The old European Silkworm Breeds, Reared in the Early 20th Century in Bulgaria and the Possibilities for Using Some of Them in the Modern Sericulture

Since the beginning of a local egg production by Pasteur’s method in 1895 mostly two local silkworm breeds have been reared in Bulgaria, namely Yellow local and White Baghdad. The origin of Yellow local breed is supposed to be from the locally spread in North and South-West Bulgaria race in 16th – 19th century while the White Baghdad originated from Asia Minor. The Yellow local race was reared in whole North and in South West Bulgaria and was characterized with yellow cocoons with elongated shape with slight constriction. The White Baghdad race was reared in South East Bulgaria and consisted of 3 types, namely Edirne type, Improved Bulgarian type and Bulgarian type. White Baghdad race cocoon color varied from snow-white to light green, but the prevailing color was white. The cocoon shape was elongate with constriction. It was detected that the old silkworm breeds, reared in Bulgaria during 20th – 30th years of the 20th century were generally characterized with not very uniform larval color and markings, cocoon color and shape, comparatively high cocoon weight, but lower silk shell percentage and filament length as well as they were comparatively tolerant to NPV disease. Due to the long maintenance of those races in Bulgaria they were well adapted to the local food and climatic conditions. Presently the Yellow local strain displays a high hatchability and survivability, shorter 5th instar duration and a comparatively good reproduction capacity. On the other hand, the Yellow local strain manifests lower values of the main productive character values such as cocoon weight, silk shell weight and percentage, silk filament length and weight, reelability and raw silk percentage characters, compared with the commercial Bulgarian white cocoon breeds. Therefore, in order to commercialize the Yellow local strain in nowadays it needs improvement by the methods of genetics and breeding. A review of the literature about main silkworm qualitative character inheritance was made. Possible research work in improvement of the old silkworm races was recommended.