N. PETKOV1, Y. NACHEVA1, Y. VASILEVA1,
Z. PETKOV1, A. MATEI2, M. CIULU2, D. BRAILOU2 and G. DINITA2
1 Regional Centre for Scientific Applied Service, National Centre for Agrarian Sciences, BG-3000 Vratza, Bulgaria
2 Commercial Society Sericarom S.A. Research Branch, RO-78431 Bucharest, Romania
PETKOV, N., Y. NACHEVA, Y. VASILEVA, Z. PETKOV, A. MATEI, M. CIULU, D. BRAILOU and G. DINITA, 2007. Evaluation of genetically sex-marked at eggs and larvae stage silkworm Bombyx moriL. hybrids based on silk productivity. Bulg. J. Agric. Sci., 13: 127-130
Raw silk productivity per day of 5th larval instar and its heterosis was studied in six F1 industrial crosses, created with participation of five original sex-limited parent lines, incl. two (T15/4 and XT215/38) sex-marked at eggs stage and three (TV3/2, TBV2/24 and B2/6) sex-marked at larvae stage.
It was determined that tested F1 hybrids created from sex-limited lines are characterized with comparatively high silk productivity per day of 5th instar and XT215/38 x TV3/2 hybrid and reciprocal cross had the highest value of this trait (3.13 - 3.19 cg).
Almost all crosses were demonstrated comparatively high heterosis manifestation concerning silk productivity over MP value within the limits of 4.81 - 12.52 % and over HP value between 3.55 - 8.63 %.