Moroccan citron
The Moroccan citron was described by the Moroccan professor Henri Chapot, as being a sweet citron, meaning that its pulp is low in acid. He discovered that the acidity in the more common citrons or lemons, is represented by red on the inner coat of seeds specifically on the chalazal spot, violet pigmentation on the outer side of the flower blossom, and also by the new buds that are reddish-purplish. The Moroccan citron which is acidless is completely lacking the red color. This designation was cited by Herbert John Webber and Leon Dexter Batchelor the editors of the fundamental treatise on citrus, namely The Citrus Industry, which was published by the University of California, Riverside in 1967.
Citrus production
While the origin of citrus fruits cannot be precisely identified, researchers believe they began to appear in Southeast Asia at least 4,000 BC. From there, they slowly spread to northern Africa, mainly through migration and trade. During the period of the Roman Empire demand by higher-ranking members of society, along with increased trade, allowed the fruits to spread to southern Europe. Citrus fruits spread throughout Europe during the Middle Ages, and were then brought to the Americas by Spanish explorers. Worldwide trade in citrus fruits didn't appear until the 20th century and trade in orange juice developed as late as 1940.