The author of this chapter is I. Sánchez Vega (National University of Cajamarca, Peru).
Botanical name: Solanum muricatum Aiton, S. variegatum R. & P., S. pedunculatum Roem & Schult, S. guatemalense Hort.
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 Palata, 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 Virú 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.
The fruit of S. muricatum is eaten ripe as a refreshing, quenching fruit after physical effort. Herdsmen of Moche and Virú 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 29 mg per 100 g of vitamin C.
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:
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.
Figure 21. Andean fruits: A) pepino (Solanum muricatum); A1) flower; A2), A3) fruits; B) tree tomato, tamarillo (Cyphomandra betacea); B1) flower; B2) cross-section of the fruit; C) mountain papaw (Carica pubescens); C1) leaf; C2) fruit; C3) cross-section of the fruit
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 2800 m. These boundaries are set within 24°C at the lower limit and 1 8°C at the 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.
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. tabanoense Correll and S. trachycarpum Bitt & 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 through out the distribution area of S. muricatum in order to set up a gene bank.
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.
Tillage 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. muricatum is not grown very much commercially and the yield per unit of area is not known, nor is the extent of its cultivation.
The limitations in the countries of origin are determined by:
Sustained promotion of S. muricatum cultivation must be based on a multidisciplinary research programme that includes:
The alternate use of vegetative and sexual propagation must be better exploited. Vegetative propagation is used to stabilize varietal forms and shorten the biological cycle and sexual propagation is used to promote genetic diversity.
Botanical names: Cyphomandra betacea (Cav.) Send., C. crassifolia (Ortega) Kuntze, Solanum crassifolium Ortega, S. betacea Cav.
Common names. English: tree tomato, tamarillo; Spanish: tomate de árbol, berenjena, sachatomate, yuncatomate (Peru), limatomate, tomate de monte, tomate de La Paz (Bolivia, Argentina)
This is a native species of the Andes whose domestication and cultivation took place before the discovery of America. In spite of its age, no names are known in native languages.
Cyphomandra betacea is cultivated for its fruit which is a food resource and a potential raw material for the preserves industry. The peasants attribute to the fruit medicinal properties for alleviating respiratory diseases and combating anaemia. The tree tomato contains adequate levels of vitamins A, B6, C and E and iron.
The fruit is eaten raw or cooked. In all cases. thc skin is removed as it has a bitter flavour. When ripe, the fruit is eaten raw as a fruit. More frequently it is eaten as a dessert of fruit in syrup. The whole pedunculated fruit is cooked for a short time in water so that the skin can be removed. Honey is then prepared with cinnamon and cloves, the peeled fruit is added and it is left to boil until it reaches a suitable consistency.
In the pre-ripe state, when the fruit takes on an orange colour, it is used in Peru to prepare a sauce together with Capsicum pubscens R. & P., a variety of large green pepper. To prepare this, the fruit is lightly grilled, which facilitates removal of the skin (epicarp). It is then ground with a large green pepper and salt. This spicy sauce is eaten as an appetizer. In those areas of the sierra where tomato (Lycopersicon sp.) is not grown, tree tomato is used to prepare stews, thus replacing tomatoes.
Cyphomandra betacea is a small tree, growing 2 to 3 m in height, with a single trunk that is monopodial and branched at a height of 1 to 1.5 m into two or three branches. The same pattern of ramification is repeated on the branches. The leaves are cordiform, 17 to 30 cm long, 12 to 19 cm wide, subcarnose and lightly pubescent on the underside. There is a caulinar inflorescence opposite the leaf. The flowers are 1.4 cm long. the calyx persists on the fruit, the corolla is pinkish white and rotate-campanulate with reflexed apices, connivent stamens that are shorter than the corolla, yellow anthers and is dehiscent through two apical pores. The style emerges between the anthers. The fruit is 5 to 7 cm long, ovoid, glabrous, greenish yellow to orange in colour, with longitudinal markings, and the mesocarp is orange.
Phenology. Apparently no research has been done on the growth phases of this plant. Consequently, the following phenological description is an approximation and the result of field observations and information provided by peasants. Propagation is most frequently by seed but can also be based on cuttings.
The plant's life is approximately three to four years and flowering begins eight to ten months after sowing in the permanent location. The flowering period begins at the same time as branching of the main stem. The first inflorescence is produced around the point of branching of the main stem and the following ones at the end of the branches. around their respective branching. Flowering is continuous and the number of inflorescences is directly proportionate to the plant's branching.
The plant is evergreen and constantly puts out leaves. However, the lower leaves later fall, leaving the main stem and lower part of the branches leafless.
C. betacea grows best in regions with temperatures between 18 and 22°C and annual precipitations of 600 to 800 mm. These climatic characteristics occur in the Andes at average altitudes (1800 to 2800 m). Observations in family gardens show that the plants grow better in association with trees (e.g. Erythrina edulis, Juglans neotropica), where a more humid microclimate has formed, with less soil dehydration and where the light is diffused. Tree tomato plants do not tolerate low temperatures (frost). High temperatures also affect flowering and fruiting, as do prolonged droughts.
C. betacea is cultivated sporadically from Mexico and the Antilles to Argentina. No wild populations are known and its domestication is presumed to be recent. Cultivation extends to subtropical areas such as New Zealand, where it is very advanced, southern Europe and tropical areas of other continents, India and Southeast Asia.
C. betacea is known only in the cultivated state. Populations display variability in the pigmentation of the young foliage and in the colour, shape and thickness of the fruit's mesocarp. Some of them have groups of silicose cells on the mesocarp, which lowers the quality of the fruit. According to growers, the yellowish green leaf colour is related to the production of yellowish fruit and the purple-green foliage with the production of orangey-red fruit. The shape of the fruit varies from subspherical to ovoid with a slightly pointed apex. Research on this aspect is necessary to elucidate the extent of variability and the phytogenetic relationship with wild species.
Related species. There are around 50 species of Cyphomandra which are found from southern Mexico to Argentina. C. bolivariensis and C. hartwegii are considered to be species related to the tree tomato. C. hartwegii produces edible fruit, is grown sporadically and has been used as grafting stock: Another species with edible fruit, C. cajanumensis or casana, originating from Ecuador, is cultivated in New Zealand.
Commercial cultivation of C. betacea is incipient, in spite of the fact that it is frequently grown in the gardens of rural and urban houses. In these gardens, very few plants (two to four) are grown for family consumption and only occasionally it is sold on local markets.
Cultivation techniques are based on propagation from seed and there are therefore two stages in cultivation:
Seed bed. Seeds from ripe fruit are left to dry outside for ten to 15 days and are then put into a seed bed. They are left there for 30 days to germinate and reach 15 to 20 cm in height (with three or four leaves), at which point they are planted out in their final location.
Sowing. Since the plants are grown in gardens where there is no regular planting, no information is available on the depth of sowing, the distance between plants, tillage practices or crop protection.
Cultivation based on vegetative propagation is very rare. In Colombia, it is reportedly grown from cuttings which must be 20 to 30 cm in length and which take root 30 days after planting, at which stage they are thus suitable for planting out. In Cajamarca in Peru, one case of propagation from cuttings is known to have been carried out experimentally by a grower.
Prospects for improvement
Cultivation of C. betacea shows promise and should be the subject of research and experimentation in commercial crops which allow relevant technologies to be developed.
The limitations of C. betacea are determined by the traditional state of cultivation rather than by the plant's characteristics. The present situation is characterized by:
The tree tomato's prospects are determined by the quality and diversity of use of its fruit. The most important and potentially exploitable is industrial processing of the fruit for preserves. This agro-industry would promote cultivation over larger areas and extend the market, while cultivars would be developed with bigger yields and better-quality fruit.
Intensive cultivation of C. betacea for industrial purposes involves carrying out various research studies aimed at achieving greater production. With this in mind, the following activities are recommended:
Botanical names: Carica pubescens Linne & Koch, Vasconcellea pubescens A. DC., C. candamarcensis Hook, C. cundinamarcensis J. Linden
Common names. English: mountain papaw; Spanish: chilhuacán, chiglacón, chamburu (Ecuador), chamburu, huanarpu hembra, papaya de monte, papaya arequipeña, papaya de altura (Peru, Bolivia); papayuela (Colombia)
Carica L. is a genus originating from tropical and subtropical America of which 40 native species have been described from Mexico to northern Argentina. Of these, C. papaya L. is the most widely grown species in the tropics worldwide.
In the Andes, at altitudes where C. papaya cannot be grown, several species of Carica grow which might represent promising crops, including C. pubescens, which is grown in family gardens from Colombia to Bolivia. It is probable that this species was removed from the evergreen Andean forests and put into gardens to grow as a decorative plant and for its fruit, which in the ripe state is eaten raw or cooked. Not much is known about the history of this Andean fruit-tree, but its cultivation may be relatively recent, although it was grown before the introduction of C. papaya.
It can be assumed that the introduction of C. papaya into South America could have held back development of the cultivation of C. pubescens and other related species. The marginalization of this species can also be attributed to the indifference of the Andean populations and to the lack of incentives for undertaking botanical studies, as is currently the case with species of other families.
C. pubescens is used mainly for its fruit, although other parts of the plant have a medicinal importance. The ripe fruit is used in households to make preserves and drinks. The boiled or baked green fruit can be eaten as a vegetable; when green it is also a source material for latex. Because of its papayan content, it is accepted on the international market for use in the pharmacological industry and as a meat tenderizer. In the area of greatest cultivation (Colombia, Chile and northern Ecuador), the fruit is used to treat arterial sclerosis.
In Peru, at 2800 m in the gardens of Urubamba (Cuzco), much taller, more robust and branching plants than the Cajamarca biotypes have been observed. These characteristics mean greater production and larger fruit size, with up to 200 fruits being counted on one adult plant. The fruit is used to tenderize tough beef. To do this, the latex is removed and rubbed into the meat, which is then set aside for four to six hours. According to popular knowledge, latex is used against skin mycosis and verruca plana. It is also used as an anthelmintic, in the treatment of enteritis in children during the teething period, and against diabetes and liver diseases. Through its proteolytic effect, it acts on the cells of the skin surface and its pathogens.
C. pubescens is a shrub of 1 to 2 m. Its main stem has little branching and is broad-based with conspicuous leaf scars. It has the appearance of a small palm. The leaves are petiolate and the petioles are 17 to 34 cm long; the leaf blade is dentalobulate, pentagonal, 20 to 26 cm long and 34 to 40 cm wide. The leaves have a medium lobule with three to five oblong-acuminate side lobelets. The fruit is small (10 to 15 cm), five-sided and yellow. Most plants are dioecious.
Phenology. Few phenological studies have been done, particularly regarding the aspects of the plant's age at flowering and length of production. Empirical evaluations indicate that plants obtained from seed reach their flowering age at ten to 12 months and that the biological cycle ends at five years. Growth is slow and leaf emission is continuous, but the lower leaves fall off. Very few side branches are produced, except when the main shoot is cut. When the flowering stage is reached, it is continuous and simultaneous with leaf emission.
The ripe fruit is eaten by birds which pierce the mesocarp causing the seeds to fall. These have a high germination capacity, without having to go through a period of dormancy. Seeds begin to germinate at 30 days and a 60 percent germination rate has been noted.
This fruit-tree grows in temperate to warm climates. In general, highland Caricaceae inhabit the low dry mountain forest area. In the Andes, these areas are situated between 2000 and 3000 m, depending on the latitude, and correspond to the jalca and quechua agro-ecological zones in Peru. with an annual precipitation between 500 and 1000 mm. Mean temperatures range between 12 and 1 8°C (22°C in winter at midday) and the climate is subhumid.
The species is sensitive to low dawn temperatures and intense midday sun during the winter (May-September). These temperature extremes affect the foliage and normal ripening of the fruit. Although further investigation should be carried out, it is recommended that the plant be cultivated in association with other shrubs. This is deduced from its good performance in gardens that have deep soil and abundant organic matter. The plant does not tolerate prolonged drought on account of its over-profuse leaf fall.
C. pubescens is widely distributed geographically over the Andes. It covers the western and eastern slopes and inter-Andean valleys from Colombia to Bolivia. It grows spontaneously on the Bolivian mountain ridge along with other wild species, and in Colombia as a roadside species up to the edges of the high bleak plateau.
C. pubescens is a clearly defined and delimited species as regards its morphological characteristics, although these show variations such as plant height and branching; the number of lobules and pubescence of the leaves; fruit size and colour and the quantity of latex. However, the most important differences are noted in the sexual forms of the plants. In this species, as in C. papaya, there are three sexual forms: pistillate plants, staminate plants and andromonoecious plants. Pistillate and staminate specimens do not respond to seasonal climatic changes while the andromonoecious specimens, which are sexually ambivalent, form female, male and perfect (hermaphrodite) flowers in different proportions, depending on the characteristics of the season.
There is no doubt that the sexual variation described, together with the ability to form hybrids with other species, offers the possibility of creating new combinations and increasing variability. The Ecuadorian species C. pentagona and C. chrysopetala have been changed to interspecific hybrids. It has been shown that C. pentagona resulted from hybridization between C. pubescens and C. stipulata and that C. chrysopetala is the result of hybridization between C. pubescens and C. monoica.
No cultivars are recognized in the geographical distribution area of C. pubescens, but it may be assumed that the greatest centre of diversity is in Ecuador and northern Peru. Nor is there any news of the organization of a gene bank for this species, which would prevent the loss of cultivars or biotypes created through crop selection and by ecological factors.
Current agricultural knowledge concerning C. pubescens in the Andes is limited. Its cultivation is traditional and it is grown in rural home gardens as a decorative plant and for fruit for household consumption. One to three plants are grown in each garden and these receive the same agricultural management as other species on the plot, so there are no specific cultivation techniques to describe for this species.
The peasants reproduce this fruit-tree from seed or occasionally from cuttings. The seeds are removed from the fruit and, after a short period of drying in the open air, they are left to germinate in baked clay vessels (flower pots) or in containers which act as germinators.
The seedlings are planted out when they are 10 to 15 cm high (two to four leaves). Pure cultivations have not been tried out and so the distance between plants is not known. However, according to the diameter of the crown, it can be estimated to be 3 x 3 m.
Yields per unit of area are not known, but garden plant countings indicate that they can produce 50 to 60 fruits in a growth period which lasts approximately four months.
The marketing of C. papaya fruit at the markets of the villages and towns of the sierra limits the consumption of C. pubescens fruit. It could be said that the main consumers are the rural populations. Occasionally it is offered at the markets of the sierra. The best prospects for turning this species into a commercial crop, with cultivation still on a small scale, are to remove the latex in the green, semi-ripe state and to prepare processed products such as juices and preserves.
The monoecy and/or dioecy in the Carica species growing on high land (Andes) have given rise to some inaccuracies in species delimitation. If we add to this the affinities which exist between these species and the possibility of creating interspecific hybrids, there is an evident need to carry out basic taxonomic studies.
Lines of research The following lines of research are suggested: