Paspalum guenoarum


Scientific name

Paspalum guenoarum Arechav.

Subordinate taxa:
Paspalum guenoarum Arechav. var. guenoarum
Paspalum guenoarum Arechav. var. rojasii (Hack.) Parodi

Synonyms

Paspalum plicatulum Michx. var. robustum Hack.
Paspalum plicatulum subsp. guenoarum (Arechav.) Roseng., B.R. Arrill. & Izag.
Paspalum rojasii Hack.

Family/tribe

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

Common names

wintergreen paspalum, pasto rojo, capim-guenoaro, capim ramirez, pasto-ramirez.

Morphological description

A leafy, upright (decumbent to ascending when young), perennial tussock , with short basal rhizomes;  foliage to 0.6 or 1.0 m tall (depending on ecotype), fertile culms to 1.5 or 2 m.  Leaf blades to 60 cm long and 3 cm wide, mostly brittle, even when mature;  varying in colour from shiny green (similar to P. atratum ) to grey-green (glaucescent) on the upper surface, and usually grey-green on the underside;  largely glabrous except for a few long hairs at the base of the leaf blade in some provenances;  leaf margins scabrous (minutely saw-toothed);  ligule yellowish, membranous.  Seed borne in a simple panicle comprising 3-10 (-15) racemes, mostly 6-15 cm long, with lower racemes up to 20 cm long.  Spikelets about 3-3.5 mm long and 2-2.5 mm wide.  About 270,000-380,000 seeds/kg.
Large green forms can be readily distinguished from P. atratum by virtue of a grey-green or glaucescent underside to the leaf.

Distribution

Native to:
South America:  Argentina (Corrientes, Misiones, Tucumán), Bolivia (Chuquisaca, La Paz, Santa Cruz, Tarija), Brazil (Paraná, Rio Grande do Sul, Santa Catarina), Paraguay, Uruguay.

Uses/applications

Perennial forage for grazing or cut-and-carry.  Has been successfully conserved as hay and silage .

Ecology

Soil requirements

Often occurs on moist, sometimes poorly drained, fertile sandy soils.  Appears adapted to most soils provided there is good moisture.  Moderately tolerant of waterlogging .

Moisture

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Rainfall at collection sites ranges from 1,200-1,600 mm/yr.  In cultivation, it grows well between about 1,200 mm and 2,000 mm annual rainfall, and even up to 4,000 mm.  Under very high rainfall conditions, susceptible types may be affected by leafspot.  Moderate drought tolerance.

Temperature

Occurs from about 15-32ºS, and from near sea level to 1,750 m asl.  This represents an unusually narrow range of annual average temperatures of 19-21ºC.  However, 'Bela Vista' has performed well in areas with average annual temperature as high as 27ºC.  Some types have good frost tolerance, sustaining no damage at grass temperatures of -4ºC.

Light

Poor to moderate shade tolerance, like other members of the Plicatula group, Paspalum atratum and P. nicorae .

Reproductive development

Commencement of flowering varies with provenance , from early February to late March in the southern hemisphere subtropics.

Defoliation

Tolerant of low grazing and regular cutting, although best results obtained from more lenient management.  Very easy to cut with scythe or mower.  Recommended to cut or graze when the stand is about 60 cm high.

Fire

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Original stand depleted by fire, but stand recovers from seedlings.

Agronomy

Establishment

In controlled environment, germination and speed of germination are highest at 20/35ºC.  Other factors are probably the same as for the closely related P. atratum .  "Reports of dormancy levels in fresh seed vary from low to quite high, but, even with dormant seed, germination reaches acceptable levels after 3-4 months.  Germination of fresh seed can be improved from about 20% to nearly 100% by removal of the lemma and palea.  Seed has a very limited "shelf life" under ambient conditions, and may remain viable for less than a year.  Seed stored for several years should be stored at low temperature and low relative humidity."  Seed is normally sown at up to 15 kg/ha in pure swards or 10 kg/ha with other species, either broadcast or in rows 0.5-1 m apart.  Establishes rapidly from seed, or from rooted tillers.

Fertiliser

Survives at low fertility but responds to nitrogen applications of the order of 150-200 kg/ha/yr N.  Other deficiencies should be corrected.

Compatibility (with other species)

Good growth form to grow with legumes.  Lower growing types are not aggressive, but taller types may be more competitive.

Companion species

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Pests and diseases

Subject to Pythium blight in some situations.  A leaf spot, possibly caused by Helminthosporium sp., can be a problem on older leaves under high rainfall conditions.  Resistant to or little affected by Meloidogyne javanica, M. arenaria, M. hapla and M. incognita.
Resistant to attack by spittle bugs/cigarrinhas/cercopids (Deois flavopicta and Zulia entreriana), but susceptible to burrower bugs (Scaptocoris: Cydnidae).

Ability to spread

Seedlings develop close to parent stand.

Weed potential

Little indication of weediness.

Feeding value

Nutritive value

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Varies with age of material and soil nutrient status (including fertiliser use).  CP levels, leaf proportion and digestibility all decrease, and DM content increases, with increasing maturity.  CP values vary from 8-13%, often lower than for other grasses tested, and IVDMD from 58-67%.

Palatability/acceptability

A very leafy grass that is well eaten by cattle and horses.

Toxicity

No record of toxicity.

Production potential

Dry matter

Yields from about 4-25 (mostly 10-20) t/ha DM, depending on genotype, N fertilisation and moisture availability.

Animal production

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Has produced up to 370 kg/ha over a 222 day period.

Genetics/breeding

Aposporous apomicts, 2n = 4x = 40;  possibly also 2n = 20.

Seed production

Like P. atratum , flowering may be disrupted if the stand is cut or grazed low within 2 months of commencement of flowering, destroying the elongating apical meristem .  Seed tends to be shed as soon as it matures (shatters).  Yields of seed for various genotypes range from very low to about 400 kg/ha.

Herbicide effects

Very susceptible to atrazine.

Strengths

  • Palatable, high quality feed.
  • Tolerant of poor drainage and flooding.
  • No serious pests or diseases.

Limitations

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  • Leaf spot in high rainfall areas.
  • Low to moderate dry matter yields.

Other comments

  

Selected references

Bogdan, A.V. (1977) Tropical Pasture and Fodder Plants (Grasses and Legumes). pp. 203-204. (Longman: London and New York).
Espinoza, F., Urbani, M.H., Martínez, E.J. and Quarín C.L. (2001) The breeding system of three Paspalum species with forage potential. Tropical Grasslands, 35, 211-217.
Evers, G.W. and Burson, B.L. (2004) Dallisgrass and Other Paspalum Species. In: Moser, L.E., Burson, B.L. and Sollenberger, L.E. (eds) Warm-season (C4) grasses. Agronomy Monograph 45 . pp. 681-713. (ASA, CSSA, and SSSA, Madison, WI).
Hacker, J.B., Williams, R.J., Vieritz, A.M., Cook, B.G. and Pengelly, B.C. (1999) An evaluation of a collection of Paspalum species as pasture plants for southeast Queensland. Genetic Resources Communication No. 32. CSIRO Tropical Agriculture, Australia. ISBN 0 643 05915 6.
Ramirez, J.R. (1954) El Pasto Rojas: una gramínea forrajera promisoria en el Paraguay. Revista Argentina de Agronomia, 21, 84-101.
Takayama, S.Y., Freitas, P.M., Pagliarini, M.S. and Batista, L.A.R. (1998) Chromosome number in germplasm accessions of Paspalum (Plicatula group) from different regions in Brazil. Euphytica, 99, 89-94.

Internet links

  

Cultivars

Cultivars

Country/date released

Details

'Bela Vista'
(BRA 003824, CIAT 26985, ATF 1053)
Brazil, south-east Asia From Mato Grosso do Sul, Brazil (22ºS, 180 m asl, rainfall 1,600 mm).  Similar to P. atratum , less productive, softer leaves, very palatable.
'Chané' Argentina (Corrientes Province) From Santa Cruz, Bolivia (16ºS, 480 m asl, rainfall 1,200 mm).  Late flowering perennial .  Best growth between February and May (southern hemisphere subtropics).  Produces up to 21 t/ha DM;  very good quality from spring to autumn.  No serious diseases;  resistant to spittle bug and spider mite.
'Siempre verde'
(BRA 003824)
Brazil (Rondônia) 2 m tall.  Higher nitrogen and phosphorus contents during the rainy season than other grasses tested.  (see 'Bela Vista').
'Azulão'
(No 586)
Brazil (Rio Grande do Sul) (1980s) From Paraguay.  1.5-2.0 m tall, dark green to blue leaves, well accepted by the animals, good frost resistance, late flowering.  Similar DM yield to 'Baio', but higher leaf proportion and IVOMD (56.2%).
'Baio' Brazil (Rio Grande do Sul) Origin unknown.  Similar DM yield to'Azulão', but lower leaf proportion and IVOMD (53.3%).
'Duro' Brazil Origin unknown.  No data.
'Ramirez' Argentina (1969) Origin unknown.  No longer commercially available.
'Rojas' Paraguay (1953) Origin unknown.  Easily established from seed;  grows on a wide range of soils.  Palatable, drought tolerant, tolerates trampling by animals, requires high level of grazing management. No longer commercially available.
'Veludoso' Brazil Origin unknown.  Hairy leaves, medium to high palatability .
'Wintergreen' Zimbabwe (1963) Origin unknown.  No longer used commercially.
No 844 Brazil and Paraguay (1976) Origin unknown.  Sage green leaves, hairy leaves, early flowering, large spikelets (3.5mm).

Promising accessions

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Promising accessions

Country

Details

CPI 39962 Australia (Northern Territory) From São Paulo, Brazil (21ºS, 460 m asl, rainfall 1,200 mm).  About 80 cm tall, good production (15 t/ha DM) and seed yields (175 kg/ha), some spread at Mt Bundey, NT.
CPI 27682, CPI 39964, CPI 39966 Australia (Queensland) Negligible frost damage at -4ºC.
BRA-010707 (CIAT 26668, CPAC 3135) Brazil (Mato Grosso do Sul) Well adapted to poor drainage and occasional flooding conditions on an infertile plinthaquox soil in the cerrado.
FCAP-43 Brazil (Rondônia) Good DM production at Ariquemes and Porto Velho, 9-10ºS.