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Dichanthium annulatum (Forsk.) Stapf.

Poaceae
Diaz bluestem, Marvel

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

Uses

Highly esteemed as fodder grass, especially in India, where it is eagerly eatenby cattle. It is fed green, when it is young, and when in flower; alsosuitable for silage and.hay if cut before flowering. Shows promise forreseeding degraded grasslands; also used for rough lawns.

Folk Medicine

No data available.

Chemistry

Per 100 g, the wet matter (25.0% DM) is reported to contain (ZMB) 10.4 gprotein, 1.7 g fat, 75.8 g total carbohydrate, 34.9 g fiber, 12.1 g ash, 1.7 gEE, and 40.9 NFE (Gohl, 1981). Per 100 g, the hay is reported to contain (ZMB):2.7 g protein, 1.2 g fat, 84.6 g total carbohydrates, 39.1 g fiber, 11.5 g ash,1.2 g EE, and 45.4 g NFE (Gohl, 1981).

Description

A highly variable perennial grass, forming dense tufts, with erect culms up to1 m tall from a decumbent base, nodes pubescent; blades flat, 5-20 cm long,tapering to a fine point, inflorescence of subdigitately arranged racemes,these 3-6, sometimes more [var.bladhii (Retz.) Hack.], 3-7 cm long; notmore than 3 pairs of the lowest spikelets sterile; peduncle of raceme glabrous;sessile and pedicellate spikelets alike, usually overlapping, the pedicelsusually in part visible; lower glumes of pedicellate spikelets not armed withmarginal bulbous-based bristles; lower glume of sessile spikelet oblong, obtuseor truncate, keel not winged, median vein present; sheaths terete; ligulelongish; upper lemma the hyaline base of the awn.

Germplasm

Reported from the, African & Hindustani Centers of Diversity, diaz bluestemor cvs thereof is reported to tolerate drought, fire, high ph, salt, poor soil,and sand. In India it occurs in a great variety of forms, Pseudogamousapomict. Tetraploids with chromosome number 2n = 40 prevail in the mainarea of its distribution, but diploids have also been found in India. In S.E.Africa, plants are hexaploids. Diploid races of India are genetically isolatedbut tetraploids cross relatively easily and crosses withD. aristatumand D. caricosum have been obtained (Bogdan, 1977). (2n = 40)

Distribution

Common throughout the plains and hills of India up to 1660 m; also in tropicaland North Africa extending east through Southeast Asia to China, Australia,Fiji and New Guinea. Introduced to West Indies (Cuba, Haiti, and Puerto Rico).

Ecology

Ranging from Subtropical Dry to Moist through Tropical Very Dry to Dry ForestLife Zones, Diaz bluestem is reported to tolerate annual precipitation of 7.0to 26.4 dm (mean of 6 cases = 12.3) annual temperature of 12.5 to 27.5°C(mean of 6 cases = 21.6) and pH of 5.5 to 7.8 (mean of 6 cases = 6.7). Foundnaturally in weedy lawns, sand dunes, fallow fields, roadsides, open wasteland,in hedges and pastures; often escaping and becoming weedy. Thrives insheltered and disturbed areas, neglected areas near crop fields, and in grassfields where it tends to be a grass weed. Adapted to tropical and subtropicalsummer rainfall areas. Quite drought-resistant, and tolerates seasonal burning.

Cultivation

Propagated by seed. Plants are good seed producers but show great variabilityin their ability to germinate. Usually the very light seeds are spread bywind, allowing invasion of new areas. Experiments indicate that seeds producedby plants from protected areas give maximum germination of 95.3%, whereas thosefrom shady areas give 84.6% and those from grazed fields, 36%. Seeds withglumes intact give 56.6% germination, and those with glumes removed give 94.6%.Due to glume removal, the embryo becomes exposed directly to light andmoisture, causing higher germination. Also increased depth of planting of seedlowers the germination percentage. Seed germinates at a temperature range of 15-40°C; optimum, temperature for germination being 32°C (up to 78%). Seeds preheated to a sub-freezing temperature of -10°C for 15 days germinate 78.6% at room temperature (27°C +/-5°). Periodic tillering from the underground rhizome maintains the perennial habit of this grass. Forms open turf under grazing.

Harvesting

Cut before flowering, for use as hay and silage.

Yields and Economics

Dichanthuium. annulatum is regarded as one of the best pasture grassesin India and Burma, although the CP content of herbage is usually low tomedium. Used extensively throughout the range of Southeast Asia and the EastIndies. Sometimes used in the West Indies as well, especially for rough lawns.In India unclipped plots yield 8925 Kg/ha compared with 3225-3570 for clippedplots. (Gupta, 1980)

Energy

According to the phytomass files (Duke, 1981b) , annual productivity rangesfrom 7 to 17 MT/ha. Diaz bluestem yields more than 10 MThay/ha, and standscutting well (Reed, 1976); Duke (1978) reports 8 MT hay/ha. Herbage in India,depending on soil moisture yields 2-20 MT/ha; in a semi-arid area in Cuba - 17MT DM/ha (46% of yield from dry season with sprinkler irrigation); in India,'Marvel 8' yielded 25 MT green fodder/ha under irrigation and 12 MT under dryland conditions (Bogdan, 1977).

Biotic Factors

The following fungi have been reported on this grass;Balansia sclerotica,Chaetostroma atrum, Curvularia andropogonis, C. lunata, Ellisiella caudata,Jamesdicksonia obesa, Physoderma dichanthicola, Puccinia cesatii, P. duthiae P.propinqua, Sclerospora dichanthicola, Sphacelotheca annulata, S.andropogonis-annulati, Tolyposporella obesa. Uredo susica, Uromycesandropogonis-annulati, U. clygni, Ustilago duthiei. It also parasitizedby Striga lutea.

References

Bogdan, A.V. 1977. Tropical pasture and fodder plants. Longman, London.
Duke, J.A. 1978. The quest for tolerant germplasm. p. 1-61. In: ASA SpecialSymposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.Madison, WI.
Duke, J.A. 1981b. The gene revolution. Paper 1. p. 89-150. In: Office ofTechnology Assessment, Background papers for innovative biological technologiesfor lesser developed countries. USGPO. Washington.
Gohl, B. 1981. Tropical feeds. Feed information summaries and nutritive values.FAO Animal Production and Health Series 12. FAO, Rome.
Gupta, S.K. 1980. Effect of clipping on biomass and net productivity ofunderground parts in grassland ecosystem. Indian J. Ecol. 7(2):215-223.
Reed, C.F. 1976. Information summaries on 1000 economic plants. Typescriptssubmitted to the USDA.

Complete list of references for Duke, Handbook of Energy Crops

last update July 10, 1996

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