Excerpt:
With its numerous cultivated varieties, the sweet orange (Citrus sinensis Osbeck) constitutes one of the world's most popular and recognizable fruit crops. Sweet oranges are citrus fruits (Citrus spp.), which are regarded as high sources of vitamin C (ascorbic acid) and other fruit acids. These fruits are hesperidiums, because of their fleshiness and separable rind. Physically, citrus fruits consist of forty to fifty percent juice, twenty to forty percent rind and twenty to thirty-five percent pulp and seeds. Chemically, they contain eighty-six to ninety-two percent water, five to eight percent sugars and one to two percent pectin with lesser amounts of acids, protein, essential oils and minerals (Janick et. al. 1981). Citrus fruits grow on small evergreen trees, many of which depend on root mycorrhizae (Janick et. al. 1981). Most of these C3 plants are cultivated as scions on rootstocks. All Citrus species have a diploid chromosome number of eighteen and are interfertile.