Orange. An orange is a fruit of various citrus species in the family Rutaceae; it primarily refers to Citrus sinensis, which is also called sweet orange, to distinguish it from the related Citrus aurantium, referred to as bitter orange. The sweet orange reproduces asexually; varieties of the sweet orange arise through mutations. The orange is a hybrid between pomelo and mandarin. The chloroplast genome, and therefore the maternal line, is that of pomelo. The sweet orange has had its full genome sequenced. The orange originated in a region encompassing Southern China, Northeast India, and Myanmar, and the earliest mention of the sweet orange was in Chinese literature in 314 BC. As of 1987, orange trees were found to be the most cultivated fruit tree in the world. Orange trees are widely grown in tropical and subtropical climates for their sweet fruit. The fruit of the orange tree can be eaten fresh, or processed for its juice or fragrant peel. As of 2012, sweet oranges accounted for approximately 70% of citrus production. In 2019, 79 million tonnes of oranges were grown worldwide, with Brazil producing 22% of the total, followed by China and India. Main article: Citrus taxonomy All citrus trees are angiosperms, belong to the single genus Citrus, and remain almost entirely interfertile. This includes grapefruits, lemons, limes, oranges, and various other types and hybrids. As the interfertility of oranges and other citrus has produced numerous hybrids and cultivars, and bud mutations have also been selected, citrus taxonomy is fairly controversial, confusing, or inconsistent. The fruit of any citrus tree is considered a hesperidium, a kind of modified berry; it is covered by a rind originated by a rugged thickening of the ovary wall. The sweet orange is not a wild fruit, having arisen in domestication from a cross between a non-pure mandarin orange and a hybrid pomelo that had a substantial mandarin component. Since its chloroplast DNA is that of pomelo, it was likely the hybrid pomelo, perhaps a BC1 pomelo backcross, that was the maternal parent of the first orange. Based on genomic analysis, the relative proportions of the ancestral species in the sweet orange are approximately 42% pomelo and 58% mandarin. All varieties of the sweet orange descend from this prototype cross, differing only by mutations selected for during agricultural propagation. Sweet oranges have a distinct origin from the bitter orange, which arose independently, perhaps in the wild, from a cross between pure mandarin and pomelo parents. The earliest mention of the sweet orange in Chinese literature dates from 314 BC. In Europe, the Moors introduced the orange to the Iberian Peninsula, which was known as Al-Andalus, with large-scale cultivation starting in the 10th century, as evidenced by complex irrigation techniques specifically adapted to support orange orchards. Citrus fruits, among them the bitter orange, were introduced to Sicily in the 9th century during the period of the Emirate of Sicily, but the sweet orange was unknown until the late 15th century or the beginnings of the 16th century, when Italian and Portuguese merchants brought orange trees into the Mediterranean area. Shortly afterward, the sweet orange quickly was adopted as an edible fruit. It was considered a luxury food grown by wealthy people in private conservatories, called orangeries. By 1646, the sweet orange was well known throughout Europe. Louis XIV of France had a great love of orange trees and built the grandest of all royal Orangeries at the Palace of Versailles. At Versailles, potted orange trees in solid silver tubs were placed throughout the rooms of the palace, while the Orangerie allowed year-round cultivation of the fruit to supply the court. When Louis condemned his finance minister, Nicolas Fouquet, in 1664, part of the treasures that he confiscated were over 1,000 orange trees from Fouquet's estate at Vaux-le-Vicomte. Spanish travelers introduced the sweet orange to the American continent. On his second voyage in 1493, Christopher Columbus may have planted the fruit on Hispaniola. Subsequent expeditions in the mid-1500s brought sweet oranges to South America and Mexico, and to Florida in 1565, when Pedro Menéndez de Avilés founded St Augustine. Spanish missionaries brought orange trees to Arizona between 1707 and 1710, while the Franciscans did the same in San Diego, California, in 1769. An orchard was planted at the San Gabriel Mission around 1804, and a commercial orchard was established in 1841 near present-day Los Angeles. In Louisiana, oranges were probably introduced by French explorers. Archibald Menzies, the botanist and naturalist on the Vancouver Expedition, collected orange seeds in South Africa, raised the seedlings onboard, and gave them to several Hawaiian chiefs in 1792.