Stability and path analysis for yield and related traits in silkworm, (Bombyx mori L.) reared under stress conditions

The silkworm, Bombyx mori L. is a poikilothermic organism whose growth and development is adversely affected by high temperatures. Rearing of silkworm at high temperature conditions of tropical countries like India causes extensive crop loss by reducing cocoon yield. Breeding new silkworm breeds tolerant to high temperatures is the most effective and economical method to increase cocoon yield. Introduction of stable genotypes in such breeding programs and knowledge on the relationships between cocoon yield and other traits would be more advantageous in increasing cocoon yield at high temperatures. Therefore, in this study twenty silkworm genotypes were reared in five artificially simulated environments with different temperatures ranging from 25?C to 38?C. Based on coefficient of variation (%) values, the traits cocoon yield / 10,000 larvae by weight (CY) and cocoon weight showed maximum and minimal variation among the traits in all the five environments. Analysis of variance revealed a substantial genetic variability among the genotypes for most of the traits studied. The results of combined analysis of variance showed significant differences over traits indicating that the traits are influenced by genotype ? environment interactions. Stability analysis with respect to CY showed higher mean value compared to grand mean, regression coefficient equal to unity and less deviation from regression in ATR16, CSR17, BHR2, S-5 and D13 genotypes, suggesting that they are consistent with the CY over the different environments. Clustering based on the stability parameters resulted in separation of twenty silkworm genotypes into 5 clusters based on their ability to tolerate high temperatures. Correlation studies demonstrated positive and significant (P < 0.05) correlations between CY and other traits. Pupation rate was most positively associated with CY followed by larval weight, cocoon weight, cocoon shell weight and cocoon shell percent. Path coefficient analysis also revealed that the pupation rate had the maximum direct effect on CY followed by cocoon shell weight and larval weight. Cocoon shell percent and cocoon weight exhibited negative direct path effect on cocoon yield / 10,000 larvae by weight. Therefore, the selection based on pupation rate, larval weight and cocoon shell weight can be effective in improving cocoon yield in silkworm at different environments with varying temperature.

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Seasonal Variations in the Silk Yield Contributing Characters of Forty-two Strains of the Silkworm, Bombyx mori (Lepidoptera: Bombycidae)

Journal of Entomological Science ◽

10.18474/0749-8004-30.3.297 ◽

1995 ◽

Vol 30 (3) ◽

pp. 297-311

Author(s):

S. K. Bhargava

Keyword(s):

Bombyx Mori ◽

Economic Value ◽

Filament Length ◽

Shell Weight ◽

Pupation Rate ◽

Bombyx Mori L ◽

And Training ◽

Silk Filament ◽

Training Institute ◽

Silkworm Bombyx Mori

Forty-two strains of the silkworm, Bombyx mori (L.), collected from China, Japan, Vietnam, South Korea, Brazil, India, and France were reared in the spring, summer and autumn seasons during 1991–92 at the Regional Station of Central Sericultural Research and Training Institute, Coonoor, Tamilnadu State, India. Analyses were made on five silk yield-contributing characters, namely pupation rate, cocoon weight, shell weight, cocoon shell ratio, and silk filament length. Results indicated the superiority of the following strains for all the above mentioned characters: 14M and JC2P (in spring); NBJPO and JC2P (in summer); and M2, NBJPO and SPJ2 (in autumn). The importance of rearing a given strain of silkworm in the optimal season for its maximum economic value in terms of silk yield is discussed.

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The QTLs, Determination of Cocoon Shell Weight Trait in Mulberry Silkworm (Bombyx mori L.)

Biotechnology(Faisalabad) ◽

10.3923/biotech.2010.41.47 ◽

2009 ◽

Vol 9 (1) ◽

pp. 41-47 ◽

Cited By ~ 1

Author(s):

A.R. Bizhannia ◽

S.Z. Mirhossein ◽

B. Rabiee ◽

M. Taeb

Keyword(s):

Bombyx Mori ◽

Shell Weight ◽

Bombyx Mori L ◽

Mulberry Silkworm ◽

Weight Trait ◽

Silkworm Bombyx Mori

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Effects of Minerals on Growth of Silkworm, Bombyx mori L. and Their Impact on Cocoon Economic Parameters

Madras Agricultural Journal ◽

10.29321/maj.10.000487 ◽

2021 ◽

Vol 108 (March) ◽

pp. 1-5

Author(s):

MURUGESH K.A ◽

◽

ARUNA A ◽

CHOZHAN K ◽

◽

...

Keyword(s):

Potassium Chloride ◽

Bombyx Mori ◽

Magnesium Sulphate ◽

Zinc Sulphate ◽

Pupal Weight ◽

Shell Weight ◽

Mulberry Leaves ◽

Economic Parameters ◽

Bombyx Mori L ◽

Silkworm Bombyx Mori

The present study aimed at increasing the cocoon yield by fortifying the mulberry leaves with minerals such as zinc sulphate, magnesium sulphate and potassium chloride at different concentrations (10, 25, 50, 100 and 200 ppm) and feeding them to the silkworm Bombyx mori L. The oral application of minerals through mulberry leaves to silkworm larva during lateage instars significantly improved its larval and cocoon economic parameters. Among the five concentrations tested, it was observed that the zinc sulphate @ 100 ppm, magnesium sulphate @ 200 ppm and potassium chloride @ 100 ppm registered significantly higher mature larval weight, effective rate of rearing (ERR), cocoon weight, pupal weight, shell weight and shell ratio than the control. Per os administration of minerals also significantly reduced the fifth instar larval duration of silkworm.

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Performance of Double Hybrid of Silkworm (Bombyx mori L.) Fed on Leaf Raised under Different Fertilizer Schedules

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2020/v39i4831256 ◽

2020 ◽

pp. 439-444

Author(s):

Naveena Nazim ◽

M. R. Mir ◽

M. F. Baqual ◽

. Noor-ul-Din ◽

Farida Akther ◽

...

Keyword(s):

Bombyx Mori ◽

Standard Procedure ◽

Larval Duration ◽

Larval Weight ◽

Pupation Rate ◽

Randomized Design ◽

Silk Worm ◽

Bombyx Mori L ◽

Completely Randomized Design ◽

Disease Free

Aim: The present study was aimed to see the performance of silk worm (Bombyx mori L.) double hybrid fed on leaf raised through splitting the recommended dose of chemical fertilizers. Study Design: Completely Randomized Design (CRD). Place and Duration of Study: College of Temperate Sericulture (CoTS) Mirgund, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), during 2017 and 2018. Methodology: The present investigation was carried out at the experimental farm of College of Temperate Sericulture-Mirgund. Goshoerami a popular variety of mulberry in the region was used for the study. Disease free layings (dfl’s) of the popular double hybrid were obtained from the Germplasm Bank maintained at College of Temperate Sericulture (CoTS) Mirgund. These dfl’s were incubated, brushed and reared up to 3rd instar en masse following the standard rearing procedure. After 3rd moult, 3 replications of 100 larvae in each treatment were maintained. Different larval and Cocoon parameters were recorded during the course of experimentation. Standard procedure was followed to record observations. The data was compiled and analyzed. Results: T11 recorded the shortest values for total larval and fifth instar larval duration being statistically at par with treatments/ fertilizer schedules T12, T9, T10, T3, T4, T1, T2 and T7. Weight of ten mature larvae was recorded higher in treatment T14 being statistically at par with treatments T13, T16 and T15 respectively. Cocoon yield per 10,000 larvae by number was recorded highest In T14 treatment, which was recorded statistically at par with treatments T13 and T16 respectively. Cocoon yield by weight was more in treatment T14 being at par with treatments T13 and T16. Pupation rate was found higher in treatment T14 being at par treatment T13. Conclusion: Double hybrid performed better under parameters like- total as well as fifth instar larval duration in case of fertilizer schedule - T11 (N3P2K1), while as in case of larval weight, cocoon yield by number and by weight and pupation rate, the hybrid performed better under T14 (N4P1K2) fertilizer Schedule.

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