Poplar hybrid breeding in China started late, starting from 1946- 1947. Ye Pei is a pioneer in this work. In the 1940s, when he was working in Tianshui Soil and Water Conservation Experimental Zone, Gansu Province, he used local Populus hopeiensis, Populus tomentosa and Populus simonii for the first time, and obtained better hybrid seedlings than his parents. Although the scale of the experiment was small at that time, it accumulated valuable experimental data, which opened the way for carrying out poplar hybridization experiments in China in the future. In order to commemorate Ye Pei's achievements in Tianshui, the workers in Tianshui Soil and Water Conservation Experimental Zone named a new poplar variety he cultivated as "Yeshi Poplar". After the founding of the People's Republic of China, poplar hybrid breeding in China was basically carried out on the basis of Ye Pei's work in the 1940s. According to incomplete statistics, 400 hybrid combinations have been carried out in China, including intraspecific and interspecific hybridization, interspecific hybridization, interspecific hybridization and compound hybridization. Among them, there are about 40 hybrid combinations with excellent growth performance, including Populus tomentosa, Populus euphratica, Populus saishanensis, etc. These poplar hybrid varieties have been popularized and propagated in vast areas of the country. In the late 1950s, he established a poplar introduction area in the Arboretum of Nanjing Forestry College, and introduced more than 200 poplar clones at home and abroad, becoming one of the research and experimental bases of poplar breeding in China.
From 65438 to 0972, a forestry delegation from China led by Liang Changwu and Wu visited Italian forestry after attending the 7th Forestry Congress in Buenos Aires, Argentina, and brought back a batch of southern clones of Populus deltoides. Wu sent these cuttings to Chinese Academy of Forestry, Nanjing Forestry College, Hubei Forestry Research Institute and Heilongjiang Forestry Research Institute for introduction experiments. The southern clones I-63, I-69, I-72 and I-2 14 of Populus deltoides introduced by Nanjing Forestry College are 6 1 cuttings. Due to the delay of cutting, it has begun to change color and turn black, and it is in a dying state. After receiving these cuttings, Ye Peizhong immediately organized some teachers in the Tree Breeding Teaching and Research Section to rescue them. They cut branches in the school nursery. After scientific cultivation and careful management, these dying cuttings miraculously cultivated into seedlings. In that year, 49 seedlings were planted, with a plant height of two or three meters. Later, they used these seedlings for asexual propagation, and by the end of 1974, they had cultivated 1000 large seedlings, and the introduction experiment was successful. Ye Pei Zhonghe and his assistant did not stop the introduction research on campus, but promoted the application of these excellent clones in forestry production. Referring to the climatic and ecological conditions of the origin of these excellent clones (southern United States), they chose the northern plain of Jiangsu Province for small-scale trial planting, and the effect was remarkable. The DBH of 23-year-old clones can reach more than 20 cm. This achievement won the second prize of scientific and technological achievements of the Ministry of Forestry 1979 and the first prize of national scientific and technological progress 1985. By the end of 1980s, these four excellent poplar clones had been widely planted in the middle and lower reaches of the Yangtze River and Huanghuai area. According to incomplete statistics, the planting area is more than 5.2 million mu, and the annual net income exceeds 500 million yuan. The successful introduction and cultivation of southern clones of Populus deltoides not only has great economic benefits, but also breaks the traditional view that poplar cannot be cultivated in large areas in the south and enriches the theory of forest introduction.
Chinese fir is the main afforestation tree species in southern China. Ye Pei attached great importance to the genetic improvement of Chinese fir, and instructed Chen to carry out research since the early 1960s. In order to improve Chinese fir varieties, they went deep into various Chinese fir forest areas in Fujian, Jiangxi, Hunan, Sichuan, Guizhou and other provinces to investigate the biological characteristics of Chinese fir and select excellent Chinese fir types. On the basis of investigation and study, a large number of systematic breeding experiments were carried out on the natural type division, superior tree selection method, early selection, interaction between genetic types and environment, genetic stability, seed viability variation and genetic gain of seed orchards. Through selection, introduction and cross pollination, some excellent new strains of Chinese fir have been cultivated. 1966, they established the first regular primary clone seed orchard of Chinese fir in China under the auspices of Yangkou Forest Farm in Fujian Province. When the descendants of the first seed orchard are used for afforestation, the wood yield is higher than that of ordinary commercial seeds 15-20%. This achievement has important theoretical and practical significance for the development of fast-growing and high-yield Chinese fir forests in China. 1978 won the national science conference award, 1982 won the first prize of scientific and technological achievements of the Ministry of Forestry, and later won the agricultural and forestry science and technology promotion award of the State Planning Commission, the State Science and Technology Commission, the Ministry of Agriculture, Animal Husbandry and Fisheries and the Ministry of Forestry. In addition, during the long-term research on genetic improvement of Chinese fir in Ye Pei, it was found in the early 1970s that Chinese fir pollen could keep vitality 17 years under general storage conditions. Because Chinese fir pollen can preserve vitality for a long time, it can be sent to other places. Therefore, it is of great significance to introduce and breed Chinese fir simply by citing foreign pollen.
Ye Pei has not only made remarkable achievements in the breeding and introduction of poplar and Chinese fir, but also made pioneering achievements in the breeding experiments of Liriodendron chinense, Catalpa bungeana, pine and Mexican larch. For example, he used artificial cross pollination between Liriodendron China and Liriodendron North America. The hybrid Liriodendron grew better than its parents, and the plant height and root neck growth increased by 42% and 137% respectively. The hybrid has strong resistance, and the defoliation time in autumn is later than that of its parents. Catalpa bungeana does not bear fruit by self-pollination, and it blooms every year with little fruit, so large-scale propagation and afforestation are restricted. In order to solve this problem, Ye Peizhong used three cross combinations of Catalpa bungeana and Catalpa bungeana and Catalpa bungeana to obtain more than 0/000 hybrid seeds, which solved the problem that Catalpa bungeana could not reproduce sexually in the past. In order to popularize this fine variety, he used 13 kinds of pine trees to select nearly 30 hybrid combinations, and selected three excellent combinations: Pinus thunbergii and Pinus longleaf, Pinus thunbergii and Pinus yunnanensis, and Pinus thunbergii and mixed pollen (Pinus elliottii, Pinus loblollipop and Pinus yunnanensis). The first generation hybrids of these three cross combinations grew stronger than the open-pollinated progeny of black pine, with plant height growth exceeding that of the female parent by 55%, 35% and 69% respectively, and root neck growth exceeding that of the female parent by 44%, 20% and 34% respectively.
1on March 20th, 963, Cryptomeria China was used as the male parent and Taxodium ascendens was used as the female parent in Ye Pei, and then three cones were miraculously obtained. After sowing, the hybrid Taxodium ascendens 12 seedlings were cultivated. After years of continuous cutting propagation, more than 6,000 hybrid seedlings of Metasequoia glyptostroboides were cultivated in the forest farm of Nanjing Forestry College by 1972. He distributed the seedlings of hybrid Metasequoia glyptostroboides to several forestry production departments in Shanghai, Wuhan and other places for trial planting. 1978 After the death of Ye Pei Zhong, this variety was once ignored by people. Many years later, the excellent characteristics of this tree species, such as fast growth, typhoon resistance, salt and alkali resistance, water and humidity resistance, short defoliation period and air purification, were discovered by Ye Zengji, chief engineer of Shanghai Forestry Station, and Shen Lieying, stationmaster, and they tried their best to rescue, cut down and reproduce. The seedlings they cultivated created nearly 2000 hybrid Taxodium ascendens populations in Chuansha Forest Farm, Pudong, Shanghai. In August 2003, Ye Zengji, Xu Bingsheng and others published a paper in the American magazine SIDA, introducing this new tree species to the world. According to the international plant naming rules, they officially named the hybrid Metasequoia "xTaxodiomeria peizhongii" with the trade name "Abies orientalis". In July, 2004, the State Forestry Administration approved the granting of the new variety right of Abies orientalis, and Shanghai Forestry Station and Nanjing Forestry University were the variety rights holders. In 2007, the United States Federal Patent Office invited experts from the same industry in the world to examine and verify that the national intellectual property rights of Taxodium ascendens belong to China, and issued a certificate to obtain the American plant patent (US patent PP 17767). This is the first time that a new variety of woody plants in China has been patented abroad, and this new hybrid variety has been unanimously recognized at home and abroad. As a production practice, soil and water conservation has existed in China since ancient times, but as a specialized subject, it began in the 1940s.
1in the spring of 943, Ye Pei Middle School participated in the northwest soil and water conservation investigation group headed by Dr. Lowdermilk of the United States, and took the task of investigating soil and water conservation plants. During the four-month investigation, he collected more than 2000 plant specimens, among which Gramineae and Leguminosae plants in northwest China are the most complete; Seeds of cold-tolerant and drought-tolerant soil and water conservation plants were collected, including 54 species of Gramineae, 0/4 species of leguminous woody plants, 0/7 species of shrubs and 0/7 species of others. These plant specimens and seeds provide important information for soil and water conservation in northwest China. After the investigation of soil and water conservation in northwest China, he was left to work in Tianshui soil and water conservation experimental area of the Ministry of Agriculture and Forestry. At that time, together with Fu Huanguang (director of the experimental area), Ren Chengtong, Jiang Deqi and others, he overcame many difficulties and worked hard for the cause of soil and water conservation in China. Most of the specific scientific research work in the experimental area is directed and handled by Ye Pei Middle School. He often runs between the experimental fields in the experimental area in the hot sun and cold. 1June, 945, Fu Huanguang visited the United States, and he took over as the director of the experimental area. Since then, his work has become heavier and busier.
Ye Pei Middle School has worked in Tianshui Soil and Water Conservation Experimental Zone for more than five years, and has done a lot of soil and water conservation experiments, such as the construction, breeding and seed selection experiments of nursery pasture in Hebei Province; Plant experiment of soil conservation; Introduction and propagation test of special economic plants; Afforestation experiment in barren hills and ditches. These experiments have achieved fruitful results. For example, he founded the Hebei Nursery Pasture Seed Farm, which was a large-scale pasture experimental base in China at that time. There are about 300 varieties introduced to the farm, among which the excellent varieties are sweet clover, Pennisetum, wild grass, Sudan grass, two-leaf grass, kudzu vine and so on. Sweet clover was cultivated by 1946 by introducing American varieties. Widely planted in the northwest, it is known as the "baby grass" in the northwest. Pennisetum is a famous fine forage grass in China, which is widely planted in northwest China and is known as "Pennisetum striatum". The weeds he cultivated were introduced to Beijing from Tianshui in 1959, and propagated around the "Ten Buildings", becoming one of the main grass species in Beijing lawn. Pueraria lobata, identified by Ye Peizhong 1945, is native to Li Ziyuan, Tianshui County, and planted in Tianshui Soil and Water Conservation Experimental Zone, which is more cold-resistant and drought-resistant than Pueraria lobata introduced from southwest China. 1948 was sent to Beltsville, Baelz, USA for trial planting. It can safely overwinter at the low temperature of-10℃, and was adopted as an improved variety in the United States. In addition, in the afforestation experiment in barren hills and ditches, he also compared the experimental results of more than 20 tree species and found that Robinia pseudoacacia was a remarkable afforestation tree species in barren hills and ditches. Robinia pseudoacacia, known as one of the three treasures in Tianshui, is not only widely planted in Gansu Province, but also popularized throughout the country.