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

Radostina Guncheva1, Panomir Tsenov2 and Yolanda Vasileva2
1 Trakiа University, Faculty of Agriculture, Department of Animal Science – Non-ruminants and other Animals, 6000 Stara Zagora, Bulgaria
2 Agriculutural Academy, Scientific Center on Sericulture, 3000 Vratsa, Bulgaria

Abstract

Guncheva, R., Tsenov, P. & Vasileva, Y. (2021). Productivity of newly created F1 tetrahybrids of the silkworm Bombyx mori L. reared with artificial diet low in mulberry powder. Bulg. J. Agric. Sci., 27 (6), 1221–1226

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

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