Capsicum (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Capsicum L.

Protologue: Sp. pl.: 188 (1753); Gen. pl. ed. 5: 86 (1754).

Family: Solanaceae

Chromosome number: x= 12; 2n= 24 (C. annuum, C. frutescens)

Major species and synonyms

• Capsicum annuum L., Sp. pl.: 188 (1753).

• Capsicum frutescens L., Sp. pl.: 189 (1753).

Vernacular names

• Capsicum pepper, chilli, bird pepper, bird's eye chilli (En)
• Hot pepper, chile, paprika, sweet pepper, bird pepper (Am)
• Piment, poivron (Fr)
• Indonesia: lombok, cabai, cabai keriting, cabai rawit, cabai besar
• Malaysia: cili, cili padi, cili api, cili sayur
• Papua New Guinea: kapsikam, lombo
• Philippines: sili, pasete
• Cambodia: mo-tééhs phlaôk, mo-tééhs khmeang
• Laos: ph'ik, phéd
• Thailand: phrik
• Vietnam: ớt.

Origin and geographic distribution

The genus Capsicum is of New World origin. It comprises 5 domesticated and about 25 wild species. Mexico is believed to be the centre of origin of C. annuum , whereas C. frutescens and the other cultivated species (C. baccatum L. var. pendulum (Willd.) Eshbaugh, C. chinense Jacq., and C. pubescens Ruiz & Pavón) originated in South America. Capsicum peppers were introduced to Asia in the 16th Century by Portuguese and Spanish explorers via trade routes from South America. Widespread geographic distribution of C. annuum and C. frutescens has occurred on all continents, whereas the others are little distributed outside South America. Capsicum peppers are cultivated throughout South-East Asia, the pungent forms having the greatest distribution and importance.

Uses

Capsicum pepper is the most popular and most widely used condiment all over the world. Its fruits are consumed in fresh, dried or processed form as table vegetable or spice. Capsicum peppers are extensively pickled in salt and vinegar. Colour and flavour extracts are used in both the food and feed industries, e.g. ginger beer, hot sauces and poultry feed, as well as for some pharmaceutical products. In the Philippines and Indonesia, the shoot tips are cooked and used as condiment or vegetable. Sweet, non-pungent capsicum peppers are widely used in the immature, green-mature or mature-mixed-colours stage as a vegetable, especially in the temperate zones.

Production and international trade

World production of capsicum peppers is estimated at 9.1 million t from 1.1 million ha. These figures, however, do not include production for home consumption and production for dried fruits, which constitute a significant part of the production in Asia. Regional statistics estimate production (fresh weight basis) for Asia alone at 8 million t from 1.6 million ha, with India, China, Indonesia and Korea having the largest areas in production. For South-East Asia the following statistics are available (1988-1992): Indonesia: 440 000 t from 137 000 ha; Malaysia: 21 000 t from 1685 ha; Philippines: 3625 t from 1450 ha; Thailand: 328 000 t from 121 000 ha. Although Thailand has been a major supplier of capsicum peppers in the region, its imports have exceeded exports in recent years. Malaysia exports a large volume of fresh peppers to Singapore, but imports dried peppers as well from India, China and Korea. Despite the large acreage grown in Indonesia, yields are low and small quantities must still be imported.

Properties

The pungent principles of capsicum peppers are capsaicinoids (alkaloids) and are found in variable quantities (0.01-1.0% of dry weight) in the cross-walls and placental tissue. Mature fruits are rich in pigments such as carotenoids and xanthophylls. Per 100 g edible fresh portion, hot capsicum pepper contains: moisture 86 g, protein 1.9 g, fat 1.9 g, carbohydrates 9.2 g, Fe 1.2 mg, Ca 14.4 mg, vitamin A 700-21 600 IU, vitamin C 242 mg. The energy value is 257 kJ/100 g. For sweet capsicum pepper: moisture 92 g, protein 1.2 g, fat 0.35 g, carbohydrates 5.4 g, Fe 0.6 mg, Ca 9.0 mg, vitamin A 420-5700 IU, vitamin C 163 mg. The energy value is 109 kJ/100 g. The 1000-seed weight is 4-8 g.

Description

C. annuum :

• a very variable, normally annual herb or subshrub, 0.5-1.5 m tall, erect, much branched, grown as an annual.
• Taproot strong, lateral roots numerous.
• Stem irregularly angular to subterete, up to 1 cm in diameter, much branched, often tomentose near branchings, green to brown-green, often with purplish spots near nodes.
• Leaves alternate, simple, very variable; petiole up to 10 cm long; leaf-blade ovate, up to 10(-16) cm × 5(-8) cm, acuminate at apex, margin usually entire, subglabrous, light to dark green.
• Flowers usually borne singly, terminal; pedicel up to 3 cm long in flower, up to 8 cm long in fruit; calyx cup-shaped, persistent and enlarging in fruit, usually with 5 conspicuous teeth; corolla campanulate to rotate with 5-7 lobes, 8-15 mm in diameter, usually white; stamens 5-7 with pale blue to purplish anthers; ovary 2(-4)-locular, style filiform, white or purplish, stigma capitate.
• Fruit a non-pulpy berry, very variable in size, shape, colour, and degree of pungency, usually more or less conical, up to 30 cm long, green, yellow, cream or purplish when immature, red, orange, yellow, brown when mature.
• Seed orbicular, flattened, 3-4.5 mm in diameter, ca. 1 mm thick, pale yellow.

C. frutescens :

• perennial subshrub, usually living 2-3 years.
• Structure similar to C. annuum but with usually 2 or more pedicels at a node and flowers with waxy greenish-white corolla.
• Fruit usually upright, usually small and narrow, up to 5 cm × 1 cm, extremely pungent, green to cream or yellow when immature, orange to red when mature.

Growth and development

Seeds germinate in 6-21 days after sowing and continuous flowering begins at 60-90 days after sowing. Flowers are open for 2-3 days. Although normally considered a self-pollinated crop, outcrossing up to 91% may occur, depending on bee activity and heterostyly. Under normal circumstances ca. 40-50% of the flowers set fruit. Fruits begin to mature at 4-5 weeks after flowering, and can be picked in sequences of 5-7 days. The peak harvest period is 4-7 months after sowing, but perennial growth continues in the absence of frost or disease.

Other botanical information

Although it is general practice to consider C. annuum and C. frutescens as two different species, many intermediate forms occur which are difficult to identify as one of the two. Therefore, sometimes both species are united into one species C. annuum s.l. In the literature, the rich variation of C. annuum s.s. has mainly been classified according to fruit shape, but there is no satisfactory cultivar group classification. Until a better system is proposed, it seems best to follow the system of Irish who distinguished seven botanical varieties, now often considered as cv. groups:

• cv. group Abbreviatum: fruits ovate, wrinkled, 2-5 cm long. Also called Wrinkled Pepper.

• cv. group Acuminatum: fruits slender, curved, up to 11 cm long, mild to extremely pungent. Also called Chilli.

• cv. group Cerasiforme: fruits globose with firm flesh, up to 2.5 cm in diameter, mild to pungent, red, yellow or purple. Also called Cherry Pepper or Bird's Eye Pepper.

• cv. group Conoides: fruits subconical, up to 3 cm long, very pungent. Also called Cone Pepper.

• cv. group Fasciculatum: fruits clustered, erect, up to 7.5 cm long, very pungent. Also called Cluster Pepper.

• cv. group Grossum: fruits large with basal depression, inflated, red, orange, yellow, or purple, flesh thick and mild. Also called Sweet Pepper or Paprika.

• cv. group Longum: fruits drooping, up to 30 cm long, mild or pungent, red, yellow or whitish. Also called Long Pepper.

Some well-known C. annuum cultivars in Indonesia are "Jatilaba", "Tit", "Super", "Paris" and "Tampar". Within C. frutescens all cultivars are extremely pungent and no cv. groups are distinguished. It also comprises Bird Peppers or Bird's Eye Peppers. Some Indonesian cultivars are "Jempling", "Jemprit", and "Mentek" and "Rawit". Farmers use different cultivars for low and high elevations.

Common cultivars of the Acuminatum group in Malaysia are "Kulai", "Langkap", "Bukir Gambit", "Tanjung Minyak", "MC4" and "MC5". The bird's eye chillies are commonly referred to as "Cili Padi" and "Cili Burung". Bird's eye chillies are the most popular types grown in Papua New Guinea. In Thailand, common cultivars of the Acuminatum group are "Bang Chang", "Yuak" (waxy yellow-green), "Luang" (orange-mature), "Mun", "Chee Fah" and "San Pa Thong" to name a few. "KKU Cluster" and "Chau Mankau" belong to the Fasciculatum cultivar group. "Huay Sithon" is a very popular cultivar in the Conoides group with fruits up to 5 cm. In the Philippines, sweet capsicum peppers are more commonly grown than pungent capsicum peppers. Besides some imported cultivars like "California Wonder" and "Yolo Wonder" the few local sweet capsicum cultivars are "All Season", "Sinagtala" and the hybrid "Annabelle". Local cultivars of pungent capsicums are "Matikas", "Kawit", "Bontoc" and "Hot Shot". A cultivar of the small pungent Conoides group is "Pacete".

Ecology

Capsicum peppers are considered to be warm season, day-neutral plants, although certain forms may show a photoperiodic reaction. The vegetative cycle may be hastened by imposing certain photoperiods, but reports in the literature are conflicting. Capsicum peppers tend to tolerate shade conditions up to 45% of prevailing solar radiation, although shade may delay flowering. Capsicum peppers grow best on well-drained loamy soils at pH 5.5-6.8. They grow at a wide range of altitudes, with rainfall between 600-1250 mm. Severe flooding or drought is injurious to most cultivars. Seeds germinate best at 25-30 °C. Optimal temperatures for productivity are between 18-30 °C. Cooler night temperatures down to 15 °C favour fruit setting, although flowering will be delayed as temperatures drop below 25 °C. Flower buds will usually abort rather than develop to maturity if night temperatures reach 30 °C. Pollen viability is significantly reduced at temperatures above 30 °C and below 15 °C.

Propagation and planting

Capsicum peppers are propagated by seed. Seeds should be harvested from mature fresh fruits after 2 weeks of post-harvest ripening. Seeds remain viable for 2-3 years without special conservation methods if kept dry, but they rapidly lose viability if improperly stored at high temperature or humidity. Seed dormancy may occur to a limited extent, especially if seed is harvested from under-ripe fruits. Seed priming treatments are sometimes effective in invigorating germination. To plant 1 ha, 200-800 g of seed is needed depending on plant density. In Asia seeds are usually sown shallow in nursery beds or flats, and transplanted bare-rooted to the field. Seed-beds are usually covered with straw, leaves or protective tunnels. For better production, seedlings should be transferred to seedling pots (plastic pots, paper cups, banana leaf-rolls, etc.) when the cotyledons are fully expanded. In the nursery, starter fertilizer is recommended at 2-week intervals. Transplants are planted out in the field at the 8-10 true leaf stage, usually 30-40 days after sowing. Hardy transplants can be produced by restricting water and removing shade protection, starting 4-7 days before transplanting. Transplanting should be done during cloudy days or in the late afternoon, and should be followed immediately by irrigation. Direct sowing in the field is practised to a limited extent. Plant populations may range from 10 000-130 000 plants per ha, depending on the region, management practices, and cultivar. Capsicum peppers are well adapted to sole cropping and intercropping systems. In Asia, production is usually practised on small-scale farms on plots of 0.1-0.5 ha, although total acreage may be substantial. Capsicum peppers are often relay-cropped with tomatoes, shallots, onions, garlic, okra, Brassica spp. and pulses. They also grow well among newly established perennial crops.

Husbandry

Capsicum peppers thrive best if supplied with liberal quantities of organic matter and a balance of mineral fertilizers. A reasonable recommendation is to supply 10-20 t/ha of organic amendments. General nutrient requirements are 130 kg/ha of N, 80 kg/ha of P and 110 kg/ha of K, split into basal plus side dressings at 3-4-week intervals, beginning at first flowering. Boron at the rate of 10 kg/ha is also recommended. Nutrient availability is subject to soil type and environmental conditions, so local recommendations vary. In Asia, manual weeding is the common practice for weed control. It is most critical at the reproductive phase. Organic or plastic mulches are very effective for weed control, and reflective mulches help to minimize insect vectors of plant viruses. Staking is not a common practice in most of Asia, but may help to minimize lodging. Capsicum peppers may be grown under rainfed or irrigated conditions. To avoid certain diseases, pests or allelopathic damage, capsicum peppers should not be planted after other solanaceous crops, sweet potato or jute.

Diseases and pests

Viruses cause the most serious damage. The most obvious method of control is to use resistant cultivars. Unfortunately only few cultivars with virus resistances are known. Cucumber mosaic virus (CMV), chilli veinal mottle virus (CVMV), potato virus Y (PVY) and a complex of the tobamovirus group are the most important in Asia. Anthracnose caused by Colletotrichum spp. is a major problem of ripened fruits and is best controlled by proper crop management to minimize the source of inoculum via seeds or host debris. Partial resistance has been found. Phytophthora blight and crown rot (P. capsici), Cercospora leaf-spot (C. capsici), bacterial spot (Xanthomonas campestris pv. vesicatoria) and bacterial wilt (Pseudomonas solanacearum) are other important diseases and are best controlled by integrated pest management, including resistant cultivars that may be available. The major pests are thrips, aphids, mites, bollworms (Heliothis spp.), and fruit flies (Dacus spp.). As most of these are polyphagous pests, control is difficult. Resistances are not yet available, but field tolerance is observed in some cultivars and landraces. Inappropriate pesticides and over-use of pesticides often augment the pest problems on capsicum peppers. Integrated crop management is suggested to overcome multiple pest and disease problems.

Harvesting

Capsicum peppers are ready for harvest 3-6 weeks after flowering depending on the fruit maturity desired. Green fruits are mature when firm; if gently squeezed they make a characteristic popping sound. Harvesting is done by hand or with the aid of a small knife. Sweet capsicum peppers are often harvested at the green mature stage, although sometimes they are harvested red. Assorted fruit colours such as yellow, orange, chocolate and purple are also available in specialized markets. Hot capsicum peppers are harvested green or red depending on their utilization. For the fresh market, fruits are harvested mature but firm, whereas capsicum peppers sold as dried pods may be left to partially dry on the plants before harvesting.

Yield

Capsicum pepper yields vary widely from 1.5-18 t/ha, particularly in Asia. Maximum dry weight recovery of hot capsicum peppers is near 25-30%. Yields under irrigated conditions tend to be higher than for rainfed production, but vary with other management practices.

Handling after harvest

Unless sold for the fresh market, hot capsicum peppers are sun-dried in most of Asia. Sun-drying usually takes place in a vacant field or roadside, on mats or a well-swept area. In the sun, capsicum peppers will dry adequately in 10-20 days, with frequent turning of fruits. Steaming of hot capsicum pepper before being sun-dried is normally practised in southern Thailand. It tends to improve the appearance, making dried fruits look glossy. Marketing is usually conducted from wholesale to retail markets, but there are also many informal marketing channels. Dried capsicum peppers may be stored for months in wholesale warehouses to supply year-round demands. Fresh fruits can be stored for up to 5 weeks at 4 °C and 95% humidity.

Genetic resources

There are a number of working collections of Capsicum germplasm. The largest is at the Asian Vegetable Research and Development Center in Taiwan, which was targeted as a global back-up for other base and working collections. Near major production areas and centres of genetic diversity, many regional collections exist. A fine collection of wild species is maintained at the Universidade Federal in Viçosa, Brazil.

Breeding

Breeding for disease resistance takes precedence in most programmes, although yield, abiotic stress tolerance, earliness and quality in pungency, flavour and colour are overall objectives for capsicum pepper improvement in the tropics. The cultivars in Asia are mostly open-pollinated and farmers tend to save and plant their own seed. National programmes and private seed companies play a role in supplying quality seed stocks and improved cultivars. There is some interest in the promotion of hybrid cultivars, produced by hand emasculation and pollination or through the use of male sterility.

Prospects

Capsicum peppers have a high nutritional and economic value and are adapted to an array of production and marketing systems. Production can only be promoted if seed quality and supply are guaranteed. Efforts to improve seed production, storage and distribution systems will strongly influence the adoption of suitable cultivars.

Literature

• Abd. Jabar, K., Othman Y. & Paramanathan, S., 1984. Fertilizer requirement of chilli. In: Mohammad Md. Ali & Lim Eng Siong (Editors). Proceedings of the symposium on vegetables and ornamentals in the tropics, October 27-28, 1982. Agricultural University of Malaysia, Serdang, Selangor, Malaysia. pp. 85-88.
• Andrews, J., 1984. Peppers: the domesticated Capsicums. University of Texas Press, Austin, Texas, United States. 170 pp.
• AVRDC, 1989. Tomato and pepper production in the tropics. Proceedings of the international symposium on integrated management practices, March 21-26, 1988. Asian Vegetable Research and Development Center (AVRDC), Shanhua, Tainan, Taiwan. 619 pp.
• Bosland, P.W., Bailey, A.L. & Inglesias-Olivas, J., 1990. Capsicum pepper varieties and classification. New Mexico State University Cooperative Extension Service Circular 530, College of Agriculture and Home Economics, Albuquerque, United States. 13 pp.
• IBPGR, 1983. Genetic resources of Capsicum. International Board for Plant Genetic Resources (IBPGR), Rome, Italy. 49 pp.
• Irish, H.C., 1898. A revision of the genus Capsicum with special reference to the garden varieties. Annual Report of the Missouri Botanical Garden 9: 53-110.
• Martin, F.W., Santiago, J. & Cook, A.A., 1979. Vegetables for the hot, humid tropics. Part 7. The peppers, Capsicum species. Agricultural Research Science and Education Administration. United Sates Department of Agriculture, New Orleans, United States. 18 pp.
• Rylski, I., 1985. Capsicum. In: Halevy, A.H. (Editor): Handbook of flowering. Vol II. CRC Press, Boca Raton, Florida, United States. pp. 140-146.

Authors

• J.M. Poulos