Central Sericultural Germplasm Resources Centre, Central Silk Board, Hosur 635 109, Tamil Nadu, India
The genetic variation and diversity among fifty-eight polyvoltine silkworm genotypes was estimated by using ten economic traits. The results revealed that the single shell weight showed higher genetic variation such as PCV% (17.20%), GCV% (12.93%), and heritability (56.5%) followed by single cocoon weight, shell ratio and matured larval weight. The D2 (Mahalonobis? distance) statistics revealed nine clusters with substantial inter and intra cluster distances. The genotypes included in different clusters varied from 1 to 16. The genotype Pure Mysore was included in isolated cluster indicates its longer adaptation. The genotypes included in cluster VIII and IX showed optimum genetic distance along with higher cluster mean emphasised for utilization in the silkworm breeding.
Anonymous (1997) Principles and techniques of silkworm breeding. ESCAP, Oxford & IBH Publishing Co. Pvt. Ltd., United Nations, New York, 114 p.
Arunachalam, S., Bandyopadhy, S.N., Nigam, R. W. and Gibbons (1984) Heterosis in relation to genetic divergence and specific combining ability in groundnut (Arachis hypgaea). Euphytica, 33‚ 33-39.
Chatterjee, S.N. and Mohandas, T.P. (2003) Identification of ISSR markers associated with productivity traits in silkworm Bombyx mori L. Genome, 46: 438-447.
Chatterjee, S.N., Ramamohana Rao, P., Ravindra Singh and Datta, R.K. (1993) Genetic variability in mulberry silkworm Bombyx mori L. breeds with low silk yield. Indian J. Seric. 32‚ 69- 86.
Dalton, D.C. (1987) An introduction to practical animal breeding. 2nd Edition, English Language Book Society/Collins, 182 p.
Frankel, O.H. and Brown, A.H.D. (1983) Current plant genetic resources a critical appraisal. In: Genetics: New Frontiers, Volume IV Applied Genetics, Proceedings XV International Congress of Genetics, New Delhi, V.L. Chopra, B.C. Joshi, R.P. Sharma and H.C. Bansal, eds.) (New Delhi: Oxford and IBH Publishing Co) pp: 3-13.
Jolly, M.S., Datta, R.K., Noamani, M.K.R., Iyengar, M.N.S., Nagaraj, C.S., Basavaraj, H.K., Kshamarani, G. and Ramamohana Rao, P. (1989) Studies on the genetic divergence in mulberry silkworm Bombyx mori L. Sericologia, 29‚ 545- 559.
Krishnaswamy, S. (1978) New technology of silkworm rearing. CSR&TI., Central Silk Board, Mysore, India, Bullettin No. 2.
Kumaresan, P., Sinha, R.K., Sahni, N.K. and Sekar, S. (2000) Genetic variability and selection indices for economic quantitative traits of multivoltine mulberry silkworm (Bombyx mori L.) genotypes. Sericologia, 40‚ 595-605.
Kumaresan, P. and Sinha, R.K. (2002) Genetic divergence in multivoltine silkworm germplasm in relation to cocoon characters. Indian J. Genet. 62‚ 183-184.
Kumaresan, P., Sinha, R.K. and Thangavelu, K. (2003) Heterosis studies in some elite multivoltine silkworm (Bombyx mori L.) races with popular bivoltine NB4D2. Int. J. Indust. Entomol. 7‚ 221- 229.
Kumaresan, P., Mahadevamurthy, T.S., Thangavelu, K. and Sinha, R.K. (2003a ) Further studies on the genetic divergence of multivoltine silkworm (Bombyx mori L.) genotypes based on economic characters. Entomon, 28‚ 193-198.
Kumaresan, P., Sinha, R.K., Mohan, B. and Thangavelu, K. (2004) Conservation of multivoltine silkworm (Bombyx mori L.) germplasm in IndiaAn Overview. Int. J. Indust. Entomol. 9‚ 1-13.
Kumaresan, P., Sinha, R.K. and Thangavelu, K. (2005) Phenotypic stability and G E interaction in cocoon weight of multivoltine silkworm (Bombyx mori L.) genotypes. Indian J. Seric. 44‚ 136-138.
Murakami, A. (1994) Growth phenomena in Bombyx mori L. with a special reference to genetic factors responsible for growth acceleration and moultinism. Indian J. Seric. 33‚ 12-14.
Mukherjee, P., Mukherjee, S. and Kumaresan, P. (1999) An analysis of genetic divergence in Indian multivoltine silkworm (Bombyx mori L.) germplasm. Sericologia, 39‚ 337-347.
Narasimharaju, R., Govindan, R., Ashoka, J., Rayar, S.G. (1990) Genetic variability for quantitative traits in silkworm B. mori. Entomon, 15‚ 197-201.
Ramamohana Rao, P. and Nakada, T. (1998) Clustering of polyvoltine strains of the silkworm B. mori by image processing method: Significance of cocoon size and weight variables. Indian J. Seric. 37‚ 33-39.