There is no universally accepted treatment for the various species that make up the potatoes. We are following the treatment of Spooner D.M. Et al in 2007 in the 'Proceedings of the National. Academy of Science USA 104: 19398-19403, in which only four distinct genera are maintained - viz; S. Ajanhuiri (diploid forms); S. Curtilobum (pentaploid forms); S. Juzepczukii (triploid forms) and S. Tuberosum, which is subdivided into two two cultivar-groups (Andigenum Group of upland Andean genotypes containing diploids, triploids and tetraploids, and the Chilotanum Group of lowland tetraploid Chilean landraces)[].
Solanum curtilobum is a hybrid cultivar resulting from a cross between S. Juzepczukii and tetraploid cultivars of S. tuberosum[].

Common Name: Rucki

General Information

Solanum curtilobum is a herbaceous perennial plant producing stems 50 - 90cm tall from a tuberous rootstock.
A pentaploid form of the common potato (Solanum tuberosum), it is cultivated in parts of the Andes for its edible tubers.

Known Hazards

Although providing many well-known foods for people, including the potato, tomato, pepper and aubergine, most species in this genus also contain toxic alkaloids. Whilst these alkaloids can make the plant useful in treaing a range of medical conditions, they can also cause problems such as nausea, vomiting, salivation, drowsiness, abdominal pain, diarrhoea, weakness and respiratory depression[].
Unless there are specific entries with information on edible uses, it would be unwise to ingest any part of this plant[].

Botanical References

Range

S. America - northern Argentina, Bolivia, Peru.

Habitat

Cultivated fields, at elevations usually above 3,800 metres[].

Properties

Edibility Rating
Habit	Perennial
Height	0.75 m
Cultivation Status	Cultivated

Cultivation Details

Solanum curtilobum is a plant of high elevations in the tropics, it can also be cultivated at lower elevations in the subtropical and temperate regions. This plant is one of the S. American species of potatoes. It is one of the most frost hardy of the potato species and grows in areas that can experience frosts on 300 days of the year[]. It can probably be grown in the temperate zone in much the same way as potatoes are grown, by planting out the tubers in spring and harvesting in the autumn[]. It is sometimes cultivated for its edible tubers in the Andes, mainly as insurance against cold weather[].
Succeeds in most soils[]. Dislikes wet or heavy clay soils[, ]. Prefers a slightly acid soil, the tubers are subject to scab on limy soils or those deficient in humus. Yields best on a fertile soil rich in organic matter.
Yields are quite low[].Plants might have strict daylength requirements and may yield poorly in temperate zones because they need short-days in order to induce tuber-formation[].
A pentaploid species, it produces fertile seed[].

Edible Uses

Tubers - cooked[, ]. A good source of starch but the root has a bitter taste, which can be removed by freeze-drying the tubers to make a food called 'chuño'[]. This is one of the principle species used in the Andes for the production of 'chuno', a freeze-dried potato product[]. White chuno is made by freezing, peeling, soaking and then sun-drying the potatoes. Black chuno is made by the same process, but without the soaking[]. White chuno is much less bitter than black[]. Chuno is most commonly used in soups and stews, combined with barley and herbs[]. Chuno can be stored for 3 - 4 years[].

Medicinal

None known

Other Uses

None known

Propagation

Seed - sow early spring in a warm greenhouse. Prick out the seedlings into a fairly rich compost as soon as they are large enough to handle and grow them on fast. Plant them out after the last expected frosts.
Division. Harvest the tubers in autumn after the top-growth has been cut back by frost. Store the tubers in a cool frost-free place overwinter and replant in mid spring.