Silkworm Breeding Research Articles

Hemocyte Changes During the Progressive Infection of Beauveria bassiana in Different Breeds of Silkworm (Bombyx mori L.)

The immune system in insects involves in clearing the haemolymph of foreign pathogens by haemocytes and humoral factor. They can accomplish this in a couple of different ways. One is a cellular mediated response by physically clearing the haemolymph by phagocytosis, nodulation and encapsulation and the other is by humoral secretion of proteins. Pathogenic infection in silkworm, Bombyx mori L. is common and there is a possibility of differential response by haemocytes in different breeds to microbial infection. Hence, the differential response in the form of difference in Total haemocyte count (THC) and Differential haemocyte count (DHC) in susceptible and tolerant breeds were investigated under normal and Beauveria bassiana invasion conditions. Under normal condition, there was a gradual increase in THC as the age of the silkworm increases and high THC was recorded in Nistari, PM and NB4D2 (tolerant breeds) compared to susceptible breeds (NB7, NB18 and KA). There was a gradual increase in THC, gradual decrease in prohaemocyte and oenocyte counts and increase in plasmatocyte and granulocyte counts during the progressive infection by Beauveria bassiana.

Proteolytic enzymes as markers of productivity and heterosis of silkworm

A positive correlation between the activity level of cysteine proteinases in developing eggs of common silkworm moth (Bombyx mori L.), on the one hand, and a set of commercial characteristics, on the other, was found. This allows the determination of cysteine proteinase activities (pH optima of 3.0, 3.6, and 8.6) to be recommended as a biochemical test for an early prediction of potential productivity of silkworm breeds. A positive correlation between the activity level of acid cysteine proteinases in eggs of parental breeds and a set of commercial characteristics of their hybrids was detected, indicating a principal possibility of predicting the degree of heterosis.

Toxic Effects of Cadmium on Morus alba L. and Bombyx moril L.

A 3-year micro-plot experiment of mulberry cultivation with Cd-polluted soil and silkworm breeding experiments by feeding with exogenous or endogenous -Cd-polluted mulberry leaves were conducted to evaluate the toxic effects of Cd on mulberry and silkworms. There was no apparent harmful effect on mulberry plant growth at a soil Cd content of 8.49 mg/kg. At a soil Cd content of 75.8 mg/kg, a yield reduction in the leaves became apparent, whereas at 145 mg Cd/kg soil, the plants exhibited marginal growth. There was a significant decrease of the ingestive rate of leaves at an exogenous Cd content of 1.98 mg Cd/kg leaf, whereas the digestive rate decreased significantly at an exogenous Cd content of 0.50 mg/kg. The endogenous Cd content that significantly affected the ingestive and digestive rates was 1.66 mg/kg. The influence of exogenous and endogenous Cd on the biomass of the silkworms decreased with increase of the instar stage. The weight of cocoons and rate of silk reeling was significantly reduced at exogenous and endogenous Cd contents of 5.17 mg/kg and 1.66 mg/kg, respectively.

Screening of molecular markers for NPV resistance in Bombyx mori L. (Lep., Bombycidae)

Abstract: Silkworm (Bombyx mori L.) is one of the important economic insects. Silkworm rearing and silk industry plays an important role in China, India and other developing countries. In the long history of sericultural practice, introduction of silkworm strains with high resistance to diseases has greatly improved cocoon and silk quality and productivity. However, current silkworm breeding is mainly based on traditional method that involves high input of time and labour. In order to increase the selection efficiency and accuracy for future silkworm breeding, it is necessary to establish a molecular marker‐assisted selection system. In our study, three silkworm near isogenic lines that had different resistance to nuclear polyhedrosis virus (NPV) were established by means of different hybridization methods. A total of 150 random amplified polymorphic DNA (RAPD) random primers were used to screen molecular markers. Among them, two molecular markers OPA‐18700 and OPY‐11400 were found linked to major genes resistant and susceptible to NPV, respectively. Validity of the molecular markers was proved in F2 populations.

Sericulture in Boka Kotorska Bay (17th-20th)

In the 19th century Boka Kotorska, sericulture - silk-worm breeding and processing -was highly developed. Based on unpublished arhivalia from the Montenegro National Archives, - Records Department of Herceg Novi - and on published materials from the Historic Archives of Kotor and the Historic Archives of Zadar, along with the related literature, the paper deals with the silk-worm breeding, scope of silk production, operation of spinner mills, planting and cultivation of mulberry trees, whose leaves were used for silk-worm feeding. The Austrian authorities, ranging from the Zadar Regency and the Kotor County Hall, with local councils, through the Silk-Worm Breeding Society and the Bay of Kotor Economy Association, were actively engaged in developing the silk production and enhancing the quality of this economic activity. According to what has been said, it appears that silk-worm breeding was practiced in both rural and urban settlements of the entire Boka Kotorska Bay. The silk-worm breeding entailed the planting of mulberry trees which survived even after the silk-worm breeding had ceased to exist, as mulberry fruit was used to feed pigs and poultry, to make brandy, and because the wood - mulberry lumber - was highly valued in ship building. Mulberry trees were grown in urban settlements as they provided a reliable shade. The silk-worm breeding was discontinued towards and during World War One, whereas the mulberry tree planting persisted until World War Two.

Sericulture-based agroforestry systems for hilly areas of north-east India

Sericulture-based agroforestry systems (AFS) have great potential for higher returns in the north-eastern region with sloping and valley-land conditions. A field investigation was initiated in November, 1992 at Research Farm, Barapani (980 m above msl, 26°N and 92°E and average rainfall 2428 mm/year) on acid Alfisol. Seven mulberry (Morus alba L.) varieties, seven silkworm breeds and rearing performance of a bivoltine breed, NB-18 were evaluated in different trials. Three sericulture-based AFS viz. sericulture with 1. fruit trees and fodder grasses, 2. field (upland) crops, and 3. lowland rice were developed at the Research Farm. Mulberry varieties TR-4, S-1635 and TR-10, and NB-18 — a bivoltine silkworm breed were found better suited for this region. Sericulture with field crops (French bean-groundnut-mustard/vegetables) for valley land, with fruit plants (guava, pineapple) and grasses for mid-hill situations, and with rice for low lands were found suitable at the Farm and for possible adoption in the north-eastern hill region of India.

Correlation between yield and biochemical parameters in the mulberry silkworm,Bombyx mori L

A detailed study was carried out on six biochemical parameters and four yield attributes using multiple regression analysis to investigate their relationship in the mulberry silkworm,Bombyx mori. The study generated new information on the importance of digestive amylase activity for the survival of the silkworm and revealed the inability of other enzymes to affect this relationship. Data also substantiate the observations made earlier on the genetic variability of amylase in the mulberry silkworm. Analyses extend the positive role of alkaline phosphatase and invertase in the expression of the other yield traits studied and indicate the definite possibility of using biochemical markers for silkworm breeding.

Hierarchical clustering of 54 races and strains of the mulberry silkworm, Bombyx mori L: Significance of biochemical parameters

A detailed analysis was undertaken to test the efficacy of hierarchical agglomerative clustering (UPGMA method) in grouping the races and strains of the mulberry silkworm, Bombyx moti L., and to ascertain the importance of biochemical parameters in the clustering process. The analysis was based on data from two rearing seasons with 54 selected races/strains of different geographic origin and varying yield potentials. The results indicate that seven clusters can be realised with yield parameters alone, whereas the inclusion of biochemical parameters in clustering resulted into two broad groups: one having all the breeds with high cocoon weight and shell weight, the other having all the low-yielding silkworm strains both from India and from other countries. Further sub-grouping under these two groups highlights genetical differences associated with the differentiation of various groups of races in temperate and tropical areas as well as their significance for silkworm breeding. Estimates of all ten variables were further subjected to 'quick clustering' and the results showed that cluster 5, constituted by 38 lowyielding strains of India, China and Europe, had the highest values of the final cluster centre for amylase and the effective rate of rearing (ERR), while clusters 1 and 4 had the highest values for invertase and alkaline phosphatase. The evolutionary aspect of the genetic channelisation of silkworm races from various countries is discussed against the background of differences in the biochemical parameters and yield variables.

Breeding of polyphagous silkworms by early selection for feeding ability on LP-1 artificial diet

Breeding of polyphagous silkworms by early selection for feeding ability on LP-1 artificial diet

Studies on the W-Translocation of Yellow blood Gene in the Silkworm

The authors has been succeeded to induce the translocation of yellow blood (Y) gene on the 2 nd chromosome to the W-chromosome in the silkworm, by the irradiation of pupae with γ-rays at 6000 R for 20 min. This strain shows sex-limited inheritance on the blood color, namely the color is white in the male and yellow in the female. By the coexistence of cocoon color gene C, the cocoon color also shows sex-limited inheritance ; white in the male and yellowin the female. Therefore, the sexes can be easily discriminated by cocoon color and this translocation is very usefull for the crossing to produce F1-or poly-hybrids in commercial silkworm breeds.

Results of silkworm breeding for these ten years(1951∼60)

Results of silkworm breeding for these ten years(1951∼60)

THE STATUS OF SERICULTURE IN ITALY

Italy dominates the raw silk market of Europe to about the same degree as the Far East does that of the world as a whole. The proportion in each case is about 90 per cent. Of the total world output of 7S,000 to 100,000 metric tons of raw silk, the Italian contribution of 4,000 to 5,000 metric tons, or about 5 per cent, is of small consequence. Sericulture is one of the oldest Italian industries, the breeding of silk worms having been introduced into Sicily in the early years

A relation of the designed progress to be made in the breeding of silk worms, and the making of silk, in France

The French King Henry the Fourth, having made a general establishment all over France, of planting and propagating of mulberry-trees, and breeding of silkworms, in order to set up and entertain a silk-trade there; and having prospered so well in that design, that in many parts of his dominions great store of such trees were raised, and multitudes of silk-works propagated, to the great benefit of the French people, forasmuch is it was a considerable beginning to avoid the transport of several millions abroad for buying of silk, and withall an excellent means of well-imploying abundance or poor orphans and widows, and many old, lame, and other indigent and helpless people;