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Common names
Koemataballi (Suriname), tencilla, zornia, barba de burro (El
Salvador).
Description
A perennial herb. Stems 20 to 50 cm long, glabrous or pubescent,
with a prostrate growth habit and intense branching. Stipules lanceolate,
striate, to 1 cm long. Leaves bifoliate. Leaflets lanceolate-oblong, acute
at the apex, glabrous or pubescent, 1 to 4 cm long. Inflorescence a terminal
peduncled spike, flowers alternate, 1 to 35 per inflorescence, bractlets
stipuliform, to 1.5 cm long, nearly enclosing the flower. Calyx hyaline,
4 mm long, ciliate. Petals yellow, approximately 1 cm long. Pods two- to-eight
jointed, shortly beaked, more or less spiny, pubescent, the inferior margin
deeply crenate, the superior margin nearly straight, joints rounded, 2
to 3 mm long and wide (Pulle, 1976; Jutzi and Nosberger, 1984).
Distribution
Native to and widely distributed through tropical South America
and north into the West Indies; possibly through Central America to southern
Mexico and the United States. It is found as far south as Rio Grande do
Sul in Brazil, and possibly north-eastern Argentina. Its chief habitats
are open fields and grassy areas. Z. latifolia has been naturalized as
a weed in West Africa and the Congo, where it occurs in gardens and lawns,
on roadsides, airfields and in savannas.
Mohlenbrock (1961) lists two varieties, var. latifolia, which is the
widespread material, and var. bernardinensis (Chod & Hassl) Mohlenbrock
which is confined to the savanna regions of Paraguay.
Breeding system
Flowering occurs sequentially from the basal to the terminal
flowers of the inflorescence; flowers open for five to ten hours at anthesis.
No insect tripping is needed for selfing but cross-breeding is possible.
Fertilization is mainly autogamous, with a very low proportion of insect-dependent
crossing (Jutzi and Nosberger, 1984).
Main reference
Jutzi and Nosberger (1984).
General features
Long confused with Zornia diphylla, an Old World plant based
on Hedysarum diphyllum L., the true nature and extent of Z. latifolia still
appear unclear. It has attracted attention in South America as a plant
well adapted to the high-aluminium soils of the Brazilian Cerrado and Colombian
Llanos. It has been under evaluation by CIAT since 1975 and has given consistently
high forage yields and high forage quality on these toxic aluminium soils.
One accession, CIAT 728, a Colombian ecotype, has been selected for possible
development to cultivar status (Jutzi and Nosberger, 1984).
Active growth during the dry season is one of the important characteristics.
In the Colombian Llanos Orientales, its dry-matter yield ranges from 617
to 4 917 kg./ha and protein yields from 60 to 801 kg./ha when grown in
association with Brachiaria decumbens and Andropogon gayanus (CIAT, 1978).
Z. latifolia has also formed a complete ground cover within 12 months when
planted in a low-density system (1 000 hills/ha) with initial fertilizer
applied only to the hills (CIAT, 1978).
Diseases and pests
Currently, the main limitation to the use of CIAT 728 in pastures
is its susceptibility to disease. It is attacked by scab (Sphaceloma zorniae)
and a virus-blackmould (Meliola sp.) complex, which is common in the native
Zornia spp. in Brazil and causes leafrolling distortion and stunted growth.
It was also attacked in seed stands by the bud worm (Stegasta bosqueella),
which, however, is easily controlled by insecticides (de Andrade, Thomas
and Ferguson, 1983).
Seeding features
The fruit is a one- to seven-articulated lomentum but most
articulations are abortive. Disintegration occurs readily and pod shattering
can begin as early as the third week after anthesis, before the seeds have
matured.
CIAT 728 has a short-day flowering response, with a critical photoperiod
of about 12.5 hours and optimum temperature for seed set ranging from 20
to 27°C. Higher temperatures are necessary for vigorous growth. Relatively
high plant densities improved the seeding performance (Jutzi and Nosberger,
1984).
At the Cerrados Agricultural Research Centre, north-east of Brasilia,
CIAT 728 yielded from 175 to 692 kg. per ha per year over three years and
was one of few, of the nine legumes tested, to yield seed each year. It
had the highest mean annual yield. Seed-line maintenance was complicated
by the presence of native lines of Z. latifolia (de Andrade, Thomas and
Ferguson, 1983). In Jutzi and Nosberger (1984) studies, seed yields of
400 to 700 kg./ha were recorded, with 90 percent hard seed at harvest and
770 000 seeds/kg.
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