Cocoon Yield Research Articles

Impact of Front Line Demonstration on Muga Cocoon Yield at Farmers’ Level in Assam, India

Impact of Front Line Demonstration on Muga Cocoon Yield at Farmers’ Level in Assam, India

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.

An economic analysis of mulberry cultivation and cocoon production in non-traditional area

Sericulture is a farm based, labor intensive and economic activity supporting farm families and cottage and small scale sector. Being one of the important sector in Indian economy it checks poverty and migration. Sericulture involves a series of activities like mulberry cultivation, cocoon production, silk reeling and the products in different forms. Sericulture is not only limited to the few areas where it is been intensively practiced called traditional areas but also for non-traditional areas. This study aims to know the profitability of mulberry cultivation and cocoon production by using primary data collected from 120 farmers of North Karnataka, India. The cost of mulberry cultivation per acre worked out to be 12699.82/-for rearing 300 Disease Free Laying (DFL's) of which 77.95 per cent is composed of variable component mainly human labour and the rest is fixed component. The gross returns on selling of mulberry leaves and stalks amounts 9472.91/-. So it is not profitable to cultivate mulberry for selling leaves instead one could rear the silkworm by purchasing leaves, but availability of mulberry leaves during all times is not assured. The cost of rearing 100 DFL's is worked out to be 33738.84/-and returns amounts 38604.96/-with a marginal net returns of 4866.12/-. The lower net returns attributed to lower prices due to poor established markets in non-traditional areas and low productivity (cocoon yield per 100 DFL's) i.e. 59.02 kg compared to traditional areas i.e. 90.00 kg.

Improvement of Eri Silkworm (Samia ricini D.) Tolerant to High Temperature and Low Humidity Conditions by Continuously Regime

Improvement of eri silkworm tolerant to high temperature condition was carried out by selection and continuous rearing (1 – 12 generation) under high temperature (42±1 °C) and low relative humidity (50±5%R.H.). The eri silkworm rearing at a normal temperature (25±2 °C; 80±5%R.H.) served as control treatment. The result revealed that eri silkworm was continuously tolerant to high temperature of 42±1˚C with low relative humidity (50±5%R.H.) up to 12 generations. Among treated generations with high temperature, the silkworm survived from larva stage (1st – 5th instar) to adult in all generations ranking 16.67 – 54.17%. Between F12 and F1, survival rate of larva – adult stage of F12 was 43.33% less than F1 (54.17%), but not significantly different (P<0.05). For cocoon yields, fresh cocoon weight, pupa weight and cocoon shell weight of F12 were lower than F1. Shell ratio of F12 (11.84%), total cocoon shell weight (5.72g) and fresh cocoon/10,000 larvae (9.39 kg) were not significantly different to F1(11.61 %, 5.72 g and 10.55 kg, respectively). It was clearly, if the egg yields were considered, egg laying/moth, hatchability, total egg laying and total hatchability increased from F1 to F12. The result indicates that the thermotolerant property of eri silkworm SaKKU1 is heritable by high temperature up to F12. This study is a first report on continuously heat tolerant improvement of eri silkworm in Thailand and elsewhere.

누에 장려품종간 교잡누에의 실용형질 비교

This study was conducted to consider practical use of F2 hybrid and intervariety crossing for the improvement of silkworm eggs export and silkworm eggs manufacture. Now Kumokjam and Baegokjam come into wide use to sericulture farmers but comparison test of F1, F2 hybrid and intervariety have not been done. We weighed against the productivity among economical character. While larval period of F2 among them is most long time, pupation percentage and cocoon yield per 10,000 3rd molted larvae are lower than intervariety. With comparing F2 and intervariety, single cocoon weight of F2 is lower 9 ~ 21% than intervariety, and cocoon shell weight of F2 was lower 10 ~ 18% than intervariety. By number of cocoons per liter, F2 hybrid was lower and more irregular size than intervariety. In coparison with number of egg laid, F2 hybrid Baegokjam was 655 ea (14%) and Kumokjam 625 ea (40%) more than F1 hybrid. Also, F2 hybrid for filament grade went down than F1 hybrid. The advantage of egg production in F2 hybrid can reduce costs because there is no necessity for sex discrimination and germination control. But besides increase of number of egg laid, the productivity including economical characters was greatly lowered. Except for being a lot of laying eggs, cocoon productivity of the F2 was greatly reduced by degeneration of practical traits. Therefore the further studies are needed in order to increase utilization value of the F2 hybrid silkworm.

Occurrence of Diseases on Muga Silkworm Host PlantPerseabombycinaKost. in District Bageshwar, Uttarakhand-A Survey Report

In sericulture, diseases of silkworm host plants are the major constraint in realising the foliage potentiality of the plant under feeding of silkworms and the ultimate conversion of cocoons during crops. Diseases make the leaf unpalatable for muga silkworms and cause reduction in total leaf yield and ultimately affect cocoon yield production. In the present article, a survey of foliage diseases was carried out on one of the primary host plant Persea bombycina Kost. of Muga silkworm during the calendar year 2012 and 2013. It was observed that foliar diseases like red rust, leaf spot, grey blight and brown blight are common diseases occurring on the plant species in District Bageshwar of Uttarakhand state, which affects the foliage yield of the plant as well as quality and quantity of cocoon production.

Impact of maternal crowd on the reproductive performance of an ecto-pupal parasitoid Nesolynx thymus (Hymenoptera: Eulophidae)

Nesolynx thymus Girault (Hymenoptera: Eulophidae) is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mori accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age and size of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Three day-old uzi pupae were offered to varying numbers (1 - 10) of 2 day old Nesolynx thymus adults for parasitization. The progeny production per pupa (84.44 - 132.77) increased significantly with increase in the number of foraging parasitoid adults (1 - 10) however, progeny production per female decreased. The sex ratio (M : F) (1:25.49 - 1:1.53) decreased significantly with increase in foraging parasitoid adults. The morphometric parameters except female abdomen width of first generation parasitoid showed significant negative correlation with number of foraging adults. However, correlation between the parasitoid size in first generation and their reproductive performance was nonsignificant.

Life History of Antheraea frithi Moore, (Lepidoptera: Saturniidae) on Terminalia arjuna (Roxb.) W&amp;A Syn. in North Eastern Region of India

Antheraea frithi Moore, the source of wild tasar silk, is an indigenous wild silk moth of north-east India. The detailed life history, bionomics and rearing performance of A. frithi in relation to a newly reported food plant, Terminalia arjuna (Roxb.) has been described in the present study. Life cycle of A. frithi has five larval instars. The first instar larva measures 1.98 ± 0.13 cm × 0.198 ± 0.010 cm in length and breadth and 0.0142 ± 0.002 g in weight while the fifth instar larva measures 6.98 ± 0.18 cm × 1.12 ± 0.13 cm in length and breadth and 4.76 ± 0.45 g in weight. Wing span of male and female is recorded as 11.4–13.5 and 13.0–14.7 cm respectively. The incubation period (6–7 days), larval duration (35–39 days), fecundity (162–176 eggs), hatching (78–81 %), effective rate of rearing (57–59 %) and cocoon yield (67–79 nos) has been recorded. The reelable cocoons with a filament length (mts) and filament denier (d) is 493–575 m and 4.6–5.3 respectively. The shell weight (g) of male and female cocoons measures as 0.19–0.39 and 0.2–0.6, respectively. The shell ratio (%) for male and female cocoons stands as 8.1–8.4 and 9.4–9.8 % respectively.

Correlation and path analysis in mulberry silkworm, Bombyx mori L. (Lepidoptera: Bombycidae)

The correlation and path analysis for nine quantitative characters in sixty five varieties of silkworm, Bombyx mori L. have been investigated. Out of all contributing characters studied expected cocoon yield 100 dfls (ECY) showed significant positive associations with majority of the characters except filament size (FS) both at the phenotypic and genotypic levels. It suggested a strong association of these traits with yield. The direct and indirect effects of the component characters of ECY at phenotypic and genotypic levels were obtained separately. Here surviving percentage of larvae (SPL) and cocoon weight (CW) showed positive and high direct effect which indicated a true relationship as obtained from correlation values. Other characters showed positive correlations but the direct effects were either negative or negligible. In such a situation indirect causal factors are to be considered simultaneously&#x0D; J. Asiat. Soc. Bangladesh, Sci. 40(1): 151-156, June 2014

Performance of Multivoltine Silkworm Races on M-5 Variety of Mulberry (Bombyx Mori L)

The studies on nine different multivoltine races viz., Pure Mysore, Hosa Mysore, Mysore Princes, Kolar Gold, C. Nichi, G Race, P2D1, CB5 and Nistari on M-5 variety of mulberry larval duration, weight of ten matured larvae, diseases mortality (%), single cocoon weight, denier and fecundity were undertaken during 2012-13. The studies shows that Kolar Gold race was recorded superior for weight of the ten mature larvae (22.16 g), Pure Mysore was recorded significantly superior for incidence of disease (1.50%) and fecundity (508.61 eggs). The race P2D1found superior for single cocoon weight (0.980g) and cocoon yield (9.800 kg). The race C.Nichi was recorded superior for denier (1.68) and larval duration (22.96). Hosa Mysore race (16.10%) was found significantly superior over rest of the races for shell ratio.

Yield Gap Analysis of Mulberry Sericulture in Northwest India

At the interface of reducing agricultural income and increasing unemployment in agrarian economy of rural India, this article summarizes and evaluates the state of mulberry sericulture in northwest India, which includes Himachal Pradesh, Punjab, Rajasthan, Uttarakhand, and Uttar Pradesh. In 11 th plan period (2007-2012), there was an addition of 6 196 ha (217.09 %) of mulberry acreage at annual linier growth rate of 33.44%. However, total silk production could increase only by 54.64 MT (78.57%) at annual linier growth rate of 15.59 %, due to 43.93% (10.82 kg/ha) reduction in silk productivity at negative growth rate of -13.46%, annually. And now, average raw silk productivity in north-western states of India remains at 13.81 kg/ha, which is lower by 452.93 % (76.36 kg) in comparison to the national average of 100.90 kg/ha. Paper summaries the reasons for increasing cocoon yield gap at farmer’s level and discuss the ways and means to increase raw silk productivity to improve the livelihood delivery of mulberry sericulture in northwest India.

Correlation among Shell Percent, Cocoon Yield and Reeling Parameters of Multi × Bi Cocoons under Different Agro-Climatic Conditions of West Bengal, India

Three new Multi <TEX>${\times}$</TEX> Bi combinations M.Con.4 <TEX>${\times}$</TEX> (SK6 <TEX>${\times}$</TEX> SK7), M.Con.4 <TEX>${\times}$</TEX> NB4D2 and Nistari <TEX>${\times}$</TEX> (SK6 <TEX>${\times}$</TEX> SK7) were studied in five seasons i.e. during the period of <TEX>$18^{th}$</TEX> June - <TEX>$12^{th}$</TEX> July, <TEX>$30^{th}$</TEX> August - <TEX>$23^{rd}$</TEX> September, <TEX>$3^{rd}$</TEX> November - <TEX>$2^{nd}$</TEX> December, <TEX>$29^{th}$</TEX> January- <TEX>$2^{nd}$</TEX> March and <TEX>$30^{th}$</TEX> March-<TEX>$25^{th}$</TEX> April with one control Nistari <TEX>${\times}$</TEX> NB4D2 considering nine reeling characteristics along with shell percent and cocoon yield per 100 disease free layings (DFLs) to establish the seasonal effect on all the parameters. Results reveal that all the characters performed well in November-December. Highest yield per 100 DFLs was recorded during November-December in all combinations showing >60 kg yield. Higher correlation of yield/100 DFLs with filament length, non-breakable filament length, denier, raw silk percent, reelability percent and recovery percent was recorded in all combinations of Multi <TEX>${\times}$</TEX> Bi considered in this study. Variability observed among four combinations indicates the effect of different temperature and humidity of different seasons on expression of different traits. The results indicate that there is significant relationship of raw silk percent with reelability percent, recovery percent and evenness. Reelability percent showed higher correlation with recovery percent. It was observed that neatness was positively correlated with evenness. The overall performance of the newly evolved combinations with regard to productivity and reeling characteristics is discussed emphasizing their utilization at commercial level.

춘잠기 강건 다수성 한성황견 누에품종 "황보잠" 육성

8개 연구기관의 지역적응 시험을 통해 황보잠은 기존 보급 누에품종인 금황잠보다 화용비율이 높은 강건성 품종으로 대조 품종대비 5령 3일 유충 무게가 3%정도 무겁고, 전견중이 무거워 수량성이 높은 다수성 양친한성황견 품종으로 육성하게 되었다. 이 품종의 일본종계 원종 잠317는 1994년에 Y1, 8013의 교잡으로 2011년에 육성기호 Y9411으로 명명하였다. 암수 모두 무늬가 있는 형잠 품종으로 고치모양은 땅콩형이며 암수고치색깔이 다른 한성황견 품종이다. 중국종계 잠318은 1994년에 Y1, 9134 의 교잡으로 2004년에 육성기호 Y9416으로 명명하였다. 암수 모두 무늬가 없는 희잠 품종으로 고치모양은 타원형이며 암수고치색깔이 다른 한성황견 품종이다. 황보잠은 춘잠기에 적합한 품종으로 사육성적에서 화용 비율이 93.2%, 1만두 수견량이 21.3 kg, 견층중이 54.8 cg으로 대조 품종 금황잠보다 우수하였으며, 또한 실켜기 성적에서 해서율, 생사량이 80%, 4.65kg로 대조 78%, 4.05 kg보다 우수하였다. DNJ(1-Deoxynojirimycin)함량은 황보잠이 대조 금황잠보다 낮았고, 누에 동충하초 생산성에서 감염율은 대조보다 3,9%로 높았고 생체중은 개당 1.32 g으로 대조 1.19 g 보다 무거웠다. A new silkworm variety "WhangBoJam" for spring rearing season is F1 hybrid between Jam317, a japanese strain bred from introduction breeding and Jam318, a chinese strain from introduction breeding. In the local adaptability test performed at 8 local areas in spring of 2012, the hatchability rate of WhangBoJam was recorded 95% similar to Kum HwangJam. The larval period was 8hours more long than KumHwangJam. The pupation percentage was recorded 6.6% higher than KumHwangJam. Single cocoon weight was recorded 2.29 g similar to KumHwangJam and cocoon yield(21.3 kg) was higher than KumHwangJam. The concentration of DNJ was measured to 0.22% in WhangBoJam, lower than DaePoongJam(0.26%). In the Paecilomyces tenuipes production ability test, the pupal weight of Whang BoJam was 1.33 g/individual, higher than KumHwangJam (1.19 g/individual).

General Performance and Cocoon Yields of Two Hybrids of the Silkworm, Bombyx Mori L. (Lepidoptera: Bombicidae), Fed on Mulberry Leaves from Different Amended Soils

The performance and cocoon yields of two silkworm hybrids – W1D2 and C1J2 – grown on mulberry leaves from NPK fertilizer-, poultry manure– or non-amended soils were investigated in a 2 x 3 factorial experiment fitted into a completely randomized design with four replicates. Mulberry leaves from the three treatment plots were randomly selected for proximate analysis. Cocoon yield was significantly higher in silkworm hybrid 1 W1D2, irrespective of soil amendments, compared to hybrid 2 C1J2. Number of cocoons, single cocoon weight and shell weight were significantly higher from amended soils compared with the control. Larval and pupal weights were not influenced significantly by silkworm hybrid, soil amendments or their interaction. Fecundity was significantly higher in silkworm fed with leaves amended with NPK compared to leaves from soil amended with manure, which was not significantly different from the control. Larval and adult emergence was not affected by the two amendment factors; however, mortality was significantly higher in the control. Nitrogen, phosphorus and calcium contents were positively correlated with number of cocoons, single cocoon weight, and shell weight. Mineral contents were significantly higher in poultry manure-grown leaves than in NPK-grown ones which was higher than the control. On the other hand, cocoon yield was significantly higher in the NPK-grown leaves. However, both soil amendment methods could be adopted for mulberry leaf production for silkworm rearing.

Muga silkworm, Antheraea assamensis (Lepidoptera: Saturniidae) - an overview of distribution, biology and breeding

Muga silkworm (Antheraea assamensis Helfer) is endemic to Assam and adjoining areas in North-Eastern India, and naturally produces golden silk. From time immemorial, many ethnic and tribal groups have produced muga silk. Muga silkworms are mostly wild unlike the mulberry silkworm, which is completely domesticated. The muga silkworm is a single species with little genetic variation among populations, survives harsh climatic conditions and is subject to various diseases, pests and predators. Due to the high incidence of disease and natural enemies, and variations in climatic conditions, the production of muga silk has recently declined dramatically. In order to improve the productivity of this silkworm it is important to have a better knowledge of both its host plants and biology. Lack of knowledge of its genetics and host plants is a major bottleneck. This paper reviews various aspects of muga silkworm culture, including the availability of different populations, and methods used to select for improvement in survival, cocoon yield, disease resistance, conservation and egg production.

Developmental and Cocoon Parameters of the Silkworm, Bombyx mori L. (Lepidopter: Bombicidae), Fed on Mulberry Leaves Preserved for Different Durations under Tropical Conditions

The effects on the general performance and cocoon yield of two silkworm hybrids fed with mulberry leaves preserved for 0, 24, 48, 72 and 96 hours were investigated. Leaf samples of each of the treatments were analyzed for nutrient contents. The experiment was a 2 x 5 factorial arrangement fitted into a completely randomized design in 4 replications. One hundred silkworm larvae of each hybrid were allocated to each replicate treatment and fed on the preserved leaves throughout the larval stages. Results showed that duration of preservation and silkworm hybrids significantly influenced the shell ratio, both singly and jointly. Interaction between the two factors was significant for the number of cocoons and cocoon weight. Single cocoon weight and shell weight were significantly higher in larvae fed with leaves preserved at 0 and 24 hours. Fecundity, larval and pupal emergence were not influenced by the two factors. However, higher larval and pupal weights were observed in silkworms fed on leaves preserved for 0 and 24 hours.

Improvement in Cocoon Yield Induced by a Juvenile Hormone Analogue, SB-515 in the Bivoltine Silkworm (Bombyx mori L.) Hybrid, CSR2 x CSR4 and its Reciprocal Combination

Improvement in Cocoon Yield Induced by a Juvenile Hormone Analogue, SB-515 in the Bivoltine Silkworm (Bombyx mori L.) Hybrid, CSR2 x CSR4 and its Reciprocal Combination

Does host age affect progeny production and progeny fitness in Trichopria sp.?

The gregarious endoparasitoid Trichopria sp. (Hymenoptera: Diapriidae) is currently under evaluation for its potential to suppress the levels of parasitism in larvae of the silkworm Bombyx mori (Lepidoptera: Bombycidae) caused by the tachinid fly Exoristabombycis (Louis) (Diptera: Tachinidae) in the rearing houses of sericulture farmers in southern India. Parasitism by E. bombycis currently results in cocoon yield reductions of 10–20 %. Prior to the mass production and release of Trichopria sp., there is a need to understand the factors that affect progeny production and fitness. Within this framework, we have attempted to determine whether host age has an impact on the numbers of Trichopria sp. progeny produced and on the subsequent fitness of the adults of the wasp. Two day-old adult females of the parasitoid were allowed to parasitize day (D) 1, 3, 5, 7, and 9 puparia of E.bombycis at a ratio of 1:4 (wasp:host). After eclosion of the parasitoid adults, data on the rate of parasitism, developmental period, brood allocation, progeny production, sex ratio, female progeny longevity and adult size were recorded. The reproductive performance of the adult progeny was also recorded by allowing them to parasitize three day-old E.bombycis puparia. Host age was seen to have an effect on several of the parameters recorded, such that while the most progeny were produced by the youngest (D1) hosts, larger wasps emerged from older E. bombycis puparia. It was, however, apparent that all but the oldest hosts (D9) examined were able to support adequate parasitoid development. Further, only relatively minor impacts on progeny fitness were observed between wasps deriving from hosts of different ages. However, the results strongly indicate that optimal production and parasitoid performance will be obtained by using young hosts of less than three days old.

애누에 인공사료 적합성 봄누에 품종

A new silkworm variety SooOkJam for spring rearing season is F1 hybrid between Jam157, a japanese race bred from introduction breeding and Jam158, a chinese race from introduction breeding. In the local adaptability test performed at 8 local areas in spring of 2011, the hatchability rate of SooOkJam was recorded 2% higher than the authorized silkworm variety, DaePoongJam. The larval period was recorded 12 hour shorter than DaePoongJam. The pupation percentage was recorded 0.8% higher than DaePoongJam. Single cocoon weight (2.40 g), Cocoon yield (22.6 kg) and best cocoon rate (95.5%) was similar to DaePoongJam. The concentration of DNJ was measured 4.12 mg in SooOkJam, lower than DaePoongJam (4.45 mg). Test of the artificial diet of SooOkJam showed excellent adaptability of the artificial diet for larval period from 1st to 3rd, similar to KumOkJam. In the Paecilomyces tenuipes production ability test, the pupal weight of SooOkJam was 1.61 g/individual, similar to DaePoongJam (1.65 g/individual).

Genetic variability, correlation, path analysis and construction of selection index in mulberry silkworm, &lt;i&gt;Bombyx mori&lt;/i&gt; L. I. Genetic variability

The genotypic variability and heritability for nine quantitative characters in 65 varieties of silkworm, B. mori L. have been investigated. Variation among genotypes were highly significant (p&lt;0.001) for all the characters indicating the existence of a real difference among the genotypes which are suitable for breeding purposes. The highest heritability was obtained for shell weight followed by filament size (FS), filament length (FL), expected cocoon yield out of 100 dfls (ECY), surviving percentage of larvae (SPL), cocoon weight (CW), egg hatching percentage (EHP) and mature larval weight (MLW). Comparatively high heritability accompanied by a genetic advance was recorded for FL and total number of eggs laid per female (TEL) indicating the importance of additive gene effects of these characters, but shell weight, cocoon weight and filament size showed high heritability and low genetic advance indicating the involvement of non-additive gene systems in the inheritance of these characters. So selection on the basis of these characters, with relatively more emphasis upon filament length and total number of eggs laid per female to obtain high yielding varieties of B. mori is suggested. DOI: http://dx.doi.org/10.3329/ujzru.v30i0.10744 Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp.33-36