In terms of food security, these are the three most important Andean ARTCs. Combination cropping of potato with oca, ulluco ,and mashua is a tradition that goes back thousands of years, and these crops provide valuable additional nutrients to the basic diet of potatoes.
Oca (Oxalis tuberosa)
Oca produces the second most widely cultivated tuber after potato. It is hardy and frost resistant, with long, cylindrical tubers from white to deep grayish purple. High in protein, with a good balance of amino acids, it is also a good source of fiber, and high in antioxidants.
Described in the chronicles of the Spanish conquest, ceramic representations indicate that oca was a highly revered staple dating back to pre-Colombian times. Its high yield and pleasant taste make it very popular in rural Andean cuisine where it is traditionally boiled in soups or stews. Tubers are also baked or roasted and often left in the sun to sweeten before cooking.
The crop’s main enemy is the oca weevil, a particularly destructive beetle that can lay waste to entire crops.
Most production is still for home consumption but CIP’s ALTAGRO project is helping smallholders produce oca marmalades in a variety of colors. Repositioning the crop for new markets encourages the conservation of the crop’s diversity, and helps to overcome its reputation as a poor man’s tuber.
Ulluco (Ullucus tuberosus)
Ulluco is the most widely recognized and commercially viable of the ARTC’s, popular for its taste. It is easy to grow, frost resistant, and is moderately drought resistant, although the plant prefers soils that are rich in organic matter.
Ulluco tubers come in a variety of colors and shapes. Because of their high water content, they are most suitable for boiling, and the soft, shiny skins need no peeling before eating.
The leaves are also edible. Rich in protein, calcium, and carotene, they are similar in texture to spinach. A spoonful of cooked leaves can produce a considerable part of a child’s daily essential nutrient requirement.
Mashua (Tropaeolum tuberosum)
Mashua is one of the highest yielding Andean tubers (yield can reach 70 tons per hectare) and one of the easiest to grow. It thrives on marginal soils, develops rapidly, and competes successfully with weeds.
The cone shaped tubers are usually white, yellow, red or purple. They contain high levels of isothiocyanates (glucosinolates), well known for their insecticidal and medicinal properties. This may explain the virtual absence of pests and disease in the crop. This strong resistance is one reason why mashua is traditionally intercropped with other plants; farmers use it as a natural way to repel insects and pathogens.
Mashua is a traditional diuretic and remedy for kidney ailments. More recently it has been shown to prevent the development of cancerous cells in stomach, colon, skin, and prostate.
Despite its high nutritional value, mashua is not widely commercialized. Because it is used in traditional medicine to regulate libido (the Incas reportedly used it to dampen sexual desire in campaigning armies), men are reluctant to eat it.