| The long pupal stage in silkworms can be achieved by crossing wild silkworms with extended pupal durations with domesticated varieties that exhibit a pupal stage at least 10 days longer than those commonly used in production. In this study, the hybridization of YSCAK8 wild silkworms and 872A domesticated silkworms was conducted during the spring silkworm rearing period. The female moths of YSCAK8 wild silkworms produced cocoons in the spring, with a pupal stage lasting 20 days. A single generation of crossbreeding was performed in the autumn, and the resulting hybrid moths were backcrossed with male YSCAK8 moths, which exhibited a pupal stage of 122 days. After nine generations of directed breeding and selection, the genes controlling the pupal stage duration were fully stabilized in the hybrid material. The basic material 8728 was developed, with pupae remaining un-emerged for at least 18 days. The distribution of pupal stages was as follows: 19~25 days (1.77%), 26~30 days (3.89%), 31~50 days (39.75%), 51~70 days (31.27%), 71~90 days (18.38%), 91~110 days (4.06%), and 111~116 days (0.88%). The total cocoon weight averaged 1.24 g, with a cocoon layer weight of 0.20 g and a cocoon layer rate of 16.42%. The dead cage rate was 7.1%. |
