Articles

Lycopersicon esculentum Miller

Lycopersicon esculentum Miller

Family

Solanaceae

Synonyms

Solanum lycopersicum L., Lycopersicon lycopersicum (L.) Karsten.

Vernacular Names

Malaysia Tomato.
English Tomato, love apple.
Indonesia Tomat.
Papua New Guinea Tamato.
Philippines Kamatis (Tagalog), butinggan (Ilocano), ang-angseg (Bontoc).
Cambodia Peeng pâh.
Laos Khüa sômz.
Thailand Makhua-thet (General), makhua-som (Northern).
Vietnam C[af] chua.
French Tomate.

Geographical Distributions

Lycopersicon esculentum originated from the Andean region of South America, in the area now covered by parts of Bolivia, Chile, Ecuador, Colombia and Peru. The related species of cultivated L. esculentum are native and widely distributed in this region. Archaeological and circumstantial evidences (diversity of types and culinary uses, abundance of local names) suggested that L. esculentum was domesticated in Mexico, outside its centre of origin, and the most likely ancestor is the primitive cherry tomato (L. esculentum var. cerasiforme (Dunal) Gray). L. esculentum was introduced into Europe in already fairly advanced stage of domestication soon after the discovery of the New World. From there, it was taken to other parts of the world at various times: in the 17th Century to China, South and Southeast Asia; and in the 18th Century to Japan and the United States. Although initially grown only as a curiosity in Europe because of its erroneous reputation as a poisonous fruit, L. esculentum has now become one of the most important vegetables worldwide.

Description

L. esculentum is a variable annual herb that can reach up to 2 m tall or taller. The taproot is strong, measures up to 0.5 m deep or more, often damaged at transplanting and with a dense system of lateral and adventitious roots.

The stem is solid, coarsely hairy and glandular. The growth habit varies from indeterminate with several metres long stems and prostrate when not supported, carrying an inflorescence in every 3rd to 4th leaf, to determinate with several short and more erect stems with inflorescences (4-6 per stem) on every second leaf and one terminates the shoot apex.

The leaves are arranged spirally with a 2/5 phyllotaxy, imparipinnate and measuring 15-50 cm x 10-30 cm in outline. The petiole is 3-6 cm long. The major pinnae is 7-9, opposite or alternate, ovate to oblong, measures 5-10 cm long, with irregularly toothed and sometimes pinnatifid at the base. A variable number of smaller pinnae occur between the larger leaflets. The leaflets are petiolate, covered with (glandular) hairs and produce a characteristic and species-specific odour.

The inflorescence is cymose, normally with 6-12 flowers, but in compound inflorescences are with 30-100 flowers. The flowers are regular, measuring about 2 cm in diametre, pendent, bisexual, hypogynous and usually with 6-merous. The sepal tube is short and green with pointed lobes. It is persistent and enlarged in fruit. The petal is rotate, yellow, stellate, reflexed later and drop off after pollination. There are 6 stamens, with bright yellow anthers, conically arranged, surrounding the style and prolonged into a sterile beak. The superior ovary is with 2-9 loculi and a fleshy central placenta.

The fruit is a berry, flattened, globular or oblate, smooth or furrowed, measuring 2-15 cm in diametre, green and hairy when young, hairless and shiny, red, pink, orange or yellow when ripen.

The seed is a flattened ovoid, measuring 3-5 mm x 2-4 mm, up to 250 per fruit, light brown and hairy. Germination is epigeal. Seedlings have a thin taproot and cordate cotyledons. The first leaves have a few leaflets.

Ecology / Cultivation

Ideally, L. esculentum requires a relatively cool, dry climate for high yield and premium quality. However, it is adapted to a wide range of climatic conditions. L. esculentum has been grown as far north as the Arctic circle (under protection) down to the hot and humid equator. The optimum temperature range for growth and development is between 21-24°C. Prolonged exposure to temperatures below 12°C can cause chilling injury. Mean temperatures above 27°C severely impair the growth and fruit set. Destruction of pollen and egg cells occur when the maximum daytime temperature is 38°C or above for 5-10 days. Fruit set is also generally poor if the night temperatures are above 21°C during the few days before and after anthesis. Hot dry winds can also cause flower abortion. Light intensities below 1000 ft-candles retard the plant growth and delay flowering. L. esculentum is not sensitive to day length and set fruits in photoperiods ranging from 7-19 hours. L. esculentum can be grown in many soil types ranging from sandy loam to clay-loam soils that are rich in organic matter. The ideal soil pH range is 6.0-6.5; higher or lower pHs can cause mineral deficiencies or toxicities. Long periods of flooding are detrimental to L. esculentum growth and development.

Line Drawing / Photograph

Lycopersicon_esculentum

References

  1. Plant Resources of South-East Asia No. 8: Vegetables.