Starchy Crops

Edible Canna (Canna indica)

Edible canna (Canna indica syn. Canna edulis Ker-Gwal).

Family: Cannaceae (Cannaceae).

Other names: achira, purple arrowroot, Queensland arrowroot, tous-les-mois.

Edible canna is a large lily-like perennial that produces branched underground starchy rhizomes. It is native to tropical America and has a long history of cultivation. Dried rhizomes found during excavations in Peru date from 2000 to 4000 years old.

Fleshy stems grow up to 2.5 m tall with green leaves, entire, long and narrow, with a thick middle. At the base of the edible stem, near or slightly below the soil surface, starchy rhizomes develop. Two types of plants are known, producing rhizomes with white or purple skin. Flowers, red to orange, produce three-celled fruit capsules containing fertile round black seeds. However, for propagation, part of the rhizome is transplanted or left to produce a crop.

Plants are adapted to moist soils. The best temperature for cultivation is 25 to 28 °C; plants are sensitive to higher temperatures and drought. An important property of canna is its adaptability to altitudes up to 2600 m above sea level and low temperatures, where other starchy crops such as cassava are less productive.

The crop can be harvested as needed about 8 months after planting, although higher yields, ranging from 12 to 25 t/ha, usually require more time. Some of the largest rhizomes reach 60 cm in length and weigh more than 25 kg. Delaying harvest generally increases the fiber content of rhizomes.

The preferred method of preparation is baking; rhizomes can, but rarely, be eaten raw. Rhizomes contain about 25% of a unique and easily digestible starch consisting of the largest known starch grains, approximately 100 times larger than aroid starch grains. Production is concentrated in South America, especially Peru and Colombia, although in Australia canna is produced on a relatively intensive scale for industrial starch. In Vietnam, the highly valued starch is used to make noodles, and in other East Asian countries as a luxury food.

Other edible canna species are known as brick canna (Canna discolor), Mexican canna (Canna glauca), iris canna (Canna iridiflora), broadleaf canna (Canna latifolia), Inca canna (Canna languinosa), and Andean canna (Canna paniculata).

Edible Cyperus (Cyperus esculentus)

Edible Cyperus (Cyperus esculentus L. var. sativus Boeck.), or chufa, tiger nut, yellow nut, earth almond.

Family: Cyperaceae (Cyperaceae).

Chufa is a perennial plant with herbaceous stems and leaves; it occurs throughout the tropics and in many warm temperate areas. Although chufa is better known as a common noxious weed, it is grown for small, 1–2 cm, fleshy underground tubers with an almond flavor. Chufa can reproduce by seeds, as well as by rhizomes or tubers. Tuber initiation is a response to shortening day length. Most elongated tubers are located under the plant, each at the end of a thread-like rhizome. Although most tubers sprout in the first year, some remain without sprouting until the second year.

Tubers mature in about 3–4 months and contain about 25% starch, 20% fat, and 5% protein on a dry weight basis; fiber content is quite high. Cultivated and uncultivated tubers are a common food in many parts of North Africa. In cultivated plantings, tubers are larger, and yields reach more than 10 t/ha. Tubers are used as a raw or baked vegetable. In Spain, tubers are used in a drink called horchata de chufa. They are also used roasted as a coffee substitute and sometimes as livestock feed.

A closely related species is purple nutsedge (Cyperus rotundus), or purple nut, and although the tubers are similar, they are rarely eaten because of bitterness.

Lilies (Lilium)

Species of the genus Lily (Lilium L. spp.)

Family: Liliaceae (Liliaceae).

Cultivated bulbs of several Lilium species, many native to Japan and China, are a popular food in the East. Non-bitter or only slightly bitter species are used as boiled or steamed vegetables. Propagation is by bulbs or scales planted in autumn, and the crop is dug and harvested the following autumn after the leaves have completely yellowed. Cultivation usually occurs in a cool climate, as this improves the edible quality of the bulb. Bulbs contain about 17% starch, some sugars, and about 2% protein; these values can vary. Sometimes bulbs are dried before use to increase the starch proportion.

Some of the most popular species are Lilium leichtlinii var. maximo-wiczii, known as devil or tiger lily, and Lilium lancifolium (syn. Lilium tigrinum), also known as tiger lily. Varieties of Lilium auratum, known as mountain, golden, golden-striped, or golden-rayed lily, are also popular, as is the old Hong Kong variety of Lilium brownii var. viridulum. Daylily species (Hemerocallis spp.), such as Hemerocallis fulva (tawny daylily, orange daylily, or ditch lily) and Hemerocallis lilioasphodelus (yellow daylily, lemon lily, or yellow lily), are also grown, but mainly for their large edible flowers.

Arrowroot (Maranta arundinacea)

Arrowroot (Maranta arundinacea L.).

Family: Marantaceae (Marantaceae).

Other names: English West Indian arrowroot, English true arrowroot, English jamachipeke.

Arrowroot, a tropical perennial, is native to northern South America and possibly the West Indies. A related perennial species, Maranta ruiziana, is also cultivated in the western Amazon.

The name arrowroot is believed to have arisen because the rhizomes were used to treat wounds inflicted by poisoned arrows. Another possible explanation is the leaf shape, resembling an arrowhead. “Arrowroot” is also a general term applied to several similar species that are eaten after cooking or from which flour is made.

Arrowroot grows to 1–1.5 m in height and has small roots with deeply penetrating fibrous and thick rhizomes. Leaves are lanceolate, about 20 cm long and 10 cm wide. White flowers open after 3 months, but seeds are rarely formed.

Propagation is by small pieces of rhizome with several buds. Plants are usually planted at a spacing of 40 × 80 cm. Optimal growth occurs at high temperatures and high humidity. Sandy soils and abundant, even moisture are necessary for productivity. Toward the end of the growing season, the foliage yellows, and the rhizomes are harvested. Rhizomes 20 to 40 cm long are enclosed in scaly bracts; yield is usually 4 to 10 t/ha, sometimes higher. Plantings can remain productive for 5–7 years due to regrowth of rhizome parts left after harvest.

Two varieties are usually grown. The ‘Creole’ variety has good storage quality, but its long and thin rhizomes are difficult to harvest. The banana form has shorter and thicker, easily dug rhizomes; because of poor storage quality, they should be consumed within a short period. Rhizomes are reported to contain more than 12% starch on a dry weight basis, and protein content is about 1–2%. The main benefit of arrowroot is its easily digestible starch, which has a smooth consistency and high viscosity.

Calathea (Calathea allouia)

Calathea (Calathea allouia (Aubl.) Lindl., according to modern classification Goeppertia allouia).

Family: Marantaceae (Marantaceae).

Other local names: Guinea arrowroot, leren, bamboo tuber, calathea, allouis, topi, tambu, aria, Guinea arrowroot, sweet corn tuber.

Calathea, grown for its tuberous roots, is a perennial plant endemic to tropical America, namely Brazil and the Amazon region. It is cultivated in the Caribbean, India, and many high-temperature and humid regions of Southeast Asia and Indonesia. The need for abundant and even moisture, as well as sensitivity to drought, limits wider cultivation. Plants are shade tolerant but more productive in full light.

Mature plants reach 60 to 120 cm in height and show dense growth of multi-branched rhizomes, some of which may become fleshy, while others become pseudostems with elongated leaves. Leaf blades are simple, oval, 30–60 cm long. Edible, elongated, spherical, root-like tuberous roots 2–4 cm wide and up to 8 cm long are formed at the end of fibrous roots.

Green or pale yellow flowers usually do not produce seeds, so propagation is by suckers or pre-sprouted short sections of rhizomes. Planting is done at the beginning of the rainy season, and harvest is planned for the dry season; tuberous roots are harvested after 10–12 months.

The presence of sufficient and even moisture strongly affects yield, which ranges from 2 to 12 t/ha. In the dry season, the plant is leafless and dormant. Leren can be stored at room temperature for several months with slight drying or loss of quality. Low-temperature storage causes chilling injury.

A strong feature is its crunchy texture, which is retained even after frying. The tuberous roots are eaten like white potatoes. The main method of preparation is boiling, but removing the thin bark-like skin is quite difficult. The flesh is white and tastes like sweet corn; sometimes it may have a slightly bitter aftertaste. Protein content on a dry weight basis is up to 6%, and starch is 13% to 15%. Young flowers of a related species, Calathea violacea (syn. Goeppertia violacea), are used as food in Brazil.

Tacca (Tacca leontopetaloides)

Tacca leontopetaloides, Tacca leontopetaloides (L.) Kuntze (syn. Tacca pinnatifida (L.) Kuntze).

Family: Dioscoreaceae (Dioscoreaceae), formerly Taccaceae (Taccaceae).

Other names: piam, mokmok, east Indian arrowroot, tacca.

Tacca leontopetaloides is a perennial grown for its starchy underground tubers. Native to Southeast Asia, the plant is also cultivated in other parts of tropical Asia and Oceania. Its importance is declining, displaced by other, more easily produced starchy vegetables.

The leaves, resembling aroid leaves, are entire and large, with long petioles. Plants are deciduous and go dormant in winter. On a tall peduncle, many yellow-green or violet flowers are formed. Fruits are berries with many ovate and flattened seeds. Seeds can be used for propagation, but tubers or stem division are usually used.

The tubers, similar to potatoes, are about 15–20 cm long, weigh less than 1 kg, and mature in 8–10 months. Other cultivated tacca forms produce smaller tubers. Tubers with white flesh are acrid and inedible raw, so to remove the bitter substance, taccalin, they must be soaked and/or boiled. The recovered starch is used in many food products, including for preparing poi-type dishes. On a dry weight basis, starch content in tubers averages about 25%, and protein about 5%.

Zedoary (Curcuma zedoaria)

Zedoary (Curcuma zedoaria (Christm.) Roscoe), zedoary root, zedoaria, wild turmeric, white turmeric.

Family: Zingiberaceae (Zingiberaceae).

Other names: shoti, zedoary.

Zedoary, native to northeastern India, is cultivated in India, Sri Lanka, and throughout Southeast Asia. A perennial creeping plant with some tolerance to poor drainage, it produces upright stems arising from the tips of lateral rhizomes. Green leaves have purple-brown veins. Fleshy rhizomes become tubers and are used for their easily digestible starch, similar to semolina, whose content in fresh weight is about 12%. Yield reaches 10 t/ha. Young buds and shoots are used in salads.

Arracacha (Arracacia xanthorrhiza)

Arracacha (Arracacia xanthorrhiza E.N. Bancroft, syn. Arracacia esculenta).

Family: Apiaceae (Apiaceae).

Other names: apio, Peruvian carrot, Peruvian parsnip, mandioquina-salsa, zanahoria, racacha.

Arracacha, a native perennial of the Andean highlands, continues to be an important and often preferred staple food in much of South America. Wild species have been found in Peru, and significant diversity occurs in Ecuador.

Short-day requirement and sensitivity to frost limit the spread of arracacha to other regions. Plants are not suitable for growing in lowlands, but good productivity is achieved when grown at altitudes from 1000 to 2500 m. The favorable temperature for cultivation ranges between 14 °C and 21 °C, while temperatures above 25 °C suppress growth. Ideal soils are light, well-drained, slightly acidic (pH 5–6). Loose soils promote increased lateral roots and smoothness. Plants consume a lot of water (600–1000 mm), so moisture must be evenly available. Surprisingly, nutrient demand is higher for phosphorus than for nitrogen. Nitrogen application is minimized to avoid excessive leaf growth, which competes with root enlargement. Plants are susceptible to spider mites, nematodes, and viruses.

Arracacha is in some respects similar to carrot and celery. The enlarged, fleshy lateral roots resemble white carrots with yellowish flesh; sometimes a ring of cambial tissue has a purple tint. Productive plants develop from several to 10 carrot-sized lateral roots grouped around the main rootstock. Root length is usually 5 to 25 cm with a diameter of 2 to 6 cm. Yield ranges from 5 to 15 t/ha.

Dark green petioles with a purple tint resemble celery and are eaten raw or boiled. The petioles are tied together for blanching. Leaves are deeply divided and can reach about 1 m in height. Small yellow or purple flowers are arranged in loose inflorescences. If allowed, seeds can set, but they are not used for propagation.

Arracacha is propagated by suckers that form a crown at the base of the main stem. Interestingly, to stimulate better and more uniform development of shoots and lateral roots, light pruning of the base of shoots is practiced after their removal. After a 2–3-day wound-healing period, they are transplanted. Plantings usually begin at the start of the rainy season. In most cases, planting material density is 25,000 to 30,000 plants per hectare. Good root formation requires short-day conditions, although varieties differ in this respect. Depending on root color, three varieties are distinguished: ‘blanca’ (white), ‘amarilla’ (yellow), and ‘morada’ (purple).

Harvest usually precedes flowering, but to enhance root growth farmers remove flowers as they appear. In addition, after flowering begins, root quality declines. Arracacha is usually harvested by hand, digging or plowing out the roots. At the expense of yield, harvest can begin as early as 4–5 months. In a more normal situation, obtaining a mature crop and high yield requires more time, 10–14 months of growth. Delaying harvest results in fibrous and unpalatable roots. Because its production is cheaper, arracacha often replaces potato in many diets. Roots have a short postharvest life, so they are rarely stored. If they are stored, they are placed at 3–5 °C, during which part of the starch turns into sugar.

To be edible, the roots must be cooked, so they are usually fried, boiled, or baked. They have an unusual flavor reminiscent of a mixture of celery, carrot, and parsnip. Some describe the taste as roasted chestnuts combined with celery and carrot. Starch content varies from 10% to 25%; starch granules are small, similar to cassava granules. The starch is easily digested, so it is often prepared for infants and the elderly.

Perideridia gairdneri

Perideridia gairdneri (Hook & Arn.) Mathias.

Family: Apiaceae (Apiaceae).

Other names: squaw root, yampah, epos root.

Perideridia gairdneri grows wild in the western United States (southern Oregon, northern California). Related species grow in the western United States and British Columbia. Plants are perennial and prefer moist soils. Enlarged stored roots are collected in summer and autumn by local people and eaten raw or boiled. They are also dried for winter use. Epos served as food for indigenous people and early settlers in these regions. The starchy dark-skinned roots resemble nuts with white flesh.

Jerusalem Artichoke (Helianthus tuberosus)

Main page: Jerusalem artichoke

Yacon (Polymnia sonchifolia)

Yacon (Smallanthus sonchifolius, syn. Polymnia sonchifolia Poepp. & Endl. and Polymnia edulis Weddell.).

Family: Asteraceae (Asteraceae).

Other names: jiquama, jacon, apple of the earth, yacon.

Wild forms of yacon occur in the Andean regions of Colombia, Ecuador, and Peru. In these areas it is cultivated at high altitudes, but not above 3000 m. A perennial cold-hardy plant, when the aboveground part is damaged or killed by frost, it regenerates by regrowth from the underground part. Plants also have some tolerance to high temperatures. Yacon has potential for cultivation in semi-tropical and some temperate climates due to broad adaptation, a day-neutral regime, and relatively easy culture even on poor soils. This crop is grown as an annual for foliage and as a perennial for underground tuberous roots.

Plants reach 1.5 m in height; stems are hairy, green with purple spots, with yellow or orange flowers formed on lower axillary stems. After flowering, the tops age and die. Propagation uses suckers from the base of aboveground stems and stem cuttings. The developing tuberous roots, usually four or more, form a cluster, each about 15 cm long. They appear fused to the swollen stem and are enlarged parts of basal stems and storage root tissues. Shape varies from spindle-shaped to round, and the tuberous roots usually separate easily. The thin skin is tan or purple-brown. The flesh may be white, pale yellow, or orange and have varying sweetness.

Tuberous roots are usually harvested after a long growth period exceeding 200 days. Their weight is usually 200 to 500 g, and some reach 2 kg. Yacon yield is relatively high, often more than 20 t/ha. After harvest, they can store well for several weeks if kept in a cool place (5 °C) and in darkness.

The tuberous roots have a crunchy texture, are juicy, and are often eaten raw in snacks and salads, as well as boiled or baked. Sun-drying is used to extend shelf life; exposure to sunlight is believed to improve flavor and sugar concentration. The skin must be peeled because it is resinous. Most varieties have a sweet taste due to fructose content, although this trait is not uniform. Breeding can achieve greater uniformity in sweet varieties. Moisture content is 70% to 85%; almost 65% of dry weight is sugar. As in some other Asteraceae species, carbohydrates are stored as inulin, a fructose polymer, abundantly and in very pure form. Tuberous roots contain about 6–7% protein and much potassium. Stems and leaves, most often fed to animals, can be used as a boiled vegetable or eaten raw.

Ulluco (Ullucus tuberosus)

Ulluco (Ullucus tuberosus Lozano).

Family: Basellaceae (Basellaceae).

Other names: olluco, melloco, papalisa, ulluco.

Ulluco, an Andean tuber, has been cultivated for more than 4000 years in Peru, Bolivia, Ecuador, and northern Argentina. In these countries, wild forms can still be found. This crop is most popular in the Andean regions, although tubers are sold in many parts of South America. In Peru alone, production exceeds 20,000 ha. Ulluco and other Andean tubers, wood sorrel or oca (Oxalis tuberosa) and mashua (Tropaeolum tuberosum), were considered for introduction to Europe, especially after the potato blight epidemic, but the results were disappointing. The main obstacle to successful cultivation is the short day length for introduced plants.

The crop has good cold hardiness, necessary at the high altitudes (2500–4000 m) where it is grown. Plants are highly resistant to drought, as well as to high soil moisture, and are relatively productive on marginal soils. In hot climates, tubers grow poorly. Overall adaptability is comparable to that of potato (Solanum tuberosum).

Ulluco is a succulent plant whose forms range from upright to bushy and semi-shrubby vines. Tubers are brightly multicolored, almost ornamental, with inconspicuous superficial buds and a thin, soft, waxy skin. The fleshy texture, from white to light yellow, remains crunchy even after cooking; some describe its taste as nutty. Tubers are elongated, some strongly curved and small (4–7 cm). On regional markets, small sizes are preferred.

Tubers initiate during the short day and enlarge at the ends of stolons. Stolons form along the stem, and a common cultural practice is to hill soil high against the stem to stimulate development of additional stolons and therefore increase tuber number.

Propagation is vegetative, using small whole tubers. Greenish-yellow or reddish flowers rarely produce seeds, although fertile seeds have been obtained experimentally. Ulluco is often grown in intercrops with potato, mashua, and oca, although pure stands in crop rotation with potato are typical. Ulluco has relatively few diseases and pests, except for a virus complex present in almost all material. Although plants are productive even when infected, meristem tip culture can be used to obtain virus-free planting material. Nematodes can also cause yield losses.

Tubers mature in 6–8 months. Average yield of 5 to 9 t/ha is lower than that of white potato grown on the same area. Ulluco tubers store well at cool temperature; they are stored in darkness to avoid greening.

The starchy tubers are used to thicken soups and stews. They can be dehydrated and stored for many years as a product of the ‘chuño’ type. The edible foliage contains about 12% protein on a dry weight basis and has mucilaginous properties resembling Malabar spinach (Basella alba). Mucilage is also present in the tubers, but it can be washed off before cooking.

Maca (Lepidium meyenii)

Maca, or Meyen's pepperwort (Lepidium meyenii Walp.).

Family: Brassicaceae (Brassicaceae).

Other names: maka, Peruvian ginseng, maca.

Except for some potato species adapted to high altitudes, maca is unique in being cultivated at very high altitude (3800–4200 m) and under the harsh conditions of the puna region in Peru. The labor-intensive cultivation of this annual plant, most often for subsistence, goes back at least 3000 years. At high altitudes, the plant tolerates intense sunlight, shows good growth at average temperatures of 5 °C to 10 °C, and has good resistance to cold and frost. Some believe that maca depletes soils in these high Andean areas and that several years of rest are required before the land is cultivated again.

The plant has a mat-like growth habit; leaves form a prostrate rosette. Long, deeply toothed leaves resemble watercress and are reported to be edible. Flowers are white, self-fertile, and produce a two-celled silique. It is considered a biennial, but maca is probably a long-lived annual. It reproduces by seeds, for which a special culture is required. The tuberous hypocotyl is harvested and then replanted, often after a short storage period, to renew leaf growth and obtain seeds. Seeds are usually broadcast and trampled into the soil by sheep. Flowering is not sensitive to photoperiod, and low-temperature vernalization may not be required.

The edible organ is a turnip-shaped tuber with hypocotyl and root axis. They reach about 8 cm in diameter, taper into a root, and have varied coloration from creamy yellow to purple or almost black; yellow is preferred; the inner flesh is white or creamy yellow.

Harvest occurs 7–11 months or more after planting and usually at the beginning of the dry season. Yield is relatively low, about 3 t/ha. The tuberous roots are lifted and allowed to dry in the sun. After drying, they become brown, sweet, and aromatic, acquiring a musky, astringent taste and an iris-like odor. Dried tuberous roots store for a long time, often more than a year, but their quality declines over time. Besides baking and frying as vegetables, the tuberous roots are used to prepare desserts and various drinks. On a dry weight basis, maca contains much sugar and starch and about 10% protein. However, the tuberous roots also contain alkaloids, tannins, saponins, and glucosinolates, most of which have not yet been identified. Maca is also used medicinally, and folk beliefs claim that its consumption increases human and animal fertility.

Buffalo Gourd (Cucurbita foetidissima)

Buffalo gourd, or coyote gourd (Cucurbita foetidissima).

Family: Cucurbitaceae (Cucurbitaceae).

Other names: buffalo gourd.

Buffalo gourd is a long-lived endemic perennial native to the southwestern United States and northwestern Mexico. This crop is able to grow in arid conditions, being extremely drought-resistant due to a large and deep root system with food reserves. Plants are sensitive to poorly drained soils, but otherwise grow quite well even on arid and nutrient-poor soils. For good growth, plants require a long period of warm dry weather, but at temperatures above 40 °C vine growth is limited.

New plantings are propagated by adventitious rooting from vine shoots. Renewal of vine growth from rooted plants usually begins after the last spring frosts and continues until the first frost in autumn. Initially, large fleshy and deeply penetrating roots develop; some reach 4 or 5 m in length. Roots continue to increase (thicken) each year; many reach a weight of 30 kg after two seasons and up to 50 kg after 3–4 years. Yields of more than 30 t/ha have been reported. The roots are very rich in starch, often up to 60% of dry weight; in starch composition they are similar to cassava. Roots also contain glycosides, but these are easily washed out by soaking in water.

Fruits are small, inedible, round, yellow, in a hard shell, about 5–7 cm in diameter; there can be up to 100 per plant. Seeds are white and flat, about 1 cm long and 0.5 cm wide. Indigenous peoples used mature seeds as food for centuries. Seeds contain about 30–35% protein and about 30% oil; seed yield reaches 1 t/ha.

Currently, buffalo gourd is grown mainly in the wild, but the plant is in the process of domestication because of its potential for starch production and as a high-protein, edible seed oil crop.

Apios americana

Apios americana Medikus.

Family: Fabaceae (Fabaceae).

Currently Apios americana is a mainly uncultivated perennial vine-like plant, endemic to streams and rivers from southeastern Canada to the southeastern United States. Tubers with white flesh and starch were used by indigenous peoples of these regions for centuries; seeds are also edible.

On succulent vines 1 to 6 m long grow white, pink, purple, or brown-red flowers. Seed pods are 5–13 cm long. Plants produce rhizomes, from which several tubers are formed as threads, brown to black-brown with white flesh. In addition, tubers may be clustered or widely spaced. Tuber sizes vary from 3 to 10 cm in length and from 2 to 5 cm in width. Varieties from different regions show wide differences in number, shape, and development of tubers; some plants do not form tubers. Yield varies from negligible to almost 4 kg per plant.

Propagation is by seeds or tubers, which leads to large differences between plants. Tubers collected early show varying levels of dormancy, which appears to be influenced by position along the rhizome. Dormancy is broken when tubers are exposed to low temperatures for several months. Seed production and germination are also inconsistent; pods are often seedless, and pod dehiscence is common.

In its native habitat, Apios americana occurs on swampy and acidic soils, but growth and yield are better on well-drained soils with pH 5 to 7. Best growth is observed with trellis planting. Tubers can be harvested at any time, although yield increases until frost kills the tops. Tubers can be left in the ground for harvest in spring.

Some tubers contain up to 45% carbohydrates and 15% crude protein on a dry weight basis. Protease inhibitors are present, but they are inactivated by cooking. The taste of tubers resembles a combination of boiled peanut and Irish potato; the texture is more mealy than that of potato. Recent interest in domesticating the plant as a food crop includes selection and breeding. Most varieties are diploid (2n = 22), although triploids also occur.

Pachyrhizus ahipa

Pachyrhizus ahipa (Wedd.) Parodi.

Pachyrhizus tuberosus (Lam.) Sprengel.

Family: Fabaceae (Fabaceae).

Other names: ajipa, ashipa, frijol chuncho, Central American yam bean, ahipa.

No wild forms of Pachyrhizus ahipa have been found; its probable origin is the southwestern Amazon basin near Bolivia or northern Argentina, where it was domesticated at least 2000 years ago. Production and consumption remain mainly regional in Bolivia and Peru, although the potential for spread to other areas is high.

The potato bean has broad adaptation, growing from sea level to 3000 m in tropical, subtropical, and some temperate regions in wet or dry environments. Warm climate and moderate rainfall are the most favorable environment for growth. Although plants are grown at high altitudes, they are sensitive to frost. However, despite some similarity to jicama (Pachyrhizus erosus), some varieties of potato bean are neutral with respect to flowering and root initiation.

Plants are propagated by seeds. Growth of semi-upright, climbing vines 3–6 m long is rapid; vines of Pachyrhizus ahipa are shorter than those of Pachyrhizus tuberosus. Leaves are entire and rhombic-ovate. Flowering occurs 2–3 months after planting; lavender or white flowers produce pods with black kidney-shaped seeds. Gardeners often remove developing flowers to enhance root growth.

The edible organ is an underground, swollen, tuber-like root. Immature pods are not eaten because of irritating hairs and toxicity; all other parts of the plant are toxic. When the root is ready for harvest, it is elongated, about 15 cm long, and tapers at each end. Tuberous roots are harvested as early as 5–6 months; their weight is 500 to 800 g. The thin, pale, yellow skin does little to prevent drying, so they are usually left in the ground until needed. Roots of Pachyrhizus ahipa are smaller and mature earlier than those of Pachyrhizus tuberosus. Potato bean roots have juicy, crunchy white interior, and cut surfaces slowly discolor. They are eaten mainly raw for salads, but when cooked the texture remains crunchy.

The Asian yam bean (Pachyrhizus angulatus, now identified as jicama Pachyrhizus erosus), is another edible root crop. Confusion in identifying different yam bean species is not unusual, since common and species names are often interchanged.

Jicama (Pachyrhizus erosus)

Jicama, or yam bean (Pachyrhizus erosus (L.) Urban.).

Family: Fabaceae (Fabaceae).

Other names: yam bean, jicama.

Kudzu (Pueraria lobata)

Kudzu, or lobed kudzu (Pueraria montana var. lobata, syn. Pueraria lobata (Willd.) Ohwi, Pueraria thunbergiana).

Family: Fabaceae (Fabaceae).

Other names: English fankot, Chinese ko, Japanese kuzu, kudzu.

Kudzu is a perennial, hairy, twining vine commonly grown in Japan and China for starch accumulated in an enlarged taproot. Kudzu vines are deciduous and vigorous, growing up to 8 m long, which is useful for growing forage or cover crops. In some areas kudzu spreads and becomes a persistent weed. A related tropical plant, Neustanthus phaseoloides (syn. Pueraria phaseoloides (Roxb.) Benth., known as tropical kudzu, is also perennial, even more vigorous, and widely used as forage and pasture.

Kudzu leaves are large and rhombic. Flowers are purple, and from them grow hairy, oblong, narrow pods about 8 cm long. It reproduces usually by seeds, but in some climatic conditions few seeds are formed, and plants are propagated vegetatively by stem cuttings. Plants are usually tied to stakes to support the vines.

At harvest, some enlarged roots can reach 1 m in length, weigh up to 35 kg, and contain more than 25% starch. However, it is the young roots that are used as food, baked or boiled (Fig. 14.9). The starch resembles arrowroot in properties and is similarly used in cooking. A potential use of kudzu starch is ethanol production.

Sphenostylis stenocarpa

Sphenostylis stenocarpa Hochst. ex A. Rich) Harms. (syn. Dolichos stenocarpa).

Family: Fabaceae (Fabaceae).

Other names: English African yam bean.

Sphenostylis stenocarpa possibly originates from Ethiopia, although wild forms are known from West Africa and Zaire. This plant is cultivated in many tropical areas of Africa. In some places, wild and domesticated plants are cultivated. The plant is a twining vine about 2 m long with triangular leaves and purple or pink flowers; some have yellow or greenish-white petals. It reproduces by seeds or stem cuttings.

The edible parts are a small spindle-shaped underground root, similar to sweet potato and tasting like white potato, and mature seeds. Roots are harvested after 8 months; the flesh is white and watery, with starch content in fresh weight of 20% and about 3.5% protein, and is highly valued for its taste.

In central Africa, the main part of the crop is the root, while in West Africa it is the seeds. Plants cultivated in West Africa produce large (10–12 mm) seeds compared with seeds (2–3 mm) produced by plants grown for root storage. A disadvantage of the seeds is that they require a long cooking period before consumption.

Icacina senegalensis

Icacina oliviformis var. oliviformis, syn. Icacina senegalensis A. Jess.

Family: Icacinaceae (Icacinaceae).

Other names: English false yam.

Icacina oliviformis var. oliviformis is a rarely cultivated perennial shrub of West and Central African origin, grown for its tuberous hypocotyl. From the fleshy underground organ, upright shoots grow to 90 cm. Plants have ovate or obovate leaves about 5–10 cm long, which become leathery and dark green at maturity. White inconspicuous flowers produce bright red fruits containing one seed covered with white pulp.

The main plant value of this plant is the large turnip-like hypocotyl, which can reach about 40 and 25 cm in length and width, respectively. They contain 10–15% starch, but of edible quality, which is better suited for industrial use. In addition, the white flesh contains a bitter-tasting resinous compound.

Potato Coleus

Potato coleus (English coleus potatoes).

Family: Lamiaceae (Lamiaceae).

Coleus parviflorus (syn. Coleus tuberosus, currently assigned to Coleus rotundifolius), Chinese potato.

Solenostemon rotundifolius (Poir.) J.K. Morton, Sudan potato.

Coleus esculentus (syn. Plectranthus esculentus N.E. Br.), livingston, kaffir, or hausa potato.

Common and/or regional names of these species often lead to confusion in their identity, since they are all often called coleus or Hausa potato.

Coleus or Chinese potato, Coleus parviflorus, is a crop of some importance in southeastern India, its probable center of origin, where it is commonly called “kourka.” This crop is also grown in other dry tropical and subtropical regions of Asia and Africa.

It is an annual plant with simple leaves with toothed edges, opposite on succulent, almost four-angled stems. Despite flowering, seeds are not formed. For propagation, seed tubers are first used to obtain stem cuttings, which are then transplanted to grow the main crop. Cuttings 10–15 cm long are planted on raised beds at a density of 7–10 plants/m².

Clusters of white-colored, small, round, brown or black starchy tubers that form at the base of the primary stem are the main crop. Leaves can be used for flavoring. Tubers mature about 4–6 months after planting; harvest should not be delayed, as quality declines when overmature. Yield varies from 5 to 19 t/ha. Tubers store well in cool, well-ventilated rooms. They have an aromatic taste, contain about 11% carbohydrates and 5% protein, and are eaten raw or boiled.

Sudan or Hausa potato, Solenostemon rotundifolius, is sometimes also called coleus potato. This annual is grown in Southeast Asia, India, Sri Lanka, and Africa for its clustered growth of dark brown potato-like tubers that develop at the base of the main stem. Culture and productivity are similar to Coleus parviflorus, with good growth in areas with high rainfall, cool nights, and well-drained sandy soils. Edible tubers mature in 6–8 months; carbohydrate content is about 20%, and protein about 1%.

Livingstone potato, also called Kaffir or Hausa potato (Plectranthus esculentus), is a deciduous perennial growing to 75 cm in height with long trailing branches that root easily at the nodes. Leaves are pubescent and sessile, and yellow flowers open after the leaves fall.

Livingstone potato is grown in tropical Africa. It is propagated by seedlings obtained from tubers. Tubers mature 7–8 months after planting; yield averages 5–6 t/ha. Thick, yellow-skinned, branched, tuberous roots are eaten after cooking; the taste is similar to white potato.

The aromatic shoots of Coleus amboinicus Lour., known as Spanish thyme or Indian borage, also have culinary use in tropical America. Coleus barbatus var. barbatus (syn. Coleus forskohlii) is another aromatic perennial producing tuberous roots that in India are pickled and eaten as a condiment.

Chinese Artichoke (Stachys affinis)

Chinese artichoke, or Japanese artichoke (Stachys affinis Bunge, syn. Stachys tuberifera, Stachys sieboldii).

Family: Lamiaceae (Lamiaceae).

Other names: English chiyorogi, knotroot, kon loh.

Native to the Far East, Chinese artichoke is a perennial herb grown for its cylindrical tubers. They form at the tips of underground stems. Some tips of underground stems also emerge from the soil and grow above ground. Aboveground stems have the four-angled shape characteristic of the Lamiaceae family. Externally resembling nettles, these plants grow to 30–45 cm in height. Petiolate, roughly ovate leaves are arranged on stems in opposite pairs. Flowers are white or pink. The thin white tubers, which are also used for propagation, are 5–8 cm long and about 1–2 cm in diameter, with characteristic constricted internodes resembling a string of beads. Instead of starch, most carbohydrates (about 60%) consist of the tetrasaccharide stachyose.

Tubers are dug, washed, and eaten after cooking, like white potatoes. Because of the thin skin, tubers quickly lose moisture and are easily damaged, so they are usually stored in moist sand. Tubers, usually pickled, are a popular food in China and Japan; they are also eaten fried or fresh in salads.

Mirabilis expansa

Mirabilis expansa (Mirabilis expansa (Ruiz & Paron) Standley).

Family: Nyctaginaceae (Nyctaginaceae).

Other names: yuca inca, chago, miso, arracacha de toro, mauka.

Mirabilis expansa is a little-known highland tuber crop. Wild ancestors occur in the Andean mountain regions. Plants tolerate cold well and are able to adapt to both wet and dry conditions, but are sensitive to heat. Although the plant is perennial, it is grown as an annual, but under mountain conditions it takes at least a year to reach crop maturity.

Low, compact plants produce succulent leaves. The edible parts are the tuberous parts of the lower stems and upper root. Flowers are purple or white. Although seed propagation is possible, stem parts or offshoots are used.

At maturity, an edible, thickened, fleshy axis forms at or just below the surface. The length of the tuberous part varies from 20 to more than 30 cm; diameter is usually 5–8 cm. The flesh is white to yellow. These tuberous forms are grouped at the base of the stems. They can be left in the ground for a second year for further growth; yield reaches 20 t/ha. Freshly harvested tubers of some varieties have a strong astringent taste, which can be reduced by exposure to sunlight. Solar exposure and drying also promote conversion of starch to sugar. Mauka is used boiled and is often mixed with other products. On a dry weight basis, the tuber contains about 85% carbohydrates and about 7% proteins. Leaves are also eaten in salads and stews.

Oca (Oxalis tuberosa)

Oca (Oxalis tuberosa Molina.).

Family: Oxalidaceae (Oxalidaceae).

Other names: papa roja (Mexico), truffette acide (France) knollen-sauerklee (Germany), New Zealand yam, apilla, ibia, oca.

Oca is an ancient crop cultivated by pre-Columbian peoples and currently by farmers in the high Andes. For these people, oca is almost as important as potato, Solanum tuberosum. Under these mountain conditions, oca yield can be twice that of potato. Peru leads the world in production with more than 20,000 ha. Besides production in the Andean region, commercial production occurs in Mexico, Central America, and the South Island of New Zealand, where it is unfortunately incorrectly called “yam.”

A compact, bushy perennial has a height of 20 to 30 cm. Hardy to harsh climate, oca grows at altitudes up to 4000 m, at relatively low temperatures and over a wide range of precipitation. Although frost kills the foliage, the plant usually regrows. Oca is sensitive to heat, and at temperatures above 28 °C growth stops. Leaves are purple and hairy. Overall, flowering is abundant, and viable seeds are formed. However, propagation occurs by using whole tubers. Plantings are made at the beginning of the rainy season. Oca is often planted together with other tuber crops, legumes, or cereals. Oca is also often considered in crop rotation with potato in the high Andes.

As in potato, edible tubers develop on underground stolons, and tuberization begins under short day length. Tuberization is also affected by temperature, and usually occurs about 4 months after planting, with maturity after 2–3 months. Tubers are small and elongated, about 6–8 cm long, wrinkled, with a white or bright red surface and firm white flesh (Fig. 14.12). There are sweet and bitter varieties because of differences in sugar and oxalic acid content. Some, usually white-colored tubers, have somewhat higher oxalic acid content.

Tubers can be eaten immediately after harvest, but their taste improves if they are left in the sun to reduce bitterness. Oca is eaten after boiling, baking, frying, or pickling, and can also be eaten uncooked. Leaves and young shoots are eaten in salads or as boiled vegetables. Bitter varieties are usually processed into dried forms or made into “chuño de oca,” also called “kaya” or “okaya.” The taste of oca chuño is considered better than that of white potato chuño. Oca chuño is made by pre-soaking tubers for several weeks in running water, then subjecting them to alternating freezing and drying in the open air. The taste is reported to resemble dried figs. Tubers are also processed by canning.

With proper handling and minimal moisture loss, oca storage characteristics are relatively good. Nutritional quality is comparable to potato. On a dry weight basis, about 85% of tubers are carbohydrates; starch is of good quality.

Solanum hygrothermicum

Solanum hygrothermicum (currently assigned to potato species Solanum tuberosum).

Family: Solanaceae (Solanaceae).

Other names: peruvian potato, urahji, kurahji, cachariqui, moshaki.

Peruvian potato is grown in the warm humid eastern lowlands of Peru. Plants and tubers resemble potato (Solanum tuberosum), and, like cultivated potato, plants are tetraploids. Tubers are small, oval, or somewhat cylindrical. Skin is yellowish-white, and small eyes are surrounded by purple pigment. Tubers are reported to have a short dormancy period.

Mashua (Tropaeolum tuberosum)

Mashua (Tropaeolum tuberosum Ruiz & Pavon.).

Family: Tropaeolaceae (Tropaeolaceae).

Other names: mashua, anu, isano (Peru), nabos, cubios (Colombia).

Mashua, grown for its tubers, is endemic to the Andean region and also an ancient domesticated plant. About 5000 ha are grown in Peru, but production outside the Andean region is relatively small. This crop is well adapted to cultivation at high altitudes (2500–4000 m), and it is often grown together with other Andean crops such as oca, ulluco, or potato. Plants are resistant to low temperatures and frost and have the short day length required for tuberization.

A semi-upright perennial with vigorous spreading growth capable of branching, mashua resembles garden nasturtium (Tropaeolum majus). Orange to dark red, bisexual, edible flowers grow abundantly, and fruits contain many seeds. Seeds are not used for propagation because of resulting plant variability; small tubers are used instead.

Since tubers develop near the surface, soil is moved to the base of the plant to ensure tuber development below the surface. The crop is harvested about 6–8 months after planting. Tubers are the size of a small potato and somewhat conical, have attractive coloration, often in combinations of white, yellow, and red; the flesh is yellow.

Tubers quickly lose moisture, but if stored at low temperature and in darkness, they keep well for several weeks. They can also be left in the ground and collected as needed. Because of their strong pungency, tubers are not eaten raw. The sharp mustard taste is due to glucosinolates, which disappear after tubers are exposed to sunlight for 4–5 days or after cooking. Tubers are boiled and used in soups and other dishes. Tender young leaves are used as a potherb. The nutritional value of mashua is comparable to that of other root and tuber crops.

Plantain and Starchy Banana

Main page: Plantain and starchy banana

Breadfruit (Artocarpus altilis)

Breadfruit (Artocarpus altilis (Parkins.) Fosb.).

Family: Moraceae (Moraceae).

Other names: English Breadfruit, Arbre a pain (France), fruta de pan (Spain), ulu (Polynesia).

Breadfruit, named for its similarity in texture and taste to bread, is native to Malaysia and is grown in the humid tropics. Although the starchy vegetable is of some importance and is a staple food in some regions, its production is declining in the main areas of Indonesia, Polynesia, and the Caribbean. Breadfruit grows best at warm temperatures of 21–33 °C and in the lowland tropics, where annual rainfall ranges from 1500 to 2500 mm. Some clones are known to tolerate drought, salt spray, and soil salinity well. It is best grown on well-drained soils and in wind-protected sites.

Breadfruit is a tall (12–25 m) evergreen tree of the humid tropics, with large (50 cm), glossy, pinnately lobed leaves. Dwarf varieties (4–6 m) have been identified, but they differ significantly in leaf size and shape. There are seedless and seeded types, designated as Artocarpus altilis var. apyrena and Artocarpus altilis var. seminifera, respectively. The latter, sometimes called breadnut, is wind-pollinated. Seedless varieties are propagated by root cuttings or rooted adventitious shoots; micropropagation can also be used. For propagation of seeded varieties, either vegetative methods or seeds are used. Seeds are prone to drying out, so they should be planted immediately after removal from the fruit.

Trees are monoecious and begin bearing about 2–6 years after planting. Staminate flowers are arranged on an elongated inflorescence; on the same branch, an oval-spherical inflorescence bears pistillate flowers. The fruit structure is a syncarp consisting of a cluster of up to 2000 small fruits fused together and enclosed in a fleshy perianth. The fruit surface, usually very rough, has a pronounced segmented appearance, although some varieties have a relatively smooth surface. Fruits mature about 60–90 days after flowering begins; their diameter is 10 to 20 cm, length 20–30 cm, and weight 1–4 kg. Large mature trees can produce up to 700 fruits. Production tends to be cyclic, with higher yields in summer than in winter. Harvest is usually done when fruits turn brown-green and the flesh is still white and mealy. After removing the yellowish-green outer skin, the pale yellow or whitish flesh becomes firm and starchy, resembling white potato in consistency.

Consumption usually occurs soon after harvest, since the postharvest period is very short. Under ambient conditions, fruits soften within 2–3 days and often spoil in less than 5 days. Slowing softening is important for improving market prospects. Some extension of storage life is achieved at low temperature (12–13 °C) and 90% relative humidity; however, temperatures below 12 °C cause chilling injury. Controlled atmosphere storage and the use of various films or wax can extend storage life by 2–3 weeks. Part of breadfruit production is processed by canning or dehydration.

Breadfruit is usually prepared after removing the skin and central core. It can also be used without removing the skin. Sliced or whole, it can be boiled, baked, or fried. Seeds are boiled or roasted as a snack. Flour is sometimes made from the starch-rich flesh. Seeds are a better source of protein than the flesh.

Jackfruit (Artocarpus heterophyllus)

Jackfruit (Artocarpus heterophyllus Lam.).

Family: Moraceae (Moraceae).

Other names: Jackfruit, Jak, jaca.

Jackfruit, native to southern India, is closely related to breadfruit. It grows best in lowland tropical climates, and the plant tolerates slightly lower temperatures than breadfruit. As with breadfruit, well-drained soils are preferred. Other similarities are the tall tree and late fruiting, which begins about 4–6 years after planting.

Jackfruit differs from breadfruit in several respects. Leaves are relatively small and entire, so the tree has a different appearance. Syncarp fruits are oblong and very large; some reach 70 cm in length and 40 cm in width and weigh more than 25 kg. However, most fruits are not that large and weigh about 8–10 kg. Another important difference is the cauliflorous fruiting type, in which fruits are borne singly or in clusters attached directly to the tree trunk by a short, strong stalk; all fruits are seeded.

Large trees can produce 150–250 fruits per year. Fruits reach full maturity in 100–120 days. The edible part is the fleshy and juicy yellowish pulp (perianth tissue) surrounding individual gelatinous coated seeds. The pulp, which has a sweet-sour taste, makes up about 30% of the fruit; seeds about 5%. There are two types of jackfruit: one with soft and melting pulp, the other with firm fleshy pulp. Fruit shape is mainly oblong with a surface of numerous short, sharp, hexagonal fleshy spines.

Propagation by seed is more common than vegetative propagation, despite the resulting plants being highly heterozygous. Relatively large seeds quickly lose viability soon after extraction, often within a month, so they should be planted without delay. Seeds are sown directly in the field, since transplanted seedlings establish poorly, mainly due to damage to the delicate root. Results of propagation by budding or grafting have been variable, but success has been achieved with cuttings, air layering, and stem cuttings; satisfactory in vitro propagation has also been reported.

Like breadfruit, jackfruit is a very perishable and chilling-sensitive fruit, but it can be stored after harvest for several days at about 12 °C.

It is best used without delay. The fruit composition is approximately 75% water, almost 25% carbohydrates, and contains little protein. At the immature stage, the pulp has a vegetable use similar to breadfruit.

Seeds prepared boiled, baked, or roasted taste like chestnuts. They contain about 6% protein and almost 40% carbohydrates. In Java, young flower clusters are eaten with syrup and agar-agar. Seeds of other related species, such as Artocarpus ovatus and Artocarpus blancoi, are eaten in the Philippines. Other related species with minor vegetable use are Artocarpus hypargyreus and Artocarpus hirsutus.