Breeding of New Productive Bivoltine Hybrid, CSR12×CSR6 of Silkworm Bombyx mori L.

( R. K. Datta ),( H. K. Basavaraja ),( N. Mal Reddy ),( S. Nirmal Kumar ),( N. Suresh Kumar ),( M. Ramesh Babu ),( M. M. Ahsan ),( K. P. Jayaswal ) 한국잠사학회 2001 International Journal of Industrial Entomology Vol.3 No.2

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8×BCS25 and Shunrei×Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8×BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei×Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12×CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12×CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA×NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12×CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Breeding of New Productive Bivoltine Hybrid, CSR12 $\times$ CSR6 of Silkworm Bombyx mori L.

Datta, R.K.,Basavaraja, H.K.,Reddy, N.Mal,Kumar, S.Nirmal,Kumar, N.Suresh,Babu, M.Ramesh,Ahsan, M.M.,Jayaswal, K.P. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.3 No.2

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8$\times$BCS25 and Shunrei$\times$Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8 ${\times}$ BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei${\times}$Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12${\times}$CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12$\times$CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA ${\times}$ NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12$\times$CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Development of a Robust Polyvoltine Breed $'NP_1'$ of the Mulberry Silkworm, Bombyx mori L.

Singh Ravindra,Rao D. Raghavendra,Sharma S.D.,Chandrashekaran K.,Basavaraja H.K.,Kariappa B.K.,Dandin S.B. Korean Society of Sericultural Science 2006 International Journal of Industrial Entomology Vol.12 No.1

A breeding programme was initiated during 2001 utilizing two polyvoltine silkworm breeds viz. $BL_{69}$, an evolved breed tolerant to high temperature and MAR, comparatively resistant to Bombyx mori nuclear polyhedrosis virus (BmNPV) with the objective to develop robust polyvoltine breeds and hybrids. The breed $NP_1$ was developed by exposing the fifth instar larvae to high temperature $(36{\pm}1^{\circ}C)$, high Relative Humidity ($85{\pm}5%$ R.H.) and inoculating third instar larvae with BmNPV inoculum. At $F_{12}$, the breed was tested for hybrid forming ability utilizing six bivoltine silkworm breeds viz. $CSR_2,\;CSR_4,\;CSR_{17},\;CSR_{18},\;CSR_{19}\;and\;NB_4D_2$. The hybrid $'NP_1{\times}CSR_{17}'$ exhibited its superiority by recording 97.2% survival, 1.892 g cocoon weight, 0.406 g cocoon shell weight, 21.5% cocoon shell ratio, 16.6% raw silk percentage and 890 m filament length whereas the control $(PM{\times}CSR_2)$ has recorded 90.2% survival, 1.599 g cocoon weight, 0.304 g cocoon shell weight, 18.9% cocoon shell ratio, 13.1 % raw silk percentage and 768 m filament length. Commercial exploitation of the new $polyvoltine{\times}bivoltine$ hybrid in sericulture industry has been discussed.

On the Breeding of "CSR18 x CSR19" - A Robust Bivoltine Hybrid of Silkworm,Bombyx mori L. for the Tropics

N.SureshKumar,H.K.Basavaraja,C.M.KishorKumar,N.MalReddy,R.K.Datta 한국잠사학회 2002 International Journal of Industrial Entomology Vol.5 No.2

Evolution of a Productive Bivoltine Hybrid of Silkworm Bombyx mori L. (SD7 x SD12) with Shorter Larval duration

P. Sudhakara Rao,H. K. Basavaraja,G. V. Kalpana,V. Nishitha Naik,K. C. Mahalingappa,S. N. Pallavi 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

With an objective of evolving quantitatively and qualitatively superior bivoltine silkworm hybrid of Bombyx mori L. for tropics with shorter larval duration without compromising on productivity traits, a breeding programme was initiated at this institute during 1997 by utilizing breeding resource material from the institutes Germplasm collection. The breed SD7 is characterized with plain larvae spinning white oval cocoons and SD12 is characterized by sex-limited larval markings spinning white dumb-bell cocoons. After fixation, these breeds along with other newly evolved breeds were subjected for hybrid evaluation in the laboratory. Based on the hybrid studies, the hybrid SD7 ´ SD12 was selected and evaluated for one year comprising three major seasons (6 trials) of tropics viz., Pre-monsoon (characterized by high temperature, low humidity and without any rain fall), Monsoon (characterized by moderate temperature, heavy rain fall with high humidity) and post-monsoon season (characterized by low temperature and low humidity with frequent rain fall) to know the fluctuations in the larval duration. The evaluation studies indicated that the hybrid is having shorter larval duration with productive merits. The hybrid SD7 ´ SD12 recorded survival percent of 92.74, shell weight of 46.7 cg, shell ratio % of 24.0 and filament length of 1,200 meters with a shorter larval duration of 24 hrs; when compared to productive hybrid CSR2 ´ CSR5 (control). The breeding methodologies and hybrids usefulness for tropics were discussed.

Evolution of a Productive Bivoltine Hybrid of Silkworm Bombyx mori L. (SD7×SD12) with Shorter Larval Duration

( P. Sudhakara Rao ),( H. K. Basavaraja ),( G. V. Kalpana ),( V. Nishitha Naik ),( K. C. Mahalingappa ),( S. N. Pallavi ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

With an objective of evolving quantitatively and qualitatively superior bivolitine silkworm hybrid of Bombyx mori L. for tropics with shorter larval duration without compromising on productivity traits, a breeding programme was initiated at this institute during 1997 by utilizing breeding resource material from the institutes Germplasm collection. The breed SD7 is characterized with plain larvae spinning white oval cocoons and SD12 is characterized by sex-limited larval markings spinning white dumb-bell cocoons. After fixation, these breeds along with other newly evolved breeds were subjected for hybrid evaluation in the laboratory. Based on the hybrid studies, the hybrid SD7×SD12 was selected and evaluated for one year comprising three major seasons (6 trials) of tropics viz., Pre-monsoon (characterized by high temperature, low humidity and without any rain fall), Monsoon (characterized by moderate temperature, heavy rain fall with high humidity) and post-monsoon season (characterized by low temperature and low humidity with frequent rain fall) to know the fluctuations in the larval duration. The evaluation studies indicated that the hybrid is having shorter larval duration with productive merits. The hybrid SD7×SD12 recorded survival percent of 92.74, shell weight of 46.7 cg, shell ratio % of 24.0 and filament length of 1,200 meters with a shorter larval duration of 24 hrs; when compared to productive hybrid CSR2×CSR5 (control). The breeding methodologies and hybrids usefulness for tropics were discussed.

Breeding of Productive Bivoltine Hybrid, CSR16${\times}$CSR17 of Silkworm Bombyx mori L.

Reddy, N.Mal,Basavaraja, H.K.,Kumar, N.Suresh,Joge, P.G.,Kalpana, G.V.,Dandin, S.B.,Datta, R.K. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.2

The breeding work was initiated by utilizing two Japanese hybrids namely C135${\times}$N134 and N137${\times}$C146 along with two evolved Indian breeds, J14 and A24. The breed CSR16 which is characterized with marked larvae and white dumbbell cocoons was evolved from the Japanese hybrid C135${\times}$N134 by crossing with J14, while the breed CSR17 which is characterized with plain larvae and white oval cocoons was evolved from the Japanese hybrid N137${\times}$C146 by crossing with A24. The hybrid of these evolved breeds i.e., CSR16${\times}$CSR17 has shown superior over control hybrid $KA{\times}{NB_4}{D_2}$ and on par with the ruling hybrid of CSR2${\times}$CSR4. The hybrid CSR16${\times}$CSR17 was authorized during 1999 by Central Silk Board, Bangalore, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Effect of High Temperature and High Humidity on the Quantitative Traits of Parents, Foundation Crosses, Single and Double Hybrids of Bivoltine Silkworm, Bombyx mori L.

Kumar, N.Suresh,Basavaraja, H.K.,Reddy, N.Mal,Dandin, S.B. Korean Society of Sericultural Science 2003 International Journal of Industrial Entomology Vol.6 No.2

The hot climatic conditions prevailing particularly in summer are not conducive to rear these high yielding bivoltine hybrids throughout the year, In order to select efficiently the breeds with high temperature tolerance, it is very important to analyze critically the impact of high temperature on many silk yielding attributes of silkworm races. Keeping the above in view, the present study was undertaken to determine the effect of high temperature $(36 {\pm} 1^{\circ}C)$ and high humidity $(80 {\pm} 5% Relative Humidity)$ on the rearing performance of pure races, foundation crosses, single hybrids and double hybrids of bivoltine silkworm, Bombyx mori L. The robust bivoltine breeds, CSR18, CSR19, 8HT and 5HT, eight foundation crosses, eight single hybrids and eight double hybrids involving these breeds were chosen as materials in this study.

Evolution of a Productive Bivoltine Hybrid of Silkworm Bombyx mori L.(SD7${\times}$SD12) with Shorter Larval Duration

Rao, P.Sudhakara,Basavaraja, H.K.,Kalpana, G.V.,Naik, V.Nishitha,Mahalingappa, K.C.,Pallavi, S.N. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.1

With an objective of evolving quantitatively and qualitatively superior bivolitine silkworm hybrid of Bombyxmori L. for tropics with shorter larval duration without compromising on productivity traits, a breeding programme was initiated at this institute during 1997 by utilizing breeding resource material from the institutes Germplasm collection. The breed SD7 is characterized with plain larvae spinning white oval cocoons and SD12 is characterized by sex-limited larval markings spinning white dumb-bell cocoons. After fixation, these breeds along with other newly evolved breeds were subjected for hybrid evaluation in the laboratory. Based on the hybrid studies, the hybrid SD7${\times}$SD12 was selected and evaluated for one year comprising three major sea- sons (6 trials) of tropics viz., Pre-monsoon (characterized by high temperature, low humidity and without any rain fall), Monsoon (characterized by moderate temperature, heavy rain fall with high humidity) and post-monsoon season (characterized by low temperature and low humidity with frequent rain fall) to know the fluctuations in the larval duration. The evaluation studies indicated that the hybrid is having shorter larval duration with productive merits. The hybrid SD7${\times}$SD12 recorded survival percent of 92.74, shell weight of 46.7 cg, shell ratio % of 24.0 and filament length of 1,200 meters with a shorter larval duration of 24 hrs; when compared to productive hybrid CSR2${\times}$CSR5(control). The breeding methodologies and hybrids usefulness for tropics were discussed.

Performance of Newly Evolved Bivoltine Silkworm Hybrids of Bombyx mori with Reference to Hybrid Vigour

Reddy, N.Mal,Basavaraja, H.K.,Kumar, N.Suresh,Joge, P.G.,Kalpana, G.V.,Dandin, S.B. Korean Society of Sericultural Science 2003 International Journal of Industrial Entomology Vol.7 No.1

In the present study, hybrid vigour in terms of heterosis and over dominance of newly evolved bivoltine hybrids and their reciprocals raised from the promising newly evolved bivoltine breeds were calculated for the important parameters like pupation, cocoon yield, cocoon weight, shell weight, shell ratio, raw silk percentage, filament length and neatness. Through there was no significant difference among the hybrids for the characters pupation, cocoon yield and cocoon weight, the magnitude of heterosis and over dominance were varied significantly for these characters. However, significant differences were observed between new hybrids and control hybrid for the characters like cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage. The results indicate that majority of new hybrids have shown higher heterosis and over dominance than control hybrid. The data also indicate that highest mean heterosis of all new hybrids was recorded for cocoon yield followed by filament length. Whereas highest mean over dominance was recorded for cocoon yield followed by cocoon weight. Negative mean heterosis and over dominance were recorded for the trait cocoon shell ratio. Based on the results, the importance of three hybrids viz., CSR2 ${\times}$ CSR4, CSR2 ${\times}$ CSR5 and CSR3 ${\times}$ CSR6 and their reciprocals (CSR4 ${\times}$ CSR2, CSR5 ${\times}$ CSR2 and CSR6 ${\times}$ CSR3) which exhibited significant heterosis and over dominance, for commercial exploitation was discussed.