Citrus breeding

Abstract

With a total world production of 105.4 million tons, citrus is one of the world's most important fruit crops (FAO 2006). Its importance to agriculture and the world's economy is demonstrated by its wide distribution and large-scale production (Soost and Roose 1996). It is grown throughout the tropical and subtropical regions of the world where the winter temperatures are sufficiently moderate for tree survival and enough water is available for its growth (Gmitter et al. 1992). The best fruit quality is achieved under subtropical conditions. The most significant citrus-producing regions are in the Americas (Brazil, USA, Argentina, and Mexico primarily), the Mediterranean basin (Southern Europe, Southwest Asia, and North Africa), Asia (including China, India, and Japan) and South Africa. Citrus industries in many production areas generate substantial regional revenue. Brazil, USA, China, Mexico, and Spain are the five largest citrus producers in the world (Table 1, FAO 2006). Sweet orange is grown on about 3.6 million ha in 114 countries with an approximate production of 64 million tons (t) with Brazil being the largest producer. The world production of grapefruits and pummelo is 4 million t and is grown in 74 countries on about 264,000 ha. USA is the largest producer of grapefruits and pummelo. China produces 38% of 18 million t of mandarins and their hybrids produced in the world. Lemons and limes are produced in 94 countries on about 0.8 million ha with a production of approximately 7.7 million t with Mexico being the largest producer. Brazil and Florida (USA) produce citrus fruit primarily destined for the juice or concentrate market, while China, Mexico, Spain, and California (USA) produce primarily fresh-market fruit. Citrus is valued as a fresh fruit and is also processed into juice, or added to dishes and beverages. Citrus is widely produced in dooryard plantings for personal and local consumption as well.