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Mashua Mashua, (Tropaeolum tuberosum) is probably the Andean region's fourth most important root cropafter potato, oca, and ulluco. It is a hardy plant, and in the poorest regions, where pesticides and fertilizers are too costly to use, mashua is sometimes the prevalent root crop. Its tubers can be found in almost any rural Andean market. Mashua (pronounced mah-shoo-ah or mah-shwah) is closely related to the garden nasturtium, an Inca ornamental that is now well-known throughout most temperate zones. In fact, these two beautiful plants are often found together in Andean gardens, one grown for its edible tubers, the other for its pretty and edible flowers. Among Andean tubers, mashua is one of the highest yielding, easiest to grow, and most resistant to cold. It also repels many insects, nematodes, and other pathogens, thus making it a valuable plant to intercrop with other species.2 Yet, in spite of its productivity, pest resistance, and popularity, mashua is not widely commercialized- either in its native land or elsewhere. The tubers about the size of small potatoes have shapes ranging from conical to carrotlike. Eaten raw, some have a peppery taste- reminiscent of hot radishes. But when boiled, they lose their sharpness and become mild even sweet. Boiled mashua is used to add variety to other foods. It is popular in soups. In Bolivia and some parts of Peru, it is topped with molasses and frozen to make a special dessert. Like oca, mace, ulluco, and bitter potatoes,3 mashua can provide food at high elevations. This frost-tolerant crop is cultivated in small plots on hillsides- especially on ancient terraces in cool and moist upland valleys of Argentina, Colombia, Ecuador, Peru, and Bolivia. Peru, it is reported, grows 4,000 hectares of mashua each year. Within Andean communities, some families choose to plant mashua ' Also widely known as afiu (pronounced ahn-yoo) and isano (e-sahn-yo). 2 In the Peruvian highlands, mashua, oca, ulluco, and native potatoes are often grown together in a multicrop system. Farmers believe that this is the best and cheapest way to control pests and diseases. 3 These root crops are all described elsewhere in this section of the report. 67
68 LOST CROPS OF THE INCAS because it is easier and less labor intensive to grow, and because its tubers are traditionally reserved for children and women. In the higher, colder altitudes, mashua functions like cassava in the tropical lowlands: a food that can be stored in the ground, harvested when needed, and is almost unaffected by poor management. PROSPECTS Andean Region. In the Andes, mashua is associated with poverty. It is shunned by the upper classes because of its Indian origin and because it is eaten by poor country folk. It is disappearing rapidly and in a few years most people will not remember it. Yet mashua is a vital, although still underrated, part of the Andean agricultural cycle. So little is known about it that its potential is almost certainly unrealized at present. It is a productive and robust plant, and its tubers are visually appealing. It could be selected for greater nutritional quality and palatability. It could also play an important part in pest control in intercropping situations because it suffers from almost no pest, is resistant to the Andean weevil that attacks potatoes and other root crops, and climbs over weeds and smothers them. Although high yielding and particularly high in vitamin C, mashua is not as palatable as other tubers, and where people have access to rice, noodles, and sugar, it tends to be abandoned more readily than other traditional crops. Recently, it has been found that mashua in the Andes carries virus infections that are probably extremely debilitating to the plants. Methods have now been developed to produce virus-free stocks. These healthy plants grow much more vigorously, and they represent a way for rapidly improving mashua throughout the Andean region.4 Other Developing Areas. Mashua will probably never be widely grown outside the Andes, but it is worth trying in other tropical highland regions (for example, the Himalayas). Its pest and pathogen resistance alone may make it valuable. It is likely to be productive in areas with moderate temperatures and long growing seasons. Only virus-free germplasm should be introduced. Industrialized Regions. Mashua, along with more common nas- turtiums, is grown as a flowering ornamental in Britain and, though 4 Information from A.A. Brunt. A research team led by R. Estrada at the University of San Marcos Laboratories in Lima, Peru, is producing disease-free plants for growing by Andean farmers.
MASHUA 69 rarely, in the United States. The fact that it grows well so far from its Andean home suggests that, like the other Inca tuber crops, it, too, deserves much wider testing and recognition as a food plant. Coastal areas at high latitudes could well be ideal for production of mashua. It has already produced good yields in the Pacific Northwest of North America and in New Zealand. Nonetheless, daylength sensitivity may limit its widespread adoption until insensitive strains can be located. USES The sharp flavor of most mashua tubers makes them unsuitable for eating raw,s so they are usually boiled with meat to form a stew. (An ideal Andean stew contains meat, mashua, oca, potatoes, greens, quinoa, corn, rice, eggs, and herbs.) They are also eaten as a baked or fried vegetable and may be fried with eggs and onions. Near La Paz, they are soaked in molasses and eaten as sweets. In New Zealand, where the plant has been newly introduced, it sets tubers well in open fields during a normal spring-to-autumn growing season. One grower cooks the tubers in soups and stews, to which they add a delicate, slightly fragrant flavor.6 After boiling for five minutes, the tubers appear whitish with purplish spots at the nodes. Young tubers need no peeling, but older tubers are always peeled. In addition to the tubers, the tender young leaves are eaten as a boiled green vegetable. The flowers are also eaten. (The blossoms of the garden nasturtium are used in restaurants all across the United States, for instance.) Because mashua is high yielding and its tubers are rich in carbo- hydrates as well as other nutrients, it has been suggested that it could be grown as a feed for pigs and calves. It could become an especially valuable and cheap stock feed because of its high yield and the high protein content of its foliage. NCITRITION Mashua is quite nutritious for a root crop. Solids comprise about 20 percent and protein as much as 16 percent of the dry matter.7 However, 5 The hot taste is due to isothiocyanates (mustard oils), the compounds also responsible for the hot taste of radishes, mustard, and many crucifers, to which it is unrelated. Many mashua types are bland, however. 6 Information from A. Endt. 7 In one analysis, dry samples of the roots (per 100 g) contained: 371 calories, 11.4 g protein, 4.3 g fat, 78.6 g total carbohydrate, 5.7 g fiber, 5.7 g ash, 50 mg calcium, 300 mg phosphorus, 8.6 mg iron, 214 micrograms beta-carotene equivalent, 0.43 mg thiamin, 0.57 mg riboflavin, 4.3 mg niacin, and 476 mg ascorbic acid. Information from J. Duke.
70 LOST CROPS OF THE INCAS the protein content is highly variable. One variety was found with tubers containing 14-16 percent protein (dry weight).8 Mashua traditionally has many folk-medicine uses. It is considered an anti-aphrodisiac and, hence, many Andean men recommend it for women while refusing to eat it themselves.9 Male rats fed a tuber diet showed no decline in fertility, but did show a 45 percent drop in total levels of testosterone and dihydrotestosterone.'° AGRONOMY Mashua is one of the common terrace crops of the Andes. Under traditional practices fields are small and often on precipitous slopes. It is planted much like oca and potatoes, using small tubers. The plant often sprawls over the ground, but it has tiny, threadlike outgrowths that wind around anything they touch, and this allows it to twine up cornstalks or other supports. To improve yields, earth is mounded around the base of the stem as the plant grows. As noted, mashua is extremely resistant to diseases and insects. It contains nematocidal, bactericidal, and insecticidal compounds (glu- cosinolates).'~ HARVESTING AND llANDLING The tubers are ready for harvest in 6-8 months. They form near the surface and are harvested like potatoes. Because they have a high moisture content and no waxy surface, the tubers have a shorter storage life than other tubers. Nonetheless, they can be successfully stored for up to 6 months if cool (for instance, 2°C), well ventilated, and protected from strong light. Mashua is high yielding. Even under conditions of almost no management, harvests are reported to be between 20 and 30 tons per hectare. Yields approaching 50 tons per hectare are reported from experimental plots near Cuzco. i2 A single plant may yield more than 4 kg of tubers. 8 Originally from Bolivia, this variety was lost when terrorists blew up the research station in Ayacucho, Peru. Attempts to relocate the source are being planned. Information from J. Valladolid R. 9 The Spanish chronicler Cobo stated that Inca emperors fed their armies on the march with such tubers, "that they should forget their wives." 'I Johns, 1981. " Tubers are antibiotic against Candida albicans, Escherichia coli, and Staphylococcus albus, the activity paralleled by benzyl isothiocyanate at 100 micrograms. The compound is also nematocidal (Johns et al., 1982). " Information from H. Cortes.
MASHUA l ~ ill 1 ~ _... _ _~ ~~.~ -A Mar -. ~ ....... _ = Mashua tubers. In the high, cold altitudes of the Andes, mashua functions like cassava in the tropical lowlands. It requires little care and can be stored in the ground and harvested when the need arises. For this reason, therefore, mashua appeals to poor people and has been unjustly stigmatized as being an undesirable crop. To the thousands of highland people who know it best, however, it is a delicious food. (S. King) 71 ~ ... ,,.~ . Hi:' ~-~ LIMITATIONS Like arracacha, oca, and ulluco, mashua is apparently heavily infected with plant viruses, most of which are undescribed.'3 One recent test identified it as a carrier of potato leaf roll virus. ]4 There is a possibility that consuming large quantities of mashua, combined with low intakes of iodine, could cause goiter.'s This is unlikely in most diets; nonetheless, goiter is a problem in parts of the Andesfor instance, Bolivia. RESEARCH NEEDS Further collections of mashua germplasm are needed throughout the Andes. Relict populations from Argentina and Chile may provide germplasm with more adaptability to long daylengths. Mashua sets seed freely and hybridizes well. Thus, there seems to be considerable potential for breeding new and improved types. Much basic information on the plant's gross horticultural require- ments is needed. Investigation of its ecology in field situations and evaluation of its intercropping potential could lead to higher yields and, consequently, to broader utilization. |3 Information from A. B. Brunt. t4 Information from J. Martineau. t5 Glucosinolates are metabolized into isothiocyanates, thiocynates, and thioureas, a class of chemicals that is goitrogenic. Information from T. Johns.
72 LOST CROPS OF THE INCAS The insecticidal, nematocidal, bactericidal, pharmacological, and other medicinal effects should be investigated. These might prove useful in practice. Because it yields so prodigiously, mashua may be suited for industrial production of starch. Needed are analyses of the kinds of starch it contains and the amounts that might be produced under field, regional' and national conditions. Selection for varieties with low levels of glucosinolates should be attempted. SPECIES INFORMATION Botanical Name Tropaeolum tuberosum Ruiz & Pavon Family Tropaeolaceae (nasturtium family) Common Names Quechua: mashua, anu, apinu, apina-mama, yanaoca (black oca) Aymara: isau, issanu, kkayacha Paez (southern Colombia): puel Spanish: mashua (or majua, mafua, mauja, maxua), mashuar, and, anyu (Peru); cubios, navies, navo (Colombia); isano, isanu, apilla (Bolivia); ysano (South America) English: mashua, anu Origins. Mashua has been cultivated since ancient times and its tubers show up in many archeological sites. The ancestral plant is uncertain. Weedy types are common in moist, wooded, brushy areas around 3,000 m elevation in Peru and Ecuador and may be represen- tative of the ancestral type. Mashua may have originated in the same regions as the potato, but even today it is virtually unknown outside Bolivia, Peru, and Ecuador. Descr~ption. Mashua is a perennial, herbaceous, semiprostrate climber occasionally reaching above 2 m in height. Both erect and prostrate forms are known. It has circular, peltate, 3- to 5-lobed leaves, and glabrous, twining stems that attach themselves to other plants by tactile petioles. The long-stalked, solitary, axial, bisexual, occasionally double flow- ers (favored by birds and insects) are orange to scarlet in color. Smaller than those of the garden nasturtium (Tropaeolum majus), they are borne profusely. The fruit (schizocarp) has 3-4 lobes that contain joined seeds lacking endosperm. The abundant, viable seeds separate at maturity. The tubers vary in color from white to yellow. Occasionally, the
MASHUA 73 skin is purplish or red. Often, they are mottled or striped with red or purple, especially below the eyes. The flesh is yellow. Studies have shown there is a high correlation between the yield of tubers on the one hand and plant height, tuber size, and number of tubers on the other. ~6 Horticultural Varieties. More than 100 varieties have been rec- ognized; there are probably more. One reported in Colombia is var. pilifera, slender, long, deeply furrowed, and white, sometimes with pink-purple ends. Another, var. Iineovaculata, in Colombia, Peru, and Bolivia, is white, streaked and spotted with red. Others may be yellow, orange, reddish violet, or dark purple, often stippled with bright red or purple dots and lines. Color variants are recognized by a number of native descriptive names, among them in Peru are yana-anu (black), puca-anu (red), yurac-anu (white), sapullu-anu (yellow), and muru-anu (spotted). Collections are maintained at Quito (INIAP, Santa Catalina), Ay- acucho, Jun~n, and Huancayo. Environmental Requirements Daylength. The plant seems to require 12-hour days (or perhaps less) for tuber formation, although it has successfully developed tubers outdoors in Vancouver, Canada (in October when daylight was less than 12 hours),'7 and under glass in southeast England.'8 Rainfall. The crop requires heavy rainfall; in its native range it receives between 700 and 1,600 mm. It seems to thrive in misty and cloudy weather. Altitude. Mashua grows best between 2,400 and 4,300 m above sea level along the Andean cordillera. However, altitude may not be an important factor, considering its productivity in Canada, England, and New Zealand. Low Temperature. It will tolerate light frost and is unaffected by temperatures as low as 4°C. In many parts of its range, it is regularly exposed to mild frosts. High Temperature. Unknown. Probably above 20°C. Soil Type. Mashua grows in soils ranging from pH 5.3 to 7.5. While it is tolerant of alkaline conditions, it performs best in fertile, organic soils. Good drainage helps inhibit soil fungi infestations. |6 Deigado, 1977. |7 Information from T. Johns. |8 Information from A.A. Brunt.