Sex ratio of the pupal stage in cocoons with different fluorescence characteristics from silkworm Bombyx mori L. breeds and hybrids

Radostina Guncheva

Abstract: Establishing the influence of the sex of individuals of breeds, di- and tetrahybrids of the silkworms Bombyx mori L. on the fluorescence of the silk sheaths, when exposed to ultraviolet (UV) rays with a wavelength in the range 254-365 nm was the aim of this paper. The study was conducted during 2018-2021 at the training experimental station of the Sericulture section of the Faculty of Agriculture at Trakia University – Stara Zagora. In fulfillment of the purpose and tasks, biological material from 8 breeds, 14 dihybrids and 10 tetrahybrids, grown with mulberry leaf was used. The analysis of the obtained data shows that the sex has significantly proven influence on the character of the silk sheaths fluorescence, shown when exposed to them with UV rays. In fractions with violet fluorescence, the sex ratio is 1.44:1 in favor of the female, and in fractions with yellow fluorescence – 1:1.42 in favor of the male sex. This gives reason to consider that the established sexual differentiation between the fractions of ultraviolet fluorescence and the influence of the fluorescence of the cocoons on their technological characteristics, proven in the literature, can be used for selection purposes, as well as for increasing the economic efficiency of the sericulture.

Keywords: Bombyx mori L.; breeds and hybrids; cocoons; fluorescence; sex of the pupa; silk sheaths

Date published: 2023-02-24