The author of this chapter is J. Axayacatl Cuevas (Department of Plant Science, Ethnobotanical Unit, UACH, Mexico).
Common names. English: Spanish plum, red mombin; Nahuatl: ateyaxocotl; Spanish. jocose (Mexico [Oaxaca], Central America), ciruelo (Mexico [Jalisco, Yucatán])
Spondias purpurea was grown widely from Mexico to the northern region of South America when the Europeans arrived, as can be deduced from the descriptions of the first chroniclers ( Oviedo, Sahagún). It spread through the Antilles and the rest of South America and was possibly taken from Mexico to the Philippines. The fresh fruit has a very pleasant taste and its consumption is increasing. It is a valuable but economical raw material for the preparation of soft drinks, preserves and syrups and is also eaten as a dried fruit. The current marginalization and scarcity of commercial plantations are largely due to a lack of attention on the part of producers, technical experts and agricultural extension workers, who are concentrating their efforts on other fruit-trees in greater demand on the foreign market.
The most widespread use of S. purpurea is as a fresh fruit for local consumption and for supplying city markets. In Mexico and Guatemala. it is used in other forms which are possibly of post-Hispanic origin. In one form, the fruit is boiled in brine for five to ten minutes and then dried in the sun, either on tables with a wire mesh or reeds for three days or on driers on mobile units for ten to 12 hours. By this process, the dried fruit is reduced to one-quarter of its fresh volume. Another way to prepare the fruit is to heat it in unsalted water and dry it in the sun, while a third process, used in Mexico to obtain ciruelo negro, consists of pricking the skin of the fruit, placing it in syrup (1 kg of sugar in a bottle of water) and letting it simmer until the sugar burns or becomes concentrated. Ciruela cristillina is a fourth method of preparing the fruit, similar to the previous one, only the fruit is gathered while it is ripening and is boiled for a shorter time.
Other uses of Spondias pulp include as an atole, mixed with maize flour and sugar, and in the preparation of wine, chicha (maize liquor) and soft drinks.
Analyses of the fresh fruit show that the percentage of moisture in the flesh ranges from 76 to 86 percent; it is very low in protein and fat and contains appreciable quantities of calcium, phosphorus, iron and ascorbic acid.
Its consumption is currently increasing throughout Mesoamerica. The bulk of production comes from isolated trees or hedges, while very little comes from well-ordered and maintained plantations, such as the ones seen around the city of Oaxaca. However, it is a very promising fruit-tree because it is accepted on the market; it is a hardy species with a high resistance to drought; it is easy to produce on poor soil; and its propagation is exclusively vegetative, which ensures an early harvest.
S. purpurea is a small tree, growing 4 to 8 m, with a broad crown, irregular trunk and fragile branches; its leaves are composed of five to 12 pairs of elliptical-acute leaflets, 2 to 4 cm in length and which fall before the flowering period. It has red flowers in 3 to 5 cm panicles, situated along the small branches; the fruit is an irregular oval drupe, somewhat gibbous, smooth and shiny, 4 to 5.5 cm long and a violet to yellow colour, with a woody kernel which contains the seeds. The flesh is sparse, creamy, yellowish and bitter-sweet in the cultivated plants and very acid in the wild plants. It contains malic acid, sugar, calcium malate and starch. The growth cycle has only been studied in Mexico, in Sinaloa and Puebla. In Sinaloa, the trees have foliage from June to October, leaves fall from October to December and the trees are without foliage from January to May. Flowering occurs in February and March and fruiting in June. In Puebla, the trees have leaves from March to October, leaf fall occurs from October to December and the trees remain leafless from January to April. Flowering takes place from December to January and the fruit ripens in April and May. Of great interest is the absence of seed formation in this species, an aspect that was first studied in the Philippines. In the "nut", which occupies the central part of the fruit, only remnants of aborted seeds are found. This is due to both poor pollen formation and the oosphere. Natural distribution is thus completely limited, but the ease with which stems and branches sprout, together with their fragility, allows a very limited natural propagation. Recognition and conservation of the numerous variants which this species displays is possibly due to the action of humans.
Figure 10. Spanish plum, red mombin (Spondias purpurea)
The natural populations of S. purpurea grow from sea level to an altitude of 1 200 m in areas
with alternating seasons from Sinaloa and Jalisco in Mexico to Colombia. It is known that S. purpurea was taken from Nicaragua to Panama and South America in the form of cuttings with a viability of several weeks. It grows in regions of low humidity and remains leafless during the dry season. It has been introduced into similar tropical regions in Southeast Asia and also in subtropical areas (Florida).
Numerous clonal varieties of S. purpurea are known, but there has been no formal characterization of them. In Yucatán there are 20 varieties and, although some may be S. Iutea, this is perhaps the most notable varietal concentration in Mesoamerica. Ak-abal, with small, poor-quality fruit and smooth succulent roots, like those of the Brazilian species S. tuberosa, is used for pickles. The cultivated varieties may be divided into two groups:
Summer mombin. This fruits (in Central America) during the dry season from February to May, has ellipsoidal fruit that is 2.5 to 3 cm long with smooth, purple-red skin and yellow, smooth, sweet and slightly acid flesh. When green, these varieties look like olives. The varieties Tronador, Criollo, Nica and Morado grow between 0 and 800 m.
Winter mombin. This is of superior quality, with fruit that is 3.5 to 4.5 cm long, red or yellow, smooth or with protuberances, and has firm, sweet, slightly acid flesh. It ripens at the end of the rainy season (September to December). Most of these varieties grow between 800 and 1200 m and those known include Petapa, Corona and Cabeza de loro.
It has been suggested that these two groups should be considered as different species, but their distinctive characteristics are within the normal varietal range in the cultivated species. Wild populations, such as the iguana mombin in Costa Rica. have very attractive, red or purple fruit. with yellow flesh similar to certain grapes, although it is acidic and astringent. There are other wild varieties in Central America, some with common names. Being a species in which crossings must be very difficult, neither varietal richness nor related species, such as the jobo (S. lutea), are of great use in genetic improvement.
On the other hand, the study and evaluation of clonal variation may offer new material. In this connection. regions of particular interest are: the Pacific area of Nicaragua which has been famous for its mombin or Spanish plum since the days of colonial settlement; Yucatán, where numerous varieties exist; and southwestern Mexico and the neighbouring region of Guatemala. There are no collections of germplasm, but they should not be difficult to establish and maintain. In addition to S. lutea, there are two cultivated species: ambarella, Jew's plum or golden or Otatheite apple (S. dulcis) from Polynesia, which is grown sporadically in tropical America; and imbu mombin (S. tuberosa) from the dry region of northwestern Brazil, whose fruits are of excellent quality. These three species are propagated by seed.
Being a vegetatively propagated species, the sowing material consists of straight cuttings, more than 6 cm thick and at least 1.5 m long, with horizontal cuts. They are cut at the start of leaf production which generally coincides with the beginning of the rains. The cuttings are kept in the shade for a couple of weeks and are planted 8 x 8 m apart at a depth of 30 cm. As a rule, the only cultivation practice is pruning of the branches to cause numerous shoots to form along the main branches. Pruning can be done every year, since the flowers bud on the current year's branches. The experience of producers in Mexico is that pruning increases the size and weight of the fruit.
In Oaxaca, there are commercial plantations on which the trees are pruned at a height of 2 m; the cuttings are planted in double, inclined rows, with 3 m between the pairs of rows; when pruned, they look like European apple orchards.
There are no serious pests apart from the Mediterranean fruit fly (Ceratitis capitata) and Mexican fruit fly (Anastrepha ludens) which cause serious damage.
Harvesting on the pruned trees is an easy operation, performed by shaking the branches with poles or sticks; the fruit is gathered from the ground. Throughout the region where mombin is produced, the green fruit is eaten a great deal, as is the green fruit of the ambarela (S. dulcis).
S. purpurea can be grown on marginal land of low agricultural value, on which the tree could be used for reforestation and produce extra profit for growers. Its production season is short, and late or early varieties that extend this period must be sought. Marketing, whether locally or in major towns, does not pose any major problems, as it is a widely accepted product.
The main limitation is attack from fruit flies, since control is expensive and beyond the range of small producers. An evaluation of cultivars that have some degree of resistance would be very advantageous, as would agronomic measures that tend to reduce infection by flies. Another theme to be investigated is the effect of defoliants on the acceleration of fruit formation.
So far, there has not been any industrialization of the fruit. Improving the primitive processes described earlier and research into others, as has been done in Florida with the artificial drying of slices of the flesh, may open up new possibilities for consumption.
Varieties of S. purpurea urgently need to be collected in one or more gene banks, which allow a quick evaluation of their genetic characteristics (resistance to insects, production period, response to pruning), and sowing material must be distributed among growers. In areas with sufficient space, it is recommended that S. purpurea be planted as a hedge, since its fruit production represents extra profit for the grower. Finally, transport and packaging problems must be studied to see how they can be Improved, since they are at a very primitive stage.