FACTORS AFFECTING THE HATCHABILITY OF EGGS OF THE SILKWORM, BOMBYX MORI, AFTER SHORT PERIOD OF COLD STORAGE AND ACID TREATMENT
Wang Yu-qing, Yang Ming-guan( Department of Sericulture Zhejiang Agricultural University )
Generally, the hatchability for practical use of the silkworm eggs after cold storage and acid treatment is not satisfactory, when the chilling period is less than 30 days, In order to increase the hatchability of silkworm eggs. Am experiment involving four factors: (A) duration of cold storage. (B) degree of high temperature exposed after the cold storage. (C) time exposed to high temperature and (D) duration of acid treatment was carried out to investigate their effect on the hatchability of silkworm eggs in 4 perent strains: Zhejiang Agricultural University No. 1 (ZAU No. 1), Dong34 Sul2 and Dong Fei.Results obtained were as follows:1. After oviposition, the eggs of 4 races were kept in cold storage after having been under protection at 24℃ for 50-60 hours. For those races that were kept in cold storage for less than 30 days, (A), (B), and (D) had more effect than (C), There was interaction among 4 factors. These findings suggest that in practice selection for the integrated factor combination should be emphasized. 2. There were significant differences among races as to the range of the factors used so arrive at a satisfactory hatchability for practical use, There was broader range of these factors to be eelected for Dong 34 and Su 12. The range was narrower for ZAU No.1, and as for Dong Fei, no satisfactory factor combination had yet been found from the range of the 4 factors set for the present experiment.3. Results showed that for the current summer and autnmn races ZAU No.1, Dong 34 and Su 12, with the normal treatment, cold storage of 20 days would be sufficient to bring about a hatchability for parctical use of more than 90%. The effect of time of acid treatment on ZAU No. 1 was especially marked, and in case of short time cold stroage, appropriately prolong the duration of acid treatment would be worthy of consideration.