Sweet orange production area distribution and appearance varieties

Everyone knows that sweet orange is a delicious fruit, but do you know the functions and effects of sweet orange ? Let me introduce it to you.

Sweet Orange

Sweet orange is a fruit tree of the genus Citrus in the subfamily Citrus of the family Rutaceae. It is also known as Guanggan, Huangguo, Cheng, Guangju. Its scientific name is Citrussinensis (L.) Osbeck. [Synonyms] Huangguo (Yunnan Hui Yuheng Zhi), Chengzi (Yunnan Materia Medica), Xinhui Cheng (Botanical Names and Pictures), Guangju (Chinese Tree Taxonomy), Xuegan, Yinzigan, Guanggan (Guangzhou Flora). The term "sweet orange" was first seen in the "Shaoxing Prefecture Chronicle" of Zhejiang Province in the 14th year of the Wanli reign of the Ming Dynasty (1586).

Sweet Orange - Origin and Distribution

Sweet oranges are native to southern China and the Indochina Peninsula in Asia. There are records of "yellow oranges, oranges, and tangerines" in the Western Han Dynasty (117 BC). Sweet oranges are distributed in 13 provinces (autonomous regions) in China, and are mainly produced in Sichuan, Guangdong, Taiwan, Guangxi, Fujian, Hunan, Jiangxi, Hubei and other provinces (autonomous regions). They were introduced from China to Europe in the early 15th century and to America in the late 15th century. In the world's citrus production, sweet oranges account for the largest proportion, with an annual output of about 2/3 of the total citrus production.

Sweet Orange - Plant Characteristics

Sweet orange is an evergreen small tree, 2 to 3 meters high, with a medium-sized crown, rounded or semicircular. There are many branches, no hair, and the twigs are flat and angular, without thorns or slightly thorny. The leaves are degenerate into simple leaves: the petiole is 0.8 to 1.8 cm long, the leaf wings are narrow, 2 to 3 mm wide, and there is a clear septum at the junction with the leaves; the leaf blade is elliptical, 6 to 12 cm long, 3 to 5.5 cm wide, with acuminate tips, broad cuneate bases, and inconspicuous wavy serrations on the edges; leathery. The calyx is cup-shaped, 3 to 5 lobes, the lobes are oval, and the apex is narrow and pointed; the petals are 4 to 8, usually 5, oblong, up to 1.5 cm long and 0.7 cm wide; there are many stamens, and the filaments are often clustered and fused on the disk; the ovary is superior, with 10 to 13 chambers, each with 4 to 8 ovules, and the ovary is nearly spherical. The style is thick and often falls off early. The fruit is large, 7 to 9 cm in diameter, round to oblong, with a yellowish, orange-yellow or light blood-red peel, which is relatively tough and smooth. The oil bubble is slightly protruding, and the flesh is orange-yellow to blood-red, soft, juicy and fragrant. The peel and flesh are not easy to separate. The fruit core is small and full. There are many, few or no seeds, depending on the variety. They are ovate or oblong, polyembryonic, and white. The chromosome 2n=18, and there are also triploid, tetraploid and hexaploid. The fruit contains a large amount of sugar and a certain amount of citric acid as well as rich vitamin C. It has high nutritional value, good color, fragrance and taste, and is an excellent fruit for fresh consumption. Sweet oranges have high yield and stable yield, and produce about 30-40 tons per hectare in China.

Sweet Orange - Ecological Adaptability

Sweet oranges are native to tropical and subtropical regions. They prefer warm weather, are not cold-resistant, and are relatively shade-tolerant. They require fertile soil with good water permeability and air permeability. They are mainly distributed in areas with an annual average temperature of more than 15°C. The lowest temperature for germination of sweet orange branches and seeds is 13°C. The optimum temperature range for branch growth is 23-31°C, and growth stops at 37-38°C. The relative humidity of the air is the key to the success of the introduction of navel oranges. There are three ecological types of navel oranges in the world: low-humidity or medium-humidity (relative humidity 50-60%) varieties, such as Washington navel oranges, Thomson navel oranges, Fengjie 72-1 navel oranges (Sichuan), etc.; high (relative humidity 80%) varieties, such as Greathead, Dream, Meishan less-core Hua navel (Sichuan), etc.; intermediate varieties, such as Robertson navel oranges, Taxas, Caeter, etc. Sweet orange has a wide adaptability to soil and can be planted and produce high yields in soils with an adaptable pH range of 5.0-8.5. It is best to plant and produce high yields in soils with a pH of 6.0-6.5 and deep, loose and fertile soil.

Sweet Orange - Variety Group

Among citrus fruits, sweet orange has the most abundant varieties, with more than 400 varieties in the world. According to the maturity period, it can be divided into early, medium and late maturity. Generally, it is divided into ordinary sweet orange, navel orange and blood orange. According to the shape and characteristics of the fruit, it can be divided into the following four varieties: ① Ordinary sweet orange. The fruit is generally round, orange, with no navel on the top of the fruit, or with a circle mark in between. It is the most numerous variety among sweet oranges. ② Sugar orange. Also known as acid-free sweet orange, the fruit shape is similar to that of ordinary sweet orange. Because of its extremely low acid content, it can be harvested and put on the market when the juice content reaches an appropriate level. It is an extremely early-maturing sweet orange variety. It is produced in small quantities in the Mediterranean coast and Brazil and supplies local markets. ③ Blood orange. The flesh and juice are all purple-red or dark red. The flesh is tender and juicy, with a special aroma. The Mediterranean region is its origin and main production area. ④ Navel orange. The characteristic is that there is a navel on the top of the fruit, that is, there is an underdeveloped small fruit embedded in the top of the fruit. It is seedless, tender and crispy, with a strong sweet and slightly sour taste. It is easy to peel and split. The fruit is large and matures early. It is mainly eaten fresh and is an important fine variety in international trade. The United States introduced Washington from Brazil in 1870 and gradually cultivated it into the famous variety "Washington Orange". The main production areas are now the United States, Brazil, Spain, South Africa, Australia and Morocco. The main varieties of sweet oranges in China are mostly ordinary sweet oranges. Among them, the important varieties are "Xinhui Orange", "Liucheng" ("Dark Liucheng" is the best variety), "Perfume Orange" (also known as "Leaf Orange", "Water Orange") and "Xuegan" originating in Guangdong, "Jincheng" and "Xianfeng Orange" originating in Sichuan, and "Dahong Sweet Orange" originating in Hunan, "Zhangzhou Orange" (formerly known as "Improved Orange", also known as "Red Meat Orange") originating in Fujian, etc. In addition, there are "Hamlin Orange", "Fuling Summer Orange", "Washington Navel Orange" and "Ruby Blood Orange" (also known as "Ruby Blood Orange") introduced from the United States.