Bothriochloa pertusa


Scientific name

Bothriochloa pertusa (L.) A. Camus

Synonyms

Andropogon pertusus (L.) Willd.
Dichanthium pertusum (L.) Clayton
Holcus pertusus L.
Amphilophis pertusa (L.) Stapf

Family/tribe

Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Andropogoneae.

Common names

Indian bluegrass, Indian couch grass, sweet pitted grass, pitted beardgrass, hurricane pitted-bluestem, hurricane grass (English);  yerba huracán (Spanish);  seymour grass, Barbados sour grass (Caribbean);  camagueyana (Cuba);  silver grass (New Caledonia);  suket putihan, rebha las-alasan (Indonesia);  rumput embun (Malaysia);  salay-parang, salay (Philippines);  ya-hom, ya-hangma (Thailand);  huyêt tha'o lô (Vietnam).

Morphological description

A stoloniferous and/or tufted perennial, commonly with pink to red stolons;  upright culms to 50 cm pre-flowering and 90 cm at maturity.  Leaf blades greyish green, linear, 5-10 (rarely -30 cm) long, and 2-6 mm wide;  usually glabrous except for few sparse hairs at base;  ligule a short, fringed membrane.  Flowering culms, 2-3 branched;  nodes glabrous or pubescentInflorescence subdigitate, or digitate, purplish in colour, emitting an aromatic odour when crushed;  axis 5-15 mm long, with 3-13 racemes, 2-7 cm long;  sessile spikelet with geniculate and twisted awn 10-18 mm long;  pedicellate spikelet unawned, usually neuter, often bearing a pit in apical third of lower glume.  1.1-1.6 million seed units/kg (1 seed unit = sessile spikelet + pedicellate spikelet + awn< /A > ).

Distribution

Native to:
South Asia:  India,  Pakistan, Sri Lanka.
South East Asia:  Indochina, Thailand, Indonesia, Malaysia.
Also found in southern and eastern Africa (including Democratic Republic of Congo (formerly Zaire), Eritrea, Ethiopia, Kenya, Tanzania, Uganda, Zimbabwe), the Arabian Peninsula and Afghanistan, Myanmar, and southern China, where it may be native or introduced.  It is found in Rodriguez and Réunion in the Indian Ocean, in the Caribbean archipelago, central America, northern South America and southern USA (W) and Cape Verde (E) in the Atlantic, and in Australia, Hawai'i, New Caledonia, and the Philippines in the Pacific.  Some of the African material referred to as B. pertusa may in fact be the morphologically similar, but more robust, B. insculpta.
It is common in heavily grazed or frequently mowed areas of grassland and open woodland on clay and clay-loam soils.  Common in disturbed and undisturbed areas, along roadsides.

Uses/applications

A permanent pasture for grazing systems in poorer soils.  Generally too low for cut-and-carry.  Can be ensiled or cut for hay.  Little value for standover as it becomes unpalatable with flowering.  Can be used in no-till vegetable system in which B. pertusa stand killed with herbicide prior to introduction of vegetable seedlings, providing mulch .  Also used for erosion control, reseeding eroded land, lining floodways, stabilising and revegetating mine waste, and for turf and amenity plantings.

Ecology

Soil requirements

Common on neutral to alkaline, cracking clay soils of India, but also grows on well drained, coarse to fine- textured soils with a pH as low as 5.0.  Colonises poorer soils where other grasses may not grow, particularly when management favours spread of the species (see Defoliation ).

Moisture

Top

Most commonly found in areas with annual rainfall from 600-900 mm, but also grows at >2,000 mm rainfall and down to 500 mm.  Considered as a perennial, drought-evading species, with growth declining rapidly with the onset of dry conditions.  Can tolerate short periods of waterlogging .

Temperature

Native and naturalised over a wide latitudinal range, from near the equator to latitude 28º, and from sea level to >2,000 m asl.  This equates to a range in average annual temperature from about 17-27ºC.  There is little growth once grass temperatures reach 3-4ºC.  Tops and stolons are killed by frost, but stand recovers from the tufted crowns along the stolons, provided grass temperatures do not fall much below about -6ºC.

Light

Grows in light shade, but best in full sunlight.  Does not grow well when shaded by taller pasture plants or weeds.

Reproductive development

Flowering time varies markedly with ecotype, with first flowers emerging from late January to early May in the southern hemisphere subtropics.  Late flowering varieties may fail to set seed before the onset of frost in some environments.

Defoliation

Distribution is strongly controlled by management.  It is favoured by heavy grazing or frequent mowing, and represents the first stage in degradation of the Sehima/Dichanthium cover in India.  Early flowering varieties in particular should be grazed fairly heavily to reduce the increase in fibre content of the forage that occurs with flowering.  Also becomes dominant in heavily grazed, degrading tussock grass pastures, notably those based on Cenchrus ciliaris and Heteropogon contortus .

Fire

Top

Survives fire, recovering from the tufted crowns along the stolons.  Severe fire can thin a stand.

Agronomy

Establishment

Established from seed or stolons.  High level of dormancy in freshly harvested seed, which breaks down after 4-9 months storage.  Seed best sown on or near the surface of a fine, clean seedbed, at 1-3 kg/ha.  To avoid erosion resulting from cultivation, it can be sown into the ashes following fire, although this results in poorer establishment.  Germinates quickly and establishes readily.  Difficult to achieve flow of fluffy seed through some mechanical planters unless seed is pelleted.

Fertiliser

Responds to both nitrogen and phosphorous on very infertile soils, but only at moderately low levels, probably of the order of 10-20 kg/ha P and 50-100 kg/ha N.

Compatibility (with other species)

Forms dense sward and can suppress associated species.  Companion species must be equally tolerant of heavy grazing.

Companion species

Top

Pests and diseases

Main diseases in cultivation are rust caused by Puccinia duthiae and ergot caused by Claviceps pusilla.  A smut caused by Sporisorium sp., and other fungal diseases caused by Balansia sclerotica, Claviceps purpurea, Physoderma bothriochloae, Puccinia cesatii, P. erythroaeensis, P. pusilla, Sphacelotheca tenuis, Ustilago bothrioch-loae, and Uromyces andropogonis-annulati have also been reported on B. pertusa .
Not as susceptible to attack by army worm (Spodoptera spp.) and other lepidopterous larvae as the morphologically similar Digitaria didactyla .

Ability to spread

B. pertusa is a very successful coloniser due to its tolerance of low fertility soils and regular defoliation, the ability to produce significant yields of seed, and strong stolon development.  Early flowering types are generally the most aggressive in this regard.  Fluffy seeds adhere to animal fur.

Weed potential

Considered a weed of pastures in some areas, although usually a symptom of declining fertility and excessive grazing.

Feeding value

Nutritive value

Top

Quality declines with age and more rapidly with the onset of flowering.  CP levels in young leaf may be of the order of 12%, and P, 0.2%, with 70% IVDMD .  In a mature stand with large numbers of inflorescences, corresponding values are more of the order of 3 or 4 %, 0.05% and 45%.

Palatability/acceptability

Well eaten when young and leafy.  Hayed off material retains its quality and is eaten during the dry season.  The yield is low but bluegrass hay is well eaten by cattle and horses.

Toxicity

None reported.

Production potential

Dry matter

Generally low yielding at 1-5 t/ha DM, because of the environment in which it mostly grows - poor soils and low rainfall .  However, with dry season irrigation, it is capable of producing 15 t/ha DM.

Animal production

Top

80-140 kg LWG /hd/yr with 1.3-0.7 steers/ha.

Genetics/breeding

2n = 40, 50, 60.  Generally considered apomictic, although sexual reproduction demonstrated in some tetraploid ecotypes.

Seed production

Seed can be harvested manually or mechanically.  With direct heading machinery, yields of the order of 70-100 kg/ha can be obtained.  Double this amount of higher quality seed can be produced by making sequential passes with a vacuum assisted brush harvester.  As with most grasses, an application of 100 kg/ha N following a clearing cut helps to ensure a high density of well-filled heads.

Herbicide effects

No information available.

Strengths

  • Palatable.
  • Tolerant of heavy grazing.
  • Grows on infertile soils.
  • Effective ground cover to combat erosion.

Limitations

Top

  • Can become a weed.
  • Not very productive.

Other comments

Experiments indicate allelopathic properties.

Selected references

Bisset, W.J. (1981) Indian bluegrass has special uses.  Queensland Agricultural Journal, 105, 507-517.
McIvor, J.G. and Howden, S.M. (1992) Bothriochloa pertusa (L.) A. Camus. In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages . pp. 54-56. (Pudoc Scientific Publishers, Wageningen, the Netherlands).
Pengelly, B.C., Staples, I.B. and Scattini, W.J. (1997) Variation in collections of Bothriochloa pertusa and B. insculpta Genetic Resources Communication No 27.  CSIRO Tropical Agriculture, St Lucia, Australia.
Truong, P.N. and McDowell, M (1985) Indian bluegrass for soil conservation and land stabilization in Queensland. Journal of Soil Conservation of N.S.W., 41, 38-44.

Internet links

Cultivars

Cultivars

Country/date released

Details

'Ghana Marvel 20' Maharashtra State, India High yielding variety, producing 40-100% more dry matter than local strain.
'Dawson'
(Biloela ecotype)
Queensland, Australia (1991) Origin unknown.  Fine, densely stoloniferous (stolons dark red, c. 1 mm diameter), low growing (10-30 cm, -50cm at maturity), late flowering (commencing early May in southern hemisphere subtropics) type, selected as a turf variety.  Widely adapted.  Rust (Puccinia duthiae) resistant.
Bowen ecotype Queensland, Australia (unofficially released) Origin unknown. 2n = 40.  Stolons about 1.5 mm diameter, 25-40 cm high (-60 cm at maturity) early flowering (commencing late January in southern hemisphere subtropics).  Morphologically similar to 'Emerald' but earlier flowering.  Susceptible to rust.  Least desirable ecotype from forage perspective.
Capella ecotype Queensland, Australia (unofficially released) Origin unknown.  Flowering commences late April in southern hemisphere subtropics.
'Medway' Queensland, Australia (1991) Origin unknown.  2n = 60.  More robust type, with foliage to 50 cm and mature culms to 80 cm.  Flowering commences late March in southern hemisphere subtropics.  Rust resistant.  Appears best adapted to lower rainfall areas.  Good forage variety.
'Keppel'
(Yeppoon ecotype)
Queensland, Australia (1987) Origin unknown.  More robust type, with foliage to 50 cm and mature culms to 80cm.  Flowering commences early May in southern hemisphere subtropics.  Rust resistant.  Widely adapted.  Good forage variety.
Emerald or Emerald Downs ecotype Queensland, Australia (unofficially released) Origin unknown.  Morphologically similar to 'Bowen', although slightly taller, with slightly finer stolons and later flowering.  Susceptible to rust.

Promising accessions

Top

Promising accessions

Country

Details

CPI 59586 Queensland, Australia From Moshi, Tanzania (4ºS, 667 m asl, rainfall 750 mm).  Good agronomic performance in humid subtropics.
CPI 104642      From Madhya Pradesh, India (23.15ºN, 460 m asl, rainfall 1,200 mm).  Good agronomic performance in sub-humid central Queensland.
CPI 104935 B      From Madhya Pradesh, India (22.37ºN, 310 m asl, rainfall 1,200 mm).  Good agronomic performance in central Queensland.
CPI 104968      From Madhya Pradesh, India (22.39ºN, 520 m asl, rainfall 1,030 mm).  Good agronomic performance in sub-humid central Queensland.
CPI 106629      From Tamil Nadu, India (11.12ºN, 350 m asl, rainfall 700 mm.  Good drought tolerance.
CPI 106712      From Kerala, India (8.15ºN, 70 m asl, rainfall 1,400 mm).  Low growing, short internodes.  Could have application as turf/amenity planting.