Solanum melongena L.

Kew Species Profiles

General Description

Solanum melongena, commonly known as eggplant or aubergine, belongs in the plant family Solanaceae, which also houses tomato, potato, nicotine and the poisonous deadly nightshade plant. The Latin name 'melongena' has its roots in the Italian name 'melanzane', which derives from 'mela insane' meaning 'mad apple'. First domesticated in India, aubergine is now cultivated worldwide and is a popular ingredient in many traditional recipes. 

Species Profile

Geography and distribution

Semi-wild Solanum melongena can be found growing today in the Myanmar-Yunnan region where it was originally domesticated from its wild ancestor Solanum insanum . The area between India, Myanmar and China is where domestication first took place although today there are many more closely-related wild relatives in Africa than in Asia.

Evidence of the cultivation and use of Solanum melongena appeared in Sanskrit and Chinese agro-botanical literature dating back 2,000 years. The Muslim expansion in the 8th century AD was responsible for the spread of aubergine through Africa and Europe. Today, the main production regions of eggplant are Asia and the Mediterranean. 

Description

Overview: Solanum melongena is a much-branched shrub up to 2 metres tall with a long taproot which extends deep into the ground. 

Leaves: The stems and leaves are densely covered with star-shaped (stellate) hairs and sometimes prickles. The leaves are arranged alternately along the stem, each with a petiole (appendage which connects the blade to the stem) 6-10 cm long. The leaves are 3-25 x 2-15 cm with hairy margins.

Flowers:  Hermaphrodite flowers are usually solitary and are supported by a 1-3 cm long pedicel (stalk which subtends the flower). Smaller, functionally male flowers appear on the same inflorescence. The hermaphrodite flowers are 3-4 cm in diameter and are mostly violet and very rarely white. The anthers are supported by short, thick filaments and have openings at their tips. The ovary (female reproductive organ) is positioned above the sepals, petals and stamens. 

Fruit:  A globose to oblong fleshy berry, 2-35 cm (sometimes longer) and 2-20 cm broad. The fruit is generally smooth and shiny and has many seeds. When produced commercially, the colour ranges from white, green or from purple to black. The seeds are 3 x 4 mm and are kidney or lentil shaped and pale brown in colour. 

Uses

Eggplant is widely grown for its attractive fruits which are an accompaniment to many dishes around the world. The fruit is eaten in its immature state, when glossy and colourful. When mature the flesh becomes bitter and stringy and the seeds are hard. Although the fruits of some cultivars are eaten raw (such as in southeast Asia) the fullness of the flavour comes out when cooked and is comparable to that of mushrooms. Aubergine flesh has a delicate texture and is commonly grilled, fried, steamed, roasted, stewed with other vegetables or prepared with meat or fish.

In southern India, eggplant is crowned 'king of the vegetables' and is an important ingredient in curries, sambhars and chutneys. In Italy, eggplant is marinated in olive oil, seasoned with salt and garlic and served as an antipasto. In Greece, eggplant is used to prepare mousaka and in France it is a key ingredient in ratatouille.

Besides its value as a food crop, eggplant is widely used for medicinal purposes. The plant is used in decoction as powder or ash for curing diabetes, cholera, bronchitis, dysuria, dysentery, otitis, toothache, skin infections, asthenia and haemorrhoids and is also ascribed narcotic, anti-asthmatic and anti-rheumatic properties. In several countries it is imbued with magical qualities and is a symbol of protection, good health and female fertility. 

Crop wild relatives of aubergine

The Millennium Seed Bank and the Global Crop Diversity Trust are engaged in a ten-year project, called 'Adapting Agriculture to Climate Change'. The project aims to protect, collect and prepare the wild relatives of 29 key food crops, including aubergine, so that they are available to pre-breeders for the development of new varieties that are more resilient to the effects of climate change.

Solanum ruvu and the need for crop wild relatives

Solanum ruvu  is a wild relative of aubergine now thought to be extinct in the wild. This rare, African spiny aubergine was collected once as part of a general survey in 2000. Unfortunately, by the time it was identified as a new species by Kew botanist Maria Vorontsova in 2010, its native habitat had been destroyed. Attempts to recollect it were made in 2010 but the plant could not be found and is now considered to be extinct.

Many other crop wild relatives are listed as threatened species and are in need of conservation. Threats include habitat degradation, soil erosion and climate change to name a few. Crop wild relatives serve as a genetic back up. Rising global temperatures, changes in rainfall and weather patterns resulting from climate change indicate decreases in the yield of crops and greater susceptibility to pests and diseases. Through introducing crop wild relatives into traditional breeding programs we are able to harness their genetic potential and cultivate a more resilient crop that will feed rising human populations.

The tragedy of  Solanum ruvu illustrates the urgent need we have to collect and protect crop wild relatives before they become extinct and the genetic diversity they hold is lost to us forever.

Millennium Seed Bank: Seed storage

The  Millennium Seed Bank Partnership aims to save plants worldwide, focusing on those plants which are under threat and those which are of most use in the future. Once seeds have been collected they are dried, packaged and stored at -20°C in Kew's Millennium Seed Bank vault.

Description of seeds: Average weight of 1,000 seeds = 3.6g

Number of seed collections stored in the Millennium Seed Bank: One

Seed storage behaviour: Orthodox (the seeds of this plant can be dried to low moisture contents without significantly reducing their viability. This means they are suitable for long-term frozen storage such as at the MSB)

Germination testing: Successful

This species at Kew

Pressed and dried specimens of aubergine are held in Kew's Herbarium, where they are available to researchers by appointment. Details and images of some of these specimens can be seen online in Kew's Herbarium Catalogue.

Distribution

China, India, Myanmar

Ecology

Grows best in warm, light conditions with plenty of water.

Conservation

Widespread in cultivation.

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Distribution

Cultivada en Colombia; Alt. 1500 m.; Andes.

Morphology General Habit

Hierba, trepadora

Bernal, R., G. Galeano, A. Rodríguez, H. Sarmiento y M. Gutiérrez. 2017. Nombres Comunes de las Plantas de Colombia. http://www.biovirtual.unal.edu.co/nombrescomunes/

Vernacular

berenjena, berenjena de monte, manzana de amor, pepino morado, ponedora

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Herb or shrub up to c. 1 m high, in cultivation usually unarmed (wild plants may be prickly), but occasionally with scattered prickles, floccose-pubescent with stellate hairs, especially on younger parts

Morphology Leaves

Leaves alternate, all of approximately the same size, only decreasing in size near the top; petiole 2–5 cm long; blade elliptic to ovate, 14–18 x 3–11 cm, base truncate to subcordate, often obliquely so, margin ± deeply lobed, softly stellate-pubescent on both sides, but mostly beneath, occasionally with prickles along the midrib

Morphology Reproductive morphology Inflorescences

Inflorescence lateral, raceme-like, few-flowered, or flowers solitary; the basal flower bisexual and much larger than the functionally male flowers; peduncle obsolete, the first flower at the base of the 3–5 cm long rachis; pedicels 1–1.5 cm long, elongating in fruit to 7–10 cm

Morphology Reproductive morphology Flowers Calyx

Calyx stellate-pubescent, 1–1.7 cm long in flower, enlarging to 4 cm or more in fruit; lobes narrowly triangular to almost linear

Morphology Reproductive morphology Flowers Corolla

Corolla bluish violet, 1.5–4 cm in diam. in bisexual flowers, less in functionally male flowers, campanulate-stellate

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers c. 7 mm long, subsessile

Morphology Reproductive morphology Flowers Gynoecium Style

Style in bisexual flowers only, hardly exceeding the anthers

Morphology Reproductive morphology Fruits

Fruit variable in colour, shape and size, usually dark purple, occasionally almost white but eventually becoming yellow or brown, globose to ovoid, up to 20 cm long

Morphology Reproductive morphology Seeds

Seeds brown.

Distribution

Cultivated in N1 and N2; widely grown in all warm parts of the world.

Ecology

Cultivated at intermediate altitudes

Vernacular

Aubergine, egg plant (English).

Solanaceae, Jennifer M Edmonds. Oliganthes, Melongena & Monodolichopus, Maria S. Vorontsova & Sandra Knapp. Flora of Tropical East Africa. 2012

Morphology Reproductive morphology Fruits

Berries 1 per infructescence, green, sometimes mottled or striped, white, pink, mauve, purple, or black when young, usually white or dark purple at maturity, variously shaped, 3–20 × 3–7 cm; fruiting calyx unarmed or with up to 30 prickles

Morphology Reproductive morphology Seeds

Seeds 2.9–3.2 × 2.2–2.5 mm

Ecology

Cultivated species: “Aubergine/eggplant”

Note

The characters distinguishing S. melongena from the rest of the incanum group are mainly those directly associated with cultivation: larger fruit, altered fruit shape and colour, and lack of prickles. Like the fruit crop cultivars of S. aethiopicum, it can be recognised by fasciation in the flowers: increase in the number of flower parts up to 8, inflated ovaries, and straight thick styles not exserted further than 2 mm above the anthers.  The cultivated eggplant has close relationships with S. campylacanthum and S. incanum sensu stricto but was domesticated in Indo-China (Wang et al. in Ann. Botany 102: 891–897, 2008; Weese & Bohs in Taxon 59: 49–56, 2010). One uniform South East Asian cultivar is commonly grown in East Africa but it does not represent a significant food source.

Type

Type: Hort. Uppsala, Anonymous s.n. (LINN 248.28!, lecto., designated by Schönbeck-Temesy in Fl. Iran. 100: 70, 1972)

Morphology General Habit

Annual or perennial herb, 0.2–0.5 m, erect, unarmed(armed); young stems moderately stellate-pubescent to glabrescent, trichomes porrect, translucent, sessile or stalked, stalks up to 0.2 mm, rays 8–15, 0.3–0.7 mm, midpoints ± same length as rays or to 1 mm; prickles straight, 0–6 mm long, 0.2–1 mm wide at base

Morphology Leaves

Leaf blades drying concolorous to weakly discolorous, green-brown, ovate, 7–23 × 5–17 cm, 1.5–2 times longer than wide, base usually rounded, sometimes obtuse to cordate, often unequal and oblique, margin lobed, the broadly rounded lobes 1–3 on each side, 0.5–2 cm long, apically rounded, extending 1/4–1/3 of the distance to the midvein; apex rounded to acute; moderately stellate-pubescent on both sides, trichomes on abaxial surface porrect, sessile or stalked, stalks to 0.2, rays 5–8, 0.3–1 mm, midpoints ± same length as rays, trichomes of adaxial surface smaller; primary veins 4–5(–7) pairs; petiole 1.5–5(–10) cm, 1/4–1/3(–2/3) of the leaf length

Morphology Reproductive morphology Inflorescences

Inflorescences not branched, 4–7 cm long, with 1–5 flowers; peduncle 0–2 mm long; rachis 0–4 cm long; peduncle and rachis unarmed; pedicels 2–3 cm on long-styled flowers, 0.8–2 cm long on short-styled flowers, in fruit 2–9 cm long, unarmed or with up to 5 prickles

Morphology Reproductive morphology Flowers

Flowers heterostylous, 4–8-merous, only the basal one long-styled

Morphology Reproductive morphology Flowers Calyx

Calyx 8–23 mm on long-styled flowers, 7–12 mm long on short-styled flowers, lobes deltate to longdeltate, 6–12 mm long, 3–8 mm long on short-styled flowers, acute to longacuminate, unarmed or with up to 20 prickles

Morphology Reproductive morphology Flowers Corolla

Corolla white to purple, 2.5–5 cm in diameter on long-styled flowers, 2.4–4 cm in diameter on short-styled flowers, lobed for 1/4–1/2 of its length, lobes broadly deltate, 6–18 × 7–12 mm on long-styled flowers, 5–13 × 6–12 mm on short-styled flowers. Stamens equal; anthers 5.5–7.5 mm on longstyled flowers, 5.5–7 mm on short-styled flowers

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary stellate-pubescent in the upper 1/4; style ± 9 mm long on long-styled flowers

Distribution

Range: Probably cultivated throughout, but collections are sporadic: Sierra Leone, Ghana, Togo, Nigeria, Central African Republic, Zambia Flora districts: U K T Range: South East Asia