How are Fruit Trees Classified?
A general term for identifying and distinguishing fruit tree species and varieties according to different purposes and methods. Through fruit tree classification research, it can provide scientific basis for fruit tree cultivation, genetics and breeding, which is beneficial to the development of fruit tree industry.
The range of fruit tree classification
This includes both cultivated and wild fruit trees. Therefore, in the classification of fruit trees, in addition to the classification of species, it also includes cultivars and strains. Different from species, varieties and strains are not formed naturally, but are the result of artificial selection and directional cultivation for many years; they require certain natural conditions and agricultural technical measures, so varieties also have their own adaptation areas. The characteristics of varieties are mostly economic traits of the whole or part of the plant. Among the varieties of fruit trees, the fruit size, shape, color, aroma, quality, maturity and other characters are the main characters; in addition, biological characteristics such as high yield and adaptability are also very important. Most of these characteristics can be maintained through asexual reproduction such as grafting and cuttings. Generally, the varieties of fruit trees will change if they are propagated by seed.
Plant taxonomy is the main basis for the classification of fruit trees, which is of great help to the development and utilization of wild fruit trees and the improvement of cultivated fruit trees. But as a cultivated crop, in addition to the classification of fruit trees according to the plant system, there are other classification methods, that is, artificial classification that is practical in horticulture. These classifications are sometimes not as rigorous as the plant system classification, but each has its application value in cultivation.
Methods of classifying fruit trees
The classification of fruit trees according to the natural classification system. The natural classification system, or phylogenetic classification, began in the second half of the 19th century. This taxonomy seeks to objectively reflect the kinship and evolutionary development of the biological world. Plant taxonomists take species as their research objects and establish a hierarchical classification system from numerous plants. There is a hierarchical relationship between various levels, such as the position of white pear in the botanical classification:
Although most modern plants are still classified according to anatomical traits, a lot of research has been done on the taxonomic significance of previously unappreciated non-structural traits such as physiology and biochemistry. Modern electron microscopy, cytology, genetics and phytochemistry have provided new conditions for phylogenetic classification. The advent of computers also enabled quantitative classification techniques. The natural classification system is improving day by day, and the classification of some phylogroups that have been fully studied is close to the real phylogeny. Therefore, it has important reference value in the development and utilization of fruit tree resources, the selection of rootstocks and pollinator trees, the control of pests and diseases, and the improvement of varieties, mainly according to the arrangement of families, genera and species in plant taxonomy.
Due to the continuous discovery of wild fruit trees and different statistical standards, scholars from various countries have inconsistent statistical results on fruit tree species. There are 2792 species of fruit trees in the world, belonging to 134 families and 659 genera. Among them, there are about 300 species. According to Yu Dejun’s preliminary statistics (1979), there are 59 families, 158 genera and more than 670 species of fruit trees in China. Among them, Rosaceae, Rutaceae, Vitisaceae, Rhamnaceae, Sapinaceae, Moraceae and other species are more abundant, and the economic value is also the highest. From the perspective of the world’s fruit trees, the beech family, the walnut family, the musa family, the palm family, the bromeliad family, the myrtle family, the sumac family, the mangosteen family, and the papaya family are all important. In terms of genera, citrus, plum, apple, pear, raspberry, grape, mangosteen, and kiwi are all genera with more fruit tree species.
There are various classifications. The simplest is to divide fruit trees into two main categories: fruits and nuts.
By leaf growth period
It can be divided into deciduous fruit trees and evergreen fruit trees. The former is mainly produced in temperate regions, such as grapes, peaches, plums, apricots, apples, etc. The latter is mainly produced in tropical and subtropical regions, such as citrus, litchi, loquat, etc.
According to the growth habit of fruit trees
①Arbor fruit trees, such as apples, pears, walnuts, etc.; ②Shrub fruit trees, such as raspberries, gooseberries, bilberries, etc.; ③Vine fruit trees, such as grapes, kiwi fruit, passion fruit, etc.; , strawberries, etc.
According to the suitable climatic conditions for the cultivation of fruit trees
① Tropical fruit trees, suitable for frost-free areas, most of them stop growing when the temperature is lower than 20℃. Some species are forced to go dormant due to a dry climate, such as grapefruit, lemon, nutmeg, avocado, and cashew; while others, such as pineapple, banana, papaya, and coconut, prefer a climate with an even distribution of rainfall throughout the year. The cultivation distribution of tropical fruit trees is mostly between 20°N and 20°S. Tropical fruit trees on Hainan Island, China include bananas, pineapples, tree pineapples, mangosteens, sapodillas, coconuts, papayas, etc. Foreign tropical fruit trees include date palm, mangosteen, rambutan, durian, palm-colored fruit, custard apple, guava and so on. ②Subtropical fruit trees grow in areas with occasional light frost. Subtropical fruit trees usually need to go through a dormant period of 1 to 2 months in a cool climate below 10 to 13 ° C every year before they can bloom and bear fruit well. The cultivation and distribution range of subtropical fruit trees is between the Tropic of Cancer and 30° north-south latitude. Including cold-resistant evergreen fruit trees lychee, longan, star fruit, Pu Tao, Ping Po, lemon, yellow peel, etc., cold-resistant evergreen fruit trees loquat, Wenzhou mandarin orange, kumquat, bayberry, olive, etc. Deciduous subtropical fruit trees include figs and pomegranates. ③ Temperate fruit trees often require a certain freezing period every year for normal flowering and fruiting. Among them, the distribution range of fruit trees in the warm temperate zone is between 31°N～40°N and 31°S～40°S, such as between the Yangtze River and the Yellow River in China. There are peach, plum, pear, persimmon, jujube, grape and so on. Generally temperate fruit trees are distributed between 40°N～55°N and 40°S～55°S, such as North China and Northeast China, there are Qiuzi pear, white pear, apple, hawthorn, European plum, walnut, gooseberry, Mountain grapes, etc. There is some disagreement in the classification of tree species. In some countries, figs, olives, pistachios and pomegranates are used as warm temperate fruit trees; in some countries, persimmon and kiwi are used as subtropical fruit trees. This is due to the fact that some fruit trees are difficult to categorize categorically, and the differences within species are very large, especially after long-term domestication and cultivation, many varieties have appeared, expanding their adaptability. The cultivated distribution of fruit trees has far exceeded the natural distribution of their original species. Tropical fruit trees such as bananas, pineapples, papayas and some citrus fruit trees have been mass-produced in subtropical regions are good examples.
The horticultural practical classification method of fruit trees varies from country to country. At present, the more general classification method is basically divided into 6 categories according to the morphological structure and utilization characteristics of the fruit and combined with the growth habit: 1. Stone fruit trees, the endocarp lignified to form the fruit Central hard core, edible part is mainly fleshy mesocarp and exocarp. There are peaches, plums, apricots, plums, cherries and dates. Some drupes, such as bayberry, olive, walnut, etc., are also drupes in terms of plant morphology. Due to their different habits, cultivation methods or utilization, they are generally not included in the drupe category in fruit tree gardening. Many countries in Europe and the United States claim that stone fruit trees are actually limited to some fruit trees of the genus Prunus of the Rosaceae family (see stone fruit). ②Pome fruit trees, which belong to the Rosaceae fruit tree of the subfamily Pomoideae. All are deciduous trees. The edible part is mainly developed from the fleshy receptacle, and the carpel forms the heart of the fruit (see pome). There are pear, apple, bonus, hawthorn, quince and so on. The loquat fruit in the evergreen fruit tree is also a pome fruit in terms of plant morphology, but it is mostly included in the subtropical fruit tree category in fruit tree gardening. ③Berry fruit trees, the fruit is generally thin peel, juicy and soft pulp, small seeds, whole fruit or mesocarp and endocarp for consumption (see berries). There are grapes, strawberries, kiwi, figs, gooseberries, lingonberries, etc. However, in some European and American countries, there is another category called small fruits, including raspberries, strawberries, bilberries, etc. In fact, in terms of plant morphology, strawberries and raspberries are aggregated fruits, and figs and mulberries are multi-fruited or multi-flowered fruits. These fruits have different fruits and different edible parts, but they are soft and juicy, and the fruits are not very large. ④ Citrus fruit trees, the outside of the fruit is a leathery exocarp with oil bubbles, and the edible part is the juice bubbles with tumor-like protrusions of the endocarp (see citrus fruit). There are citrus fruit trees such as tangerines, tangerines, oranges, grapefruits, and lemons. ⑤ Nut fruit trees, the fruit has a hard outer shell, and the edible parts are mostly seeds, which have less water content and are rich in starch, fat and protein (see nuts). There are walnuts, pecans, chestnuts, hazel, torreya, ginkgo, almonds, cashews and so on. Among them, walnuts, pecans, and almonds should be drupes according to their plant morphology, while ginkgo and torreya belong to gymnosperms, which are seeds rather than fruits. They are collectively referred to as nuts only for the convenience of application. Because the post-harvest handling, storage, processing and utilization of these fruit tree products have a lot in common. ⑥Subtropical and tropical fruit trees, although the origin is relatively similar, but the fruit structure is very different, cultivated in subtropical and tropical fruit trees. There are longan, lychee, busy fruit, coconut, banana, pineapple, papaya, avocado, etc., which are more complex in terms of plant classification.
The above classifications are not strictly classified according to the morphological structure of the fruit, except that the boundaries between pome fruit and citrus fruit trees are relatively obvious. Scholars from all over the world have different opinions on the classification method of fruit trees. Mainly in accordance with their respective horticultural practical habits classification.
Classification of fruit tree varieties
In the classification of fruit trees, the classification standards of cultivars are also very inconsistent. Varieties are the result of artificial selection and cultivation. Therefore, it is often emphasized that as long as one or two economic traits are selected, they can be used as the basis for classification. Although this method is relatively simple and convenient to apply, the disadvantage is that it is not easy to divide fruit trees with a large number of varieties. Many varieties with different morphological characteristics are arranged together, and there is no relationship between them. Since cultivated fruit trees originate from wild plants, the classification standard of varieties should first be placed on the basis of species classification. The method generally adopted is to classify the varieties of the same origin or the same variety, whether it is a variety of a species or a polyploid formed by doubling of chromosomes, into a variety system. For example, the total number of Chinese pear varieties is more than 1,000, and it is difficult to distinguish only from the fruit shape or its economic characteristics. If the system is first divided into Qiuzi pears, white pears, sand pears, Sichuan pears, Western pears, Xinjiang pears and other systems according to the comprehensive characteristics of the species, the complexity of variety classification can be greatly reduced. Naturally, careful consideration should also be given to the classification of hybrids.
After the classification of the system to which the varieties belong, if there are many similar varieties, the classification of varieties and subgroups should be carried out. In addition to 1 or 2 economic characters, the characteristics of each variety group should also select a number of other related agrobiological characteristics, so that the variety classification can be placed on a relatively stable basis for easy application.
Fruit trees are named according to the International Botanical Nomenclature. In order to facilitate international exchanges and unify plant names, this rule has been revised and supplemented every 4 to 5 years since the International Botany Conference in Paris in 1866, and has been gradually perfected and widely used in the world. The main principles of the rule are as follows: ① A plant can only have one legal Latin name; ② Latin names adopt the dual name system, that is, a genus name and a species name. The genus name is in the front, the species name is in the back; ③ The genus name is a noun, and the first character is capitalized. The species name should be an adjective, with the first letter lowercase; ④The entire species name of the plant should include the surname of the person who named the species name, and the first letter should be capitalized after the species name; ⑤The legal scientific name must be accompanied by an officially published description in Latin; ⑥If When a plant has two or more scientific names, only the earliest and the one that does not violate the nomenclature is legal. Compared with the names of modern plant classifications, the names of fruit trees in China are mostly equivalent to the genus names of plants, and sometimes add adjectives to the genus names to become species names. Such as white pears, sand pears, bean pears, Xinjiang pears, etc. in the genus Pyrus.
Most fruit tree varieties that have played a role in production already have appropriate names. Most of them are named according to the characteristics of fruit shape, color, size, maturity period or other economic characters, and sometimes according to the place of origin, history or person’s name, so that people have certain convenience as the name suggests. However, due to the economic influence of small farmers in China for thousands of years, the distribution of varieties has great regional restrictions. Often the same name represents completely different varieties in different regions, and confusion in naming is common. For example, ‘Perfume pear’ belongs to a variety in the Qiuzi pear system in Hebei and Liaoning, and the fruit is small and oval; in Shandong, it refers to a variety in the white pear system with large and flat spherical fruit. The same variety has different names in different regions. For example, ‘Pingli’ in Nao County, Shanxi is called ‘Banjinsu’ in Changli, Hebei, ‘Yuanli’ in Funing, Hebei, and ‘Tutou pear’ in Shandong. The confusion of the same name and the same name and the same name is very serious. In addition to sorting out and publishing on the basis of investigation and research, attention should be paid to avoiding duplication of names when registering and naming new fruit tree varieties in the future. The name strives to express the characteristics of the breed and to be consistent with the breed system or breed group. For varieties introduced from abroad, try to keep their original names and give them appropriate Chinese translations.
According to the International Nomenclature of Cultivated Plants, the nomenclature of cultivated plants is divided into three levels, namely genus name, species name and cultivar name. The genus and species names are formulated in accordance with the general principles of International Botanical Nomenclature. Breed names can be named in modern, not Latin. When a new variety is published internationally, it is valid to use any national language for the name, and it is not necessary to have Latin, but it is suggested that an English, French, German, Russian or Spanish abstract should be attached at the end of the text for wide dissemination. The cultivar name can be added with the cv. symbol (abbreviation of cultivar) or expressed in single quotation marks after the Latin scientific name of the plant, and the first word is capitalized. For example, the scientific name of the apple variety of ‘Guoguang’ is written as Malus pumila cv.Ralls, or the scientific name of the variety of ‘Ba Li’ is written as Pyrus communis ‘Bartlett’, etc.
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Post time: Apr-10-2022