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Ullucus tuberosus Caldas
Chigua (Col.); Chuguas (Ecu.); Hubas (Ecu., Col.); Melloco (Ecu., Col.); MichiruÃ, Miguri, Muchuchi (Venez.); Olloco (Ecu., Col.); Papa Lisa (Sp.); Ruba(s) (S. Am.); Timbos, TiquiÃ±o (Venez.); Ulluco(s) (Arg., Peru).
Ullucu is a perennial herb with a small number of erect stems 20-30 cm high, and fibrous roots, some of which thicken at the end and produce tubers. Stolons arise in the leaf axils and trail over the ground, rooting and producing small tubers at the nodes: often tubers are borne aerially on stolons that do not reach the ground. The alternate leaves are broadly oval to cordate, 5-20 cm long and 5-12 cm broad, somewhat fleshy, variable in colour according to cultivar, ranging from dull green to bright green with red spots and purplish-yellow borders. The skin of the tubers also varies with cultivar, being white, red or yellow or red-spotted and the flesh is normally yellow: over 70 cultivars have been recognised. A yield of 30 tubers per plant is described as 'average'. The tubers are small, rather longer than broad, measuring 3-7 cm in length.
Origin and distribution
Ullucu originated in the high Andes of Peru, Bolivia and north-west Argentina. It was introduced into Sri Lanka early in the present century, but its cultivation is still virtually confined to the Andes.
The plant grows best in cool moist conditions under short day-lengths of about 12 hours (the production of stolons and stolon-borne tubers is stimulated by even shorter days of 10 hours). Ullucu has considerable resistance to frost and thus it is well suited to the Andean altiplano or high valley conditions. It is cultivated at elevations between 1 500 and 4 000 m, where it gives higher yields than the Andean cultivars of potato. It is frequently intercropped with oca (Oxalis tuberosa).
Material-usually small tubers, weighing about 20 g.
Method-the tubers are planted in September-October in furrows in well-cultivated soil. Weeding is important. The plants are earthed up two or three times during their growing period to aid tuberisation.
Field spacing-highest yield of usable tubers has been observed with furrows 80-90 cm apart and plants at 30 cm along the rows.
Pests and diseases
The most important pest is stated to be the Andean weevil, Premnotrypes solani. Nematodes of Globodera spp. attack the plant. Reported fungi include Aecidium cantense and Rhizoctonia solani. A number of viruses have been found in virtually all ullucu material examined; these include an ullucu strain of tobacco mosaic virus (TMV/U) and of papaya mosaic virus (PMV/U), as well as three new viruses designated ullucu virus A, B and C respectively. Apart from slight leaf mottling, these viruses appear to be symptomless, but laboratory experiments using virus-free material prepared by meristem culture suggest that growth and yield are considerably retarded by their presence-which is the general state of the crop as at present cultivated. No vector is known to be involved in transmitting these viruses.
The tubers are ready for harvest in 4-6 months.
Harvesting and handling
The tubers are dug by hand and often eaten immediately.
Tubers-which may be cylindrical, ellipsoidal or spherical, with shallow eyes, often resembling small potatoes. The skin is soft and the flesh is normally yellow and mucilaginous.
Yields are reported to average 5-11 t/ha.
Ullucu is a staple carbohydrate foodstuff in parts of the Andes where it is cooked and eaten in a manner similar to potatoes.
The tubers may be made into chuÃ±o (see Potato-Processing), called 'lingli' in the Cusco region, in which form they may be left for several months.
Secondary and waste products
It has been suggested that the leaves could be cooked as a vegetable.
An analysis of the edible portion of the tubers has been published as: energy 214 kJ/100 g; water 85.9 per cent; protein I per cent; fat 0 per cent; carbohydrate 12.5 per cent; fibre 0.6 per cent; ash 0.6 per cent; calcium 3 mg/100 g; iron 0.8 mg/100 g; phosphorus 35 mg/100 g; vitamin A 0 mg/100 g; thiamine 0.04 mg/100 g; riboflavin 0.02 mg/100 g; niacin 0.3 mg/100 g; ascorbic acid 23 mg/100 g.
The high level of ascorbic acid is noteworthy.
Production and trade
Ullucu is a popular root crop in parts of South America, notably Peru, where production was estimated to be about 35 000 t/a in the middle 1960s, of which 26 000 t was for human consumption, 5 000 t was used for seed, and losses due to spoilage were estimated at about 3 600 t. At the time it was projected that the demand for ullucu in Peru would increase to 66 000 t by 1980, but up to date information appears not to be available.
Ullucu is an important tuber crop in the Andean region and germplasm collections are being made, housed at Cusco and Puno in Peru. It is considered a delicacy by many people and is found on sale in modern packaging in many supermarkets in Peru. Attempts to introduce it into Europe at the time of the potato famine in the mid-19th century were unsuccessful, as were attempts to introduce it into Sri Lanka in the early part of this century. However, especially if virus-free material can be substituted commercially, thus increasing yields and reducing costs, a wider market may be found for the processed product.
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BRUNT, A. A., BARTON, R. J., PHILLIPS, S. and JONES, R. A. C. 1982. Ullucus virus C, a newly recognised comovirus infecting Ullucus tuberosus (Basellaceae). Annals of Applied Biology, 101, 73-78.
BRUNT, A. A., PHILLIPS, S., JONES, R. A. C. and KENTEN, R. H. 1982. Viruses detected in Ullucus tuberosus (Basellaceae) from Peru and Bolivia. Annals of Applied Biology, 101, 65-72.
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