Specific breeding approach and screening methods to develop congenic silkworm, Bombyx mori L.

摘要

Embryonic diapausing, both pigmented purple colour univoltine, bivoltine and non-diapausing non-pigmented yellow colour multivoltine is maternally influenced sex-linked character. Non-diapausing avoltine breed character controlled by autosome linked homozygous Id (inhibitor of diapause) gene in male and female producing pseudo pigmented purple colour eggs and has no maternal influence that has immense importance in tropical sericulture like India. Dominant homozygous Id gene possessing avoltine males and females are used for crossing with both bivoltine females and males for hybrid egg production without rejecting bivoltine females and multivoltine males, thus save paucity of hybrid egg production as no acid treatment is required. However, in conventional method hot or cold acid treatment is essential when bivoltine females are utilized in commercial hybrid eggs production. Problem behind the utilization of avoltine breed is the poor survival and highly vulnerable to diseases. To overcome this barrier, introgression of dominant homozygous Id gene was carried out in female and male of already developed better survival ruling multivoltine congenic breed. It is a difficult task to develop such congenic breed carrier of homozygous Id gene. This paper deals with very specific breeding approach and screening method to develop homozygous Id gene carrier both females and males congenic breed for betterment of sericulture industry.