种传病原的带菌阈值就是在有利于发病的环境条件下,种子感染或传染的植物病原菌能够在田间引起病害并造成经济损失的带菌菌量。当选用清洁种子作为病害防治措施时,确定带菌阈值是十分重要的。由于种子在世界范围内广泛交换,而种子也传播着植物病原菌,所以清洁种子是病害防治的一项重要措施。每年,通过世界性商业种子贸易、国际组织间以及与农作物改良有关的公立或私营科研单位间的种质交流等途径,使种子在全世界相互交换。由于许多植物病原菌可以潜伏于种子内部、种 The germ-carrying threshold of species-borne pathogens is the amount of bacteria carrying pathogens that cause disease in the field and cause economic losses, in the favorable environmental conditions of the disease. When using clean seeds as a disease control measure, it is important to determine the threshold for carriage. As seeds are widely exchanged around the world, and seeds also spread plant pathogens, cleaning seeds is an important measure for disease prevention and control. Each year, seeds are exchanged around the world through trade in the world’s commercial seeds, germplasm exchange among international organizations and public or private research institutes related to crop improvement. Because many plant pathogens can lurk inside seeds, species