辽宁地区桑蚕春制越年种保护方法试验报告

0n the Protection Method for the Hibernating Eggs of Bombyx mori Produced in Spring in Liaoning Area

High temperature incubation for parent strain of Bombyx mori was adopted and rearing temperature was relatively high during the young period of larvae but relatively low during the period of grown larvae. Suitable but a little bit old mulberry leaves were used for rearing. Protection time for eggs at high temperature should be appro- priately extended after oviposition. "Mid-way" treatment during chill- ing period was employed. The result showed that the hibernating eggs were substantial in content,with diapause deepened and not easily acti- vated. As a consequence, the chilling tolerance of the hibernating eggs was enhanced and the physiological limitation of chilling tolerance was extended. In addition to the increase in hatchability, an even hatching of eggs was demonstrated.