• International Journal of Industrial Entomology and Biomaterials
• /
• v.9 no.1
• /
• pp.47-51
• /
• 2004

To evolve silkworm hybrids with higher survival and productivity and easy and effective seed cocoon production, three new evolved bivoltine hybrids of silkworm (Bombyx mori L.), created with participation of sex-limited lines at eggs and larva stage were evaluated with control Super$_1$${\times}$Hessa$_2$ hybrid at Plovdiv Agrarian University during 2000 - 2002. ANOVA analysis was employed and the performance of hybrids was observed in respect of main quantitative traits. The results obtained show significant superiority of new hybrids T$_{15}$ 4/${\times}$TBV$_{2}$24/, XT$_{215}$38/${\times}$TV$_{3}$2/, XT$_{215}$38/${\times}$B$_{2}$6/ and their reciprocal crosses over the control. They were characterized with 99% hatchability of eggs, 93-95% silkworm survival, 2.32- 2.42 g cocoon weight, 53.5-55.7 cg shell weight, 22.9-23.1% shell ratio, 1,307-1,326 m filament length, 3.08-3.17 denier, 95-96% reelability, 44.4-45.1% silk ratio, 569-593 number of normal eggs per lying and 347-364 mg weight of normal eggs per lying. Newly evolved hybrids were manifested high productivity, 41.0-43.6 kg cocoon yield and 7.33-7.78 kg raw silk yield per one box (20,000$\pm$200 viable eggs), which significant surpass the control Super$_1$${\times}$Hessa$_2$ hybrid with 7.6-14.4% and 10.8-17.6%, respectively. T$_{15}$ 4/${\times}$TBV$_{2}$24/ and XT$_{215}$38/${\times}$TV$_{3}$2/ were considered as highly productive hybrids to local conditions and found suitable to rear in spring season.n.

• Journal of Sericultural and Entomological Science
• /
• v.13 no.1
• /
• pp.61-67
• /
• 1971

This experiment was conducted to know the effects of abnormal cocoons on the silk quality during the silk reeling process. The results obtained are summarized as follows: 1. The length, the width, the weight, the layer weight, and the layer ratio of abnormal cocoons are in every case 0.83∼4.65% less than those of normal cocoons. 2. The thickness of the abnormal cocoon layer is at)out 20.62∼22.4% less than that of the normal cocoon. 3. The sericin solubility of tile abnormal cocoon layer is about 11.75∼30% more than that of the normal cocoon layer. 4. The degumming ratio of the abnormal cocoon layer is about 6.51∼9.32% more than that of the normal cocoon layer. 5. The length of a have, the weight of a tave and percentage of raw silk yield of the abnormal cocoon are decreased 9.43%, 8.53% and 6.72% each as compared with those of the normal cocoon. 6. The percentage of reelability of abnormal cocoons is decreased 9.58％ as compared with that of normal cocoons. 7. The neatness of abnormal cocoons is 3 per cent lower than that of normal cocoons. 8. In the cleanness test of abnormal cocoons, the number of split ends i9 about 1.5∼3.8 times as much as that of normal cocoons. Especially cleanness of abnormal cocoons is 16,3 per cent lower than that of normal cocoons. 9. The number of non-reelable cocoons of abnormal cocoons is increased 1.4∼5.5 times as much as that of normal cocoons. In abnormal cocoon, the number of knot which resulted in the breaking of silk end is increased 1.9∼3.5 times as much as that in normal cocoon.

• Journal of Sericultural and Entomological Science
• /
• v.32 no.2
• /
• pp.94-100
• /
• 1990

Yongchonppon, one of the native varities, is the highest clod resistant. For its practical use, feeding test has been implemented in the ordinary rearing and in the branch rearing 1987 through 1988. The results are summarized as follows. 1. The feeding of Yongchonppong at the 4th and 5th instar made 5% decrease in spring and 10% decrease of cocoon yield in autumn, respectively, while cocoon shell ratio was a little less and percentage of raw silk was a little high, as compared to the feeding of Kaeryangppong. 2. The feeding of Yongchonppong at the 4th instar only showed nearly same nearing result as the feeding of Kaeryangppon. 3. In case of the feeding of yongchonppong at the 4th instar and early stage of the 5th instar, cocoon yield and percentage of raw silk marked 96% and 97-98% of Kaeryangppong. 4. The total nitrogen and crude protein of Yongchonnppong was less, while the total carbohydrate, crude ash and crude fat were high, as compared to those of Kaeryangppong. It had more phosphate and boric and less manganese than Kaeryangppong. 5. The leaf aereal weight of Yongchonppong was 1.57g/dcm2 and the leaf thickness was 113$\mu$. The moisture reducing rate marked 41.3% after three hour exposure to the air.

• Journal of Sericultural and Entomological Science
• /
• v.21 no.1
• /
• pp.46-49
• /
• 1979

These experiments were made in order to compare the productivity of various varieties of F$_1$silkworm eggs imported from foreign sericultural countries with the productivity of some F$_1$silkworm eggs varieties produced by Turkey. The results are summarized as follows: 1. In the durations of whole instar, it lasted 30∼38 days under natural rearing conditions but Jam 107${\times}$Jam 105 about 30 days. 2. Cocoon yield per case of silkworm eggs was shown significantly among the varieties. Thaiei ${\times}$ Choan was the highest yield of cocoon, followed by Isonzo, Piave, M-198, M${\times}$N, S${\times}$P, J${\times}$C and Jam 107${\times}$Jam 108 in that order. 3. In the percentage of cocoon shell, M-197 was the highest and other varieties were almost on the same level of cocoon shell, but Jam 107${\times}$ Jam 108 was the lowest percentage. 4. In the weight of a cocoon, Choan${\times}$Thaiei was the heaviest, followed by S${\times}$P, C${\times}$J, M${\times}$N, M-197, Piave, Livenzo and Jam 107${\times}$Jam 108 in that order. 5. In the raw silk percentage of fresh cocoon, Choan${\times}$Thaiei, 3 Italian varieties and Turkish M${\times}$N. C${\times}$J belonged to the first group of better raw silk percentage, followed Polish M-197 and Jam 107${\times}$1am 108 in that order.

• Journal of Sericultural and Entomological Science
• /
• v.14 no.1
• /
• pp.15-24
• /
• 1972

During the autumn-rearing season of 1971, at the silkworm rearing house at the college of agriculture, Seoul national university in Korea, the authors carried out a series of experiments (1) on the susceptibility of four important silkworm pathogens (Aspergillus flavus, Bacillus thuringiensis, Aspergillus oryzae, and Isaria farinosa) to Halamid (Tosylchloramide Sodium), (2) on the acute toxicity of Halamid to silkworm larvae at every instar, (3) on the inhibiting effect of Halamid to the attack of two silkworm infections, fungal muscardine and viral jundice, and the chronic toxicity of Halamid to silkworm larvae, and (4) on the yield and quality of the raw silk harvested from the Halamid treated silkworms. As the results of the experiments the authors found that Halamid could be applied usefully to silk worm rearing industry as an effective disinfectant for both silkworms themselves and their envir onmental articles, rearing houses and tools, also that Halamid exerts its disinfectant effect most efficiently as a disinfectant for silkworms when sprayed in 2% or 3% aqueous solution every second day throughout all tile instars of larval stage.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.11 no.1
• /
• pp.27-36
• /
• 2005

Successful silkworm breeding attempts were made at Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI), Hindupur, India in developing productive bivoltine silkworm hybrids. One hundred hybrid combinations involving 10 parents (five each of oval and peanut) were evaluated in complete diallel pattern and identified the combination APS$_{83}$ $\times$ APS$_{102}$ as most promising. This hybrid showed economic merit for the characters fecundity (524 eggs/laying), pupation percentage (96.0$\%$), cocoon yield per 10,000 larvae by weight (19.0 kg), cocoon weight (1.85 g), shell weight (41.7 cg), shell ratio (22.5$\%$), filament length (1,004 m), reelability (88.4$\%$), raw silk recovery (18.4$\%$) and neatness (92 point) over the control hybrid APS$_{9}$ $\times$ APS$_{8}$ The breeding process and identification of APS$_{83}$ $\times$ APS$_{102}$ is discussed in the paper.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.23 no.2
• /
• pp.187-191
• /
• 2011

An attempt was made to assess the potentiality of bivoltine double hybrids under simulated conditions of farmers to identify the suitable bivoltine double hybrid combination. Four bivoltine double hybrids developed at Central Sericultural Research and Training Institute (CSRTI), Mysore along with popular single hybrid, $CSR2{\times}CSR4$ as control was assessed for economic traits. The rearing results showed significant improvement of 20-24% in fecundity of the double hybrids studied over single hybrid. Among the double hybrids, $[D7{\times}S5]{\times}[D13{\times}S1]$ recorded significantly higher survival (89.58 %), cocoon yield (76.328 kg/ 50,000 eggs), cocoon price (Rs. 180.87/kg) and lower cocoon leaf ratio of 1: 21.80. The performance of the reeling traits were also found significantly superior in $[D7{\times}S5]{\times}[D13{\times}S1]$ with higher filament length (1100 m), reelability (88%), raw silk (18.55%) and neatness (92 points) compared to $CSR2{\times}CSR4$ and other double hybrids evaluated. Besides, the cocoons of $[D7{\times}S5]{\times}[D13{\times}S1]$ exhibit uniformity in size with a standard deviation of < 8. Overall data indicated the superiority of $[D7{\times}S5]{\times}[D13{\times}S1]$ compared to the other hybrids evaluated and it has profound influence in expressing the full potentiality in the field.

• Journal of Sericultural and Entomological Science
• /
• v.25 no.1
• /
• pp.34-43
• /
• 1983

These studies have been carried out to find better locations for sericultural service regardless of the international silk market fluctuation in Korea. In order to acieve the purpose, various investigations and analyses have been carried out for more than four hundred sericultural communities to find out the main factors which caused to decrease in cocoon production in spite of a gloomy past silk market. Now, we believe that we have set up some fundamental guide lines in developing sound serviceable sericultural communities in Korea in case the government accepts the written advices, and the results obtained are as follows: 1. The Korean sericulture has been very prosperous from the 60's to the 70's. In 1976 the cocoon production was at its peak, reaching 41,704M/T from which its decline took place with annual averages of 18.5% for total cocoon production and 16.4% for mulberry field. These figures represent a quantitative decrease to one-third of the total amount in 1976. Since then, the Korean sericulture had continuously suffered from a shortage of raw silk resulting in a slow development of sericulture. At present, a steady development through all possible measures is great importance. 2. The downfall of the korean sericulture resulted from two factors of such as the external, which led to the decline in the price of raw silk at the international market and restrain of import and, the internal, resulting in the little increase of cocoon price and a comparatively lower benefits from the sericulture than from other cash crops. 3. The already established sericultural zone collapsed and then reorganized with the outstanding regional specialization so the decline in total cocoon production in the country. Based on the agricultural regions, 1980 cocoon production was very stable in the mountaineaus area of the east-south which used with intercropping. In this area there was small decline of 33% compare with that of the 1979, and with 70% decline in the dry field farming area of Kangwon Do. In an administrative districtwise, six counties beginning with Sanchnung county of Kyungsang Nam Do, showed less than 20% decline of cocoon production, sixteen counties beginning with Samchuck county of Kangwon Do marked above 80% decrease of cocoon production. In the smaller unit area-wise, there was a big difference among them. twenty-five myons rather increased and a hundrd fourty-three myons decreased above 80% of it. 4. The cocoon production was positively correlated with the decreasing percentage of cocoon production per household. It was also affected by the ratio of the mulberry field area to the total cultivated area per household and cocoon productivity per 10a. 5. Four hundred sixty-four villages in the seventeen counties were surveyed on the basis of farm management and techniques concerned ('80/'79), and then the results were evaluated by using of computer. These results are summarized as foolows: (1) Cocoon production per household There was no difference among the agricultural regions in cocoon production. The cocoon production per household in the comparatively stable villages increased from 100.8kg in 1979 to 122kg in 1981. Cocoon yield in the stable villages decreased by 20% of '81/'79. The cocoon production per house hold in while that of the unstable villages decreased by more than 40% from 102.9kg in 1979 to 82kg in 1981. (2) Cocoon yield per 10a mulberry field The cocoon yield per 10a was higher in the plain area than in the mountaineous area. The stable villages had an average of 73.4kg cocoon yield/10a while the unstabe ones had only an average of 55kg. (3) Adoption the mulberry branch rearing method The branch rearing method was more popular in the plain area than in the mountainous area. In the stable vilages adopted 24.2% in spring and 16.7% in autumn of 1979. In 1981 it shwed increases of 34.3% and 10.1% in the two seasons respectivly. However, the unstable villages showed 13.3% and 126% in both seasons, respectively. (4) The patterns of the combined management system in the sericultural farming The popular management system in the sericultural from was combined with rice and other cash crops, showing 55% of the total households surveyed. Fourteen percent of the households combined the management system with rice and other cash crops and 14% of the households combined with rice only. The villages wich earned less than 20% of the total income from the sericulture reached 81% of the total houscholds indicating that they were still far beyond a complete combination system. (5) Damage by agricultural chemicals The damage caused by agricultural chemicals was mainly due to the protection of rice against insectpests and diseases in the plain areas and took place mostly in the autumn season. The chemicals applied was 65% of Iiquid and 35% of powder forms and 35% of damage was from granulat form of the chemicals. The use of the granular chemicals was low because of high cost.

• Journal of Sericultural and Entomological Science
• /
• v.46 no.2
• /
• pp.54-57
• /
• 2004

A new silkworm variety "Buhungjam" for autumn rearing season is $F_1$ hybrid between Jam149, a japanese race bred from introduction breeding and Jam150, a chinese race from introduction breeding. Jam149, japanese parent of the "Buhungjam" showed high GCA in pupation percentage, cocoon shell percentage and filament length and Jam15, chinese parent showed high GCA in cocoon shell percentage and cocoon filament length. In the local adaptability test performed at 8 local areas in spring of 2003, Buhungjam records 7% higher in cocoon yield and 8% in raw silk yield than the check variety, Daesungjam.