Relatively harder and high production potential silkworms suitable to different ecological domains are necessary for sericulture enterprise, a farm based labor intensive agro-enterprise. The climatic data proves that mid-hill has favorable agro-eco-climate for mulberry based bivoltine sericulture. This book explores the adaptability of bivoltine silkworm pure breed and hybrid genotypes to different ecological domains through different experiments including seven ecological domains, two pure breeds and five hybrids. Based on performance through multi-location testing over years, the book finish off the suitable ecological domains for pure breeds (J12 and C12) as Pokhara and Dhunibesi, while for hybrids as Khopasi and Pokhara (J12×C12) and Dhunibesi (N109×N112). The book recommends focusing future research and development in this discipline to concentrate seed cocoon production on highly productive and low mortality ecological domains and assess best performing silkworm hybrids for quality cocoon with better economic returns. The information is useful for sericulturists, professionals working in the field of Entomology and students studying Entomology, specifically the sericulture.