• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.2
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• pp.147-151
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• 2012

Fifteen races resulted from silkworm breeding program at Sericulture Research Department (SRD) were used for hybridization. Fourteen hybrids were obtained and coded as; Giza C, D, R, S, T, U, A, V, W, P, H, L and Qanater 1, 2. The traits of cocoon weight, cocoon shell weight, pupal weight, cocoon shell ratio, silk productivity, fifth instar duration, total larval duration, number of cocoon per liter and pupation ratio were evaluated. Data were analyzed by using three formulae of heterosis over better, mid and check parent values. Hybrids of Giza V, C, N, Qanater 1 and 2 are promising and could be used in commercial cocoon production. Generally, there are some new hybrids can be exploited in commercial scale. Also, the local races can be evolved using the hybridization, inbreeding and selection program.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.155-159
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• 2000

In the spring silkworm rearing period of year 1998, some nutritional aspects were studied in the Agricultural Research Station of the Komotini town in Greece, to investigate the feeding behaviour of some Bulgarian silkworm hybrids, suitable for spring rearing, during the fourth and fifth instal under the local climatic conditions. The silkworms were fed by locally cultivated Japanese Kinriu mulberry (Morus alba L.) variety leaves. Eight Bulgarian hybrids had been used, namely Vratza-53xVratza-52, Ukraine-20xVratza-53, Super 1xHessa 2, Merefa 2xVratza 35, as well as their reciprocal crosses. The studies showed out a remarkably higher feed intake and feed utilization by the hybrids Hessa 2xSuper-1, Merefa 2xVratza 35 and Vratza-52xVratza-53. The same hybrids showed an efficient food utilization by means of daily growths cocoon shell ratio and raw silk output. In terms of food to silk conversion efficiency Hessa 2xSuper-1 hybrid gave the best results. Larval stage duration for fourth and fifth instar was not affected by feed intake and utilization. All hybrids showed a good adaptation to the local environment and their feeding performance was equal to the international existing standards. All calculated parameters were found to be around the mean values of other up to date presented results and thus considered as acceptable for the needs of the local production.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.1
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• pp.3-11
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• 1984

In order to obtain the basic information for the successful breeding of aromatic tobacco (Nicotiana tabacum L.), the heterosis, combining ability and gene distributions in 28 Fl hybrids by diallel crosses between Korea local and Oriental varieties were investigated. The yield were higher, stalk height, leaf length and leaf width were larger and days to flower was shorter for the Fl hybrids when compared to mid-parent. Estimates of general combining ability were significant for all characters investigated, and specific combining ability were significant for yield, stalk height, leaves Per Plant, leaf width and days to flower. In vr-wr graph, partial dominane was exhibited by all characters investigated.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.31-35
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• 2001

Ten newly evolved bivoltine hybrids of silkworm (Bombyx mori L) were evaluated with control hybrid KA${\pm}$NB4D2 during three seasons of a year for their seasonal performance. Analysis of variance and other statistical methods were employed and the performance was observed in respect of 10 quantitative traits. The results showed significant genotype${\pm}$environment interaction with respect to four quantitative characters viz. fecundity, yield/10,000 larvae, filament length and raw silk (%). Environmental effects were significant for nine characters out of ten characters evaluated. A 105${\pm}$J2 and B${\pm}$NB4D2 were considered as highly adaptable hybrids to local conditions with high mean for maximum characters studied and found suitable to rear in all seasons.

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

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.65-69
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• 2001

In order to evaluate the characteristics of growth and yield in $F_1$ waxy hybrids using Korean local maize lines, six hybrids including check, Chalok #1, were planted at the experinental field of the Chungnam National University. Stern and ear heights of $Yeonnong{\times}Jaerae$ and $FR805/IK_3{\times}Koryong$ hybrids were higher than the check hybrid. Number of tillers per plant in all hybrids were similar as 0.3 to 0.5 per plant. Ear length of waxy hybrids was longer than 15cm of check hybrid and ear diameter was also thicker than check except $FR805/IK_3{\times}Koryong$ waxy hybrid. A final result, $Yeonnong{\times}Jaerae$ among hybrids was comparatively superior to other hybrids in the test.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.97-104
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• 1998

Mainly due to limited genetic resources available and also urgent need for hybrids suitable to local conditions, conventional theories and regular methods for bivoltine silkworm breeding are not easily applicable in such a tropical country as Sri Lanka which is recently planning to scale-up the silk industry. A simplified but practical methodology was introduced to overcome such constraints. Through application of such modified informal breeding methods, two hybrids named DP0308 and DP0314 were selected for cocoon production. Details of the altered method of germplasm improvement in the silkworm are presented, along with combining ability and heritability estimates for six parental pure lines in a half-diallel cross.

• International Journal of Industrial Entomology and Biomaterials
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• v.42 no.2
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• pp.33-45
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• 2021

Many researchers are using the heterosis, heterobeltiosis and hybrid vigour over check parent value formulae to determine the hybrid vigour for animals, plants and silkworm breeding. These formulae are ideal for determine the hybrid vigour for the positive direction of single trait. It is difficult using these formulae for multiple traits. Suggested modification for cardinal formulae were made as well as suggestion new formula for determines hybrid vigour for multiple traits. Modifications of hybrid vigour were made to facilitate judgment of best hybrids under study for multiple traits. Nineteen local hybrids of mulberry silkworm were prepared for these investigations in addition the imported Bulgarian hybrid. Comparison between the cardinal and the modifications formulae were applied for thirteen economic characters. Nine positive and four negative direction characters were observed. Modified formulae make the judgment of heterobeltiosis, heterosis and hybrid vigour over check parent value very facilitate for positive and negative traits.

• International Journal of Industrial Entomology and Biomaterials
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• v.24 no.1
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• pp.7-16
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• 2012

To meet the local requirement i.e. the tropical stress of Andhra Pradesh and marginal farmers, twenty four new hybrid combinations were tested in Line x Tester method involving eight newly developed polyvoltine oval lines viz., MSO1, MSO2, MSO3, MSO4, MSO5, MSO6, MSO7 and MSO8 and three bivoltine silkworm breeds viz., APS12, APS45 and APS8 as testers. These hybrids were reared to evaluate their performance. Data for eight economically important metric traits viz., fecundity, cocoon yield per 10,000 larvae by number, cocoon yield per 10,000 larvae by weight, survival rate, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length was recorded. General combining ability (gca), specific combining ability (sca) and heterosis were analyzed. Further, the relative merit of the hybrids for all the traits under study was also assessed adopting Evaluation Index method. Based on combining ability effects, heterosis and evaluation index, five hybrid combinations viz., MSO3 $\times$ APS45, MSO1 $\times$ APS12, MSO7 $\times$ APS8, MSO2 $\times$ APS45 and MSO1 $\times$ APS45 were selected for further evaluation in different seasons.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.175-184
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• 1995

In order to substitute sweet and super sweet maize hybrid seeds which are introduced at current, and to meet national demand for human consumption, inbreds and hybrids of waxy maize were developed by using Korean native lines, Six inbreds were used to produce 15 hybrids in a diallel cross, Six inbreds used were significantly different in tasseling dates, plant and ear heights, leaf area, and shank length, The inbred line, Bosung showed the longest shank length among the lines used, The ear characters like ear length and diameter, 100 kernel weight, row number, and kernel number per ear varied among lines, The inbred line Bosung was again significantly different from other lines in ear length and diameter, row number and 100 kernel weight. However, ]ewon had the highest kernel yield per 100. Hybrids were also different in plant and ear characteristics depending upon the inbreds used. The hybrids of Bosung showed the longest ear length and the heaviest kernel weight. Highest kernel yield per unit area was obtained by the hybrids crossed with Dangjin, The general combining ability(GCA) of Dangjin was found very effective in reducing plant and ear height of hybrids. The GCA of Jewon was very effective in increasing tiller number per plant. The inbred line Bosung was effective in increasing ear length and 100 kernel weight and in decreasing row number. The hybrid which showed the highest specific combining ability in ear length and 100 kernel weight was Jewon Chilbo.