Finding a new approach to the breeding of insect-resistant poplars Yang Shu is one of the important tree species in China's plain afforestation and fast-growing high-yield forest construction projects. However, the constraint of insect pests has become a major obstacle to the development of poplars. Prof. Zheng Junbao from Hebei Agricultural University told the reporter that the main leaf-feeding pests of poplars are Yangshao, moths, Yangzuling, and American moths. As a result of the large number of chemical insecticides applied, the pests have become tolerant, and the use of drugs has become more and more serious, resulting in a vicious circle; excessive use of pesticides not only kills natural enemies of pests, but also seriously undermines the natural ecological balance. It threatens the safety of people and animals. The emergence of microbial insecticides overcomes the characteristics of chemical pesticides to a certain extent, but the effects are slow, the insecticidal spectrum is narrow, and they are greatly affected by environmental conditions, and thus the application range is limited. The genetic engineering of plants matured in the 1980s provided a new way to control pests. Transferring the beneficial genetic properties of distant species to trees has always been a dream for breeders. However, conventional breeding techniques are powerless, for example, the insect-resistant traits do not have prominent parents in trees. Genetic engineering can solve this problem well. Plants can accept almost any foreign gene without restriction, including genes from different species, different genera, families, and even different species of organisms. Professor Zheng said that the creation of new insect resistant varieties through the transformation of insect-resistant gene technology is safe and effective compared with traditional pest control methods, which can reduce investment and reduce environmental pollution and many other advantages. Double insect resistance gene transferred to 741 Yang So far, most of the research work is to transfer a single insect-resistant gene into plants. In order to solve the problem that insects may produce resistance to transgenic plants expressing insecticidal proteins, and in order to improve the insect resistance of transgenic plants and expand the resistance spectrum, Tian Yingchuan et al., Institute of Microbiology, Chinese Academy of Sciences, constructed a plant expression vector. The insect resistance genes of two different insecticidal mechanisms are the Bt Cry IAc gene and the proteinase inhibitor gene (API). Prof. Zheng Junbao and others spent more than eight years studying genetic transformation, feeding insect experiments in indoor and experimental areas, growth observations and morphological observations at the seedling stage, and molecular biological tests, and obtained excellent poplar-type hybrids that transposed insect resistance genes. Basic abortive female strains. Professor Zheng said that 741 Yang is a unique white Poplar hybrid in China. The main feature of the introduction of insect-resistant genes lies in the resistance to the major insect pests of Lepidoptera. During the five years of the insecticide test, the insects tested were Lepidoptera pests. Among them, 3 to 4 generations of the annual C. sinensis moth, the worldwide quarantine pest of the American moth, the world-famous pest gypsy moth, and the young moth and archaea moth. The insect-resistant clones of the 741 anti-insect poplar were resistant to mortality in the larvae of Cycad were 82.6% to 96.5% in each year, and 63.2% to 68.9% in the mid-resistance clone. The larvae mortality was 82.2% to 92.3% in the high-resistance asexual line. The resistant clones ranged from 57.6% to 61.3%. The vast majority of larvae die in the first instar. In addition to the dead insects, the insects also survived a certain number of insects during the test. The toxic proteins and protease inhibitors contained in the transgenic plants can inhibit their development, which is reflected in prolonged developmental periods of their respective ages. A four-year study of insect ecology has demonstrated that the insect-resistant poplar 741 has control over Lepidoptera, and its number is significantly less than that of the control. In the afforestation of access roads, farmland shelterbelts and farmland forests, greening of water systems, and construction of quickleaf forests, the insect-resistant 741 poplars can be used to fight less or even fight drugs, greatly reducing environmental pollution. The construction of an insect-resistant 741 Yang isolation barrier can prevent the spread of white moths. Professor Zheng said that the other good traits of the insect-resistant 741 poplar, such as growth rate, wood properties, and stress resistance, are superior to their parents, Populus tomentosa, reflecting heterosis. Under better climate and soil conditions, it is expected that the diameter of the insect-resistant poplar 741 in the 10 to 12 years can reach 26.4 cm or more, which meets the requirements for plywood. Its wood physical and mechanical properties are excellent. All the indicators have reached extremely significant differences compared with the control. The morphological characteristics of 741 Yang mainly inherited the characteristics of P. tomentosa and also contained other parental characteristics. Crowns are oval in shape, branches are sparse, distributed evenly, and branching angles are large. The trunk is straight and straight. The young trunk is smooth and green. The trees are covered with a layer of white powder. The tree is magnificent. The stems are rhombic, purple-brown, similar to the silvery white poplar pores. Prof. Zheng said that the suitable planting area of ​​insect-resistant 741 poplar is within the range of 30-40 in latitude and 105-125 in longitude. The provinces of Henan and Shandong, Beijing and Tianjin, south of the Great Wall of Hebei, and under the dam, Shaanxi Guanzhong, Shanxi Jinzhong, south river basins, northern Anhui, Huaibei plains, northeastern Jiangsu, southern Liaoning, Tianshui, Gansu South of Lanzhou and other regions. It can also be extended to the Hetao Plain in Inner Mongolia, to the west, to the Yellow River impact plain in Ningxia, and to the Datong Basin in Shanxi. The insect-resistant 741 Yang can also be planted in the distribution areas of Hebei Yang and Xinjiang Yang in the west of China. The tree species has a strong adaptability to the soil texture and prefers deeper soils. Suitable for lands with higher groundwater levels. The insect-resistant Populus 741 should become one of the first tree species for the construction of plain greenery and fast-growing high-yield forest. 741 Yang's safety is reassuring The ecological safety of genetically modified trees is a common concern. Professor Zheng explained that the insect-resistant 741 Yang is a female abortion strain and does not produce pollen. The genetically polluted environment itself is transmitted through sexual reproduction of pollen. The insect-resistant Pope 741 has no seeds and cannot reproduce sexually. Therefore, it itself has a biological barrier function; insect-resistant 741 Yang is a tree planting in the plains and fast-growing and high-yielding forests. It is planted in plain agricultural areas and is far from the natural forest and wild plant populations. The planting time is short, and it is impossible to become a natural drift and contaminate natural forests. The gene bank. In response to the suggestion that genetically engineered tree species may become new invasive alien species, Professor Zheng said that alien species intrusion is a threat to the ecosystem of native species and their habitats caused by species from other areas. The parents of the poplar-resistant poplar 741 were all unique native trees in China, and there was no invasion of alien species. In terms of prevention strategies, Professor Zheng believes that two measures can be taken in afforestation design: First, set up a physical barrier around the insect-resistant poplar 741, that is, split the insect-resistant poplar 741 into a certain area of ​​the forest on the afforestation site, and use the untransformed gene. The 741 Yang Cheng encloses it. Second, 741 Yang is not planted alone, but other economic trees and flowers needed by the market and the market are also planted.
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