauer Schwede (claimed synonym), Svartpotet fra Vegårshei (probably the same or a variant)

From
Kept in Scandinavia since the 1930s; Norwegian gene bank holds it as Svartpotet fra Vegårshei
When
Fully purple 'black potatoes' known in Europe since the 1700s; said to have reached Britain from South America early in the 1900s
Bred or kept by
unknown
Parents
none recorded
How sure
origin unverified
Shape
slightly elongated, long-oval
Proportion
1.7 times as long as wide, measured from photos
Size
unknown
Bend
none
Knobs
slight
Skin
very dark blue-purple, almost black, smooth
Flesh
violet all the way through, paler near the skin
Eyes
medium, blue
Dormancy
unknown
Flesh type
unknown
Health
Fairly early; prone to soft rot (NIBIO). Susceptible to common scab (Heritage Potatoes Canada, for a 'Congo' that may be a different clone); the licensed photo shows scab-like corky patches on the skin.
The name
unknown. 'Kongo' or 'Congo' is a trade name of unclear origin; no source explains it. Handle the name with care: a dark-skinned thing named after an African country is a naming pattern with a colonial history. Use the Norwegian folk name or a personal name for any character.

The colour swatches are the flat colours the drawings use, read from photos and lifted to even daylight; the card says how.

What it looks like. A slightly elongated tuber, about 1.7 times as long as wide in the photo, with almost black, dark blue-purple skin and violet flesh all the way through, paler in a ring just under the skin. The darkest body in this set. Skin sampled #53454D and #4B3E3C on the photo (warm indoor light, scab patches avoided); card #3D2F45, cooler and darker. Cut flesh sampled #672241 and #491A35; card #5E1F4A. A paler violet ring under the skin is a candidate signature colour.

Same inside as outside. The colour is anthocyanin, the pigment in blueberries, and it stays when cooked.

Norwegian life. In the Norwegian gene bank as Svartpotet fra Vegårshei, "probably the same or a variant" of Blå Kongo. There are several Norwegian "blåpotet" or "svartpotet" kinds with different depths of blue. Fairly early, and prone to soft rot.

Names. The cultivar name may be used in research text, but see name_meaning: for a character, prefer the Norwegian svartpotet framing or a personal name. No PGI or PDO applies.

In the cellar

Where sources disagree

identity

NIBIO: Blå Kongo, probably the same as Svartpotet fra Vegårshei

Cultivariable and Heritage Potatoes Canada: 'Congo' names at least two genetically different potatoes (All Blue in Canada, Purple Peruvian in the UK); Norwegian Wikipedia gives Blauer Schwede as a synonym

How we settled it: Unresolved. Card describes the Scandinavian Blå Kongo as NIBIO does, and treats 'Congo' elsewhere as possibly a different clone. The 2014 DNA result was not found.

maturity

NIBIO: fairly early

Heritage Potatoes Canada: late

How we settled it: Recorded NIBIO's 'fairly early' in the prose, since the card follows the Norwegian clone.

Still unknown

  • True origin and whether Blå Kongo, Svartpotet fra Vegårshei, Blauer Schwede and other 'Congo' potatoes are one clone.
  • Outcome of the 2014 DNA analysis.
  • Dormancy and cooking type for the Norwegian clone (Heritage Potatoes Canada says waxy for its Congo).
  • No CC0 photo of tubers: the CC0 'Solanum tuberosum Blue Congo' photos on Commons show only the plant.

Sources

  • kvann.no: NIBIO: Svartpotet fra Vegårshei is probably the same as or a variant of Blå Kongo (DNA test planned 2014); origin unknown, but fully coloured 'black potato' known since the 1700s; slightly elongated, dark blue outside, violet throughout; several 'blåpotet' or 'svartpotet' variants; fairly early; prone to soft rot
  • no.wikipedia.org: imported from South America to Britain early in the last century, grown in Scandinavia from the 1930s; blue flesh before and after cooking; anthocyanin; also blue congo, purple congo, Blauer Schwede
  • heritagepotato.ca: Congo: UK or US origin, blue skin, blue flesh, long to oval, late, waxy flesh, scab susceptible
  • cultivariable.com: a Congo sampled in Canada is a genetic synonym of All Blue, and a Congo sampled in the UK is a synonym of Purple Peruvian: the name covers more than one potato
  • europotato.org: ECPD 'Congo': UK and US; skin blue, eyes blue, flesh blue; long to oval

Reference photos

Used to read proportion and colour, credited here, and never traced or copied into the drawings.