22 Ara 2024 Pazar
An overview on the development and evaluation of breeds / hybrids of the Mulberry Silkworm, Bombyx mori L.
Abstract :Response of different silkworm breeds towards parthenogenetic development has been studied in newly developed bivoltine and polyvoltine silkworm breeds. Japanese type bivoltine silkworm breeds showed pronounced parthenogenetic developments as compared to Chinese ones. An increased tendency towards parthenogenetic development was observed in hybrids obtained from a mother moth having a high tendency of parthenogenesis. Three bivoltine breeds viz., DNB1, DNB6 and DNB7 were developed and evaluated. Evaluation was carried out through various statistical tools like analysis of combining ability, hybrid vigour and cocoon size uniformity. Androgenetic development was also induced in different silkworm breeds/hybrids. Polyvoltine hybrids exhibited higher androgenic development as compared to bivoltine hybrids. A breed with dominant cocoon colour gene was utilized as genetic marker to identify androgenic male individuals. Induction of androgenesis was performed by exposing the oviposited eggs to hot air (38 ºC) for 200 min. Repeated backcrosses were adopted utilizing androgenic males to introgress homozygosity in the breeding lines. Among six polyvoltine silkworm breeds developed through androgenesis, two breeds AGL3 and AGL5 were found promising. Two bivoltine hybrids viz., DNB1 × CSR4 and DNB7 × CSR2 and 2 polyvoltine × bivoltine hybrids viz., AGL3 × CSR2 and AGL5 × CSR2 were found promising.
Androgenesis, Bombyx mori, evaluation, hybrid vigour, combining ability, parthenogenesis, performance, silkworm breed and hybrids