Canna Agriculture Group

The Canna Agriculture Group contains all of the varieties of Canna used in agriculture. Canna achira is a generic term used in South America to describe the cannas that have been selectively bred for agricultural purposes, normally derived from C. discolor. It is grown especially for its edible rootstock from which starch is obtained, but the leaves and young seed are also edible, and achira was once a staple foodcrop in Peru and Ecuador.

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Farming Varieties

There are some named agricultural varieties, and published comparative studies have involved:

• C. 'Thai-purple'
• C. 'Thai-green'
• C. 'Japanese Green'
• C. 'Chinese Purple'

  Many more traditional varieties exist world-wide, they have all involved human selection and so are classified as agricultural cultivars. Traditionally, Canna 'edulis' has been reputed to be the variety grown for food in South America, but there is no scientific evidence to substantiate the name. It is probable that edulis is simply a synonym of C. discolor, which is grown for agricultural purposes throughout Asia, refer Dr Tanaka.

In the Andes, the rhizome can be harvested within 6 months from planting out and the yields range from 13 - 85 tonnes per hectare, with 22 - 50 tonnes being average, though larger yields are obtained after 8 - 10 months.

Most cultivated forms do not produce fertile seed. There are also sterile triploid forms, these contain a significantly higher proportion of starch, though their cropping potential is not known.

Animal fodder

The rhizomes and leaves are good fodder for cattle and pigs and it is grown for this purpose in Hawaii, where it is harvested 4-8 months after planting.

Human consumption

Canna is still grown for human consumption in the Andes and also in Vietnam and southern China, where the starch is used to make cellophane noodles.

Edible qualities

Rootstock - actually a rhizome, this can be eaten either raw or cooked. It is the source of canna starch which is used as a substitute for arrowroot. The starch is obtained by rasping the rhizome to a pulp, then washing and straining to get rid of the fibres. This starch is very digestible. The very young rhizomes can also be eaten cooked, they are sweet but fibrousy. The rhizome can be very large, sometimes as long as a person's forearm. In Peru the rhizomes are baked for up to 12 hours by which time they become a white, translucent, fibrous and somewhat mucilaginous mass with a sweetish taste. The starch is in very large grains, about three times the size of potato starch grains, and can be seen with the naked eye. This starch is easily separated from the fibre of the rhizome.

Young shoots - these can be cooked and eaten as a green vegetable and are quite nutritious, containing at least 10% protein.

Seeds - the immature seeds are cooked in fat in tortillas.

References

• Chaté, E. - Le Canna, 1866.
• Fang, Yang; Wang PingHua, Xie ShiQing, Zhang WeiGuang, Fang DeHua (2004). "Technique of scarifying and fermenting process of Canna starch.". Southwest China Journal of Agricultural Sciences 17 (2): 231-234.
• Khoshoo, T.N. & Guha, I. - Origin and Evolution of Cultivated Cannas. Vikas Publishing House.
• Kress, W. J. 1990. The phylogeny and classification of the Zingiberales. Ann. Missouri Bot. Gard. 77: 698--721.
• Kress, W. J. and D. E. Stone. 1982. Nature of the sporoderm in monocotyledons, with special reference to the pollen grains of Canna and Heliconia. Grana 21: 129--148.
• Lerman, J. C. and E. M. Cigliano. 1971. New carbon-14 evidence for six hundred years old Canna compacta seed. Nature 232: 568--570.
• Rogers, G. K. 1984. The Zingiberales (Cannaceae, Marantaceae, and Zingiberaceae) in the southeastern United States. J. Arnold Arbor. 65: 5--55.
• Segeren, W & Maas, PJM - The genus Canna in northern South America (1971), Acta Botanica Neerlandica. 20(6): 663-680.
• Tanaka, N. 2001. Taxonomic revision of the family Cannaceae in the New World and Asia. Makinoa ser. 2, 1:34–43.