Melocanna baccifera (PROSEA)
Melocanna baccifera (Roxb.) Kurz
- Protologue: Prelim. rep. for. veg. Pegu, app. B: 94 (1875).
- Family: Gramineae
- Chromosome number: 2n= 72 (hexaploid)
Bambusa baccifera Roxb. (1819), Melocanna bambusoides Trin. (1821).
- Muli, berry bamboo (En). India: tarai, watri, wati. Bangladesh: muli, paiyya. Burma (Myanmar): kayinwa, tabinwa.
Origin and geographic distribution
M. baccifera occurs naturally in Bangladesh, Burma (Myanmar) and north-eastern India. It is occasionally cultivated and has been introduced and planted in many botanical and private gardens all over the world, especially in South-East Asia, including Hong Kong and Taiwan.
In its native area, especially in Bangladesh, M. baccifera is one of the most useful bamboos. Its culms are widely used in house building, to make woven wares (baskets, mats, handicrafts, wall plates, screens, hats) and domestic utensils, and are an important source of superior paperpulp. The young shoots are edible and during the rainy season constitute one of the important foods of tribal people of Chittagong and Chittagong hill tracts in Bangladesh. The shoots are also sliced and dried in the sun for preservation.
The remarkable large fruits of M. baccifera are fleshy and edible; they are used as famine food and relished by wild and domestic animals. The leaves may be used in brewing liquor. Tabashir can be collected from the culms.
Production and international trade
In its native area, M. baccifera is mainly a wild growing forest species, occupying e.g. about 100 000 ha in Bangladesh (Sylhet and Chittagong hill tracts) and 700 000 ha in Burma (Myanmar) (Arakaan Yoma). Potential annual production of air-dried culms in Bangladesh is estimated at 300 000 t. Production, trade and consumption of culms and young shoots are mainly local and national, no statistics are available. In Bangladesh culms are sold at US$ 10 per 100; most are used by the paper industry (Karnaphuli). In the pulp mills culms are sold per air dry t; 1000 air dry culms weigh about 1.8-2.0 t.
The fibre dimensions of the culms are: length (1.62-)2.80(-3.85) mm, diameter 15.60μm, lumen diameter 3.55μm. For 3-year-old culms of M. baccifera , the following average physical and mechanical properties are reported: moisture content 71% (top), 102% (butt); specific gravity for green culms 0.55 (butt), 0.64 (top), for oven-dried culms 0.70 (butt), 0.75 (top); shrinkage from green to 12% moisture content is 6.6% in wall thickness and 4.1% in diameter; the modules of elasticity is 17 800-23 700 N/mm2(green culms), 18 800-28 100 N/mm2(air-dried culms); the modules of rupture is 62.2-72.8 N/mm2(green culms), 68.7-78.2 N/mm2(air-dried culms); the compression strength parallel to grain is 37.0-44.2 N/mm2(green culms) and 46.4-55.1 N/mm2(air-dried culms). The chemical composition is approximately: holocellulose 62.3%, pentosans 15.2%, lignin 24.1%, ash 1.9%, silica 1.5%; the solubility in cold water is 3.3%, in hot water 6.5%, in alcohol-benzene 1.4%, in 1% NaOH 19%. The edible portion of young shoots is about 40%; after cooking they are sweet, tender, greenish-white; they have a good canning quality.
Bamboo with a sympodial rhizome having slender elongated necks, forming an open and diffuse clump with some distance (up to 1 m) between the culms. Culm erect and straight but with pendulous tips, 10-15(-20) m tall, diameter 1.5-7.5 cm near the base, wall thick at base but thin above, green when young turning yellow or yellow-brown when old, often finely striated; internodes hollow, at midculm 25-50 cm long, smooth, glabrous, with white ring below the nodes; nodes not swollen. Branches from midculm upwards, many at each node, subequal, easily removable from the node. Culm sheath 8-15 cm long, 14 cm wide at the base, up to 6 cm wide near the truncate or concave apex, persistent, light green when young becoming stramineus, covered with pale or fine white hairs; blade erect with spreading tip, broadly to narrowly lanceolate, 10-20(-30) cm × 7-18 mm, glabrous, persistent; ligule very short; auricles indistinct. Young shoot yellowish-brown, sheath margins and top pinkish. Leaf blade oblong-lanceolate, 14-28 cm × 3-5 cm, glabrous (young seedlings have larger leaf blades than adult plants); sheath glabrous; ligule very short; auricles indistinct, bearing long bristles. Inflorescence usually terminating a leafy branch (occasionally borne on a leafless branch), 15-45 cm long, with few to several lax flexuous branches of different length, each bearing groups of pseudospikelets at each node along one side of the axis; spikelet 15 mm long, glabrous, mucronate, comprising 2-4 glumes, one fertile and one abortive floret. Fruit an ovoid to globose baccate caryopsis, 4-12 cm × 3-6 cm, pear-like with more or less curved beak, glabrous, smooth, weighing 47-180 g; pericarp fleshy, very thick but thinner at base, enclosing an oblongoid fruit cavity; endosperm much reduced; embryo with relatively large scutellum containing starch grains (food storage) and basally the plumule and radicle; the fruit often germinates while it is still on the parent plant.
Growth and development
Germination commences at the beginning of the rainy season, roots and shoots being produced from the thick end of the fruit. Seedlings, unlike those of most bamboos, grow vigorously from the beginning, producing usually 1-2, but up to 5 shoots (the latest up to 3 m tall) in the 1st season, crowded together in a clump. During the 2nd season more shoots are produced, up to 7 m tall and the clump expands. By the 5th season culms attain almost their maximum height but are still thin and crowded together. Per clump more than 70 culms may be present. Later, the culms become spaced out with the gradual extension of the rhizomes. Clumps are mature after about 10 years, reaching 4-5 m in diameter and producing 30-40 new culms annually. Young shoots emerge above the soil during the rainy season (May-September in Bangladesh) and develop to their full height within 4-6 months. Lateral branches emerge and develop in the following season (April-May).
M. baccifera is an aggressive bamboo, easily occupying large open areas, due to its vigorous long rhizomes and, when fruiting, due to its easily germinating fruits. It flowers gregariously, with a flowering cycle of 30-45 years. In the season before flowering no new shoots are produced. Flowering is in December or January and may continue for about 10 years over a tract that is sometimes called a flowering wave. Soon after flowering the leaves wither and fall, the culms turn yellow and the fruit forms rapidly, ripening and falling from April to June. Many fruits fail to mature and those produced from the earlier flowering part are larger than those from the later part. Eventually, clumps that have flowered die.
Other botanical information
No infraspecific taxa have been described for M. baccifera . In the vegetative stage the plant is remarkably uniform in its morphological expression. Three slightly different fruit-shapes can be distinguished. In shape and texture the culm sheath is characteristic for the species.
In one of its native areas in Bangladesh (Chittagong hill tracts) average annual minimum temperatures range from 10°C (January) to 25°C (July, August), maximum temperatures from 24°C (December) to 36°C (April). Average annual rainfall ranges from 2000-3000 mm with a long dry season from November to March. It grows well in plain or lower hill forests on well drained sandy loam or almost pure sand. It occurs in pure stands or mixed with other vegetation. Pure stands often result from shifting cultivation. The flowering and fruiting of M. baccifera appears to induce a vast and comparatively sudden increase of rats.
Propagation and planting
M. baccifera can be propagated by seed (fruit), single-culm clump division and rhizome and culm cuttings. When seeds are available they afford the best means of propagation. They are sown in a nursery and seedlings are transplanted to the field in the rainy season or directly sown in the field. Since the seed usually germinates very promptly upon maturing, even while the fruit is still on the mother plant, procurement of fruits from a distance presents special problems. Germination percentage is higher (80%) in shade than in sunlight (33%). Early produced seeds (May-June) germinate better than later ones (September). Normally seed remains viable for about 35 days. Storage in air-conditioned rooms increases its lifespan up to 45 days, and when stored with dry sand in gunny bags, up to 60 days.
Germination starts within 10 days after sowing and rhizome development begins 30-40 days after germination. Due to its tall and soft stem, the seedling gets easily damaged during handling and transportation. Therefore chopping the seedling stem tips at 3-5 nodes is recommended. Frequent shifting of seedlings from one bed to another helps in minimizing root and rhizome intermingling at the nursery stage. Most convenient for the propagation of M. baccifera is a single-culm clump division. These should be made from the youngest culms, while the lateral buds of the rhizome are still dormant, or before they have pushed more than 5.0-7.5 cm. Most of the culm and the long slender rhizome neck may be discarded for convenience. Each propagule is planted in a separate hole. Recommended spacing is 3.5 m × 3.5 m. Culm cuttings are preferably taken from 2-year-old culms. Propagation with rhizome cuttings is easy and successful. In fact the rhizomes are very vital and start growing easily. Due to this, eradication of M. baccifera from cleared bamboo forest is very difficult because every rhizome part left in the ground quickly develops into a new plant.
In artificial plantations of M. baccifera , young plants require watering during the dry season. After establishment of the plants, not much care is needed other than protection from grazing.
Diseases and pests
No serious problems are known. Root rot disease, caused by Poria rhizomorpha , and young shoot boring by the bamboo weevil Cyrtotrachelus longipes , may cause some damage. In the rainy season grazing porcupines may damage young shoots in Bangladesh.
Harvesting may start 5-6 years after planting. Young shoots are harvested in the rainy season. Culms are considered mature when 2 years old. In Bangladesh culms are harvested in a 3 years felling cycle. Harvested culms are 2 years or older and should have a minimum length of 5-6 m without any defect and a minimum diameter of 2.5 cm at 1.5 m height.
In Bangladesh the average green culm yield is estimated at 12 000 culms/ha per 3 years, weighing about 84 t. Other reported culm yield data per 3 years per ha in air dry weight are: 38 t (Bangladesh), 21 t (Burma (Myanmar)) and 17.5 t (India).
Handling after harvest
In Bangladesh harvested culms are made into bundles and often transported as rafts through waterways. Green whole culms can be treated with preservatives following the boucherie method. Split bamboo can be treated by soaking in waterborne preservatives.
Genetic resources and breeding
For M. baccifera no germplasm collections or breeding programmes are known to exist.
The possibilities for M. baccifera , with its straight and smooth, strong and durable culms and its edible shoots, to become also an important bamboo species outside its native area are promising. It is a fast grower and easy to propagate. Nevertheless, it has received little attention in South-East Asia. Investigation on cultivation techniques, food value, preservation methods and applicabilities are urgently needed, as are germplasm collections.
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