International Journal of Applied Research
Vol. 3, Issue 5, Part C (2017)
Development of cocoon colour sex-limited breeds/foundation crosses of silkworm Bombyx mori L. in the production of commercial hybrid
Seetharamulu J, SV Seshagiri, M Srilatha, K Madhavi and PJ Raju
Indian sericulture industry depends on Poly x Bivoltine hybrids and are being reared over decades. The crossbreeds are prepared through the mating of polyvoltine female with bivoltine male parent. Which involves sex separation of pupae in bivoltine parent and only males are retained and females are rejected to avoid selfing. In this context, introduction of viable breeds with sex-limited traits i.e., the character found on only one sex at different stages of life cycle assume significance in silkworm seed production. This study was designed to develop sex limited breeds and foundation crosses for cocoon colour in the production of commercial hybrid. The advantages of sex limited foundation cross is easy at farmer’s level with improved fecundity and reduced labour cost since the yellow cocoons can be reeled and males can be utilized in the preparation of cross breed. Keeping this as strategy, 10 productive bovoltine breeds along with the sex-limited donor (SLO1) were reared and based on the pupation rate and cocoon uniformity, the females of donor were crossed with the recipient males. The replication with consistency in yellow colour was selected at F1 wherein all the yellow cocoons are females and white cocoons are males. Cellular rearing was followed at early generation and back cross with recipient males was carried out from F1 - F6 generation to establish breed characters in addition to sex limited trait followed by selection and inbreeding was done from F7 to F12. After F12 generation, the consistency in the breed characters were assessed in the 10 productive sex-limited breeds. Further studies are in progress to establish sex-limited foundation crosses. The paper discusses on all the above aspects.
How to cite this article:
Seetharamulu J, SV Seshagiri, M Srilatha, K Madhavi and PJ Raju. Development of cocoon colour sex-limited breeds/foundation crosses of silkworm Bombyx mori L. in the production of commercial hybrid. International Journal of Applied Research. 2017; 3(5): 170-173.