Maranta arundinacea (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Maranta arundinacea L.

Protologue: Sp. pl.: 2 (1753).

Family: Marantaceae

Chromosome number: 2n= 48

Synonyms

• Maranta sylvatica Roscoe ex J.E. Smith (1819).

Vernacular names

• Arrowroot, West Indian arrowroot, St Vincent arrowroot (En). Arrowroot des Antilles, herbe aux flèches, arruruz (Fr)
• Indonesia: garut (Indonesian), angkrik (Javanese), larut (Sundanese)
• Malaysia: ararut, ubi garut, berolu
• Philippines: aroru (Tagalog), aru-aru (Tagalog), sagu (Bikol)
• Cambodia: saku:
• Laos: sa:kh'u:
• Thailand: sakhu (central)
• Vietnam: hoàng tinh, củdong, huỳnh tinh.

Origin and geographic distribution

The exact origin of arrowroot is not known but it is indigenous in Central America (including the Caribbean area) and northern South America with exclaves in western Ecuador and in some of the interior Guiana savannas. Nowadays, it can be found in cultivation throughout the tropics, but is important only in the West Indies (Bahamas, Antilles, especially St Vincent island). In South-East Asia, it can be found cultivated everywhere, mainly as a home garden crop.

Uses

Arrowroot is mainly cultivated for the valuable starch that can be extracted from the rhizomes. The starch is very easy to digest and is often used as a thickener in all kinds of foods, dressings, soups, sauces, candies, cookies, and desserts like puddings and ice-creams. Industrially, processed rhizome pulp is applied in the manufacturing of paper, cardboard, cushions and wallboards and the starch as basic ingredient of powders, glues and soap. Whole rhizomes can be eaten boiled or roasted when they are not yet fibrous. Medicinally, the pulp of fresh rhizomes is used in poultices to cure wounds and ulcers and the starch, prepared with water or milk, is used to cure stomach problems (e.g. against poisoning) and diarrhoea, or to prepare easily digestible food for patients with stomach or intestine problems. The rhizomes are also a good substitute for maize in broiler rations and the fibrous debris after starch extraction is used as feed and manure. Arrowroot cultivars with strikingly coloured leaves (e.g. brown-purple) are also popular as ornamentals. Leaves are used for wrapping.

Production and international trade

Commercial production of arrowroot starch started in the middle of the 19th Century in the West Indies, with St Vincent as the principal producer for the United States, Canada and Europe. Annual production fluctuated from 1000-2000 t until 1940, to 4500 t after the Second World War, and to 1500-3000 t at present. Outside the Caribbean, including in South-East Asia, arrowroot products are mainly produced and traded locally on a very small scale.

Properties

The chemical composition of fresh arrowroot rhizomes per 100 g is approximately: water 69-72 g, protein 1-2.2 g, fat 0.1 g, starch 19.4-21.7 g, fibre 0.6-1.3 g, and ash 1.3-1.4 g. The starch grains are ovoid or flattened ovoid and 15-70μm long. Arrowroot starch contains about 20% of amylose and contains a high percentage of K. It has a high viscosity which it retains at higher temperatures, in contrast with the fall in viscosity of, for example, cassava and sago starch at higher temperatures. The dried residue remaining after starch extraction contains approximately: water 12%, fibre 14% and starch 50-64%. In modern factories most of this starch can be extracted by steam grinding.

Description

• Perennial, erect herb, 0.5-1.5 m tall, shallow-rooted, with rhizomes penetrating more deeply into the soil.
• Rhizomes fleshy, cylindrical, 5-40 cm × 2-5 cm, white or reddish, covered with overlapping, persistent or deciduous, brownish-white scale leaves.
• Stem thin, usually much forked towards the apex.
• Leaves radical and cauline, distichous; petiole terete, sheathing at the base, with a thickened, glabrous to sparsely hairy pulvinus at the apex, in upper leaves petiole often absent; blade ovate-oblong, 10-30 cm × 3-10 cm, rounded to truncate at base, acute acuminate at top, largest in basal leaves, glabrous or more usually hirsute, green or sometimes variously streaked white or brownish-purple, with prominent midrib and numerous pinnately arranged, fine, closely spaced parallel veins.
• Inflorescence paniculate, terminal, often branched, each branch subtended by a deciduous bract and ending in a stalked flower pair; peduncle of flower pair thin, up to 4 cm long; pedicel of one flower of the pair 7-15 mm long, the other one 0-3 mm.
• Flowers bisexual, zygomorphic, about 2 cm long, with 3 green, free, persistent, lanceolate sepals 12-16(-18) mm long, and a white, 3-lobed, tubular, early caducous corolla; androecium in 2 whorls, attached to the corolla; outer whorl consisting of 2 petaloid staminodes, about 1 cm long; inner whorl about half as long, consisting of 1 fertile stamen, a large fleshy staminode and a smaller hooded staminode; fertile stamen with a 1-celled half anther joined to a petaloid appendage; pistil 1, with a 1-celled, 1-ovuled, inferior ovary, style adnate to corolla tube, stigma 3-lobed and enclosed by hooded staminode.
• Fruit oblongoid, about 7 mm long, berry-like, leathery, brown, glabrous to hairy. Seed 3-sided, scabrous, pinkish, with yellow, 2-lobed, basal aril.

Growth and development

After the tip of a rhizome has been planted, a shoot arises in 1-3 weeks. The new plant establishes by forming adventitious roots within 6-7 days. In the next phase more leaves and a stem develop aboveground and more roots and new rhizome material develop underground. Some of the new rhizomes become specialized storage rhizomes, others start suckering, a process which is not well understood. It appears that storage rhizomes are not found throughout the growing season but are initiated only after the plant has reached a certain stage of development. There is some kind of relation with the deciduous growth habit in which the plants die back to the rhizome in the dry season. Under optimum conditions the plant grows continuously, producing suckers and rhizomes; old leaves wither, fleshy rhizomes deteriorate or develop new plants when not harvested. Flowering starts 3-6 months after planting and flowers open in the evening. Arrowroot is predominantly autogamous according to some authors, obligately allogamous according to others; the flowers seem devised for cross-pollination by insects. Fruit development is rather abundant with about one fruit per 4 flowers, but seed viability is poor. A crop matures and can be harvested 8-12 months (depending mainly on environmental factors) after planting. Starch content reaches a maximum in the rhizomes about 12 months after planting, but then they are more fibrous and the starch is more difficult to extract. When storage rhizomes are left in the soil for more than 12 months, the starch is gradually converted into sugar. Arrowroot is mostly grown as an annual crop, but it could be grown as a perennial.

Other botanical information

There are several cultivars of arrowroot. In St Vincent the 2 main ones with white rhizomes are "Creole" and "Banana"; a cultivar with reddish rhizomes is known from Dominica. "Creole" is grown particularly by smallholders, and has widely dispersed, deeply penetrating, long, thin rhizomes (on poor soil often too thin). They can be stored for up to 7 days before processing without serious deterioration. "Banana" has shorter, thicker, less fibrous rhizomes, growing in clusters just below the soil surface. They are easier to harvest and process, are higher yielding, more suitable for mechanical harvesting and mainly grown on estates, but they should be processed within 2 days after harvest. It is not known which cultivars are grown in South-East Asia.

The genus Maranta L. comprises about 23 species, mainly occurring in tropical America and none being indigenous to South-East Asia. The species related to M. arundinacea have been classified into subgenus Maranta . In particular, M. amplifolia K. Schumann, M. linearis L. Andersson and M. incrassata L. Andersson also develop starch-storing rhizomes. M. amplifolia is very closely related to M. arundinacea , and is sometimes even united with it. It is a more robust plant with glabrous leaves, sepals 16-20 mm long, obligate allogamous and fruiting very rarely. M. linearis differs from M. arundinacea , especially in its linear or very narrowly oblong leaf blades, smaller inflorescences and shorter sepals. M. incrassata is a small plant up to 1 m tall with ovate leaf blades and simple inflorescences.

In the literature, the name arrowroot is also used for various other crops: Queensland arrowroot ( Canna indica L.), Indian arrowroot ( Curcuma angustifolia Roxburgh), Brazilian arrowroot or cassava ( Manihot esculenta Crantz), and East Indian arrowroot ( Tacca leontopetaloides (L.) O. Kuntze).

Ecology

In the wild, M. arundinacea grows primarily in the understorey of tropical deciduous or semi-deciduous forest near temporary pools and brooklets, sometimes however, also in dry pine forest. It grows best under warm humid conditions, preferring temperatures of 25-30°C and requiring an annual average rainfall of 1500-2000 mm or more, but with 1-2 dry months. Arrowroot tolerates up to 50% shading without notable yield reduction, and survives waterlogging and saturated soil conditions but does not produce storage rhizomes under such circumstances. It prefers lowland conditions, but can be cultivated up to 1000 m altitude. Arrowroot can be grown on many soil types but thrives on rich, loose, sandy loams with pH of 5-8 (e.g. the volcanic soils of St Vincent are perfectly suited for arrowroot).

Propagation and planting

Arrowroot is propagated vegetatively from rhizome apices ("bits") about 2-4 nodes long and not too thin; about 3 t are required to plant 1 ha. No special land preparation is needed besides the usual ploughing and harrowing. The bits are planted 5-7.5 cm deep and about 30 cm apart, preferably at the beginning of the rainy season. Bits can be stored for some months before being planted in the field. Suckers 30 cm tall can also be used, but they should be planted immediately after cutting. Planting distance depends on the mode of cropping, e.g. when intercropped with annual crops row distance is wider and plant distance closer (e.g. 75 cm × 15-20 cm); square planting patterns (20-50 cm) are more appropriate in sole cropping with hand-weeding and poor soil conditions. Because arrowroot tolerates shade quite well, it can be grown successfully under perennial tree crops (e.g. coconut, fruit trees). Propagation by seed is rare.

Husbandry

Usually, a field with arrowroot needs 3-4 weedings, effected manually or mechanically. Young plantings are especially susceptible to weed competition. Recommended fertilizer levels per ha are 350-650 kg ammoniumsulphate, 300 kg superphosphate and 300 kg KCl. The entire quantity of P and K can be applied at planting time, N is applied at intervals. Per t harvested rhizomes, about 16 kg N, 5 kg P and 36 kg K are withdrawn from the soil, and this should be compensated for by a balanced fertilization programme. When the crop starts flowering, the inflorescences should be removed to achieve a maximum nutrient flow to the storage rhizomes. Crop rotation is recommended for nutrient and pest management, at least every 5-6 years. Pieces of rhizome left in the soil after harvest often pose a weed problem in subsequent crops because they are difficult to eradicate.

Diseases and pests

Arrowroot does not have any serious diseases or pests. Under poor drainage conditions, burning disease, caused by Rosellinia bunodes , may cause losses. On poor soils, arrowroot may produce so-called "cigar roots", i.e. long thin fibrous rhizomes, containing little starch; this can be prevented by applying more fertilizer. In India, the banded leaf blight disease, caused by Pellicularia filamentosa , sometimes infects the crop; spraying with Bordeaux mixture is effective. Sometimes the arrowroot leaf roller ( Calpodes ethlius ) causes defoliation and, consequently, starch losses; it is usually controlled by arsenicum-based sprays.

Harvesting

Rhizomes mature in 8-12 months and can be harvested when the leaves turn yellow and stems start to lodge. Harvesting can be done manually using a fork or by ploughing carefully. One person can harvest about 450 kg rhizomes per day by hand. Weeds and aboveground parts are usually buried to provide organic matter, and "bits" are separated from the harvested rhizomes to serve as new planting material. Harvesting should be done before the next rainy season otherwise the rhizomes will start sprouting.

Yield

Rhizome yield varies considerably, ranging from 7-47 t/ha. The amount of starch obtained is 16-18% of the fresh weight of the rhizomes. The highest reported rhizome yield of 47 t/ha was obtained with a spacing of 50 cm × 30 cm and an NPK 60-60-60 fertilizer application.

Handling after harvest

To extract the starch, mature rhizomes are cleaned, washed, grated and crushed, and the remaining pulp is washed over sieves until all fibres have been removed. The starch is allowed to settle or is separated by centrifuging, then is dried, pulverized, graded and packed. Grading of starch is based on e.g. colour (should be white), purity, moisture content, pH and viscosity. Large quantities of clean fresh water are essential when processing the rhizomes. In St Vincent, usually only ordered quantities are harvested and processed immediately, to minimize deterioration.

Genetic resources

A germplasm collection of arrowroot is held in St Vincent. In South-East Asia, 35 accessions of arrowroot are available at the Philippine Root Crops Research and Training Centre, Visayas State College of Agriculture, Leyte.

Breeding

In St Vincent, a breeding programme for arrowroot is in progress aiming at the development of cultivars with higher starch yields. Because of low seed setting and poor germination it is difficult to breed arrowroot.

Prospects

The prospects for arrowroot are promising because of its high yield potential, high quality starch and multiple uses. To survive competition with other starch-producing crops, the efficiency of starch extraction should be improved and the utilization of debris optimized. In South-East Asia, the feasibility of large-scale production in areas with a short dry season should be investigated.

Literature

• Andersson, L., 1986. Revision of Maranta subgen. Maranta (Marantaceae). Nordic Journal of Botany 6: 729-756.
• Erdman, M.D. & Erdman, B.A., 1984. Arrowroot (Maranta arundinacea), food, feed, fuel, and fiber resource. Economic Botany 38: 332-341.
• Forio, A.F. & Villamayor Jr, F.G., 1988. Exploiting the yield potential of arrowroot. The Radix 10(1): 14-16.
• Martin, C.I., 1969. The arrowroot industry in St. Vincent: a case study of a unique root crop industry. In: Tai, E.A., Charles, W.B. & Iton, E.F. (Editors): Proceedings of the International Symposium on Tropical Root Crops, held at the University of the West Indies, St. Augustine, Trinidad, 2-8 April 1967. Vol. 2. pp. 125-139.
• Purseglove, J.W., 1972. Tropical crops. Monocotyledons 2. Longman, London, United Kingdom. pp. 335-342.
• Raymond, W.D. & Squires, J., 1959. Sources of starch in colonial territories. II. Arrowroot (M. arundinacea Linn.). Tropical Science 1: 182-192.
• Royal Botanic Gardens Kew, 1893. St. Vincent arrowroot. Kew Bulletin 1893: 191-204.

Authors

F.G. Villamayor Jr & J. Jukema