Productivity of newly created F1 tetrahybrids of the silkworm Bombyx mori L. reared with artificial diet low in mulberry powder

Radostina Guncheva, Panomir Tsenov and Yolanda Vasileva

Abstract: Establishing the productivity of newly created F1 tetrahybrids of the silkworm Bombyx mori L. when they are reared with artificial diet low in mulberry powder (15%) throughout the entire larval stage was the aim of this paper. The study was conducted during 2020 at the Training Experimental Station of the Sericulture section of the Faculty of Agriculture at Trakia University. Object of the study were the tetrahybrid forms of the silkworm (Bombyx mori L.) “Vraca63 × Line22/Nig2 × Merefa6” (1st experimental group) and “Nig2 × Merefa6/Vratsa63 × Line22” (2nd experimental group). Tetrahybrid “I1 x VB1/N2 × HB2” was used for the control group. Silkworms were reared with artificial diet containing 15% powder of dried mulberry leaf produced at Scientific Center on Sericulture – Vratsa and prepared by methods, developed by the manufacturer. From each of the analyzed hybrids, a dried average sample of cocoons was formed. The cocoons were assessed on the basic technological traits determining the productivity of the silkworms. The results obtained showed that the studied tetrahybrids are relatively equivalent in quality of the obtained production such as the straight tetrahybrid form (1st experimental group), although insignificantly, superior the back cross tetrahybrid (2nd experimental group) in mass of cocoons, silk sheath and silk thread by 12.83 mg, 7.9 mg and 6.1 mg, respectively. The newly created F1 hybrids do not deviate significantly in average values in all analyzed cases from the control, which gives reason to believe that they can be successfully reared throughout the larval development with artificial diet low content mulberry powder (15%). Therefore, they could be offered for testing by IASAS and approved as the first hybrids in Bulgarian sericulture, susceptible for rearing with artificial diet.

Keywords: artificial diet; Bombyx mori L.; cocoons; hybrids; low mulberry content; productivity

Date published: 2021-12-18