Brachiaria spp. hybrids


Scientific name

Synonyms

Urochloa brizantha x U. ruziziensis
Urochloa ruziziensis x U. decumbens x U. brizantha

Family/tribe

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

Common names

brachi hybrid, brachiaria hybrid .

Morphological description

Cv. Mulato (B. brizantha x B. ruziziensis).
Perennial with a semi-erect growth habit, spreading by rooting from lower culm nodes.  Leaf blade is linear-triangular in shape, broad, dark green, both abaxial and adaxial surfaces densely covered with long hairs.  Leaf sheath is densely pubescentLigule membranociliate, short.  Stigmas pink.  Inflorescence is a panicle 12 cm long, with 4–8 racemes about 6 cm long, and spikelets arranged in two rows on each raceme .

Cv. Mulato II (B. ruziziensis x B. decumbens x B. brizantha) is very similar in appearance, but has shorter hairs on the leaf, and has white/cream stigmas.

There are currently two Brachiaria spp. hybrids developed as forages and further combinations of species may be developed as hybrids in the future.

Distribution

Does not occur naturally.

Artificial hybrids suited to the tropics to 1,800 m asl and the subtropics at low altitudes.

Uses/applications

Permanent pasture for grazing and cutting.

Ecology

Soil requirements

Well-drained soils of medium to high fertility with pH 4.5–8.0 but can grow in less infertile acid soils with high Al.  Will respond strongly to added N on deficient soils.

Moisture

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Adapted to annual rainfall of 1,000–3,500 mm with good production in the dry season.

Temperature

Tropics to 1,800 m asl and warm subtropics.

Light

Likely to be similar to B. brizantha, having intermediate shade tolerance compared with other tropical grasses.

Reproductive development

No information available.

Defoliation

Tolerates intensive grazing at high stocking rates but benefits from a rest period.

Fire

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Burning is not recommended, but 'Mulato' will probably recover from an occasional fire.

Agronomy

Establishment

Cv. Mulato can be planted from seed planted into a well-prepared seedbed at 4–6 kg/ha seed.  In common with B. brizantha, freshly harvested ‘Mulato’ seed will remain dormant for several months, so that seed must be stored or acid-scarified prior to planting.  Can be planted vegetatively from stolon cuttings.  Establishes rapidly, achieving 85% ground cover at 2 months after seeding at 5 sites in Honduras.  Can be lightly grazed after 3–4 months.

Fertiliser

Responds well to additional nitrogen fertiliser.

Compatibility (with other species)

Will combine with aggressive creeping legumes.

Companion species

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Legumes:  Arachis pintoi .

Pests and diseases

Cv. Mulato has partial resistance to spittlebugs.  In the ongoing breeding program at CIAT, a group of hybrids has been identified with high levels of antibiosis resistance to spittlebugs  Aeneolamia varia, A. reducta, and Zulia carbonaria, whilst another group of hybrids showed field resistance to Z. pubescens and Mahanarva trifissa.

Ability to spread

Spreads rapidly by rooting from lower culm nodes.

Weed potential

Likely to be similar to B. brizantha, having potential to colonise disturbed areas.

Feeding value

Nutritive value

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Cv. Mulato has excellent nutritive value.  For 90 day and 168 day regrowth in Colombia, CP was 13.1% and 10.6%, respectively, and IVDMD 70.0% and 70.6%, respectively.

Palatability/acceptability

Cv. Mulato is reported to be highly palatable to grazing ruminants.

Toxicity

None reported, but may cause skin photosensitization .

Production potential

Dry matter

High yielding and vigorous.  Produces 10–25% more DM than B. brizantha or B. decumbens.  In Tabasco, Mexico, yields of up to 25 t/ha DM have been reported.

Animal production

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Individual cattle LWGs of up to 0.9 kg/head/day were reported following short periods of grazing in Honduras.

Genetics/breeding

The breeding program at CIAT, Colombia, is attempting to increase resistance to spittlebugs, and improve nutritive quality and DM production of Brachiaria species through selection and interspecific hybridisation.  The program has made use of a cross-compatible, sexual tetraploid biotype of B. ruziziensis combined with tetraploid apomicts of B. brizantha to produce the hybrid , ‘Mulato’.
A second hybrid accession , ‘Mulato II’ was developed from three generations of hybridization, commencing with the original B. ruziziensis x B. decumbens cross.  In subsequent generations, sexual parents were exposed to pollen, either from hybrids with B. brizantha or from B. brizantha accessions, through open pollination .  Microsatellite data clearly show that ‘Mulato II’ has alleles that are absent from the B. ruziziensis parent and also absent from B. decumbens cv.  ‘Basilisk’, but that are present in ‘Marandú’ and/or in other accessions of B. brizantha.

Seed production

Poor and not recommended at farm level.

Herbicide effects

No information available.

Strengths

  • High DM production.
  • Good forage quality.
  • Tall vigorous grass for cutting.
  • Tolerance to spittlebug.

Limitations

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Other comments

  

Selected references

CIAT (2002) Variety: 'Mulato'. Application no: 2001/174. Plant Varieties Journal, 15, 20–21.
Peters, M., Franco, L.H., Schmidt, A. and Hincapie, B. (2003) Especies forrajeras multipropÓsito: Opciones para productores de Centroamérica. CIAT Publication No. 333. CIAT, Cali, Colombia.

Internet links

Cultivars

Cultivars

Country/date released

Details

‘Mulato’
(CIAT 36061)
Mexico (2000) Derived from an initial cross made in 1988 between a tetraploid B. ruziziensis , clone 44-6 (sexual reproduction) and B. brizantha cv. Marandú (tetraploid, apomictic seed production).  Tested for agronomic performance in small-plot field trials and regional trials in Colombia, and has also been widely distributed through CIAT’s regional trial network for adaptational/agronomic testing in Central America, Philippines and China.  Final selection was based on tolerance of high soil aluminium, plant vigour, DM production and forage quality.
‘Mulato II’ Australia (2004) ‘Mulato II’ was selected for:  tolerance of high soil aluminium, plant vigour, dry matter production and forage quality.  Propagation:  by seed.  Breeding has improved spittlebug resistance, forage yield and quality, and seed yield.

Promising accessions

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Promising accessions

Country

Details

CIAT 36062
(BR93-NO/1371)
Brazil Better resistance to spittlebug than B. brizantha accessions (other than ‘Marandu’).
FM9503-S046-024 Colombia Excellent adaptation to both low and high fertility environments on the Colombian Llanos.  Moderate resistance to spittlebug.