STUDY ON THE BEHAVIOUR OF THE DIFFERENT ORIGIN SILKWORM HYBRIDS UNDER THE CLIMATIC CONDITIONS OF BULGARIA

Romania, Ukraine, Turkey and Uzbekistan as countries placed in the Black, Caspian Seasand Central Asia (BACSA) region, in comparison with hybrids from China, Japan, Italy andKorea has been carried out in Sericulture Station Vratza – Bulgaria.The study pointed out the superiority of the Japanese hybrid Shunrei + Shogetsu which hadthe highest cocoon yield by one box of eggs (41,10 kg) and the highest raw silk productivity(7,05 kg/box of eggs).The silkworm hybrids produced in BACSA members countries had ahatching percentage ranged from 77,50% to 98,50%, a high pupation percentage (72,86 –96,91%), cocoon weight (1,892 – 2,319 g) and fresh cocoon yield by one box of silkwormvaried from 29,894 kg to 40,982 kg.The Romanian hybrids had high values of the rawcocoon weight (2,307 g Record and 2,194 g Baneasa Super), the appreciable values of thecocoon yield/box of eggs (36,135 kg Record and 39,168 kg Baneasa Super), but low valuesof the silk content (20,38% Record and 20,51% Baneasa Super) and of the raw silkproductivity/box of eggs (4,33 kg Record and 4,80 kg Baneasa Super).The breeding works inthe BACSA member countries, should be directed towards improvement of the silkproductivity of the hybrids and the qualities of the silk fibre, by the same time preservingtheir comparatively high pupation rate and cocoon yield