园艺植物种子生产技术

作者简介

"王姗，副教授，从事园艺专业教科研工作。主编教材2部，主持国家级教学资源库子项目建设1项，参与国家级精品在线开放课程建设1项，主持或参与国家级、省级等教科研项目9项，发表论文8篇。 汤伟华，副教授，从事蔬菜生产的教科研工作。主编高等职业教育“十二五”国家规划教材《蔬菜生产技术》，参与园艺技术专业国家教学资源库课程建设，主持多项教科研项目。"

内容简介

\"Selection and Breeding Methods of New Cultivars of Horticultural Plants I. Introduction (I) The Concept and Significance of Introduction Any plant species and cultivars have a certain distribution area in nature, and so do the horticultural plants. Introduction and domestication is the process of artificially relocating a plant from its existing distribution or cultivation area to other areas for cultivation, in other words, the introduction is the method to introduce new plant species, types, and cultivars that are not yet cultivated locally from other places. Some plants are so highly adapted that they can adapt to new environmental conditions without changing their genetic characteristics. when the difference between the natural conditions of the original distribution area and the introduced place is small, or the environmental conditions of the introduced place are more suitable for the growth of the plants, the plants would even grow better. The above-mentioned is called simple introduction; some plants have low adaptability or the ecological conditions of the introduced place are so different from the original place, the plant would grow abnormally or even die. But after careful cultivation management or through hybridization, mutagenesis, selection, and other measures, the plant’s genetic properties are gradually changed, and the plant can thus adapt to the new environment and grow normally. This kind of introduction is called domestication introduction. (II) General Rules of Introduction (1) The introduction of cultivars that grow in the same latitude area is easy to succeed. Plants distributed at the same latitude have the same photoperiod and basically the same growth and development period. However, due to differences in geographic location and climate, temperature conditions vary greatly from place to place. For example, China is in the Eurasian continental monsoon climate zone, which is the coldest region in the world in winter. Tianjin is at the same latitude as Lisbon, the capital of Portugal. It has an average temperature of -4.1°C in January and an extreme minimum temperature of -22.9°C, while Lisbon has an average temperature of 9.2°C in January and an extreme minimum temperature of -1.7°C. Guangzhou is at the same latitude as Havana, but the average temperature in Guangzhou is 8°C lower than that in Havana. Therefore, low temperatures may become a limiting factor in the introduction of seeds from European and American countries. (2) The fertility period of southern species will be prolonged after being introduced to the north, and that of northern species will be shortened after being introduced to the south. Biennial herbs must go through a certain photoperiod before flowering and fruiting, so the introduction of seeds at different latitudes has a great impact on fertility. The perennial trees have overwintering problems in addition to the growth cycle, so their reaction to sunshine length is more complex than that of herbaceous plants. When the trees in the south are introduced to the north, the sun exposure is prolonged during the growing season, and thus the growing period is prolonged, which promotes the sprouting of ramulus, reduces nutrient accumulation, hinders the lignification of tissues, and transformation of protective substances before winter, and at last, reduces the trees’ cold resistance. For example, after Jiangxi’s toona is sown in Tai’an, Shandong, the above-ground part often freezes to death because it cannot stop growing in due time. The situation of trees in the north being introduced to the south is just the opposite. Because of the shorter hours of sunshine, the trees’ terminal buds stop growing in advance. This severely shortens the growing period, prevents normal life activities, and often makes the trees suffer from serious diseases and pests due to higher temperature and humidity. (3) The introduction of cultivars that grow in regions with similar climatic ecotypes is easy to succeed. According to the plants’ adaptation to environmental conditions, in production, horticultural plants are often divided into tropical plants, thermophilic plants, hardy plants, psammophytes, and aquatic plants. All types of plants have their own suitable climatic conditions and distribution areas. The introduction of the appropriate species or materials during the corresponding growing season or in corresponding artificially created protected environments is expected to be successful. (4) The annual day-neutral plants can often be introduced without restrictions. Tomatoes, beans, cucumbers, and other horticultural plants can grow and develop normally as long as they have the right temperature and light conditions. (5) Soil pH value restricts the introduction of some horticultural plants. Camellia and azalea prefer acidic soil, so it is difficult to introduce them to calcareous soil areas for open cultivation. (III) Dominant Ecological Factors Affecting the Success of Introduction and Domestication The environment of horticultural plants includes all conditions of the living space of horticultural plants, among which the factors that have an impact on the growth and development of horticultural plants are called ecological factors. Dominant ecological factors refer to the factors limiting plant growth and development, including climate, soil, and biological factors. These factors are mutually affected and constrained and work together on horticultural plants. The complex of such factors is called the ecological environment. Different plants and cultivars have different responses to the same ecological environment. The so-called ecotype is the plant’s special need for or adaptability to certain ecological factors under the long-term influence of a specific environment. This ecotype or ecological habit is formed through genetic variation during long-term artificial selection and natural selection. 1. Temperature Temperature is the most important factor influencing the acclimatization of horticultural plants. The effects of temperature on introduced plants can be broadly summarized into two categories. First, the temperature cannot adapt to or meet plants’ basic needs of growth and development, resulting in the abnormal growth of introduced plants or fatal damage to different parts and organs of the plant due to high or low temperatures. Second, although the introduced plants can survive, due to unsuitable temperatures, flower buds cannot be formed, which may affect fruit yield and quality, making the introduced plants lose their cultivation and economic values. The critical temperature is the limit of the lowest and highest temperature that a horticultural plant can tolerate, beyond which serious injury or death can be caused to plants. The critical minimum temperature in winter is critical to the success of the sorthern horticultural plants introduced to the North. For example, the critical low temperature that pineapple can tolerate is -1°C, and Guangzhou’s temperature is generally above 0°C, so pineapple cultivars can generally adapt to it; Shaoguan often sees the low temperature of -2.3°C, so Shaoguan in northern Guangdong becomes the demarcation line of pineapple introduction. The resistance of citrus fruit trees to extremely low temperatures is roughly like this: sweet oranges is -6-7°C, citrus is -8-9°C, Satsuma orange is -9°C. In Wuxi, Jiangsu province, the extremely low temperature in winter is about -12°C, so sweet oranges can’t adapt to it. However, Satsuma orange and cold-resistant citrus introduced to the microcli- mate can overwinter safely. In addition to critical low temperature, the duration of low temperature should also be considered in the introduction. For instance, blue gum, a kind of garden tree, has a certain resistance to cold and can only tolerate a short period of the low temperature of -7.3°C. In addition, the low temperature and its long duration in winter are also the limiting factors for the adaptability of overwintering vegetables. Therefore, when introducing southern overwintering vegetables to the north, they are prone to failure due to low temperature and freezing damage. High temperature is the main limiting factor for the southward introduction of plants. In the growing period of horticultural plants, the physiological process is inhibited when the temperature is up to 30-35°C, and the damage occurs when the temperature is above 35°C. For example, the critical high temperature for the growth of cabbage is 25°C. Once it’s above 25°C, its vital activities are affected. In particular, high temperature and humidity conditions often cause the spread of certain diseases, seriously limiting the southward introduction of fruit trees, vegetables, and horticultural plants. For instance, some grape cultivars introduced to the south of the Yangtze River basin are exposed to high temperature and humid ecological conditions, which often induce Elsinoe anthracnose and anthrax. Effective accumulated temperature is also an important factor affecting the adaptability of horticultural plants during their introduction. For horticultural thermophilic crops, when they are introduced to areas where the difference of effective accumulated temperature above 10°C less than 200-300°C, their growth, development, and yield will not be significantly affected. The requirements for effective cumulative temperatures for grape cultivars at different maturity stages range from 2,000-2,400°C for very early-maturing cultivars, 2,400-2,800°C for early-maturing cultivars, 2,800-3,200°C for medium-maturing cultivars, 3,000- 3,500°C for late-maturing cultivars, and 3,500°C and above for very late-maturing cultivars. In addition, the temperature of the growing season is a limiting factor affecting the adaptation of annual crops. For example, the length of the growing season of vegetables is mainly determined by the number of days between the initial growing temperature and the critical minimum and maximum temperature. For example, the low temperature at the start of cabbage growth is about 7°C, and the critical high temperature is about 25°C. The fertility period of “Beijing Daqingkou” cabbage is about 110 days in Beijing but about 80-90 days in Shenyang. Therefore, its head formation is not full after being introduced into Shenyang. 2. Illumination Illumination (illumination intensity and illumination duration) also affects plant growth and development. Illumination is related to latitude, and the illumination duration is different at different latitudes. The higher the latitude is, the greater the difference between lengths of day and night. The longer the summer day, the shorter the winter day. At lower latitudes, daylight length is not much longer in summer than in winter. Plants growing in different latitudes for a long time have a certain response to the lengths of day and night, forming short-day plants (such as chrysanthemum) that need long photoperiod in summer and short photoperiod in autumn to bloom, long-day plants (such as Gladiolus) that only bloom when receiving short photoperiod in spring and long photoperiod in summer, and plants insensitive to the length of sunlight (such as peaches, apples, Chinese roses). This is more obvious in annual vegetables (including overwintering ones). For example, beans and soybeans are short-day plants; onions, beets, carrots, lettuce, and spinach are long-day plants; tomatoes, eggplant, and peppers can flower and fruit with both long and short hours of sunlight. The length of sunshine is also a major factor affecting the development of certain vegetable organs. For instance, the bulb expansion of the onion introduced from the north to the south requires long hours of sunshine. but after being introduced to the south, it’s usually planted in autumn and harvested in spring. When the bulb expands, it only gets a short winter sunshine period. Therefore, the onion only shoots, while the bulb does not expand. 3. Moisture It is mainly the total amount of precipitation and its distribution during the year that has a great influence on the growth of horticultural plants. Water requirements of the introduced plants and their tolerance to drought and flooding should be taken into consideration when introducing them. Fruit trees like apricot, walnut, fig, and pineapple, as well as garden trees like acacia and juniper do not need so much water and have stronger drought resistance; they’re followed by pear, peach, persimmon, chestnut, and grape; citrus, loquat, plum, cherry, glossy privet, laurel, southern magnolia, etc. need much water and have weak drought tolerance. The distribution of precipitation is often an important factor in determining whether the introduced cultivars can adapt to a place, especially for horticultural plants that have been introduced from the north to the south. For example, when the northern grape cultivars are introduced to the south, the rainfall in the south is unbalanced, mainly concentrated in April to June, which is the anthesis of the grape. It would affect the pollination and fertilization of the grape, and because of the high temperature and humidity, the grape branches and leaves are prone to excessive growth, resulting in the spread of diseases and insects. This will seriously affect the yield and quality. Similarly, excessive precipitation and high air humidity during the fertility period of vegetables often become the limiting factors for the southern introduction of northern plants. therefore, these two should be considered when introducing vegetables, fruit trees, and garden flowers. According to the study on many hardy tree cultivars such as Melia azedarach, Davidia involucrata, and Ficus carica introduced in Beijing, the growth of these trees is affected by drought in early spring rather than the low temperature in winter. If the heat coefficient of moisture is large, the moisture can absorb heat at high temperatures and release heat at low temperatures, which can reduce the temperature difference and make the climate soft, favoring the growth of most plants. Therefore, some microclimatic environments in the north (e.g. near reservoirs, coastal areas) can often introduce southern horticultural plants successfully. For example, Citrus unshiu near Qingshan Reservoir in Lin’an, Zhejiang can overwinter normally. Camellia japonica from Laoshan Mountain of Qingdao can also overwinter in the open field. In addition, the height of the subterranean water level in a region will also affect the success of the introduction of a tree cultivar. For example, many species of Magnoliaceae have fleshy roots, which are not resistant to water and humidity, so they should not be introduced in places with high subterranean water levels. 4. Soil Soil ecological factors include the water holding capacity of the soil, permeability, salinity, pH value, and the level of the subterranean water level. The main factor affecting the success of the introduction is soil acidity. China’s northern and northwestern belts are mostly alkaline soils, while the red soil hilly regions of southern China are mainly acidic, and the coastal waterlogged lowlands are mostly saline-alkaline or salty soils. The adaptability of different plant species to soil pH value varies widely. Berry trees, garden plants like Gardenia jasminoides, Rhododendron simsii, camellia, and so on grow in acidic and neutral soil; drupes, garden plants like Amorpha fruticosa, Dianthus, Viola odorata, and so on grow in neutral or slightly alkaline soil; Robinia pseudoacacia, Tamarix chinensis, horsetail beefwood, and so on are more salt tolerant. 5. Other Ecological Factors Certain special limiting ecological factors should also be considered in the introduction, such as diseases and pests that are still difficult to control. For example, ulcer disease in Zhejiang, Guangdong, and certain citrus-producing areas limits the introduction of sweet oranges; jujube blight in northern and northeastern China limits the introduction of date palms; European grape cultivars are susceptible to Elsinoe anthracnose in the Yangtze River basin, which affected the development of some high-yield and high-quality grape cultivars. Some areas have suffered severe wind damage. So the differences in wind resistance between cultivars must be taken into account when introducing seeds. In addition, plants will establish coordinated or symbiotic relationships with surrounding organisms during their long-term growth and evolution. For example, Castanea mollissima, pine, and Pseudolarix amabilis have mycorrhiza, so it is prone to failure if we only introduce plants but not mycorrhiza. Besides, in the introduction, attention should also be paid to the introduction of pollinating trees and special pollinators. 6. Historical Ecological Condition Factors The adaptability of plants is not only related to the ecological conditions of the present distribution area, but also to historical ecological conditions. The natural distribution areas of modern plants are the results of the changes in a certain geological period, especially the most recent glacial period. During the glacial period, some of the plant species may have been wiped out because of the great changes in ecological history in the related areas, and only those plants that have adapted survived to this day. Therefore, extant plants, during their phylogeny, have experienced a variety of extreme living conditions and have a very rich and complex ecological history. Of course, there are also areas where the plants have not changed much during the climate change periods in geological history, so these areas’ ecological histories are not so rich. \" 本教材力求体现“专业与产业、职业岗位对接，专业课程内容与职业标准对接，教学过程与生产过程对接，职业教育与终身学习对接”的职业教育教学改革方向，并融入课程思政元素及严谨、创新的职业素质培养，力求实现校企融合、工学结合的紧密衔接。

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