Gigantochloa manggong Widjaja
Reinwardtia 10(3): 365 (1987).
Gramineae
2n = unknown
Origin and geographic distribution
The origin of G. manggong is not known. It grows wild in eastern Java (Meru Betiri National Park, Soko, Licin, Kalisetail) and in Bali (Candikuning), but it is quite rare. Occasionally it is also planted in botanical or experimental gardens (Java: Purwodadi, Bandung; India: Amherst). For map click: Map273.TIF.
Uses
Culms of G. manggong are used for construction, scaffolding and other small-scale household uses, but possibly due to their limited distribution, they are considered inferior to those of G. apus (J.A. and J.H. Schultes) Kurz. They are also suitable for making chopsticks, toothpicks and paperpulp. Young shoots are used as vegetable but taste bitter.
Production and international trade
Being a rare species, production and trade of culms and young shoots are only of some importance locally in East Java and Bali. Formerly, a small amount of culms was processed by the paper mill at Basuki Rachmat but now a larger amount is consumed by the chopstick and toothpick factory in East Java.
Description
Densely tufted, sympodial bamboo. Culm up to 15 m tall, 5-7 cm in diameter, wall up to 10 mm thick; internodes up to 34-40 cm long, smooth, green turning yellowish. Branches arising from nearly all nodes from 2-3 m upwards; usually one branch is dominant in each group of branches. Culm sheath appressed with truncate but centrally slightly raised apex, 30-33 cm long, dull yellow, dark brown glabrescent, slightly persistent; blade erect, narrowly triangular, 18-25 cm x 9-11 cm, covered with dark brown hairs adaxially, deciduous at age; ligule 5 mm long, irregularly dentate; auricles up to 4 mm long, forming a firm rim which is raised towards the end and joined to the blades, dark brown to purplish brown, without bristles. Leaf blade lanceolate, 27-29 cm x 3-4 cm, glabrous, thick; sheath yellowish with purple margins, when young covered with detaching dark brown hairs, glabrescent; ligule 1 mm long, irregularly toothed; auricles rounded, up to 1 mm long, raised, joined to ligule at the end, purplish. Inflorescences borne on leafy branches, consisting of pseudospikelet groups 0.5-5 cm apart, each containing up to 35 pseudospikelets; spikelet ovate-lanceolate in outline, 7-15 mm x 2-3 mm, slender and narrowed at the apex, comprising 2 glumes and 3 perfect florets. Caryopsis unknown.
Growth and development
Plants raised from rhizome cuttings develop one shoot in the first year. In the next two years the number of new shoots and the height they attain gradually increase. From the third year on, culms can reach full length. Three years after planting, up to 25 culms may be present. Growth of new culms starts at the beginning of the rainy season and culms attain full length in 4-5 months. Growth may be briefly interrupted by short rainy periods. G. manggong flowers gregariously, after which the clump dies, but a flowering cycle is not known.
Ecology
G. manggong occurs in a tropical climate, with average annual rainfall of 1400 mm, from sea-level up to 1500 m altitude. It grows on river banks, mountain slopes and even steep cliffs.
Agronomy
G. manggong can be propagated easily by rhizome cuttings, but culm and branch cuttings also give good results. The cuttings can best be planted in a nursery, in containers filled with a mixture of soil and manure. About one year after planting, when roots and a shoot have developed, the plants can be transplanted into the field in well-prepared holes at 5 m x 5 m. Transplanting is preferably carried out in the rainy season. No diseases and pests of G. manggong are known.
Culms are harvested when needed, selecting those that are older than 2 years and with a diameter of more than 7 cm. Yield of harvestable culms of a natural stand is estimated at 5-10 per clump per year.
Genetic resources and breeding
Small germplasm collections of G. manggong are being established by the Forest Research and Development Centre in Indonesia and kept at Darmaga Station, Bogor and Arcamanik Station, Bandung. There are no breeding programmes for G. manggong.
Prospects
G. manggong is a promising bamboo. It grows fast and is suitable for the production of paperpulp, chopsticks and toothpicks. Research should focus on physical and mechanical properties and on the feasibility of large-scale cultivation.
Sutiyono and E.A. Widjaja
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