Тhe behavioral activity of such an extremely important agricultural object in scientific and practical terms as the silkworm still remains poorly studied. Aims: Сreation of silkworm lines with alternative behaviors to prove the genetic determinacy of the behavioral activity of the silkworm Bombyx mori L. Place and Duration of Study: The work was carried out at the Research Institute of Sericulture in the Laboratory of Genetics and Breeding of the silkworm in 2015-2020. The Ipakchi 1 and Ipakchi 2 breeds widely zoned in Uzbekistan were used as research objects. Methodology and Results: The Ipakchi 1 and Ipakchi 2 breeds widely zoned in Uzbekistan were used as research objects. The breeding of alternative silkworm lines in terms of motor activity was carried out by selecting the most active caterpillars and male butterflies in the "A" -lines (active), and the least active individuals in the "P"-lines (passive). The separation of individuals by motor activity led to their separation by reproductive and biological indicators. The difference between the lines by the average number of eggs in the clutch of the Ipakchi 1 breed in 2018 was 32 eggs, in 2020 already 133 eggs; by the mass of the clutch in 2018 – 25mg, in 2020 – 78mg. The same patterns were observed in the Ipakchi 2 breed. The greatest difference between the "A" and "P" lines was observed in the viability of caterpillars: in 2018 it was 3.2%, in 2020 already 6.9%. Conclusions: Selection of hatched larvae (caterpillars) and male butterflies by the speed of movement to the feed (the larvae) and to the sexual partner (butterflies) leads to the appearance of silkworm lines with alternative forms of motor activity.

In this article, discusses the possibilities of using heterosis. It is known that industrial sericulture around the world is based on the production of first-generation hybrids for the use of heterosis, which can manifest itself in a variety of ways. The effect of heterosis depends largely on the properties of the breeds used in hybridization. in addition, crossing breeds with different characteristics lead to the emergence of new populations of silkworms, sometimes with previously incongruous properties. In this study, an attempt was made to combine the high yield of cocoons and high-quality cocoon thread in the genotypes of hybrids. Genetic and selection studies in the direction of breeding new breeds and creating silkworm hybrids with high productivity and quality properties of cocoons contribute to increasing the production of grain and cocoons of domestic breeds and hybrids, improving their quality, corresponding to international standards, and thereby increasing the export opportunities of the sericulture industry.

The article explains that the silkworm is bred worldwide only as first-generation hybrids for maximum heterosis. The study supports the idea that the effect of heterosis will be significant if the breed components of the created hybrids have outstanding properties. Therefore, the selection of breeds with certain characteristics necessary for silkworm breeders in the future is very important. It is equally important that these characteristics are as high and stable as possible. For this, breeding work is carried out with component breeds aimed at improving certain characteristics. In this study, the selection is aimed at the reproductive properties of breeds. Selection and breeding work for three years has seriously changed some of the indicators of Gren. It has been demonstrated that targeted selection to improve the reproductive performance of breeds I-120, Chinese 108, MG, Ipakchi 2, leads to an increase in the number of normal eggs in the clutch and to a decrease in physiological marriage.

The article discusses the results and methods of selection aimed at improving the biological characteristics in the rocks-components of high-yielding silkworm hybrids. High biological indicators of the breed components of the new hybrids guarantee high heterosis for many economically valuable features. Improving the viability of caterpillars and silkworm cocoons of component species can be achieved by conducting a systematic selection at all stages of development of the silkworm. Selection and breeding selection include the method of ranking breeds on the basis of productivity, the method of traditional selection, and the method of selection based on motor activity. The use of multiple selection methods in the complex leads to increased viability of the caterpillars, weight, and silkiness of caterpillars, weight, and silkiness of cocoons of MG, Ipakchi 2, Ya-120, Chinese 108 breeds.