1487

2: Edible fruits and nuts

Chrysophyllum cainito L.

Sp. Pl.: 192 (1753).

SAPOTACEAE

2n = 26

Caimito, starapple (En). Caimite, pomme surette (Fr). Indonesia: sawo ijo (Java), sawo hejo (Sunda), sawo kadu (Bantam). Malaysia: sawu duren, pepulut. Philippines: caimito. Singapore: chicle durian. Thailand: sataa appoen (Bangkok).

Caimito is indigenous to the West Indies, spread early over tropical America and now it is cultivated throughout the tropics. In South-East Asia it is most frequent in the Philippines, Thailand and southern Indo-China.

Caimito fruit is usually consumed fresh and may also be used as an ingredient of ice cream and sherbet. The bark, latex, fruit and seeds possess medicinal properties. The reddish-brown wood is suitable for construction purposes, and the mature branches are used as a medium to grow orchids. The tree is much appreciated as an ornamental.

Caimito is grown mostly as a backyard tree or as a component of mixed orchards. The Philippines had a total area of 7600 ha in 1987 and the production was 25 389 t.

Caimito fruit has 53—63% edible portion, the tough rind being inedible, and contains per 100 g edible portion: water 80.5—82.6 g, protein 0.7—1.3 g, fat 0.6—1.1 g, carbohydrates 15.3—17.4 g, fibre trace—0.7 g, ash 0.2—0.3 g, calcium 14—17 mg, phosphorus 9—13 mg, iron 0.2—0.4 mg, vitamin A trace — 10 IU, thiamine 0.01—0.02 mg, riboflavin 0.01—0.02 mg, niacin 0.8—0.9 mg, and vitamin C 6—7 mg. The energy value is 280—300 kJ per 100 g. Analyses in Central America show appreciably higher maximum values for all constituents except water, fat and carbohydrates.

An evergreen tree, conforming to Troll's architectural model, up to 30 m tall, with white gummy latex. Branchlets numerous, plagiotropic, brown hairy, glabrescent; the upright basal parts of successive leading branches align to form the trunk. Leaves alternate, spreading, oblong to obovate, 5—16 cm x 3—6 cm, leathery, reddish ferruginous-sericeous on both sides, quickly glabrescent above, almost parallel secondary nerves very characteristic; petioles 0.6—1.7 cm long. Inflorescences axillary on current season's shoots, with 5—35 clustered, small, yellowish to purplish-white flowers; sepals 5, circular to ovate; corolla tubular, ca. 4 mm long, lobes 5, ovate; stamens 5; stigma 7—11-lobed. Fruit an obovoid-globose berry, 5—10 cm in diameter, purplish-brown or yellowish-green; skin thin, glossy, glabrous, leathery; flesh purple or white, 3—12 mm thick, soft and juicy, surrounding the 4—11-celled endocarp, which is star-like when cut transversely. Seeds 3—10, flattened obovoid, about 2 cm x 1 cm x 0.5 cm, purplish-black, with chartaceous testa and a large lighter-coloured hilum.

Seeds germinate 14—40 days after sowing. Seedlings grow rapidly and usually reach bearing age 5—6 years after planting; asexually propagated trees bear fruit much earlier. The flowers are pollinated by insects and are usually self-fertile. Flowering is associated with the main shoot growth period, normally in the rainy season. Fruit ripens 4—5 months later (from late December to March or April in the Philippines, May—July in Indonesia).

The large genus Chrysophyllum L. is mainly native to tropical America, with only about 6 native South-East Asian species. Chrysophyllum oliviforme L. (Philippines: caimitillo) from tropical America has also been introduced in South-East Asia, but it is not as popular as Chrysophyllum cainito. The fruit is black, about 2 cm x 1 cm, with one large seed.
In Chrysophyllum cainito there is a clear distinction between trees with purplish and those with greenish fruits. Considerable diversity in green-fruited forms is found in Guatemala. A few cultivars have been named, including 'Grimal', 'Haitian', 'New Combe' and 'Weeping' introduced to Florida and Queensland; and 'Lunti' and 'Lila', both in the Philippines.

Caimito grows successfully on almost all types of soil and in a range of climates. Throughout South-East Asia it thrives in the lowlands (up to 400 m elevation) and in areas with a distinct dry season. In those parts of the Philippines where the dry season is most pronounced, undue loss of leaves and less juicy or even shrivelled fruit indicate that drought is too severe and irrigation is needed. Fertile, well-drained and slightly acidic soils are preferred.

Caimito may be propagated by seed and by marcotting, inarching, grafting and budding. Seeds from ripe fruit are sown 1 cm deep and 2—3 cm apart in seed boxes or seed-beds and watered regularly. When 3—5 mature leaves have developed, the seedlings are potted. The plants are watered regularly and provided with partial shade. They may be used as rootstocks after 6—8 months.
Asexual propagation is recommended to multiply outstanding trees. Cleft grafting is the most common propagation method and gives a high percentage take. Chrysophyllum oliviforme is a compatible rootstock, but most grafts are made on caimito seedlings. In the field, plants are set 10—12 m apart. Planting is done best at the onset of the rainy season.

Regular ring weeding and irrigation during prolonged rainless periods ensures uninterrupted growth of plants. Fertilizer is applied at the rate of 150—200 g of ammonium sulphate per tree twice a year for non-bearing trees. At the start of fruiting, 500 g of complete fertilizer is applied twice a year. Full-grown trees may require 3 kg or more of complete fertilizer per year. The fertilizer is applied at the onset and towards the end of the rainy season in a ring or in shallow holes beneath the tree canopy. Trees are pruned to a desirable shape by allowing only 2—3 branches to develop and by removal of sagging and interlacing branches and watershoots.

The fungus Lasiodiplodia theobromae causes dry, sooty rot on fruits. This can be controlled by copper fungicides.
In Queensland Fusarium solani kills young trees and affects limbs of older trees. The insect pests that attack caimito include twig borers, carpenter moth, mealy bugs, scales and fruit flies. The oriental fruit fly Dacus dorsalis is a serious pest of ripening fruit and renders the fruit unfit for human consumption. The damage may be reduced by wrapping young fruits and collecting and destroying the infested fruits. Birds, bats and wild cats can also cause considerable damage to ripe fruits.

Fruits should be picked when fully ripe: shiny light green or yellowish-brown skin for the green form and pale to dark purple for the purple form. Harvesting is selective because fruits on a tree do not ripen at the same time. Fruits are harvested by cutting the stalk with a pair of clippers or by using a long bamboo pole with a net.

Fully mature trees may produce as many as 1000 fruits or more per season. However, there is much variation in fruitfulness.

The protruding stalk is clipped off and the unblemished fruit is packed in bamboo baskets lined with banana leaves and delivered immediately to the market. Ripe fruit keeps only for a few days, but the fruit may be stored for a few weeks under refrigeration at 3—6°C and 90% humidity.

Preliminary evaluation of seedling trees showed a wide variability in yield and size, shape, colour, quality and period of maturity of the fruit.

Breeding work should focus on the following fruit characteristics: round shape, weight 200—300 g, medium thick skin, few or no seeds, sweet and juicy and resistant to fruit borer and fruit fly infestation. The tree should be a prolific and regular bearer.

In South-East Asia caimito will remain a characteristic garden tree for the relatively dry lowland areas. Cultivars that are so prolific that fruiting controls tree size, or that have a specific reputation in the market, might be grown commercially in orchards. Current selections still have to prove that they can meet these requirements.

Galang, F.G., 1955. Fruit and nut growing in the Philippines. AIA Printing Press, Malabon, Rizal, the Philippines. pp. 392—393.
Hensleigh, T.E. & Holaway, B.K. (Editors), 1988. Agroforestry species for the Philippines. AIA Printers, Malabon, Metro Manila, the Philippines. pp. 104—106.
Honrade, M.L., 1972. Caimito (Chrysophyllum cainito L., Sapotaceae). In: Cultural directions for Philippine agricultural crops. Vol. 1 (Fruits). Public Affairs Office Press. Bureau of Plant Industry, Manila, the Philippines. pp. 63—67.
Marshall, J.R., 1986. Star apple. Fact Sheet No 6, Rare Fruit Council of Australia, Cairns.
Morton, J.F., 1987. Fruits of warm climates. Creative Resources Systems, Winterville, N.C. pp. 408—410.
Sastrapradja, S., Sutisna, U., Panggabean, G., Mogea, J.P., Sukardjo, S. & Sunarto, A.T., 1980. Fruits. Projek Penelitian Potensi Sumber Daya Ekonomi - LIPI Publication Series No SDE-41. pp. 36—37.

F.S. dela Cruz, Jr.

dela Cruz, Jr, F.S., 1991. Chrysophyllum cainito L.. In: Verheij, E.W.M. and Coronel, R.E. (Editors): Plant Resources of South-East Asia No 2: Edible fruits and nuts. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea