Dendrocalamus latiflorus

Dendrocalamus latiflorus Munro

Trans. Linn. Soc. 26 : 152 (1868).
2n = 72 (hexaploid), 64, 48

Origin and geographic distribution
The origin of D. latiflorus is not known precisely but it is distributed from Burma (Myanmar) to southern China and Taiwan where it is also found in cultivation (most importantly in Taiwan, 90,000 ha). It has been introduced in India, Thailand, Japan, in the early 1970s in the Philippines (Davao and Cotabato Provinces) and in 1980 in Indonesia. For map click: Map165.TIF.

D. latiflorus is most important for its young shoots which are used as a vegetable and considered delicious. Mature culms are used as water pipes, to make small rafts for fishing in streams, to weave baskets, and are also used in house construction and for making paperpulp. The leaves are used to make hats, roofs for boats and as material for packing. In Taiwan D. latiflorus is also cultivated as an ornamental.

Production and international trade
Production and trade of young shoots of D. latiflorus is very important in southern China and Taiwan. China exported 140,000 t young bamboo shoots in 1985, Taiwan exports about 40,000 t yearly. The main importer is Japan (value about US$ 40 million per year), but dried or canned shoots are also exported to Europe, the United States, Canada and South-East Asian countries. Since 1973, the Philippines has also been exporting young shoots to Japan.

The fibre dimensions in the culm are: length 3.01 mm, diameter 18.1 µm, wall thickness 5.6 µm. The chemical composition of the culm is approximately: holocellulose 80.15%, pentosans 19.40%, lignin 24.76%, ash 2.82%; the solubility in hot water is 5.77%, in alcohol-benzene 7.37% and in 1% NaOH 26.60%. Per 100 g edible portion, young shoots contain: water 92 g, protein 1.2 g, carbohydrates 1.2 g, fat 0.5 g, fibre 0.8 g, ash 0.7 g.

Densely tufted, sympodial bamboo. Culm erect with pendulous tip, 14-25 m tall, 8-20 cm in diameter, wall 0.5-3.0 cm thick; internodes 20-70 cm long, smooth and glabrous, covered with white wax when young; nodes rather prominent, the lower ones often bearing aerial roots, surrounded by a ring of brown silky hairs above and below the sheath scar. Branches numerous at each node, the primary one usually distinctly larger. Culm sheath longer than the lower and shorter than the upper internodes, deciduous, coriaceous, hard and brittle, rounded at the apex, orange-yellow when young turning pale brown with age, abaxially dull brown pubescent, margin entire; blade ovate to lanceolate, deflexed, 10-15 mm x 3-4 mm, puberulent near the base abaxially; ligule 2-3 mm long, minutely fringed or toothed; auricles firm, 1.0-1.5 mm wide, ciliolate along the margins. Leaf blade elliptical to oblong-lanceolate, 15-40 cm x 2.5-7.5 cm, top acute; sheath 10-22 cm long, sparsely covered with appressed or spreading bristly glabrescent hairs; ligule very conspicuous, convex, rounded or truncate, 1.5-2 mm long; auricles absent. Inflorescences borne on leafless branches between the leafy branches at a node, up to 80 cm long, consisting of clusters of 1-7 pseudospikelets; spikelet ovoid, laterally compressed, 1-2 cm x 0.8-1.2 cm, reddish to dark purple, comprising 6-8 florets. Caryopsis cylindrical to ovoid, 8-12 mm x 4-6 mm, light brown, pericarp thin.

Growth and development
In Taiwan, vegetatively propagated plants can develop in 3 years into clumps with 20-25 culms on average 5-6 m tall and 3-4 cm in diameter. In the Philippines, 5 years after planting, average culm height was 15 m, diameter 7 cm. Flowering is rare in Taiwan; sporadic flowering and fruiting is a normal occurrence in the Philippines, Indonesia and China.

Other botanical information
In Taiwan 2 cultivars of D. latiflorus have been developed:
- 'Subconvex' (D. latiflorus Munro var. lagenarius Lin): culm 5-10 m tall, 4-12 cm in diameter; internodes 10-30 cm long, ventricose, pear-shaped; cultivated for ornamental purposes.
- 'Mei-nung': culm and branches yellow-green with narrow darker green stripes on the internodes; culm sheath yellow-brownish green with a few slender pale yellow stripes; commonly cultivated for its edible shoots and useful culms.
In China a form with puberulent branches and leaves with distinct transverse veinlets is distinguished (Sinocalamus latiflorus var. magnus T.H. Wen).

In its area of natural distribution D. latiflorus occurs under subtropical conditions as in northern Taiwan where it is found up to 1000 m altitude, tolerating temperatures as low as -4ºC. In the tropics it is cultivated in the lowlands (Indonesia) as well as in the highlands (the Philippines). It prefers high rainfall. It grows best in moist, fertile soils. Heavy clay, gravel alkaline or acidic soils are not suitable for the production of edible shoots.

Propagation and planting
D. latiflorus can be propagated by seed and by rhizome and culm cuttings. Seed rapidly loses its viability. When sown directly after collection, seed germinates within 2 weeks at a germination rate of 90%. As seed is usually rather rare, vegetative propagation by cuttings is normal practice. The preferred cuttings are taken from 2-year-old culms, are 50 cm long (2-noded), and are planted horizontally 6-10 cm deep. The rooted cuttings are preferably transplanted in the rainy season when 2 years old. Usual spacing is 4-5 m x 4-5 m, giving 400-625 plants per ha. Propagation by tissue culture is practised successfully in Taiwan.

Husbandry Regular weeding (twice a year) is necessary. The plants must never be allowed to become short of water until they are well-established. For edible shoot production it is recommended in Taiwan to:
-mulch each clump 3 times per year with 40-60 kg mulch (dry grass, bamboo or sugar-cane leaves);
-loosen the soil around each clump regularly;
-cut the culms back to 2.0-2.5 m in the second year after planting, to maintain a bush-like clump as protection against wind damage;
-apply 20-25 kg compost or manure to each clump as basic organic fertilizer before each growing season;
-apply chemical fertilizers 4 times per year, each time at a rate of 40 kg N, 10 kg P, 30 kg K and 0.65 kg Si per ha.
-maintain only 3-4 culms per mature clump, to increase the area for young shoot growth.

Diseases and pests
The most common diseases of D. latiflorus are: bamboo mosaic virus (Taiwan, the Philippines), leaf rust (the Philippines: Phakopsora louditiae; China: Uredo dendrocalami), bacterial wilt disease attacking shoots (Taiwan: Erwinia sinocalami; China: Fusarium semitectum), wood rotting (Japan: Poria vaporaria). No serious pests have been reported.

Young shoots are harvested 7-25 days after emergence, when they are 35-60 cm tall. Harvesting may start in the 2nd year of growth of a clump. Harvesting of culms may start when clumps are 3-7 years old. To ensure sustainable yields, only over-mature and a few mature culms should be harvested at one time, and the number of harvested culms should not exceed 3/5 of the standing mature culms. In the Philippines, culms are usually harvested in the dry season, i.e. from November to May.

A 1-2-year-old culm can produce 5-10 shoots weighing 3-5 kg. In Taiwan, average young shoot production per clump increases in the first 5 years after planting from 30 kg in the 2nd year to 60 kg in the 3rd year to 80 kg in the 4th year, to a maximum of about 100 kg in the 5th year. With 200-400 mature clumps per ha, total annual yield averages 20-40 t per ha. In southern China, young shoot yield per year averages 12 t/ha, but can be as high as 30 t/ha. In the Philippines, a mature clump can produce 80-160 culms annually under ideal circumstances, but usually average production is 20-30 culms or 10,000 culms per ha.

Handling after harvest
Harvested shoots are steamed, cut lengthwise, cleaned and sterilized for 15 minutes in pure or salted (2 tablespoons NaCl per 0.25 l) boiling water before eating or canning. When boiled in pure water a white compound (containing 90% tyrosine) usually precipitates, which can be removed by boiling for 1.5 hours in a 0.06-0.07% citric acid solution, followed by 12 hours of washing. For the production of fermented dry shoots, the middle parts of shoots are boiled first and then left to ferment for 2-4 weeks, and subsequently sliced into parts of 4-5 cm x 2.8 mm. In the Philippines harvested culms are either dried directly in the sun or shade or first kept in running water for several weeks before being air dried.

Genetic resources
Germplasm collections of D. latiflorus are available in China (Forest Research Institute, Guangzhou, Guandong), Taiwan, Indonesia (Lampung, Sumatra) and the Philippines (Ecosystems Research and Development Bureau, Baguio). D. latiflorus has been planted in many botanical gardens all over the world.

In China, D. latiflorus is used in breeding programmes to develop hybrid cultivars that grow fast and provide quality construction material with wide adaptability and high economic value, or to provide better tasting shoots. In a D. latiflorus floret, the pistil appears first, followed by the stamens a few days later. Pollen viability fluctuates between 5-40%. Promising hybrids have been developed from crossings of D. latiflorus with Bambusa pervariabilis McClure (for paper-making material), Bambusa textilis McClure (for culm production) and Dendrocalamus minor (McClure) Chia and Fung (for culm production). For young shoots, the hybrid with Bambusa pervariabilis is promising.

The prospects for D. latiflorus are promising, especially for edible shoot production and export. It seems worthwhile to investigate the feasibility of large-scale cultivation, including in South-East Asian countries. In the Philippines, promising experimental plantations have existed since 1971, in Indonesia since 1987.

C.A. Roxas

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