Chrysopogon orientalis (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Chrysopogon orientalis (Desv.) A. Camus

Protologue: Lecomte, Fl. Gén. de l'Indo-Chine 7: 332 (1922).

Family: Gramineae

Chromosome number: 2n= unknown

Synonyms

Rhaphis orientalis Desv. (1831), Andropogon wightianus Nees ex Steudel (1854), Chrysopogon wightianus (Nees ex Steudel) Thwaites (1864).

Vernacular names

• Philippines: tinloy (Tagalog), rukut dukut (Visaya), salsapot (Ilokano)
• Laos: hnha:z khwa:k
• Thailand: ya-phungchu
• Vietnam: co' may dông.

Origin and geographic distribution

C. orientalis originates from and is distributed in coastal Malaysia, Thailand, Indo-China and India.

Uses

C. orientalis is used as green forage. In a traditional grazing system in Thailand, cattle and buffaloes from distant villages are herded on it during the daytime and return in the evening. It also protects sandy coastal areas from wind erosion.

Properties

Nitrogen concentrations in leaves from flowering plants of C. orientalis range from 0.5-0.7%. The leaf/stem ratio is low and this stemmy condition persists almost throughout the year. A DM digestibility of 46% has been measured for flowering plants.

Botany

A perennial grass with culms up to 80 cm tall, creeping and branching or sometimes densely tufted, with short stout stolons. Leaf-sheaths and internodes distinct below, tight and more overlapping above; leaf-blades basal and cauline, linear-acuminate to oblong, 6-10(-30) cm × 3-4 mm, flat or folded, usually glabrous. Inflorescence a terminal panicle, 10-18 cm long, with whorls of slender branches, each branch with a terminal tuft of red-brown persistent hairs at the base of a group of 3 spikelets (1 sessile, 2 pedicelled); sessile spikelet bisexual, with an oblique slender golden-hairy basal callus 2.5 mm long below the base of the lower glume, glumes spinulose-hairy, upper glume with awn up to 1-5 cm long, upper lemma with awn to 6 cm long; pedicelled spikelets with lower glume awned to 1.5 cm, upper glume and upper lemma awnless.

When fully mature the panicles become a golden colour. Seed production is abundant. First flowering starts about 11 weeks after germination, and seed reaches maturity at 13 weeks after sowing.

Ecology

C. orientalis is adapted to warm, high rainfall climates. It is well adapted to sandy soils but also grows vigorously on heavy soils in central Thailand. It grows best on open fields but can also invade old coconut plantations.

Agronomy

C. orientalis can be planted vegetatively or sown at a seeding rate of 10-12 kg/ha. Seed germinates within 5 days after sowing. A spacing of 50 cm × 80 cm is recommended for vegetative planting, using 3 rooted tillers per hill. C. orientalis responds well to higher fertility and appropriate rates of complete fertilizer can be used. It is palatable and tolerates heavy grazing and fire; frequent grazing and/or burning of old swards is recommended to keep the plants in a leafy condition. It can be cut and fed to animals, but grazing is more appropriate since the leaves are normally concentrated at the base of the plant and are too low to be cut by large mowers. Annual DM yields of 5-8 t/ha are obtained in Thailand. It may be conserved as hay but it is then too coarse with little leaf. It is not suitable for silage making.

Genetic resources and breeding

It is unlikely that any substantial germplasm collections are being maintained. No variation in growth form and adaptation has been observed. Irradiation of seeds to obtain leafy mutations has been tried in Thailand but without success.

Prospects

The species has many advantages, such as its ability to grow on extremely infertile soils on sandy coastal land, its tolerance of heavy grazing and light shade and its good seed production. It has particular potential where cattle graze under old coconut plantations or sandy soils, such as occur in southern Thailand. Accessions with a higher leaf/stem ratio may increase the yield of useful forage.

Literature

• Gilliland H.B., Holttum, R.E. & Bor, N.L., 1971. Grasses of Malaya. In: Burkill, H.M. (Editor): Flora of Malaya. Vol. 3. Government Printing Office, Singapore. pp. 238-239.
• Manidool, C., 1989. Natural grassland and native grasses of Thailand [in Thai]. Technical Bulletin No 1301-26-32. Division of Animal Nutrition, Department of Livestock Development, Bangkok. pp. 16-19.
• Matthew, K.M., 1983. The flora of the Tamilnadu Carnatic. Vol 3(2). The Rapinat Herbarium, Tiruchirapalli, India. pp. 1823-1824.

Authors

C. Manidool