There are many varieties of peach trees. There are about 3, varieties in the world, including more than 1, in China. According to their adaptability to climatic conditions, growth characteristics and fruit characteristics, they can be divided into several varieties. (1) Classification of fruit characters and maturity: ① According to the shape of fruit, it can be divided into ordinary peach and flat peach (flat peach); ② According to whether the skin is hairy or not, it can be divided into hairy peach and nectarine. Nectarine is a single variation of common peach. ③ According to the degree of adhesion between core and pulp, it can be divided into detached core, sticky core and semi-sticky core. Cohesion is an evolutionary type. The pulp tissue of detached varieties is loose and has uneven maturity. Sticky kernel varieties have dense pulp, less fiber and uniform pulp maturity, so they are suitable for processing and canning. ④ According to the texture of pulp, it can be divided into three types: meat solute, meat insoluble and hard peach. Solute fruit is soft and juicy when it matures, which is suitable for fresh eating. Solute type can be divided into soft solute type and hard solute type. Insoluble fruit is tough and elastic when it matures, which is suitable for processing and canning (but the pulp is not dyed red). The flesh of hard-fleshed peach is hard and brittle when it is first ripe, and sticky when it is fully ripe, and it changes its face, so the quality before it is fully ripe is better. ⑤ According to the color of pulp, it can be divided into white peach, yellow peach and red peach. ⑥ According to the date of fruit growth, it can be divided into super early-maturing varieties, early-maturing varieties, middle-maturing varieties, late-maturing varieties and super late-maturing varieties. The fruit growth date of extra-early maturing varieties is less than 75 days. The fruit growth date of early-maturing varieties is 76-114 days. The fruit growth date of mid-mature varieties is 116-137 days. The fruit growth date of late-maturing varieties is more than 137 days. Very late-maturing peaches (that is, "winter peaches" and "snow peaches") generally mature in North China until the first and middle of November. ⑵ Ecological classification: ① Northern variety groups. Mainly distributed in North China, Northwest China and Central China. Shandong, Hebei, Beijing, Shanxi, Henan, Shaanxi, Gansu and Xinjiang are widely cultivated. The climate in these areas belongs to the sub-humid and sub-arid climate in the south temperate zone of China, with annual precipitation (4-8 mm), cool Leng Xia in winter and abundant sunshine, and the average annual temperature in suitable cultivation areas is 8-14 degrees Celsius. The population of this product is relatively cold-resistant and drought-tolerant, and is not tolerant of warm and humid climate. Its main characteristics are: the top of the fruit is pointed, the suture line is deep, the color of the fruit surface is red and white, and the pulp is hard, including two types: water honey type and crisp peach type. The tree grows vigorously, with erect branches, short fruit branches and bouquetlike fruit branches, more single flower buds and different degrees of frozen flower buds. Representative varieties are Qihe April3, Mayxian, June White, July Fresh, Feicheng Peach, Shenzhou Peach and Qingzhou Peach. ② Southern variety group. Mainly distributed in Jiangsu, Zhejiang, Sichuan, Guizhou, Hubei and Hunan provinces south of the Yangtze River in China. This area belongs to the humid climate of north subtropical zone and middle subtropical zone, with more precipitation (1-14 mm), more rainfall in spring than in the north, less solar radiation, warmer winter and higher temperature in summer, and the annual average temperature in suitable cultivation areas is 12-17 degrees Celsius. The population of this product can be divided into three types: peach, hard peach and flat peach. Peach fruit is round, with flat top, easy peeling, soft and juicy pulp, which is not resistant to storage and transportation. The potential of the tree is medium, and the tree is open or half-open, with medium-long fruit branches and multiple flower buds. The representative varieties are Yulu, Baifeng, Wuxi Baihua and Yuhualu. Hard-fleshed peaches have short tips at the top, shallow sutures, hard, crisp and dense meat, less juice, and are more resistant to storage and transportation. The tree is strong, upright, with hard branches, and the thickness of different branches is obviously different. There are many medium-long fruit branches, mainly single flower buds. Representative varieties are white hanging branches, live beads, red walnut and so on. Flat peach pulp is soft and juicy, mostly peach-shaped. The potential of the tree is medium or weak, and the tree is open. The branches are even in thickness, mainly bearing short fruit branches, with multiple flower buds. The representative varieties are Baimang Flat Peach, Taicang Flat Peach, and Sprinkled Red Flat Peach. ③ Southern European variety group. It was introduced to Europe from Gansu and Xinjiang, China, and was domesticated for a long time. Mainly distributed in Mediterranean countries, with Italy and Spain as the most. Most varieties from France, Turkey, the United States and Western Europe also belong to this product population. The region has a Mediterranean climate, with dry summers, strong sunlight and mild and rainy winters. Varieties that adapt to the above climatic conditions are suitable for cultivation in northern China, but it is not easy to obtain satisfactory results when introduced to southern China. The representative varieties are Xinduanyang, Tuscan, Simms and so on.