Dichanthium annulatum (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Dichanthium annulatum (Forssk.) Stapf

Protologue: Fl. Trop. Afr. 9: 178 (1917).

Family: Gramineae

Chromosome number: 2n= 20 (diploid), 40 (tetraploid), 60 (hexaploid)

Synonyms

Andropogon annulatus Forssk. (1775).

Vernacular names

• Hindi grass, sheda grass (En)
• Philippines: alabang-grass
• Thailand: ya hindi, ya waen
• Vietnam: song tha'o to.

Origin and geographic distribution

D. annulatum is a grass occurring in tropical and North Africa, through the Middle East to Malesia, southern China, and the Pacific Islands. It has been introduced to southern Africa, tropical America and Australia. In the Northern Hemisphere it is mainly found between latitudes 8°and 28°.

Uses

An excellent and widely used fodder grass which is sought out by stock from a mixture of grasses and is preferred to all others. In India it is promising for grazing or hay-making after reseeding into degraded grassland.

Properties

Nitrogen concentrations of D. annulatum range from 0.4-1.7%, depending on the stage of growth. It can support 7 sheep per ha in India. It gives a good "standing hay".

Botany

A perennial grass, often tufted, spreading and stoloniferous, with erect, branched or rarely geniculate culms up to 1 m tall, hairy at the nodes. Leaf-sheath terete, 3-4 cm long, sparsely hairy at the margins; ligule truncate, 2-4 mm long, membranous; leaf-blade linear, 3-30 cm × 2-8 mm, often hairy above, at the margins and in the throat. Inflorescence composed of up to 15 subdigitate, shortly peduncled racemes each 3-7 cm long; spikelets paired, one pedicelled, one sessile, alternately arranged along a filiform axis; the lowest 1-2 pairs similar, male or neuter, awnless and persistent; all other pairs dissimilar and deciduous; sessile spikelet 2-5 mm long, bisexual, upper lemma with a 1-2.5 cm long, kneed and twisted awn; pedicelled spikelet male or neuter; lower glumes pubescent to villous in lower half, upper half with long bulbous-based hairs especially on the margins. Caryopsis obovoid.

D. annulatum is a very variable species, morphologically as well as cytologically. Several varieties have been distinguished, mainly based on size and number of spikes, on hairiness of the spikelets, and on ploidy level.

Flowering commences early in the growing season and continues throughout the year. In India, recommended selections include "Marvel 8", and lines 485, 487 and 490.

Other species of the genus, occurring in Malesia, are often also good fodder grasses, e.g. D. caricosum (L.) A. Camus and D. mucronulatum Jansen.

Ecology

D. annulatum is adapted to the drier areas of the tropical and subtropical zones. It does not thrive in waterlogged places nor in shady environments, but is tolerant of grazing, burning and saline soils.

Agronomy

D. annulatum can be established by seed or by rooted tillers planted at 60 cm spacing. It is a good seed producer, but slow growing at the seedling stage. It is highly palatable when young and fresh. Frequent grazing is required to maintain it in a leafy condition, although cattle will eat the stems. In Thailand, observations of a mixture of this species and verano stylo ( Stylosanthes hamata (L.) Taub.) on road edges indicate that it may be possible to improve its quality as a forage by oversowing with a legume. Dry matter yields of 1.4-2.0 t/ha have been obtained. It can be preserved as "standing" or cut hay but not as silage.

Genetic resources and breeding

It is unlikely that substantial germplasm collections are being maintained. In India some breeding programmes on D. annulatum are being carried out.

Prospects

D. annulatum will have a place in grazing lands in drier areas. It is a promising species as it is drought-tolerant, persistent and resistant to heavy grazing. The prospects of selecting leafy strains could be investigated.

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. 282-286.
• Häfliger, E. & Scholz, H., 1980. Grass weeds 1. Ciba-Geigy Ltd., Basel, Switzerland. p. 39.
• Holm, J., 1971. Feeding tables. Nutrition Laboratory of Thai-German Dairy Project, Livestock Breeding Station, Chiangmai, Thailand. p. 25.
• Skerman, P.J. & Riveros, F., 1990. Tropical grasses. FAO, Rome. pp. 328-332.

Authors

C. Manidool