Evaluation and Identification of Promising Bivoltine Breeds inthe Silkworm Bombyx mori L.

A. Naseema Begum,H. K. Basavaraja,P. G. Joge,A. K. Palit 한국잠사학회 2008 International Journal of Industrial Entomology Vol.16 No.1

Under the all India programme of evaluation of mulberry and silkworm genotypes, twelve bivoltine silkworm breeds obtained from Central Silkworm Germplasm Resource Centre, Hosur (CSGRC) were evaluated at the bivoltine silkworm breeding laboratory, Central Sericultural Research & Training Institute, Mysore (CSR&TI). These breeds were tested during September-October 2003, August-September 2004 and February-March 2005. The average temperature and humidity during September-October 2003 was 26.5oC and 72.6% RH, while during August-September 2004, it was 26.5oC and 75.2% RH and during February-March 2005 it was 24oC and 48% RH respectively. The performance of the breeds in respect of 21 traits was studied and statistically analyzed using analysis of variance (Singh and Choudhary, 1985). Silkworm breeds were short-listed using multiple trait evaluation index method as suggested by Mano et al., (1993). Evaluation Index values were calculated for all the 11 traits of economic importance and six breeds were short-listed based on average index value 50 and above 50. Two breed viz., BV 183 (SMGS-1) have recorded average E.I. > 50 in 10 traits (except in neatness) and ranked first and the breed BV 262 (SMGS-9) with E.I. value > 50 in nine traits except in cocoon weight and neatness ranked second, in the order of merit. These two breeds may be selected as resource material for evolving region specific silkworm breeds.

Note : Line×Tester Analysis of Certain Quantitative Traits in Silkworm Bombyx mori L. under Optimum and Stress Rearing Conditions

( P. Sudhakara Rao ),( R. K. Datta ),( K. M. Vijaya Kumari ),( A. K. Palit ),( S. A. Bhat ) 한국잠사학회 2007 International Journal of Industrial Entomology Vol.8 No.1

The combining abilities in the 5 newly evolved thermo tolerant breeds viz., SR6, SR7, SR8 SR9 and SR10 of silkworm Bombyx mori L. and their 15 hybrids were made in a line×tester crossing programme. Data were analysed for seven quantitative traits i.e., pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage under optimum room temperature (25±1℃) conditions (In case of high temperature (36±1℃) stress conditions five economic traits except filament length and raw silk percentage) with 3 widely adapted testers i.e., KA, CSR2 and CC1 as lines (females) and testers (males) respectively. The performance at high temperature and low humidity conditions are only taken into consideration for selecting the best lines/hybrids. Among the lines SR6 exhibited positive General combining ability (GCA) effects for pupation rate, cocoon yield, cocoon weight and cocoon shell ratio traits, followed by SR7 for pupation rate, cocoon yield and cocoon shell weight and cocoon shell ratio. Among testers, KA exhibited positive GCA effects for two quantitative traits cocoon yield, cocoon weight and CSR2 for cocoon shell weight and cocoon shell ratio under adverse temperature conditions. The hybrid SR6×CC1 and SR7×CSR2 exhibited significant positive Specific combining ability (SCA) effects for majority of the traits in high temperature stress conditions of rearing. The better parent value of heterosis (Heterobeltiosis) was exhibited by the hybrid SR6×CC1 for pupation rate, cocoon yield, cocoon weight and cocoon shell weight and SR7×CSR2 for all the traits evaluated under high temperature conditions. Based on the results, the lines SR6 and SR7 was judged as best combiners and the hybrids SR6×CC1 and SR7×CSR2 can be selected for commercial exploitation in tropical climate.

Line × Tester Analysis of Certain Quantitative Traits in Silkworm Bombyx mori L. under Optimum and Stress Rearing Conditions

P. Sudhakara Rao,R. K. Datta,K. M. Vijaya Kumari,A. K. Palit,S. A. Bhat 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

The combining abilities in the 5 newly evolved thermo tolerant breeds viz., SR6, SR7, SR8 SR9 and SR10 of silkworm Bombyx mori L. and their 15 hybrids were made in a line ´ tester crossing programme. Data were analysed for seven quantitative traits i.e., pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage under optimum room temperature (25 ± 1oC) conditions (In case of high temperature (36 ± 1oC) stress conditions five economic traits except filament length and raw silk percentage) with 3 widely adapted testers i.e., KA, CSR2 and CC1 as lines (females) and testers (males) respectively. The performance at high temperature and low humidity conditions are only taken into consideration for selecting the best lines/ hybrids. Among the lines SR6 exhibited positive General combining ability (GCA) effects for pupation rate, cocoon yield, cocoon weight and cocoon shell ratio traits, followed by SR7 for pupation rate, cocoon yield and cocoon shell weight and cocoon shell ratio. Among testers, KA exhibited positive GCA effects for two quantitative traits cocoon yield, cocoon weight and CSR2 for cocoon shell weight and cocoon shell ratio under adverse temperature conditions. The hybrid SR6 ´ CC1 and SR7 ´ CSR2 exhibited significant positive Specific combining ability (SCA) effects for majority of the traits in high temperature stress conditions of rearing. The better parent value of heterosis (Heterobeltiosis) was exhibited by the hybrid SR6 ´ CC1 for pupation rate, cocoon yield, cocoon weight and cocoon shell weight and SR7 × CSR2 for all the traits evaluated under high temperature conditions. Based on the results, the lines SR6 and SR7 was judged as best combiners and the hybrids SR6 ´ CC1 and SR7 ´ CSR2 can be selected

Line${\times}$Tester Analysis of Certain Quantitative Traits in Silkworm Bombyx mori L. under Optimum and Stress Rearing Conditions

Rao, P.Sudhakara,Datta, R.K.,Kumari, K.M.Vijaya,Palit, A.K.,Bhat, S.A. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.8 No.1

The combining abilities in the 5 newly evolved thermo tolerant breeds viz., SR6, SR7, SR8 SR9 and SR10 of silkworm Bombyx mori L. and their 15 hybrids were made in a line${\times}$tester crossing programme. Data were analysed for seven quantitative traits i.e., pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, filament length and raw silk percentage under optimum room temperature $(25{\pm}{1^{\circ}C})$ conditions (In case of high temperature $(36{\pm}{1^{\circ}C})$ stress conditions five economic traits except filament length and raw silk percentage) with 3 widely adapted testers i.e., KA, CSR2 and CC1 as lines (females) and testers (males) respectively. The performance at high temperature and low humidity conditions aye only taken into consideration for selecting the best lines/hybrids. Among the lines SR6 exhibited positive General combining ability (GCA) effects for pupation rate, cocoon yield, cocoon weight and cocoon shell ratio traits, followed by SR7 for pupation rate, cocoon yield and cocoon shell weight and cocoon shell ratio. Among testers, KA exhibited positive GCA effects for two quantitative traits cocoon yield, cocoon weight and CSR2 for cocoon shell weight and cocoon shell ratio under adverse temperature conditions. The hybrid SR6${\times}$CC1 and SR7${\times}$CSR2 exhibited significant positive Specific combining ability (SCA) effects for majority of the traits in high temperature stress conditions of rearing. The better parent value of heterosis(Heterobeltiosis) was exhibited by the hybrid SR6${\times}$CC1 for pupation rate, cocoon yield, cocoon weight and cocoon shell weight and SR7${\times}$CSR2 for all the trails evaluated under high temperature conditions. Based on the results, the lines SR6 and SR7 was judged as best combiners and the hybrids SR6${\times}$CC1 and SR7${\times}$CSR2 can be selected for commercial exploitation in tropical climate.

Heterotic Expression in Silk Productivity of Newly Evolved Thermo-tolerant Bivoltine Hybrids of Silk worm Bombyx mori L.

( P. Sudhakara Rao ),( R. K. Datta ),( K. M. Vijaya Kumari ),( A. K. Palit ),( S. Z. Haque Rufaie ) 한국잠사학회 2004 International Journal of Industrial Entomology Vol.9 No.1

Research Articles : Seasonal Effects on the Performance of Newly Evolved Bivoltine Hybrids of the Silkworm (Bombyx mori L.) Under Tropics

( P. Sudhakara Rao ),( R. K. Datta ),( A. K. Palit ),( S. Z. Haque Rufaie ) 한국잠사학회 2004 International Journal of Industrial Entomology Vol.9 No.2

Development of Fine Denier Silkworm Hybrid CSR48×CSR5 of Bombyx mori L. for Superior Quality Silk

( G. V. Kalpana ),( N. Suresh Kumar ),( H. K. Basavaraja ),( N. Mal Reddy ),( A. K. Palit ) 한국잠사학회 2005 International Journal of Industrial Entomology Vol.10 No.2

Serious attempt for the improvement of quality parameters in silkworm hybrids came rather very late in India. Realising the need for productive breeds to the field and reorientation in breeding methodology, the silkworm breeders of CSRTI, Mysore were able to develop silkworm breeds with fine denier namely, JPN7, CSR48, B63 and B65 of specific industrial requirement through directional selection. As the success of silkworm breeds mainly depends on their combining ability, the developed breeds were subjected for hybrid evaluation. Out of 42 bivoltine hybrids studied, one hybrid, CSR48×CSR5 was identified for its superiority over the existing bivoltine hybrids namely CSR2×CSR4, CSR2×CSR5 and CSR18×CSR19 for majority of qualitative traits. Post cocoon testing of large quantity of cocoons of CSR48×CSR5 resulted in the production of high quality 3A grade silk. It is for the first time in the Indian Sericulture industry that high quality silk with longer filament length of 1474m, denier of 2.47, standard size deviation of 0.983d, maximum size deviation of 1.322, neatness of 96p, reelability of, 85% tenacity of 3.87 g/d, elongation of 22.32% and cohesion of 110 strokes was produced. The superiority of fine denier silkworm breeds and their hybrids are discussed.

Seasonal Effects on the Performance of Newly Evolved Bivoltine Hybrids of the Silkworm (Bombyx mori L.) Under Tropics

Rao, P.Sudhakara,Datta, R.K.,Palit, A.K.,Haque Rufaie, S.Z. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.9 No.2

Seasonal effects of the newly evolved bivoltine hybrid namely CSR$_2$${\times}$SR$_{5}$, SR$_1$ ${\times}$SR$_4$ and control hybrid KA${\times}$NB$_4$D$_2$ along with their parents SR$_1$, SR$_4$, SR$_{5}$, CSR$_2$ KA and NB$_4$D$_2$ were evaluated during different seasons of the year to understand genotype and environment interactions. Data were collected on five economic importance namely, pupation rate, cocoon yield, cocoon weight, cocoon shell ratio and filament length of the lines, hybrids and the control breeds/hybrid in three different seasons i.e., Pre-Monsoon, Monsoon and post-monsoon and subjected to relevant statistical methods. Seasonal performance of CSR$_2$, SR$_1$, SR$_4$ and SR$_{5}$ revealed superiority over control breeds KA and NB$_4$D$_2$. Both the hybrids i.e., CSR$_2$${\times}$SR$_{5}$ and SR$_1$${\times}$SR$_4$ performed well under diversified environmental conditions of tropical climate in a year indicating overall stability. These hybrids revealed highly significant (P < 0.01) variations for majority of the traits studied over the control hybrid KA${\times}$NB$_4$D$_2$.$.

Heterotic Expression in Silk Productivity of Newly Evolved Thermo-tolerant Bivoltine Hybrids of Silkworm Bombyx mori L.

Rao, P.Sudhakara,Datta, R.K.,Vijaya Kumari, K.M.,Palit, A.K.,Haque Rufaie, S.Z. Korean Society of Sericultural Science 2004 International Journal of Industrial Entomology Vol.9 No.1

Studies on heterotic expression in the silk productivity of 66 thermo-tolerant bivoltine hybrids reared under high temperature $(36{\times}1^{\circ}C)$ and low humidity (60${\times}$5%) conditions revealed that manifestation of heterosis was highly significant for majority of the quantitative traits contributing to more cocoon productivity. Observations were made on 8 economically important traits such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, cocoon filament length and raw silk. Analysis of variance results revealed great deal of variability indicating significant (P < 0.001) variations. Out of 66 hybrids, 7 hybrids exhibited positive heterosis for seven traits and 4 hybrids expressed significant hetero-beltiosis for 6 traits, out of 8 traits evaluated. Based on results, the hybrids ${SR_1} {\times} {SR_5}and {CSR_2} {\times} {SR_5}$ are adjudged as most promising ones and can be exploited commercially in tropical climates to increase the cocoon productivity.

Development of Fine Denier Silkworm Hybrid $CSR48{\times}CSR5$ of Bombyx mori L. for Superior Quality Silk

Kalpana G. V.,Kumar N. Suresh,Basavaraja H. K.,Reddy N. Mal,Palit A. K. Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.10 No.2

Serious attempt for the improvement of quality parameters in silkworm hybrids came rather very late in India. Realising the need for productive breeds to the field and reorientation in breeding methodology, the silkworm breeders of CSRTI, Mysore were able to develop silkworm breeds with fine denier namely, JPN7, CSR48, B63 and B65 of specific industrial requirement through directional selection. As the success of silkworm breeds mainly depends on their combining ability, the developed breeds were subjected for hybrid evaluation. Out of 42 bivoltine hybrids studied, one hybrid, $CSR48{\times}CSR5$ was identified for its superiority over the existing bivoltine hybrids namely $CSR2{\times}CSR4,\;CSR2{\times}CSR5\;and\;CSR18{\times}CSR19$ for majority of qualitative traits. Post cocoon testing of large quantity of cocoons of $CSR48{\times}CSR5$ resulted in the production of high quality '3A'grade silk. It is for the first time in the Indian Sericulture industry that high quality silk with longer filament length of 1474 m, denier of 2.47, standard size deviation of 0.983 d, maximum size deviation of 1.322, neatness of 96 p, reelability of $85\%$, tenacity of 3.87 g/d, elongation of $22.32\%$ and cohesion of 110 strokes was produced. The superiority of fine denier silkworm breeds and their hybrids are discussed.