From Neglected Crops: 1492 from a different perspective
by the Food And Agriculture Organization of the United Nations
Pepino
(Solanum muricatum)
Botanical name: Solanum muricatum Aiton, S. variegatum R. & P., S. pedunculatum Roem & Schult, S. guatemalense Hort.
Family: Solanaceae
Common
Names:
English: pepino, sweet cucumber, pear melon; Quechua: cahum, xachum;
Aymara: kachuma; Spanish: pepino, pepino dulce (Colombia, Ecuador, Peru,
Bolivia), mataserrano (central and southern Peru), peramelon (Canaries)
The pepino Solanum muricatum,
originates from the Andean region and has been domesticated since
pre-Hispanic times. At present, it is known only as a cultivated
species. Its names in native languages and representations on various
ceramic objects of the Chimú and Paracas cultures are proof that it was
a widespread and important crop in those days. This was not so during
the settlement or the Republic. During the settlement, the Viceroy
Melchor de Navarra, Count of la Patata, prohibited consumption of this
fruit and gave it the pejorative name of "mataserrano" (highlander
killer). The Spanish word pepino might have been intended to facilitate
the introduction of Cucumis sativus
L. (Cucurbitaceae), a species also known by this name, as the names
have been confused since then. On the northern coast of Peru (in the
Virti and Moche valleys), farmers believe that if pepinos are eaten
after drinking liquor, death may result. Names and beliefs have
contributed towards S. muricatum
being grown in small areas and its introduction is still at the
incipient stage. The situation is not the same in the countries where
it has been introduced, however. Commercial crops produced with
advanced technology are known in Chile, New Zealand and the United
States (California) as a result of this fruit's acceptance on North
American, European and Japanese markets.
Uses and applicatons
The fruit of S. muricatum
is eaten ripe as a refreshing, quenching fruit after physical effort.
Herdsmen of Moche and Virti take pepinos in knapsacks for eating during
long treks through the desert. Its yellowish white colour, with
speckles and longitudinal lines, and its purple colour in the ripe
state make the fruit attractive. Its smell and taste are pleasant
because of their typical mild aroma and slightly sweet flavour. Its
nutritional value is low but it is recognized for its diuretic
properties, probably because of its high water content (90 percent) and
good iodine content, for which it is recommended for treating goitre.
It also contains 7 percent of carbohydrates and 29mg per 100 g of
vitamin C.
Botanical description
S. muricatum is a
herbaceous plant of a very branching habit and with a woody base. It
has abundant foliage, with simple or pinnate leaves (one to three pairs
of folioles) and elliptical-lanceolate, strigose or glabrous laminae
and folioles. The inflorescence is subterminal with few flowers. The
flowers are pentamerous, the calyx persists on the fruit and the
actinomorphous corolla is 2 cm in diameter and bluish in colour with
whitish margins.The stamens are shorter than the corolla, the anthers
are yellow, connivent and dehiscent through apical pores. The style
emerges slightly in between the anthers. The fruit is ovoid, conical to
subspherical, and it may be with or without seeds.
Phenology
Plants propagated vegetatively grow quickly and begin to flower four or five months after sowing.
The biological cycle with this kind of propagation is as follows:
• Cuttings taking root: this is very quick (ten to 15 days) in damp soil.
• Vegetative growth: this is manifested by branches and leaves emerging in abundance and lasts three to 3.5 months.
• Flowering and fruiting: this is abundant because of the number of branches and lasts 1.5 to 2.5 months.
• Postharvest stage: this is a period of rest for the plant during
which no branches or leaves are put out; it is the right time for
taking cuttings for propagation and at the same time for pruning the
plant.
• Resprouting: with greater humidity, the plant begins a new phenological cycle.
Plants
propagated by seed take longer to develop. In spite of the fact that
the plant is perennial, growers only avail themselves of two fruiting
seasons, since fruit yield and quality subsequently diminish.The seeds
viability after removal from the fruit is not known but, in the
vegetable gardens where they are grown, seedlings frequently appear. In
the laboratory, seedlings have been obtained even after 15 to 20 days
of seed drying.
Ecology and phytogeography
S. muricatum
is a tropical species of temperate,mountain and coastal climates. In
the Andean region, cultivation takes place in the inter-Andean valleys
and on the western slopes, from 900 to approximately 2,800 m. These
boundaries are set within 24°C at the lower limit and 18°C a tthe upper
limit, with an annual precipitation of between 500 and 800 mm. The
climatic characteristics described correspond to the high part of the
subtropical dry forest and the low dry mountain forest or to the high
yungas and quechua of Peru. Coastal cultivation takes place south of
lat. 7°S. during the autumn and winter when the temperature fluctuates
between 21 and 17°C and atmospheric humidity increases as a result of
mists and drizzle.The original cultivation of S. muricatum
extended along the Andes, from southern Colombia to Bolivia and the
Peruvian coast. During the settlement, it was introduced into Mexico
and Central America, where it was known as S. guatemalense.
Genetic diversity
The
species displays wide intraspecific variability, which has given rise
to the aforementioned synonymy. Morphological variation is evident
in the division of the leaf lamina (compound and simple), the pubescence
of the stems and leaves (glabrous-strigose) and the shape, colour and
consistency of the fruit. A physiological variation has been detected
in the formation of the fruit and seeds, since there are certain
biotypes that produce fruit after pollination and contain fertile seeds
and others which, owing to the sterile pollen, form parthenocarpic
fruit without seeds. Correlations have not been established between the
characteristics described, and they warrant specific research.
Varieties and forms have been described. As regards varieties,
Protogenum is characterized by compound leaves and Typica by simple
leaves. Within the latter, the form glaberrimum, which has glabrous leaves, is distinctive.
Related wild species
This is a still undefined aspect. Research based on interspecific crossings reports S. muricatum with S. caripense H. & B.ex Dun., S. labanoense Correll and S. trachvceirpum
Bin & Sodiro. Of these, the first is regarded as having greater
potential for such genetic affinity in that fertile hybrids have been
obtained.There is less evidence in the case of the other species but,
in that of S. tabanoense, the origin of S. muricatum could be southern Colombia and Ecuador, since this is the natural area of distribution of the species to which it is related.
Known cultivars and centres of diversity
On the sierra of Cajamarca in Peru, the typical form of S. muricatum
is found with regular frequency, with subspherical fruit, a pressed
apex, and in a yellowish green colour with some purple speckles. On the
Peruvian coast, the form glaberrimum has been 'found in pure and commercial crops, of which two cultivars can be distinguished:
Morado listado:
This has dark green leaves, suberect branches and ovoid-conical fruit
of variable size. It has a yellowish, very sweet mesocarp. This is the
fruit most valued on the market.
Oreja de burro:
This has light-green leaves and long branches; it is semi-prostrate,
has elongated conical, large or medium fruit with little
pigmentation (white pepino) and its mesocarp is sandy white and less
sweet.
The variety Protogenum
has been described in the case of Colombia and Ecuador, where cultivars
are unknown. On the northern coast of Peru, a purple pepino is known,
which is subspherical in shape and very sweet. The growers consulted
say it has disappeared.
Living material needs to be collected throughout the distribution area of S. muricatum in order to set up a gene bank.
Cultivation practices
Propagation
is generally by cuttings. To prepare the cuttings, healthy, mature
branches are selected and cut at a length of 30 to 35 cm. They are then
left in the shade for two to three days to induce a slight dehydration
and encourage rapid rooting. The soil, with sufficient humidity, is
prepared by ploughing in furrows. After four to five days, the furrow
is "cleared'', which consists of breaking up the soil and deepening the
furrows to achieve a good infiltration of water, without waterlogging
the ridge. The cuttings are planted 50 cm apart under damp conditions,
on the lower third of the side of the ridge. The distance between
furrows is 80 cm.
Tilllage consists of irrigation, hoeing
and earthing up. Irrigation is frequent during the first few days after
sowing and is then carried out at intervals as required. When the fruit
is ripening, irrigation is suspended. Earthing up is carried out 30 to
35 days after sowing and is used to bury the fertilizer.
In Peru S. mumricatum is not grown very much commercially and the yield per unit of area is not known, nor is the extent of its cultivation.
Prospects for improvement
The limitations in the countries of origin are determined by:
the "social marginalization" of the fruit, which is the reason for its low consumption;
• the underuse of genetic variability;
• a lack of commercial techniques;
• inadequate transportation of the fruit.
However, these limitations are not factors which definitively prevent extensive cultivation of S. muricatum.
This is one of the native species with the greatest potential for
overcoming its current marginalization, as the availability of fruit
can easily be diversified and the potential for consumption and export
widened.
Lines of research
Sustained promotion of S. muricatum cultivation must be based on a multidisciplinary research program that includes:
•
botanical explorations within its primary distribution area that
make it possible to recognize the extent of intraspecific variability
and to define the centres of genetic diversity;
• anatomical
and morphological, floral biology and cytogenetic research to interpret
ecophysiological behaviour and genetic variability;
• research
into phenology and agronomic culivation techniques in various
ecological areas in order to establish nutritional and health
requirements and yield potential.
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© FAO 1994
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