ABSTRACT

Citrus is a genus of the plant family Rutaceae. This family is divided into 7 subfamilies comprising 11 tribes and 93 genera (Engler, 1931). Citrus belongs to the subfamily Aurantioideae or the Orange subfamily. It contains 2 tribes and 6 subtribes comprising 33 genera and over 215 species. Most members of this subfamily have white, fragrant flowers and gland-dotted aromatic fruits. The genus Citrus is the most specialized, having juicy fruits with pulp vesicles or juicy sacs. Swingle first classified the species of Citrus in 1943 and again in 1967. He recognized 16 species and 8 botanical varieties of Citrus. On the contrary Tanaka recognized 159 species (Tanaka, 1954, 1969). It has been argued (Jones, 1990) that m ost of the species described by Tanaka are hybrids or mutants.