Rhobs al-Arsa (''Citrus limon'' (L.) Burm. f.) is a very popular

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

fruit in

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

Names

Rhobs al-Arsa is

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

for bread of the garden, or ''"Garden Loaf"''. This

hybrid has many other names, such as Al-zanbu, Khoubs al-Arsa, Koubs al-Arsa, Kubbâd, Robs al-Arsa, Zamboa, Zanbo'a, and Zemboua.

Description

The plant is an evergreen shrub with young green shoots, and rounded leaves that are green and shiny. The fruit is round and rather flat, with a small nipple at the apex, and an inverted ring around the nipple. Its skin is usually smooth. The pulp is acidic and fruity, with a sweet and pleasant albedo, slightly bitter bark. Maturity in February or March. It is cold-hardy to -2 °C / 3 °C and is an open-pollinated seedling.

Genetics

The Rhobs al Arsa has long been viewed as a citron hybrid, though different cultivars have been suggested for the parents, for example, Moroccan citron as the male parent and sour orange as the female parent,Corsica SRA, citrus

citron The citron (''Citrus medica''), historically cedrate, is a large fragrant citrus fruit with a thick Peel (fruit), rind. It is said to resemble a 'huge, rough lemon'. It is one of the Citrus taxonomy#Citrons, original citrus fruits from which al ...

lemon The lemon (''Citrus'' × ''limon'') is a species of small evergreen tree in the ''Citrus'' genus of the flowering plant family Rutaceae. A true lemon is a hybrid of the citron and the bitter orange. Its origins are uncertain, but some ...

and a

mandarin Mandarin or The Mandarin may refer to: Language * Mandarin Chinese, branch of Chinese originally spoken in northern parts of the country ** Standard Chinese or Modern Standard Mandarin, the official language of China ** Taiwanese Mandarin, Stand ...

Detailed genomic analysis showed Rhobs al Arsa to be highly similar to several cultivars of the '' Citrus limetta'', the limetta or Persian

sweet lime Sweet lemon and sweet lime refer to groups of citrus hybrids that contain low acid Juice vesicles, pulp and juice. They are hybrids often similar to non-sweet lemons or lime (fruit), limes, but with less citron parentage. Sweet limes and lemon ...

, and likely shared a common origin with them, arising from a cross between citron (''Citrus medica'') and sour orange (''Citrus'' × ''aurantium''). The common lemon and several other hybrids arose from distinct hybridization events involving the same two species. This proposed parentage was confirmed by a study of the native

Sardinia Sardinia ( ; ; ) is the Mediterranean islands#By area, second-largest island in the Mediterranean Sea, after Sicily, and one of the Regions of Italy, twenty regions of Italy. It is located west of the Italian Peninsula, north of Tunisia an ...

n citrus, the pompia (''C. medica tuberosa''), which was found to be genetically

synonymous A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

with the Rhobs el Arsa, both descended from the same hybrid, the product of a citron pollinating a sour orange, with the citron likely to be a native Italian variety such as the Diamante or the Common Poncire citrons. Such citrons had been cultivated together with the sour orange around the

Mediterranean The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

after the introduction of the latter by Moors in the 8th century, and frequent spontaneous crosses are likely to have occurred. Another Mediterranean variety, the Poncire de Collioure, was likewise found to be synonymous with Rhobs el Arsa and pompia.

Notes

References

Agrumes Baches

Many photos of the fruit by Dr. Giuseppe

have one in their collection

{{citrus Agriculture in Morocco Arab cuisine Citron Citrus hybrids Moroccan cuisine