<p>The aim of the following research work is to select mulberry silkworm breeds and hybrids that are resistant to the high temperature of the summer season and low relative humidity, as well as to study the influence of environmental factors on their biological, productive and technological indicators. In the silkworm breeding laboratory of the Sericulture Research Institute, the spring grain of hybrid combinations Musaffo Tola 1 and Musaffo Tola 2, created by the scientists of the laboratory, and the foreign hybrid Jing song houyou was artificially revived by processing HCl acid, incubated and fed in the summer. The indicators of egg viability, caterpillar viability and signs of productivity were comparatively analyzed. The data obtained from different environmental conditions show that the viability of caterpillars, cocoon weight, cocoon shell weight and silkiness of the studied hybrids are different. </p>