Leucaena collinsii


Scientific name

Leucaena collinsii Britton & Rose

Subordinate taxa
Leucaena collinsii Britton & Rose subsp. collinsii
Leucaena collinsii Britton & Rose subsp. zacapana C.E. Hughes

Synonyms

Leucaena esculenta (DC.) Benth. subsp. collinsii (Britton & Rose) Zárate

Family/tribe

Family: Fabaceae (alt. Leguminosae) subfamily: Mimosoideae tribe: Mimoseae. Also placed in: Mimosaceae.

Common names

chalip (Guatemala);  chijlip (Mexico).

Morphological description

Leucaena collinsii subsp. collinsii is a small to medium tree 4-7 m high, with occasional trees up to 15 m, a wide, open crown and heavy branching.
Leaves bipinnate with 8-16 pairs of pinnae.  Petiole gland green, sessile, dome-shaped (2 x 1 mm) with a narrow central pore.  Leaflets 45-56 pairs/pinna, 4-7 mm x 1-2 mm, asymmetric about the mid vein, broadly linear.  Flower heads 15-24 mm in diameter with 140-170 pale cream-white flowers with a diameter of 1.0-2.5 cm in groups of 2-3 in leaf axils of actively growing shoots.  Leaves develop with flower heads, the flowering shoot indeterminate in growth with pods borne on older wood within crown.  Pod 16-18 cm x 1.7-1.9 cm, pendant, mid-brown at maturity.  Seeds 9-20 per pod , 6.5-8.8 mm long.
Subspecies zacapana has 6-7 pairs of pinnae;  25-40 pairs of leaflets per pinnae;  shorter (11 cm) and narrower (7-12 mm) pods;  and is more heavily branching, particularly after coppicing , compared with spp. collinsii.
Seed weight 22,000-23,000 seeds/kg for subsp. collinsii and 30,000-36,000 seeds/kg for subsp. zacapana.

Distribution

Native to:
Subsp. collinsii has a very restricted native range, occurring in the seasonally dry deciduous forests of the inland valleys of the Chiapas depression in southern Mexico extending into western Guatemala.  Found naturally at altitude from 400-900 m asl .
Subsp. zacapana occurs in a restricted range in semi-arid regions of eastern Guatemala.

Uses/applications

Subsp. collinsii is cultivated for its edible pods in Chiapas.  It has been used experimentally as directly grazed forage grown in hedgerows in Papua New Guinea, humid-tropical Australia and the Philippines or as cut-and-carry forage in Vietnam and the Philippines.  Natural stands of subsp. zacapana are managed for fuelwood and pole production in eastern Guatemala.  Neither subspecies of L. collinsii has been planted commercially in exotic locations.

Ecology

Soil requirements

In the native range, grows on highly variable soils from self-mulching vertisols to shallow limestone-derived soils.  Generally found on alkaline soils pH 7.0-8.5.  In exotic locations requires well-drained soils with pH  above 5.5, or above 5.0 where aluminium saturation is very low.  Intolerant of soils with low pH, low P, low Ca, high aluminium saturation, high salinity and waterlogging .

Moisture

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Native to sub-humid areas with 900-1,200 mm annual rainfall and a severe dry season of 5-7 months.  Trees are completely deciduous , losing all their leaves at the height of the dry season.  In exotic locations, subsp. collinsii is most productive in humid-tropical environments with only short dry seasons.  Subsp. zacapana grows in considerably drier environments than subsp. collinsii.

Temperature

Average annual temperature of 22-25ºC in the native range.  Requires temperatures of 22-30ºC for optimum growth.  Growth ceases at 16-17ºC.  Light frosts will kill leaf.  Very heavy frosts will kill stems back to ground level but will not kill mature trees.

Light

Normally grown in full sun.  Responses to shade unknown.

Reproductive development

Flowers in the early dry season into shortening days.  Pods ripen 6-7 months later in the early wet season.

Defoliation

Tolerant of repeated, heavy defoliation in cutting and grazing trials and under severe grazing in the native range.  Branches strongly following removal of apical dominance.

Fire

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Mature plants are tolerant of fire, regrowing readily from burnt stumps.  Fires are common in the native range.

Agronomy

Establishment

Relatively slow to establish, particularly in competition with weed species.  For best results plant on deep, well drained soils with a pH above 5.5 and maintain a weed-free area of at least 2 m either side of the establishing plants.  Seed must be scarified to break the impermeable testa.  Mechanical scarification, using coarse sandpaper (for small seed lots) or abrasive lined rotating drum scarifiers, is preferred to hot water treatment.  Specific rhizobium is required (eg. CB3060, TAL1145, LDK4).
Small areas can be planted by either seed or seedlings.  Seedlings are normally raised in poly bags for plug planting at 4-5 months old.  Seedlings can also be raised in beds and removed for planting as bare-rooted seedlings if 'topped and tailed'.

Fertiliser

Normally not fertilised under rain-grown conditions.  Starter N and P may be used when establishing into depleted soils on cropping lands.

Compatibility (with other species)

Will combine well with a range of tropical grasses provided that grass and weed competition is controlled during establishment.

Companion species

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Grasses:  Planted successfully in hedgerows into signal grass (Brachiaria decumbens ) in Papua New Guinea, but failed to establish well into Imperata cylindrica in the Philippines due to inadequate grass control during establishment.

Pests and diseases

L. collinsii subsp. collinsii is highly resistant to the psyllid insect (Heteropsylla cubana), unlike subsp. zacapana, which is generally psyllid-susceptible, depending on accession .
A range of pathogenic fungi and other insects occasionally attack L. collinsii .  Damping-off diseases caused by the fungal species Pythium or Rhizoctonia commonly kill newly emerged nursery and field-grown seedlings. 
The soft scale (Cocus longulus) attacks the tall stems causing a reduction in productivity.  The associated sooty mould that develops on the sugary exudates from the scale can cover the stems and temporarily kill under-storey grasses.  Soft scale is generally an infrequent pest, with populations rarely building to cause economic damage.
Soil insects such as earwigs, scarab beetles, termites and cut worms can cause serious damage to emerging seedlings and should be controlled using insecticide baits.
Seed production can be reduced by the flower-eating larvae of the moth Ithome lassula, and by two species of seed-eating bruchid beetles of the Acanthoscelides genus.
Spur-throated locusts (Austracris guttulosa) occasionally attack L. collinsii , defoliating mature plants and killing seedlings during early establishment.

Ability to spread

Very unlikely to spread under grazing or regular cutting.

Weed potential

Lower weed risk cf. L. leucocephala due to lower levels of seed production and long maturation time of pods, but is none-the-less considered to possess weed potential due to its precocity and moderate levels of seed production.  Has potential to colonise open disturbed habitats.

Feeding value

Nutritive value

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One of the highest quality Leucaena spp. for ruminant production, L. collinsii subsp. collinsii has IVDMD of 68-70%, negligible concentrations of condensed tannins (c. 0.1% of DM), and low concentrations of mimosine (<2%).

Palatability/acceptability

Highly palatable to a wide range of ruminants, monogastrics and invertebrates.  Slightly less palatable to ruminants cf. L. leucocephala , based on short term grazing and cafeteria trials.

Toxicity

Contains low concentrations of mimosine cf. L. leucocephala (<2%), but mimosine will still limit its inclusion in the diet of monogastrics to <15% of DM.
Contains only trace concentrations of condensed tannins.

Production potential

Dry matter

Most productive in humid tropical climates (>1,200 mm annual rainfall ) with short or no dry season.  May be slower to establish than L. leucocephala , but of similar subsequent productivity in humid-tropical environments, particularly where the psyllid is problematic.  Considerably less productive in sub-humid and cool climates.

Animal production

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Supported steer gains of 0.58 kg/hd/day in combination with signal grass (Brachiaria decumbens ) in Papua New Guinea, cf. 0.3 kg/hd/day for the signal grass control.  Supported steer gains of 0.35 kg/hd/day in combination with Imperata cylindrica in the Philippines, cf. 0.14 kg/hd/day for the I. cylindrica grass control.

Genetics/breeding

L. collinsii subsp. collinsii is a self-incompatible diploid (2n = 52).  Hybridises readily with L. macrophylla, L. lanceolata, L. trichandra , L. pulverulenta and L. shannonii, but relatively poorly with the tetraploid and other diploid species of Leucaena.  Subspecies collinsii is native to a contiguous, restricted region and apparently contains little genetic variability.

Seed production

Seeds over a 2-month period in the early wet season in the native range.  Seed fill occurs late in the fruiting cycle and green pods may initially appear to be without seed.  In Australia, seed production has been made difficult by the long period of pod maturity during which it is susceptible to seed-eating bruchid beetles.  Seed production potential appears to be modest (<100 kg/ha).

Herbicide effects

Can be controlled by basal bark application of herbicides containing 120 g/L picloram and 240 g/L triclopyr mixed with diesel.
Application of glyphosate to regrowth following slashing will kill trees, although repeat applications may be necessary.

Strengths

  • Very high nutritive value.
  • Highly resistant to psyllids.
  • Low condensed tannin and mimosine concentrations.
  • Persistent under grazing and cutting once established.

Limitations

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  • Slow to establish.
  • Lower growth potential cf. L. leucocephala , except in high psyllid environments.
  • Poor growth in sub-humid environments.

Other comments

    

Selected references

Galgal, K.K., Shelton, H.M. and Mullen, B.F. (2004) Animal production from some new Leucaena accessions. Tropical Grasslands, 39 , (in press).
Hughes, C.E. (1998) Leucaena, A genetic resources handbook. Oxford University Press, UK.
Shelton, H.M., Gutteridge, R.C., Mullen, B.F. and Bray, R.A. (1998) (eds) Leucaena - adaptation, quality and farming systems. ACIAR, Canberra, Australia.

Internet links

Cultivars

Cultivars

Country/date released

Details

No cultivars of L. collinsii spp. collinsii have been formally released.          

Promising accessions

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Promising accessions

Country

Details

OFI 51/88, OFI 52/88. Oxford Forestry Institute, United Kingdom. Accessions are from the Chiapas depression in southern Mexico and western Guatemala.  Little variation was found between, or within accessions, in agronomic trials.
K450, K461 and several others. Hawaii, US. Accessions are from the Chiapas depression in southern Mexico and western Guatemala.