Abstract
Walnut blight is a harmful disease that affects nut crops. It is caused by the bacterium Pantoea agglomerans and has become widespread in recent years, posing a serious threat to walnut plantations. The disease not only destroys more than half of the crop, but also causes bark cracking and slow crown desiccation, which can lead to further infections. One of the most important requirements for modern varieties of agricultural plants, including nut crops, is an increased level of resistance to diseases. In Kazakhstan, there is currently no data on the spread of diseases of nut crops and resistance of varieties to harmful diseases. This makes it difficult to recommend a suitable variety for industrial and private nut orchards. Ipmroving the breeding process and increasing the productivity of walnut plantations, it is extremely relevant to assess the resistance of varieties to the most dangerous pathogens. For the first time in Kazakhstan, a two-year monitoring study was conducted to assess the resistance of promising walnut varieties and forms to the Pantoea agglomerans, taking into account the prevailing weather and climatic conditions. The study was carried out on 23 varieties and forms in the main fruit-growing regions of the country. It was found that the walnut blight caused by the bacterium Pantoea agglomerans annually damages walnut plants, and the degree of disease damage depends on the prevailing weather and climatic conditions. The research results revealed that the Moldavian variety - Kazaku showed high resistance to walnut blight. Other resistant varieties are Miroslava, Ovidiu, Germisara, Yarivski, Peshanski, Kogylnichanu, 185, Lipin 2, Liaohe, Fernor, Plin, and Kishinevski. These varieties showed minimal damage, not exceeding 2 points, during the years of observation. These varieties are recommended as suitable varieties for increasing the productivity of industrial and private nut orchards and improving the breeding process.