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Critical analysis of correlation and heritability phenomenon in the silkworm, Bombyx mori (Lepidoptera: Bombycidae)  [PDF]
Tribhuwan Singh, Madan Mohan Bhat, Mohammad Ashraf Khan
Advances in Bioscience and Biotechnology (ABB) , 2011, DOI: 10.4236/abb.2011.25051
Abstract: Correlation and heritability studies of quantitative traits are a pre-requisite for judicious selection for genetic improvement of complex characters of economic importance. The success of selection is governed by the degree to which the desired trait is transmitted to the succeeding generation. The nature of selection is to be given due consideration at appropriate developmental stages for pursuing selection in desired direction while improving or evolving high productive breeds or hybrids of the silkworm. Characters showing high heritability as well as high genetic advance respond better to simple phenotypic selection while those having low heritability and low genetic advance may respond better to mass selection. Characters showing high heritability and low genetic advance may yield good response to hybridization and recurrent selection. An attempt has been made in this review article to briefly discuss the magnitude of correlation and heritability in selection strategies for the improvement of quantitative traits in desired direction in the silkworm, Bombyx mori (L.).
Effect of Salt, Nickel Chloride Supplementation on the Growth of Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae)  [PDF]
Md. Rezuanul Islam,Md. Abdul Ohayed Ali,Dipak Kumar Paul,Shaheen Sultana
Journal of Biological Sciences , 2004,
Abstract: The present investigation deals with the effect of nickel chloride supplementation on the growth of Bombyx mori L. (Lepidoptera: Bombycidae). The weights of mature Bombyx mori L. larvae were 1522.10 ± 78.97, 1579.67 ± 61.29, 1685.13 ± 61.77, 1781.60 ± 66.62, 1801.60 ± 60.69 and 1426.07 ± 89.48 mg for nickel chloride at 0 (Control), 100, 200, 400, 800 and 1600 ppm, respectively. The weights of male and female pupae were 648.03 ± 37.97 and 763.57 ± 55.44, 667.50 ± 51.10 and 774.23 ± 54.33, 682.60 ± 61.78 and 811.47 ± 61.13, 712.23 ± 42.46 and 841.33 ± 63.04, 746.77 ± 45.73 and 871.30 ± 50.47, 618.40 ± 30.61 and 713.70 ± 63.16 mg for nickel chloride for above applied doses. The weights of male and female adults were 300.67 ± 70.07 and 546.27 ± 61.67, 317.63 ± 42.98 and 559.50 ± 76.87, 331.90 ± 48.93 and 571.50 ± 80.46, 352.00 ± 55.14 and 597.67 ± 56.53, 373.17 ± 46.53 and 645.23 ± 55.34, 283.40 ± 43.89 and 514.27 ± 75.83 mgs for nickel chloride for above applied doses. The weights of male and female cocoons were 752.07 ± 31.70 and 87.17 ± 55.50; 769.23 ± 49.84 and 889.10 ± 50.40, 795.53 ± 61.69 and 937.10 ± 59.70, 841.33 ± 42.25 and 970.53 ± 62.33, 856.93 ± 48.50 and 979.63 ± 44.09, 717.27 ± 32.13 and 822.13 ± 64.96 mg for nickel chloride at 0(Control), 100, 200, 400, 800 and 1600 ppm, respectively. The results were statistically significant (P<0.001) among the concentrations. From the above results it may be concluded that nickel chloride can be used at low concentrations for enhancing the economic character of silkworm, Bombyx mori L.
Sensitivity of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) larvae to UV irradiation  [PDF]
SI Faruki,PK Kundu
Invertebrate Survival Journal , 2005,
Abstract: The effects of UV-radiation on some commercially relevant traits of three instars viz. 1st, 2nd and 3rdof the two multivoltine strains, Nistari-M and Urboshi-1 of the silkworm, Bombyx mori L. have beeninvestigated. UV-rays reduced the weight of larvae, pupae and adults of both the strains and sexes of B.mori independently of the instar that has been treated. The cocoon weight, shell weight and shell ratioswere also reduced due to UV-irradiation. Increased larval mortality was recorded at all the doses of UVrays.
Evaluation of economically important traits from sixteen parental strains of the silkworm Bombyx mori L (Lepidoptera: Bombycidae)
Zanatta, Daniela B;Bravo, Juliana P;Barbosa, Joice F;Munhoz, Roxelle E F;Fernandez, Maria A;
Neotropical Entomology , 2009, DOI: 10.1590/S1519-566X2009000300005
Abstract: the classification and characterization of silkworm strains are important for sericulture, which is supported by the constant development of new hybrids. in this study, 16 parental strains of bombyx mori l from the germplasm banks of the universidade estadual de maringá - uem, and associa??o dos criadores de bicho-da-seda de nova esperan?a e regi?es sericícolas do paraná - acesp, were evaluated regarding biological and productive traits economically important. the chinese c122-b and c121-a, and the japanese ha-a and ha-b strains yielded the highest cocoon weight, which is related to the raw silk percentage. our data will be useful in breeding programs for the production of superior silkworm strains and hybrids.
The effect of thyroxine on silk gland and the effect of two thyroxine-treated mulberry species feeding on silk quality in the silkworm Bombyx mori (Lepidoptera: Bombycidae)
I Ahmad, S Patrakomala, S Dwiyanti, R Putra
African Journal of Biotechnology , 2009,
Abstract: The influence of feeding mulberry leaves treated with thyroxine to the growth of the silk gland, and the effect of two different mulberry species, that is, Morus nigra and Morus multicaulis treated with thyroxine on silk quality in the silkworm were studied. The silk glands from thyroxine treated Bombyx mori larvae weighed heavier than control. The weight of the posterior silk gland, where fibroin is synthesized, increased significantly compared to the anterior and median silk glands. No difference between thyroxine treatment on the second instar and fourth instar larvae in terms of silk gland weight was observed. Different mulberry species treated with thyroxine fed to silkworm larvae, affected silk quality. Higher silk tenacity and elongation were observed when silkworm larvae were fed thyroxinetreated M. nigra, while silkworm larvae fed on thyroxine treated M. multicaulis produced longer unbreakable filament.
On the Breeding of Bivoltine Breeds of the Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), Tolerant to High Temperature and High Humidity Conditions of the Tropics  [PDF]
Harjeet Singh,N. Suresh Kumar
Psyche , 2010, DOI: 10.1155/2010/892452
Abstract: The hot climatic conditions of tropics prevailing particularly in summer are contributing to the poor performance of the bivoltine breeds and the most important aspect is that many quantitative characters such as viability and cocoon traits decline sharply when temperature is high. Hence, in a tropical country like India, it is very essential to develop bivoltine breeds/hybrids which can withstand the high temperature stress conditions. This has resulted in the development of CSR18 × CSR19, compatible hybrid for rearing throughout the year by utilizing Japanese thermotolerant hybrids as breeding resource material. Though, the introduction of CSR18 × CSR19 in the field during summer months had considerable impact, the productivity level and returns realized do not match that of other productive CSR hybrids. Therefore, the acceptance level of this hybrid with the farmers was not up to the expected level. This has necessitated the development of a temperature tolerant hybrid with better productivity traits than CSR18 × CSR19. Though, it was a difficult task to break the negative correlation associated with survival and productivity traits, attempts on this line had resulted in the development of CSR46 × CSR47, a temperature tolerant bivoltine hybrid with better productivity traits than CSR18 × CSR19. However, though, these hybrids are tolerant to high temperature environments, they are not tolerant to many of the silkworm diseases. Keeping this in view, an attempt is made to develop silkworm hybrids tolerant to high temperature environments 1. Introduction Silkworm breeding aims to achieve superior performances in respect of egg yield, cocoon raw silk yield, cocoon stability, and production followed by expansion to new areas besides others. Silkworm breeders continue to strive for an inherent gain in resistance by incorporating resistant genes into the genetic backgrounds of high yielding temperate bivoltines. Besides this, the cocoon crop stability also relies more on improving other production technologies which have to be explored. It is interesting to note that in inbreeding experiments, besides choice of parents, selection and inbreeding the hybrids are very important which have to be carefully executed since both inbreeding and hybridization are forms of nonrandom mating or selective mating, but operate in opposite ways. Inbreeding is a kind of genetic assortative mating as compared with phenotypic assortative mating in hybridization. The major effect of inbreeding which is most apparent in the reduction of mean performance of the population is in
Evaluation of productive performance of 51 different peanut cocoon strains of Iran silkworm Bombyx mori (Lepidoptera: Bombycidae) germplasm
MS Nezhad, SZ Mirhosseini, AR Seidavi, S Gharahveysi, M Mavvajpour
African Journal of Biotechnology , 2010,
Abstract: In our study, 51 peanut strains of Iran silkworm germplasm were evaluated for 36 economically important traits and for the feasibility of using these strains for breeding programs. After hatching of eggs, neonates were brushed and reared up separately on fresh leaves of mulberry (Morus alba). Newly hatched larvae of all strains were reared for experiment. Individual egg laying were prepared for each strain before rearing and each individual egg laying consisted of about 500 eggs taken from one disease free laying and decreased to 250 larvae at the beginning of the 4th instar.
Mutagenic Effect of Diethyl Sulphate (DES) on the Chromosomes of Silkworm Bombyx mori L(Lepidoptera: Bombycidae)
G Lokesh, SR Ananthanarayana
Journal of Applied Sciences and Environmental Management , 2008,
Abstract: The silkworms of NB4D2 variety were treated with chemical mutagen Diethyl sulphate (DES). The larvae were subjected to two methods of treatments i.e., oral administration of the chemical mutagen and by injection of 8mM and 10mM concentrations of chemical mutagen through body wall. The lethal effect of the mutagen was studied in the subsequent generation. The effect was drastic on structure & morphology of the meiotic chromosomes. Many structural, physiological and numerical aberrations were observed and documented. Certain numerical changes such as induction of polyploids were attributed to the improvements observed in the expression of commercial characters in the silkworm
The effect of chemical mutagen on haemolymph proteins of silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) in F1 stage
G Lokesh, M Narayanaswamy, SR Ananthanarayana
Journal of Applied Sciences and Environmental Management , 2006,
Abstract: The chemical mutagen Diethylsulphate (DES) was treated to the mulberry silkworm, NB4D2 breed at the age, fifth instar fifth day with different concentrations (8mM and 10mM) by injection and spray methods. The F1 progeny was obtained from DES treated and control sets by selfing the moths. The quantitative analysis of haemolymph proteins revealed that 8mM injection set exhibit higher levels when compared with control and treated sets. The quantitative analysis also clearly indicate the variations in the number as well as intensity of the protein bands. Journal of Applied Sciences and Environmental Management Vol. 10 (3) 2006: 21-25
Evaluation of the toxic effect of insecticide chlorantraniliprole on the silkworm Bombyx mori (Lepidoptera: Bombycidae)  [PDF]
Roxelle Ethienne Ferreira Munhoz, Thaís Souto Bignotto, Naiara Climas Pereira, Cláudia Regina das Neves Saez, Rafaela Bespalhuk, Ver?nica Aureliana Fassina, Graziele Milani Pessini, Mayarha Patrícia Dequigiovanni Baggio, Lucinéia de Fátima Chasko Ribeiro, Rose Meire Costa Brancalh?o, Shunsuke Mizuno, Willian Shigeaki Aita, Maria Aparecida Fernandez
Open Journal of Animal Sciences (OJAS) , 2013, DOI: 10.4236/ojas.2013.34051
Abstract:

The silkworm Bombyx mori feeds exclusively on mulberry leaves and is highly sensitive to pesticides in general. Although mulberry plantations are free of agrochemicals, pesticide drift can occur. Chlorantraniliprole, a novel insecticide of the anthranilic diamides class, has been used to control pests in field crops. In this study, we investigated the biological effects of different concentrations of chlorantraniliprole on B. mori silkworm commercial Brazilian hybrids. To evaluate the toxicity of chlorantraniliprole, bioassays were carried out and data on the lethal concentrations, symptomatology, morphology and variables of silk production were collected. Results indicated that B. mori is extremely sensitive to chlorantraniliprole, even in low concentrations. The highest silkworm mortality rates were observed in the two highest chlorantraniliprole concentrations, 0.2 and 0.1 ppm. Although lower chlorantraniliprole concentrations did not cause death of all the silkworm larvae, various symptoms of toxicity were observed: feeding cessation, regurgitation, late development and incomplete ecdysis. Such symptoms reflect the morphological changes we observed in the midgut epithelium, which affected nutrient uptake and metabolism, and even the production of cocoons. Exposed larvae also produced thin-shelled cocoons, which constitutes a serious economic problem because this type of cocoon is not useful for the silk industry. The results provided herein confirm the toxicity of chlorantraniliprole in silkworm larvae. Therefore, we strongly suggest that, competent authorities of the National Health Surveillance Agency, in pesticide management should take measures to reduce or eliminate the use of chlorantraniliprole in areas nearest to silkworm cultivation.

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