Articles

Citrus maxima (Burm.) Merr.

Citrus maxima (Burm.) Merr.

Family

Rutaceae

Synonyms

Citrus aurantium L. var. grandis L., Citrus grandis (L.) Osbeck, Citrus decumana L.

Vernacular Names

English

Pummelo, shaddock, pamela.

Indonesia

Jeruk besar, jeruk bali.

Papua New Guinea

Muli.

Philippines

Lukban, suha (Tagalog, Ilokano).

Burma

Shouk-ton-oh.

Cambodia

Krôoch thlông.

Laos

Kièngz s'aangz, ph'uk, sômz 'ôô.

Thailand

Som-o(General), ma-o (Northern).

Vietnam

Bu'o'i.

Frech

Pamplemoussier.

Geographical Distributions

The origin of Citrus maxima is uncertain. There is little doubt that the species is indigenous in Malaysia. It has spread to Indo-China, southern China and the southernmost part of Japan and westwards to India, the Mediterranean and tropical America. However, it remains a fruit of the Orient; neither in India nor further west has it become popular. The best match of cultivars, environmental niches and growing skills appear to be found in Thailand.

Description

C. maxima can grow up to 5-10(-15) m tall. It is a low-branching tree, branches spreading and spiny (seed propagation) or spineless (vegetative propagation), with its spines up to 5 cm long. The young parts are manifestly hairy.

The leaves are ovate to elliptical, measuring 5-10(-20) cm x 2-5(-12) cm, with rounded to subcordate base, entire to shallowly crenate margin, obtusely acute apex and dotted glandular. The petiole is broadly winged, up to 7 cm wide while its wing is obcordate.

The inflorescences are axillary, with a cluster of flowers or a single flower. The flowers are large, 2-3 cm long in bud, 3-5 cm wide when fully expanded, with 5 parts in the flower whorl and covered with soft hairs. The petals are creamy white. There are 20-25(-35) stamens while the ovary is with 11-16 loculi.

The fruit is a nearly spherical to pear-shaped berry, 10-20(-30) cm in diametre, greenish-yellow and densely glandular-dotted. The peel is 1-3(-4) cm thick. The segments are large, pale yellow or pink pulp-vesicles and filled with sweetish juice.

The seeds are usually few, large, plump, ridged, yellowish and monoembryonic.

Ecology / Cultivation

C. maxima thrives in the lowland tropics. In the production centres of Thailand, mean monthly temperatures are about 25-30°C with a few cooler (and dry) months; the dry season lasts for 3-4(-5) months and annual rainfall is about 1500-1800 mm. The crop is not grown commercially above elevations of 400 m. C. maxima tolerates a wide range of soils from coarse sand to heavy clay. However, the tree prefers deep, medium-textured and fertile soil free from injurious salts.

Line Drawing / Photograph

BOT00162

References

  1. Plant Resources of South-East Asia No.2: Edible fruits and nuts .