Bharath Kumar - Academia.edu (original) (raw)
Papers by Bharath Kumar
Research Journal of Agricultural Sciences, 2019
The silkworm, Bombyx mori is an important economic insect for its production of silk, aptly named... more The silkworm, Bombyx mori is an important economic insect for its production of silk, aptly named as the queen of natural fibres. Silkworms are classified into Japanese, Chinese, European, Korean and tropical races based on their geographical origin. The difference in the adaptability of silkworms for different regions and seasons has been studied and documented in several studies. China and Japan have achieved remarkable breakthroughs in silk production by evolving highly productive silkworm races suited to the local conditions and agronomical practices. This review is an attempt to introduce the reader to mulberry sericulture in temperate and tropical regions, role of environment, performance of some popular silkworm breeds upon relocation, followed by details of authorized region and season specific silkworm breeds of China, Japan and India and special emphasis on scope for region and season specific silkworm breeds in temperate regions of Jammu and Kashmir.
Research Journal of Agricultural Sciences, 2020
Fortification is a recent technique in advanced sericulture research and development industry to ... more Fortification is a recent technique in advanced sericulture research and development industry to enhance the cocoon yield and silk content through supplement of amino acids on mulberry leaf. The amino acid plays an important role in the growth, development and production of silk by the silkworm Bombyx mori. As per reports, the mulberry leaf during autumn season under Kashmir climatic condition is nutritionally poor. Silkworm rearers in Kashmir Valley mostly do rearing during favourable spring season (May-June) only and lesser number of rearers goes for second rearing during autumn season (August-September). The lesser number of rearers go for autumn rearing in the region is mainly due to less productivity and poor quality cocoon crops. To overcome the problem, the present study was undertaken to study the efficacy of fortification of some amino acids (Glycine, Alanine, Aspartic acid and Glutamic acid) on mulberry leaf and feeding the late instars (4 th & 5 th) of CSR double hybrid silkworm (CSR2 × CSR27) × (CS62 × CSR26) were used in the study. The results showed, the amino acids treated mulberry leaf fed silkworm larvae shows significantly higher in terms of body weight, cocoon weight, shell weight and yield/100 DFLs (kg) when compared with control. It is also found that silk filament length (m) significantly increased in amino acid treated when compared with control. The result indicates that fortification of mulberry leaf with amino acids influence the cocoon yield and silk productivity under field conditions of temperate climate of Jammu and Kashmir.
Research Journal of Agricultural Sciences, 2020
The present study was conducted to understand the potentiality and productivity of twenty silkwor... more The present study was conducted to understand the potentiality and productivity of twenty silkworm (Bombyx mori L.) breeding lines and their three shortlisted hybrids to identify breeds and their hybrids suitable for autumn season under temperate climatic conditions of Jammu & Kashmir state. Based on the results obtained through multi-traits evaluation index (EI) in F 7 generation, five breeding lines i.e. line-5, line-7, line-9, line-17 and line-18 with high potential and productivity were selected and by crossing the lines, i.e. line-5 × line-7, line-18 × line-9 and line-17 × line-9, three Autumn Specific Hybrids (ASH) namely ASH-1, ASH-2 and ASH-3 were developed. These three hybrids were incubated and reared as per the standard rearing procedure to understand their suitability during the autumn season. The rearing data was recorded for the targeted economic traits namely, Fecundity (No. of eggs per laying), hatchability (%), larval duration (days), cocoon yield by number and weight (kg) per 10,000 larvae brushed, single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation (%). Results obtained revealed that all the three hybrids have shown higher potentiality by recording productivity of cocoon yield kg per 100 DFLs with 73.35 kg in ASH-2, 70.75 kg in ASH-1 and 70.10 kg in ASH-3 and shell ratio with 21.62%, 21.77% and 22.54% respectively. Moreover, traits differences were observed among the twenty breeding lines and their three hybrids in respect of potentiality and productivity during the autumn season. The results obtained through multiple trait EI clearly showed that out of three ASH hybrids, two hybrids have shown higher index values (more than 50) and influenced significantly on the expression of quantitative traits with high potential, greater productivity and have economically importance. Hence, the lines identified from the study can conveniently be utilized for developing higher potential and productive hybrids and also the hybrids developed i.e. ASH-2 and ASH-1 can be used for commercial exploitation at farmers level during the autumn season in temperate climatic condition of Jammu & Kashmir state.
The present study was undertaken to evaluate the performance of eleven bivoltine silkworm, Bombyx... more The present study was undertaken to evaluate the performance of eleven bivoltine silkworm, Bombyx mori L, breeds (CSR2, CSR6, CSR27, CSR26, CSR50, PAM114, PAM117, APS4, APS5, SK6 and SK7) of different origin under temperate climatic conditions during spring, summer and autumn, 2018 at Central Sericultural Research and Training Institute, Pampore, Jammu and Kashmir. The rearing was carried out under uniformed laboratory condition by adopting the standard method. These eleven breeds were evaluated for their performance in eight metric traits viz., fecundity (No.), hatching (%), yield per 10,000 larvae by number and by weight (kg), single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The performance of breeds varied from season to season since they originated from different progenitors. The data generated was analyzed statistically and subjected to multiple trait Evaluation index (E.I). On the basis of the evaluation index values ranking CSR2, CSR26, CSR27, CSR50, PAM114 and PAM117 performed well in all the three seasons with E.I values above 50. Two breeds APS5 and CSR6 recorded E.I values below 50 in all the three seasons. APS4 has performed well in only spring season whereas SK6 and SK7 recorded E.I values above 50 in summer and autumn only. Based on their performance in all the three seasons, these parental breeds will be utilized for development of foundation crosses which will be further shortlisted for the development of bivoltine silkworm double hybrids suitable to temperate region of J&K as an alternate for ruling CSR double hybrid.
Agriculture and its allied sectors will inevitably face challenges caused by climate change in fu... more Agriculture and its allied sectors will inevitably face challenges caused by climate change in future which might lead to both global and local alteration. Enriched atmospheric carbon dioxide (CO2) and temperature can have various effects at different tropic levels in ecosystems (plants, herbivores, predators and parasitoids). Global CO2 concentration has been increased by approximately 30% since the industrial revolution resulted in increase of ~0.66 °C in mean annual global surface temperature. Many plant species respond to enriched CO2 with enhanced photosynthetic rate and increased biomass. Alterations of CO2 and temperature will affect the insect pests by decreasing their relative growth rate (RGR) and prolonged developmental time in Lepidoptera (leaf chewers) where as increased abundance and fecundity in homoptera (sap suckers). Changes in foliar chemistry under elevated condition are likely to alter interaction between herbivorous insect and their natural enemies. Though plant biomass increased but their nutritional quality gets deteriorated such as lower nitrogen (N) content, higher C:N ratio, starch, total soluble sugars and polyphenols that affect insect growth, consumption and digestibility. The effect of increased CO2 and temperature on mulberry plants directly affects the lifecycle of silkworm. Like other lepidopterans silkworm may also feed more quantity of mulberry leaves to balance the deteriorated nutrition in mulberry leaves which may result in increased life cycle. Therefore, it will be interesting to observe the effect of increased feeding by beneficial insects such as mulberry silkworm which feed only on mulberry leaves.
The mulberry silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is infected with a baculovirus, ... more The mulberry silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is infected with a baculovirus, Bombyx mori nucleopolyhedrovirus (BmNPV) that causes grasserie disease in silkworm and major economic losses to the silk industry. In India, >50 % of silk cocoon crop losses are attributed to BmNPV infection. Presently, there are no specific preventive measures for the occurrence and spread of BmNPV infection other than sanitized rearing methods, the only commercial practice today is to discard large stocks of worms in case of infection. Although diagnostic kits for detection of BmNPV have been developed, they are not extensively used on a commercial scale and subsequently, they fail to provide the indispensable and timely advantages desired for early disease intervention. The best emerging technology is the use of antibody-based biosensors and lateral flow assays, which have high specificity, sensitivity and the option of "onsite" pathogen detection. The use of disease resistant silkworm breeds or the utilization of inherent resistance in silkworm would be the most economical and effective way to prevent the occurrence of grasserie disease. Further, there is a great need to comprehensively analyze the host genes response to BmNPV infection and its functional analysis to prevent virus replication and its horizontal transmission.
—The present study was undertaken to assess the performance of autumn crop (August-September) ove... more —The present study was undertaken to assess the performance of autumn crop (August-September) over spring (May-June) in temperate region of Jammu and Kashmir by rearing the silkworm hybrid (CSR 2 ×CSR 4) in both spring and autumn seasons 2016. The rearing was carried out under uniformed laboratory condition by adopting standard method at Central Sericultural Research and Training Institute (CSR&TI), Central Silk Board, Pampore, Jammu and Kashmir. The farmers were more interested towards spring crop than autumn crop as in autumn crop the cocoon productivity is less as compared to spring, which may be due to leaf quality, disease incidence like BmNPV, etc during autumn season. These aspects can be managed by preventive measures if followed properly by the rearers. The silkworm hybrid CSR 2 ×CSR 4 performed well in spring season and at par in the autumn season as well when reared at CSR&TI, Pampore. A well established mulberry plantation of KNG (Japanese) for chawki rearing and Goshoerami (Japanese) for late age rearing with uniform growth and vigour were used for the study. The rearing results revealed that hatching percentage was 97.47% in spring and 97.30% in autumn and shell ratio (SR %) was 22.09% in spring and 21.42% in autumn. The total cocoon yield per 100 dfls (disease free layings) was 60.90 kg and 57.33 kg in spring and autumn seasons respectively and pupation rate was 91.50% and 91.03% in spring and autumn seasons respectively. The present results indicate that by maintaining proper hygiene and quality leaf, the cocoon productivity in autumn season can be obtained at par with the spring season.
![Research paper thumbnail of Approach to study of pigeonpea leaf webber [Grapholita critica (Meyr.)] damage dynamics and its relation to weather](https://attachments.academia-assets.com/57349321/thumbnails/1.jpg)
](Investigation of the published data of a field experiment on assessment of damage due to leaf web... more Investigation of the published data of a field experiment on assessment of damage due to leaf webber (Grapholita critica (Meyr.)Torticidae:Lepidoptera) under seven different sowing periods at weekly intervals between June IV to August II weeks of 2013-14 at Gulbarga (Karnataka) and observations on leaf webber damage recorded on weekly basis between 32 and 42 standard meteorological weeks (SMW) was done to demonstrate appropriate analytical methodology for an improved understanding of seasonal dynamics of G. critica damage and its relation to weather. Approach to analyses included reporting of calendar (SMW) based observations of G. critica damage on crop age basis, one way ANOVA for testing differences in damage levels amongst sowing periods, SMWs and crop age besides description of relations of damage with crop age and weather variables. Seasonal damage levels of G. critica for sowing periods were non-significant but significant (P<0.05) across SMWs and crop age with reduced damage during early and late crop stages irrespective of sowing periods. Seven and four weeks of higher damage and the best fit of polynomial relations of second order in respect of crop age over calendar based periods signified crop stage dependent damage due to G. critica. While MLR revealed significant influence of all weather and crop age variables (R 2 : 0.79), non-parametric regression revealed that less than 30°C of maximum temperature and greater than 23°C of minimum temperature to be favourable for G. critica damage. Crop age and calendar based observations have their importance for an area wide and field basis management of G. critica respectively.
Studies on the nature of damage and biology of leaf webber, Grapholita critica (Meyr.) (Lepidopte... more Studies on the nature of damage and biology of leaf webber, Grapholita critica (Meyr.) (Lepidoptera: Tortricidae) on pigeonpea was conducted at the University of Agricultural Sciences, Raichur, Karnataka. The results revealed that first instar larva formed a web of 6.3 x 1.2 mm by folding a leaf and scarified the lamina, culminating a whitish patch. Larva folded the leaf lamina from midrib. The 3 rd and 4 th instar larva webbed 6 to 8 leaves and started feeding lamina inside the webs. The fecundity ranged from 22 to 85 eggs with an average of 55.80±15.65 eggs per female. The average incubation, larval and pupal periods were 3.12, 18.35 and 5.43 days, respectively. The total life cycle of G. critica from egg to adult male under laboratory condition ranged from 33.76 to 38.25 days with a mean of 35.96 ± 1.71 days. The total life cycle from egg to adult female ranged from 35.08 to 39.76 days under laboratory condition with a mean of 37.38 ± 1.79 days.
– Fifty three pigeonpea genotypes were screened against leaf webbber, Grapholita critica (Meyr.),... more – Fifty three pigeonpea genotypes were screened against leaf webbber, Grapholita critica (Meyr.), of which 11 genotypes were from Multilocation trial of Medium duration (MLT-MD), 18 genotypes from All India Crop Improvement Project (AICRP) trials and 24 genotypes from International Crops Research Institute for Semi-arid Tropics (ICRISAT) trials. Under MLT-MD trials the variety Asha and TS 3R C4 recorded the lowest number of webs (2.67 webs/5 plants). In AICRP trials the lowest number of webs was observed in RVSA 81 (1.33 webs/5 plants), Rajeev lochan, P-703 (2.00 webs/5 plants), RVSA 34, RVSA 64, WRG 157 and WRG 98 (2.33 webs/5 plants). The leaf webbber population in genotypes under ICRISAT trials ranged from 2.33 webs/5 plants in ICPHRL 4979-7 to 4.67 webs/5 plants in ICPHRL 4985-1 and ICP-7035.
– Field trial was conducted to study the impact of weather parameters on the population build up ... more – Field trial was conducted to study the impact of weather parameters on the population build up of leaf webber, Grapholita critica (Meyr.) (Lepidoptera: Tortricidae) on pigeonpea. The number of webs per 50 plants was in the range of 1.34 to 25.65 in the month of August. In the month of September the number of webs per 50 plants ranged from 5.23 to 36.56. Whereas, in October the number of webs per 50 plants ranged from 1.22 to 12.35. Leaf webber damage exerted a negative association with maximum temperature (r =-0.31), minimum temperature (r =-0.05) and positive association with morning relative humidity (r= 0.22), afternoon relative humidity (r = 0.21) and rainfall (r = 0.03). However, only the influence of mean maximum temperature with leaf webber damage was found to be significant. But, the influence of minimum temperature, morning relative humidity, afternoon relative humidity and rainfall with leaf webber damage was not significant.
– Estimation of crop loss due to leaf webber, Grapholita critica Meyr. (Lepidoptera: Tortricidae)... more – Estimation of crop loss due to leaf webber, Grapholita critica Meyr. (Lepidoptera: Tortricidae) on pigeonpea was conducted at the University of Agricultural Sciences, Raichur, Karnataka. The yield loss in pigeonpea (Maruthi variety) was estimated by releasing differential population of leaf webber viz., 0, 1, 2 4, 6, 8 and 10 larvae inside the cage, with randomized block design experiment. The results revealed that the yield loss due to leaf webber was 0.15, 0.71, 1.07, 2.36, 4.16 and 5.69 per cent in 1, 2, 4, 6, 8 and 10 larva released per cage, respectively. The treatment where 10 larvae were released recorded lowest yield of 838.33 kg/ha with a highest yield loss of 5.69 per cent, compared to treatment without larvae (888.89 kg/ha).
The present investigation was carried out to improve the selected quantitative traits under unifo... more The present investigation was carried out to improve the selected quantitative traits under uniform laboratory conditions utilizing twenty five breeding lines (BL) of silkworm Bombyx mori L. during autumn season, 2017 in temperate climatic conditions of Kashmir. The breeding lines were reared over five generations and data were recorded as per the standard procedure for the calculation of all the quantitative traits namely, Fecundity (no.), hatching percentage, yield by number & weight (kg)/ 10,000 larvae brushed, single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The data generated were subjected to the multiple trait evaluation index and among all the breeding lines, eighteen lines viz., L-1, L-2, L-3, L-4, L-6, L-7, L-11, L-12, L-14, L-15, L-16, L-7, L-18, L-19, L-20, L-21, L-22 and L-24 exhibited better performance with >50 evaluation index values, L-4 & L-9 observed moderate and L-8, L-10, L-13, L-23 & L-25 recorded least evaluation index during autumn season. Based on the results obtained from the study, the traits differences were observed between the twenty five breeding lines to be considered as the variable effects among the lines during autumn season. It is found that, the 18 lines with >50 evaluation index values have shown significant influence on the expression of quantitative traits and have economical importance under the study. Hence, obtained results from the study will conveniently be utilized for selecting best breeding lines for evolving suitable breeds during autumn season in temperate region of the Kashmir and will be helpful in the field of silkworm breeding and genetics programmes.
Due to rapid urbanisation, sericulture in the state of Jammu & Kashmir has been restricted to hig... more Due to rapid urbanisation, sericulture in the state of Jammu & Kashmir has been restricted to higher peripheral areas only. For horizontal expansion of sericulture in the state, it is inevitable to introduce sericulture in unexplored areas. In this direction a study was undertaken to assess the feasibility of sericulture in Kargil area of Ladakh division, J&K. Trial rearing of silkworm double hybrid (FC2 x FC1) obtained from SSPC, Vijayapura, Bangalore was reared at village shilikchey, Kargil during 2017 (July-August) as a part of the 45 days Intensive Bivoltine Training programme to tribal farmers of Kargil conducted by Central Sericultural Research and Training Institute (CSR&TI), Central Silk Board, Pampore, J&K. Prior to this, a trial rearing was also conducted at Kargil in village Poyen during 2016 (June-August). The rearing results were encouraging to the scientific community for introducing the sericulture in Kargil. The rearing results revealed that hatching percentage was 80.32% during 2016 and 98.15% during 2017. In 2016 and 2017 double hybrid recorded total yield of 22.13 Kg/50 Dfls and 37.76 Kg/50 Dfls respectively. In 2016, Single Cocoon Weight (SCW) and Single Shell Weight (SSW) recorded as 1.60g and 0.30g whereas in 2017, Single Cocoon Weight (SCW) and Single Shell Weight (SSW) recorded as 1.72g and 0.38g. In 2016 and 2017 Shell Ratio (SR) recorded as 18.75% and 22.09% respectively. The present results indicate that by maintaining proper hygiene and feeding quality leaf the cocoon productivity in Kargil region can be at par with the other regions of the Country.
Research Journal of Agricultural Sciences, 2019
The silkworm, Bombyx mori is an important economic insect for its production of silk, aptly named... more The silkworm, Bombyx mori is an important economic insect for its production of silk, aptly named as the queen of natural fibres. Silkworms are classified into Japanese, Chinese, European, Korean and tropical races based on their geographical origin. The difference in the adaptability of silkworms for different regions and seasons has been studied and documented in several studies. China and Japan have achieved remarkable breakthroughs in silk production by evolving highly productive silkworm races suited to the local conditions and agronomical practices. This review is an attempt to introduce the reader to mulberry sericulture in temperate and tropical regions, role of environment, performance of some popular silkworm breeds upon relocation, followed by details of authorized region and season specific silkworm breeds of China, Japan and India and special emphasis on scope for region and season specific silkworm breeds in temperate regions of Jammu and Kashmir.
Research Journal of Agricultural Sciences, 2020
Fortification is a recent technique in advanced sericulture research and development industry to ... more Fortification is a recent technique in advanced sericulture research and development industry to enhance the cocoon yield and silk content through supplement of amino acids on mulberry leaf. The amino acid plays an important role in the growth, development and production of silk by the silkworm Bombyx mori. As per reports, the mulberry leaf during autumn season under Kashmir climatic condition is nutritionally poor. Silkworm rearers in Kashmir Valley mostly do rearing during favourable spring season (May-June) only and lesser number of rearers goes for second rearing during autumn season (August-September). The lesser number of rearers go for autumn rearing in the region is mainly due to less productivity and poor quality cocoon crops. To overcome the problem, the present study was undertaken to study the efficacy of fortification of some amino acids (Glycine, Alanine, Aspartic acid and Glutamic acid) on mulberry leaf and feeding the late instars (4 th & 5 th) of CSR double hybrid silkworm (CSR2 × CSR27) × (CS62 × CSR26) were used in the study. The results showed, the amino acids treated mulberry leaf fed silkworm larvae shows significantly higher in terms of body weight, cocoon weight, shell weight and yield/100 DFLs (kg) when compared with control. It is also found that silk filament length (m) significantly increased in amino acid treated when compared with control. The result indicates that fortification of mulberry leaf with amino acids influence the cocoon yield and silk productivity under field conditions of temperate climate of Jammu and Kashmir.
Research Journal of Agricultural Sciences, 2020
The present study was conducted to understand the potentiality and productivity of twenty silkwor... more The present study was conducted to understand the potentiality and productivity of twenty silkworm (Bombyx mori L.) breeding lines and their three shortlisted hybrids to identify breeds and their hybrids suitable for autumn season under temperate climatic conditions of Jammu & Kashmir state. Based on the results obtained through multi-traits evaluation index (EI) in F 7 generation, five breeding lines i.e. line-5, line-7, line-9, line-17 and line-18 with high potential and productivity were selected and by crossing the lines, i.e. line-5 × line-7, line-18 × line-9 and line-17 × line-9, three Autumn Specific Hybrids (ASH) namely ASH-1, ASH-2 and ASH-3 were developed. These three hybrids were incubated and reared as per the standard rearing procedure to understand their suitability during the autumn season. The rearing data was recorded for the targeted economic traits namely, Fecundity (No. of eggs per laying), hatchability (%), larval duration (days), cocoon yield by number and weight (kg) per 10,000 larvae brushed, single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation (%). Results obtained revealed that all the three hybrids have shown higher potentiality by recording productivity of cocoon yield kg per 100 DFLs with 73.35 kg in ASH-2, 70.75 kg in ASH-1 and 70.10 kg in ASH-3 and shell ratio with 21.62%, 21.77% and 22.54% respectively. Moreover, traits differences were observed among the twenty breeding lines and their three hybrids in respect of potentiality and productivity during the autumn season. The results obtained through multiple trait EI clearly showed that out of three ASH hybrids, two hybrids have shown higher index values (more than 50) and influenced significantly on the expression of quantitative traits with high potential, greater productivity and have economically importance. Hence, the lines identified from the study can conveniently be utilized for developing higher potential and productive hybrids and also the hybrids developed i.e. ASH-2 and ASH-1 can be used for commercial exploitation at farmers level during the autumn season in temperate climatic condition of Jammu & Kashmir state.
The present study was undertaken to evaluate the performance of eleven bivoltine silkworm, Bombyx... more The present study was undertaken to evaluate the performance of eleven bivoltine silkworm, Bombyx mori L, breeds (CSR2, CSR6, CSR27, CSR26, CSR50, PAM114, PAM117, APS4, APS5, SK6 and SK7) of different origin under temperate climatic conditions during spring, summer and autumn, 2018 at Central Sericultural Research and Training Institute, Pampore, Jammu and Kashmir. The rearing was carried out under uniformed laboratory condition by adopting the standard method. These eleven breeds were evaluated for their performance in eight metric traits viz., fecundity (No.), hatching (%), yield per 10,000 larvae by number and by weight (kg), single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The performance of breeds varied from season to season since they originated from different progenitors. The data generated was analyzed statistically and subjected to multiple trait Evaluation index (E.I). On the basis of the evaluation index values ranking CSR2, CSR26, CSR27, CSR50, PAM114 and PAM117 performed well in all the three seasons with E.I values above 50. Two breeds APS5 and CSR6 recorded E.I values below 50 in all the three seasons. APS4 has performed well in only spring season whereas SK6 and SK7 recorded E.I values above 50 in summer and autumn only. Based on their performance in all the three seasons, these parental breeds will be utilized for development of foundation crosses which will be further shortlisted for the development of bivoltine silkworm double hybrids suitable to temperate region of J&K as an alternate for ruling CSR double hybrid.
Agriculture and its allied sectors will inevitably face challenges caused by climate change in fu... more Agriculture and its allied sectors will inevitably face challenges caused by climate change in future which might lead to both global and local alteration. Enriched atmospheric carbon dioxide (CO2) and temperature can have various effects at different tropic levels in ecosystems (plants, herbivores, predators and parasitoids). Global CO2 concentration has been increased by approximately 30% since the industrial revolution resulted in increase of ~0.66 °C in mean annual global surface temperature. Many plant species respond to enriched CO2 with enhanced photosynthetic rate and increased biomass. Alterations of CO2 and temperature will affect the insect pests by decreasing their relative growth rate (RGR) and prolonged developmental time in Lepidoptera (leaf chewers) where as increased abundance and fecundity in homoptera (sap suckers). Changes in foliar chemistry under elevated condition are likely to alter interaction between herbivorous insect and their natural enemies. Though plant biomass increased but their nutritional quality gets deteriorated such as lower nitrogen (N) content, higher C:N ratio, starch, total soluble sugars and polyphenols that affect insect growth, consumption and digestibility. The effect of increased CO2 and temperature on mulberry plants directly affects the lifecycle of silkworm. Like other lepidopterans silkworm may also feed more quantity of mulberry leaves to balance the deteriorated nutrition in mulberry leaves which may result in increased life cycle. Therefore, it will be interesting to observe the effect of increased feeding by beneficial insects such as mulberry silkworm which feed only on mulberry leaves.
The mulberry silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is infected with a baculovirus, ... more The mulberry silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is infected with a baculovirus, Bombyx mori nucleopolyhedrovirus (BmNPV) that causes grasserie disease in silkworm and major economic losses to the silk industry. In India, >50 % of silk cocoon crop losses are attributed to BmNPV infection. Presently, there are no specific preventive measures for the occurrence and spread of BmNPV infection other than sanitized rearing methods, the only commercial practice today is to discard large stocks of worms in case of infection. Although diagnostic kits for detection of BmNPV have been developed, they are not extensively used on a commercial scale and subsequently, they fail to provide the indispensable and timely advantages desired for early disease intervention. The best emerging technology is the use of antibody-based biosensors and lateral flow assays, which have high specificity, sensitivity and the option of "onsite" pathogen detection. The use of disease resistant silkworm breeds or the utilization of inherent resistance in silkworm would be the most economical and effective way to prevent the occurrence of grasserie disease. Further, there is a great need to comprehensively analyze the host genes response to BmNPV infection and its functional analysis to prevent virus replication and its horizontal transmission.
—The present study was undertaken to assess the performance of autumn crop (August-September) ove... more —The present study was undertaken to assess the performance of autumn crop (August-September) over spring (May-June) in temperate region of Jammu and Kashmir by rearing the silkworm hybrid (CSR 2 ×CSR 4) in both spring and autumn seasons 2016. The rearing was carried out under uniformed laboratory condition by adopting standard method at Central Sericultural Research and Training Institute (CSR&TI), Central Silk Board, Pampore, Jammu and Kashmir. The farmers were more interested towards spring crop than autumn crop as in autumn crop the cocoon productivity is less as compared to spring, which may be due to leaf quality, disease incidence like BmNPV, etc during autumn season. These aspects can be managed by preventive measures if followed properly by the rearers. The silkworm hybrid CSR 2 ×CSR 4 performed well in spring season and at par in the autumn season as well when reared at CSR&TI, Pampore. A well established mulberry plantation of KNG (Japanese) for chawki rearing and Goshoerami (Japanese) for late age rearing with uniform growth and vigour were used for the study. The rearing results revealed that hatching percentage was 97.47% in spring and 97.30% in autumn and shell ratio (SR %) was 22.09% in spring and 21.42% in autumn. The total cocoon yield per 100 dfls (disease free layings) was 60.90 kg and 57.33 kg in spring and autumn seasons respectively and pupation rate was 91.50% and 91.03% in spring and autumn seasons respectively. The present results indicate that by maintaining proper hygiene and quality leaf, the cocoon productivity in autumn season can be obtained at par with the spring season.
Investigation of the published data of a field experiment on assessment of damage due to leaf web... more Investigation of the published data of a field experiment on assessment of damage due to leaf webber (Grapholita critica (Meyr.)Torticidae:Lepidoptera) under seven different sowing periods at weekly intervals between June IV to August II weeks of 2013-14 at Gulbarga (Karnataka) and observations on leaf webber damage recorded on weekly basis between 32 and 42 standard meteorological weeks (SMW) was done to demonstrate appropriate analytical methodology for an improved understanding of seasonal dynamics of G. critica damage and its relation to weather. Approach to analyses included reporting of calendar (SMW) based observations of G. critica damage on crop age basis, one way ANOVA for testing differences in damage levels amongst sowing periods, SMWs and crop age besides description of relations of damage with crop age and weather variables. Seasonal damage levels of G. critica for sowing periods were non-significant but significant (P<0.05) across SMWs and crop age with reduced damage during early and late crop stages irrespective of sowing periods. Seven and four weeks of higher damage and the best fit of polynomial relations of second order in respect of crop age over calendar based periods signified crop stage dependent damage due to G. critica. While MLR revealed significant influence of all weather and crop age variables (R 2 : 0.79), non-parametric regression revealed that less than 30°C of maximum temperature and greater than 23°C of minimum temperature to be favourable for G. critica damage. Crop age and calendar based observations have their importance for an area wide and field basis management of G. critica respectively.
Studies on the nature of damage and biology of leaf webber, Grapholita critica (Meyr.) (Lepidopte... more Studies on the nature of damage and biology of leaf webber, Grapholita critica (Meyr.) (Lepidoptera: Tortricidae) on pigeonpea was conducted at the University of Agricultural Sciences, Raichur, Karnataka. The results revealed that first instar larva formed a web of 6.3 x 1.2 mm by folding a leaf and scarified the lamina, culminating a whitish patch. Larva folded the leaf lamina from midrib. The 3 rd and 4 th instar larva webbed 6 to 8 leaves and started feeding lamina inside the webs. The fecundity ranged from 22 to 85 eggs with an average of 55.80±15.65 eggs per female. The average incubation, larval and pupal periods were 3.12, 18.35 and 5.43 days, respectively. The total life cycle of G. critica from egg to adult male under laboratory condition ranged from 33.76 to 38.25 days with a mean of 35.96 ± 1.71 days. The total life cycle from egg to adult female ranged from 35.08 to 39.76 days under laboratory condition with a mean of 37.38 ± 1.79 days.
– Fifty three pigeonpea genotypes were screened against leaf webbber, Grapholita critica (Meyr.),... more – Fifty three pigeonpea genotypes were screened against leaf webbber, Grapholita critica (Meyr.), of which 11 genotypes were from Multilocation trial of Medium duration (MLT-MD), 18 genotypes from All India Crop Improvement Project (AICRP) trials and 24 genotypes from International Crops Research Institute for Semi-arid Tropics (ICRISAT) trials. Under MLT-MD trials the variety Asha and TS 3R C4 recorded the lowest number of webs (2.67 webs/5 plants). In AICRP trials the lowest number of webs was observed in RVSA 81 (1.33 webs/5 plants), Rajeev lochan, P-703 (2.00 webs/5 plants), RVSA 34, RVSA 64, WRG 157 and WRG 98 (2.33 webs/5 plants). The leaf webbber population in genotypes under ICRISAT trials ranged from 2.33 webs/5 plants in ICPHRL 4979-7 to 4.67 webs/5 plants in ICPHRL 4985-1 and ICP-7035.
– Field trial was conducted to study the impact of weather parameters on the population build up ... more – Field trial was conducted to study the impact of weather parameters on the population build up of leaf webber, Grapholita critica (Meyr.) (Lepidoptera: Tortricidae) on pigeonpea. The number of webs per 50 plants was in the range of 1.34 to 25.65 in the month of August. In the month of September the number of webs per 50 plants ranged from 5.23 to 36.56. Whereas, in October the number of webs per 50 plants ranged from 1.22 to 12.35. Leaf webber damage exerted a negative association with maximum temperature (r =-0.31), minimum temperature (r =-0.05) and positive association with morning relative humidity (r= 0.22), afternoon relative humidity (r = 0.21) and rainfall (r = 0.03). However, only the influence of mean maximum temperature with leaf webber damage was found to be significant. But, the influence of minimum temperature, morning relative humidity, afternoon relative humidity and rainfall with leaf webber damage was not significant.
– Estimation of crop loss due to leaf webber, Grapholita critica Meyr. (Lepidoptera: Tortricidae)... more – Estimation of crop loss due to leaf webber, Grapholita critica Meyr. (Lepidoptera: Tortricidae) on pigeonpea was conducted at the University of Agricultural Sciences, Raichur, Karnataka. The yield loss in pigeonpea (Maruthi variety) was estimated by releasing differential population of leaf webber viz., 0, 1, 2 4, 6, 8 and 10 larvae inside the cage, with randomized block design experiment. The results revealed that the yield loss due to leaf webber was 0.15, 0.71, 1.07, 2.36, 4.16 and 5.69 per cent in 1, 2, 4, 6, 8 and 10 larva released per cage, respectively. The treatment where 10 larvae were released recorded lowest yield of 838.33 kg/ha with a highest yield loss of 5.69 per cent, compared to treatment without larvae (888.89 kg/ha).
The present investigation was carried out to improve the selected quantitative traits under unifo... more The present investigation was carried out to improve the selected quantitative traits under uniform laboratory conditions utilizing twenty five breeding lines (BL) of silkworm Bombyx mori L. during autumn season, 2017 in temperate climatic conditions of Kashmir. The breeding lines were reared over five generations and data were recorded as per the standard procedure for the calculation of all the quantitative traits namely, Fecundity (no.), hatching percentage, yield by number & weight (kg)/ 10,000 larvae brushed, single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The data generated were subjected to the multiple trait evaluation index and among all the breeding lines, eighteen lines viz., L-1, L-2, L-3, L-4, L-6, L-7, L-11, L-12, L-14, L-15, L-16, L-7, L-18, L-19, L-20, L-21, L-22 and L-24 exhibited better performance with >50 evaluation index values, L-4 & L-9 observed moderate and L-8, L-10, L-13, L-23 & L-25 recorded least evaluation index during autumn season. Based on the results obtained from the study, the traits differences were observed between the twenty five breeding lines to be considered as the variable effects among the lines during autumn season. It is found that, the 18 lines with >50 evaluation index values have shown significant influence on the expression of quantitative traits and have economical importance under the study. Hence, obtained results from the study will conveniently be utilized for selecting best breeding lines for evolving suitable breeds during autumn season in temperate region of the Kashmir and will be helpful in the field of silkworm breeding and genetics programmes.
Due to rapid urbanisation, sericulture in the state of Jammu & Kashmir has been restricted to hig... more Due to rapid urbanisation, sericulture in the state of Jammu & Kashmir has been restricted to higher peripheral areas only. For horizontal expansion of sericulture in the state, it is inevitable to introduce sericulture in unexplored areas. In this direction a study was undertaken to assess the feasibility of sericulture in Kargil area of Ladakh division, J&K. Trial rearing of silkworm double hybrid (FC2 x FC1) obtained from SSPC, Vijayapura, Bangalore was reared at village shilikchey, Kargil during 2017 (July-August) as a part of the 45 days Intensive Bivoltine Training programme to tribal farmers of Kargil conducted by Central Sericultural Research and Training Institute (CSR&TI), Central Silk Board, Pampore, J&K. Prior to this, a trial rearing was also conducted at Kargil in village Poyen during 2016 (June-August). The rearing results were encouraging to the scientific community for introducing the sericulture in Kargil. The rearing results revealed that hatching percentage was 80.32% during 2016 and 98.15% during 2017. In 2016 and 2017 double hybrid recorded total yield of 22.13 Kg/50 Dfls and 37.76 Kg/50 Dfls respectively. In 2016, Single Cocoon Weight (SCW) and Single Shell Weight (SSW) recorded as 1.60g and 0.30g whereas in 2017, Single Cocoon Weight (SCW) and Single Shell Weight (SSW) recorded as 1.72g and 0.38g. In 2016 and 2017 Shell Ratio (SR) recorded as 18.75% and 22.09% respectively. The present results indicate that by maintaining proper hygiene and feeding quality leaf the cocoon productivity in Kargil region can be at par with the other regions of the Country.