Lagenaria siceraria (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Lagenaria siceraria (Molina) Standley

Protologue: Publ. Field Mus. Nat. Hist. Chicago, Bot. Ser. 3: 435 (1930).

Family: Cucurbitaceae

Chromosome number: 2n= 22

Synonyms

• Cucurbita lagenaria L. (1753),
• Lagenaria vulgaris Seringe (1825),
• L. leucantha Rusby (1896).

Vernacular names

• Bottle gourd, calabash gourd, white-flowered gourd (En)
• Calebasse, courge bouteille (Fr)
• Indonesia: labu air, labu putih, kukuk (West Java)
• Malaysia: labu botol
• Papua New Guinea: sel kambang, botol wara
• Philippines: upo (Tagalog), tabungaw (Ilocano), kalubay (Bisaya)
• Cambodia: khlôôk
• Laos: namz taux
• Thailand: namtao (central), manamtao (northern), khi-luu-saa (Karen)
• Vietnam: bâù.

Origin and geographic distribution

Bottle gourd probably originated in tropical Africa and now has pantropical distribution. It could have been spread by ocean currents to the shores of the New World. More than 10 000 year-old archeological records of its association with man exist in both hemispheres. It is the only crop known to have been cultivated in pre-Columbian times in both the Old and the New World.

Uses

The young fruits of selected cultivars are used as a vegetable, usually boiled, fried or in stews. Cultivars differ markedly in sweetness or bitterness. Carefully selected cultivars are comparable to the popular summer squashes of temperate regions. Young shoots are frequently consumed as a green. Bottle gourd seeds are a popular snack food; oil from the seeds has been used to some extent in Africa. The green fruit, made into syrup, is employed medicinally as a pectoral against chest pains. The hard shells of dried mature fruits are used for containers, hats, decorative handicrafts, floats and musical instruments. In the central highlands of New Guinea, fruits of the elongated type are used as "holim" or penis sheath.

Cultivars with known resistance to soilborne diseases and tolerance to stress environments are used as rootstocks for grafting melon, watermelon and cucumber in Japan and China.

Production and international trade

In most places, cultivation and utilization of bottle gourd is still a small-scale undertaking for home consumption and local markets. Economic data are scarce. In the Philippines, the average annual production is about 20 000 t from 2500 ha. Cultivated area in Indonesia is also about 2500 ha.

Properties

The edible portion of immature fruits of bottle gourd is about 84%. Per 100 g edible portion, they contain: water 95 g, protein 0.5 g, fat 0.1 g, carbohydrates 3.5 g, vitamin A 10 IU, vitamin B₁ 0.04 mg, vitamin B₂ 0.02 mg, niacin 0.4 mg, vitamin C 11 mg, Ca 16 mg, Fe 0.4 mg, P 14 mg. The energy value is about 63 kJ/100 g. The seeds contain 45% oil. The weight of 1000 seeds averages 150 g.

Description

• Monoecious annual vine with a long ribbed stem and strong tendrils.
• Tendrils usually bifid with one long and one shorter branch; petioles up to 20 cm long; leaves simple, alternate, ovate-reniform or suborbicular, up to 30 cm in diameter, undivided or obscurely 5-9-lobed, dentate, pubescent, musky-scented.
• Flowers axillary, solitary, white, up to 12 cm in diameter; calyx campanulate, 5-lobed; petals 5, free; male flowers on long pedicels, 5-25 cm long; stamens with 3 free filaments, anthers lightly cohering, but not connate; female flowers on short pedicels, 2-7 cm long; ovary with 3 placentae and numerous ovules, completely clothed with white gland-tipped hairs, stigmas 3, thick, bilobed.
• Fruit a pepo, very variable in size and shape, often globular, bottle- or club-shaped, up to 1 m or more long, with hard durable rind; flesh white and soft.
• Seed corky, broad and flat, or narrow and two-pronged, 10-25 mm long, whitish or brownish.

Growth and development

Emergence takes 5-7 days from sowing. The vining stage starts 14 days after emergence and is characterized by rapid vine elongation. It occurs simultaneously with the growth of tendrils and lateral stems. Growth slows down at the onset of flowering which starts 55-65 days after sowing and continues throughout the cropping period of 6-7 months. A number of male flowers are produced before the female flowers appear. The ratio of female to male flowers is higher under cool temperatures and can be increased with growth-regulating substances (e.g. maleic hydrazide). The number of female flowers is greatly reduced if the number of maturing fruits per plant exceeds 2 to 3. Continuous picking of young fruits prolongs crop duration. Flowers open in the late afternoon and are pollinated by insects, mainly bees. Pollen is usually abundant. The stigmas are receptive from 6 hours before to 36 hours after anthesis. For seed production, the fruits need 2-3 months to mature.

Other botanical information

The existence of two subspecies of L. siceraria, one domesticated in Asia (ssp. asiatica (Kob.) Heiser) and the other in both Africa and the New World (ssp. siceraria), has been confirmed but seed trade has obscured the subspecific distinction.

Improved cultivars are available from seed companies and research institutions in the Philippines, Thailand, India, Japan and Taiwan. In the Philippines two types are used: light green, and dark green with light green spots. In Japan, bottle gourd cultivars are classified into two groups based on the usage. The "yugao" group is for vegetable use and is characterized by elongated fruits (90-100 cm long, 12-25 cm wide). The "hyotan" group is used for making containers and decorations.

Ecology

Bottle gourd can be grown year-round from sea-level up to 1600 m altitude, but the vegetable types are most common in the hot and humid lowlands. It tolerates cool but frost-free temperatures. Short days promote flower formation but have no effect on sex expression. Soils should be light and well-drained, with pH 6-7.

Propagation and planting

Bottle gourd is usually direct-seeded. Transplanting can be done if the amount of seed is limited. Before planting, seeds may be soaked in water overnight to achieve fast and uniform emergence. During the wet season, the seeds are planted on mounds, whereas during the dry season they are planted in depressions made during land preparation. 2-3 seeds are sown per hill. Weak or diseased seedlings are thinned out 3-4 weeks after emergence and one plant retained per hill. When trailing over the ground, plants should be spaced about 1 m in the row and 2 m between the rows (5000 plants/ha). When staked the density may be increased to 10 000 plants/ha. Application of fully decomposed manure or compost is beneficial and these should be incorporated into the soil during land preparation.

Husbandry

Bottle gourd is sensitive to excessive soil moisture which favours disease infection, in particular stem rot. Furrow irrigation is preferable and is generally done at weekly intervals during the driest part of the year. During the wet season adequate drainage should be provided. Bottle gourd is shallow-rooted with an extensive lateral root system. Cultivation must be minimized during the fruiting stage. Manual weeding near the base of the plants is recommended. The rate of fertilizer application depends on soil factors and weather, but 40-60 kg/ha N, 40-60 kg/ha P and 60-80 kg/ha K can be taken as a general guideline.

To check growth, growing points are often nipped out. Assisted pollination is sometimes practised. For better fruit quality, bottle gourd is best grown on trellises. The fruits can hang straight, and the natural forms of the fruits can be further varied by artificially restricting growth with bands. When trailing over the ground, it is advisable to spread dry straw or grass on the ground to keep the developing fruits from contact with wet soil.

Diseases and pests

In the hot humid tropics, diseases are the major constraint. They are more destructive to bottle gourd than insect pests. Among the major diseases are anthracnose (Colletotrichum lagenarium) during the wet months, and powdery mildew (Erysiphe cichoracearum and Sphaerotheca fuliginea) during the dry season. An unknown virus and Sclerotium basal stem rot also attack the crop. Sanitation (removal of infected leaves) and good cultural management are recommended to prevent disease build-up.

Fruit flies (Dacus spp.) and leaf folders, which can damage the fruit skin, are the most important insect pests.

Harvesting

Fruits develop fast and require much attention at harvest time. For use as a vegetable it is difficult to specify the harvest stage, as young fruits of all ages are edible, including the ovary of the flower. Maximum yield, however, is obtained by harvesting the fruits as late as possible, when they are up to half of the mature size. The number of pickings per crop varies but may be as many as 20. The fruits are best harvested with a sharp knife, leaving about 5 cm of the fruit stalk attached to the fruit.

For use as containers, bottle gourds are permitted to mature on the vine. Seeds and pulp are scooped out and the rind is carefully dried.

Yield

Under optimum conditions, crop yields of 40-60 t/ha can be realized. A yield level of 20-30 t/ha is considered good.

Handling after harvest

Sorting is done after harvest to remove undesirable and abnormal fruits. Sorted fruits are packed in crates or bamboo baskets, lined with newspapers or banana leaves for transport to the market. Young fruits can be used up to 2 weeks after harvest. Longer storage causes rapid loss of water and hardening of the skin.

Genetic resources

Sizeable germplasm collections of L. siceraria are maintained by the Institute of Plant Breeding at Los Baños (the Philippines), the Vavilov Institute of Plant Industry in St. Petersburg (Russia), the Southern Regional Plant Introduction Station in Georgia (United States), Cornell University in Geneva, New York (United States), and the USDA Research Station in Salinas, California (United States). Smaller collections are available at institutions in India, Taiwan, Ghana, Hungary and Guatemala.

Besides the bottle gourd, the genus Lagenaria Seringe comprises five wild perennial dioecious species occurring in Africa and Madagascar.

Breeding

Populations of bottle gourd are heterozygous with considerable variation. In the Philippines, both open-pollinated cultivars and F₁ hybrids are being developed. The existence of hybrid vigour and its exploitation are well-documented. Main breeding objectives are high yield, resistance to diseases and pests, and tolerance to environmental stress. The possibility to transfer desirable traits from the wild to the cultivated species is still under investigation.

Prospects

Bottle gourd is expected to remain a popular vegetable. Also its popularity as producer of calabashes seems lasting. This usage can be combined with the harvest of the seeds as a source of protein and oil. Breeding work is expected to lead to hybrids with the possibility of built-in disease resistances.

Literature

• Esquinas-Alcazar, J.T. & Gulick, P.J., 1983. Genetic resources of Cucurbitaceae. International Board of Plant Genetic Resources (IBPGR), Rome, Italy. 101 pp.
• Herklots, G.A.C., 1972. Vegetables in South-East Asia. George Allen & Unwin, London, United Kingdom. pp. 321-326.
• Jeffrey, C., 1980. A review of the Cucurbitaceae. Botanical Journal of the Linnean Society 81: 233-247.
• Martin, F.W., 1979. Vegetables for the hot, humid tropics. Part 4. Sponge and bottle gourds, Luffa and Lagenaria. Science and Education Administration, United States Department of Agriculture, New Orleans, United States. 19 pp.
• Richardson, J.B., 1972. The pre-Columbian distribution of the bottle gourd (Lagenaria siceraria): a re-evaluation. Economic Botany 26: 265-273.
• Tisbe, V.O., Deanon Jr, J.R. & Bantoc Jr, G.B., 1967. The cucurbits. In: Knott, J.E. & Deanon Jr, J.R. (Editors): Vegetable production in South-East Asia. University of the Philippines Press, Los Baños, the Philippines. pp. 138-166.

Authors

• E.A. Widjaja & M.E.C. Reyes