• Mycobiology
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• 제32권1호
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• pp.11-16
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• 2004

Winter mushroom, Flammulina velutipes, needs low temperature during its cultivation. To save on farm costs, especially during summer, a strain adaptable to a higher or elevated-temperature must be developed. At the start of breeding program, parental strains which could endure high temperature were obtained. Seuenty four dikaryotic strains were collected and divided into four groups according to the nature of temperature. They also had different fruiting temperature. Finally we selected three brown strains ASI 4048, 4057 and 4072, and collected their spores. These selected strains can germinate even at a high temperature of $32^{\circ}C$, which were dramatically higher than the other strains. Based on these results, the new white strain adapted to mid-temperature by backcross mating was developed. Molecular markers were applied to select white fruitbody producing strains without cultivation. They showed a specific band which co-segregated with brown fruitbody forming strains in $BC_1F_1$ progenies. Selected white strains were tested under several elevated temperature conditions.

• 한국수산과학회지
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• 제43권5호
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• pp.457-461
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• 2010

To estimate the effect of selective breeding on the improvement of growth in olive flounder Paralichthys olivaceus, we compared the growth of a strain selected for rapid growth to that of an unselected strain from a commercial hatchery. The fish strains were fed with either moist pellets (MP) (dry matter, 59.8% crude protein; 14.1% lipid) or extruded pellets (EP) (dry matter, 50.4% crude protein; 13.8% lipid) for 190 days and were reared under similar conditions. The mortality rates were less than 2% and were not significantly different among the experimental groups. The growth rate of the selected fish was significantly greater than that of the unselected fish regardless of the diet type, and both strains fed MP grew significantly faster than those fed EP. The selected fish consumed more feed than the unselected fish. However, there was no significant difference in the feed efficiency between the selected and unselected fish. These results demonstrate that the selected fish exhibited superior growth rates, and that this was associated with a greater intake of food. Thus, selective breeding may be useful for improving the growth of commercial olive flounder.

• 한국잠사곤충학회지
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• 제29권2호
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• pp.24-30
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• 1987

잠업시험장에서 육성중인 한성흑란계통잠의 실용형질향상을 위한 효율적인 교잡방법의 탐색을 위해 동아구교잡, 연속교잡, 단계 및 복계여교잡의 4가지 육종방법이 교잡원종세대(P)로부터 F6세대까지 비교검토되었다. 1. 화용비율의 경우 4가지 육종방법 공히 세대간에 또는 교잡방법간에 매우 변화가 심하였고 교잡효과의 양상은 연속교잡>동아구교잡·복계교잡>단계여교잡의 순으로 낮아졌다. 2. 전견중, 견층중, 견층비율의 경우 동아구교잡을 제외한 3가지 방법 공히 비교적 우수한 육종방법으로 생각된다. 3. 세대별 형질발현의 추이를 보면 화룡비율은 세대별 변화가 매우 심하여 일정한 경향이 없고, 전견중, 견층중, 견층비율은 교잡방법에 불구하고 P세대에서 F2,세대간은 교잡효과가 급상승하나 그 이후세대에서는 매우 둔화되는 양상을 보였다. 4. 육성중인 본 근성흑란계통누에의 실용형질은 육성중인 비전좌계통의 원종과 대차없다. 5. 본 근성흑란 암누에의 실용형질 발현도(E)는 정상잠에 가까워 전좌염색체편에 의한 생리적 결여가 매우 미소한 것으로 생각된다. 6. 이상의 결과에서 F7세대 이후의 근성흑란계통 누에의 실용형질 향상은 교잡육종에 의한 계통분리법이 좋을 것으로 생각되고, 아울러 형질고정도도 향상시켜야 할 것으로 생각된다.

• 한국버섯학회지
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• 제20권4호
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• pp.199-207
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• 2022

국내 시장에서는 Wolfiporia hoelen의 균핵 생산량을 늘리기 위해 새로운 균주 육종을 요구되고 있다. 이에 본 연구는 국내에서 수집한 31개의 야생 균주와 12개의 재배 균주에 대해, 최근 보고된 교배형 연관 유전자의 RPB2의 단일염기다형성(single nucleotide polymorphism, SNP)을 적용해 단핵균사와 이핵균사를 구분할 수 있는지 확인함으로써 SNP 정보가 육종에 유용한지 알아 보고자 수행되었다. 이를 위해 해당 정보를 효율적으로 얻을 수 있는 프라이머도 개발하였다. 분석 결과, 국내 야생 균주들은 동형접합인 경우가 중국 균주보다 많아 기존 SNP의 한계를 확인하였다. 이를 보완하고자 RPB2 유전자에서 3개의 SNP를 추가로 발견하였으며, 이를 통해 단핵균사와 이핵균사의 구분 능력을 높였다. 나아가 4개의 SNP를 기존에 육성한 교잡균주와 교잡에 사용한 단포자 균주에 적용함으로써 육종에서의 활용 가능성이 있음을 확인하였다.

• The Plant Pathology Journal
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• 제37권5호
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• pp.476-488
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• 2021

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 Xcc strains including 39 Xcc isolates collected from cabbage in 20 regions across China, using multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative Xcc strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for Xcc strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-Xcc interaction studies.

• Animal Bioscience
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• 제34권7호
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• pp.1193-1201
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• 2021

Objective: According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement. Methods: A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively. Results: The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p<0.01). LPDs were significantly higher than FPDs in breast muscle thickness, breast muscle weight, breast muscle rate and breast muscle shear force (p<0.01). The muscle fiber average area and fiber diameter of LPDs were significantly higher than those of FPDs (p<0.01). The muscle fiber density of LPDs was significantly lower than that of FPDs (p<0.01). The IMF of LPDs in the breast muscle was significantly higher than that in the FPDs (p<0.01). There was no significant difference between the 2 strains in IMP content (p>0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p<0.01), and FPDs had higher saturated fatty acid and monounsaturated fatty acid levels (p<0.05). Conclusion: Long-term breeding work resulted in vast differences between the two strains Pekin ducks. This study provides a reference for differences between LPD and FPD that manifest as a result of long-term selection.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.881-891
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• 2003

Paenibacillus polymyxa is a plant growth-promoting rhizobacterium (PGPR) which can be used for biological control of plant diseases. Several bacterial strains were isolated from rotten roots of Korean ginseng (Panax ginseng C. A. Meyer) that were in storage. These strains were identified as P. polymyxa, based on a RAPD analysis using a P. polymyxa-specific primer, cultural and physiological characteristics, an analysis utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME), and the 16S rDNA sequence analysis. These strains were found to cause the rot in stored ginseng roots. Twenty-six P. polymyxa strains, including twenty GBR strains, were phylogenetically classified into two groups according to the ERIC and BOX-PCR analyses and 16S rDNA sequencing, and the resulting groupings systematized to the degrees of virulence of each strain in causing root rot. In particular, highly virulent GBR strains clustered together, and this group may be considered as subspecies or biovar. The virulence of the strains seemed to be related to their starch hydrolysis enzyme activity, but not their cellulase or hemicellulase activity, since strains with reduced or no starch-hydrolytic activity showed little or no virulence. Artificial inoculation of the highly virulent strain GBR-1 onto the root surfaces of Korean ginseng resulted in small brown lesions which were sunken and confined to the outer portion of the root. Ginseng root discs inoculated in vitro or two-year-old roots grown in soil drenched with the inoculum developed significant rot only when the inoculum density was $10^{6}-10^{7}$ or more colony-forming units (CFU) per ml. These results suggest that P. polymyxa might induce ginseng root rot if their population levels are high. Based on these results, it is recommended that the concentration of P. polymyxa should be monitored, when it is used as a biocontrol agent of ginseng, especially in the treatment of stored roots.

• 한국산림과학회지
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• 제85권2호
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• pp.309-315
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• 1996

원목재배용(原木裁培用) 표고우량균주(優良菌株)를 육성(育成)하기 위해 균주수집(菌株蒐集)에 의한 선발육종(選拔育種)과 교배계(交配系)를 이용한 교잡육종(交雜育種)을 실시한 결과는 다음과 같다. 1. 국내외(國內外)에서 수집(蒐集)한 35종의 균주에 대한 원목재배를 실시하여 1세대(世代)(5년간(年間)) 버섯수확량(收穫量)이 신갈나무(Quercus mongolica) $1m^3$당(當) 139kg을 보이는 FRI 177 등 3개의 고온성균주(高溫性菌株)와 120kg을 나타낸 FRI 188 등 2개의 중온성균주(中溫性菌株) 및 96kg의 FRI 187 등 저온성(低溫性) 7개 균주를 우량품종(優良品種)으로 선발하였다. 2. Di-mon교배법(交配法)을 이용하여 제조한 교잡균주중(交雜菌株中) 실내검정(室內檢定)을 통하여 독립계통(獨立系統)으로 확인된 12균주(菌株)에 대하여 원목재배(原木栽培)를 실시하여 1세대(世代) 버섯수확량이 원목(原木) $1m^3$당(當) 108kg에 달하는 고온성균주(高溫性菌株) FRI 182와 103kg을 보이는 저온성균주(低溫性菌株) FRI 184 등 2개를 우량종균(優良種菌)으로 선발하였다. 3. 고온성, 중온성 및 저온성 등 온도형(溫度型)에 따른 생산성(生産性)의 유의차(有意差)는 없었으나, 계통간(系統間)의 생산성차이(生産性差異)는 인정(認定)되었다. 한편 원목재배(原木栽培)와 톱밥재배간(栽培間)의 생산성에는 어떤 상관관계(相關關係)도 보이지 않았다.

• Mycobiology
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• 제39권4호
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• pp.272-277
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• 2011

Chemical mutagenesis of basidiospores of Hypsizygus marmoreus generated new mushroom strains. The basidospores were treated with methanesulfonate methylester, an alkylating agent, to yield 400 mutant monokaryotic mycelia. Twenty fast-growing mycelia were selected and mated each other by hyphal fusion. Fifty out of the 190 matings were successful (mating rate of 26.3%), judged by the formation of clamp connections. The mutant dikaryons were cultivated to investigate their morphological and cultivation characteristics. Mutant strains No. 3 and No. 5 showed 10% and 6% increase in fruiting body production, respectively. Eight mutant strains showed delayed and reduced primordia formation, resulting in the reduced production yield with prolonged cultivation period. The number of the fruiting bodies of mutant No. 31, which displayed reduced primordial formation, was only 15, compared to the parental number of 65. Another interesting phenotype was a fruiting body with a flattened stipe and pileus. Dikaryons generated by mating with the mutant spore No. 14 produced flat fruiting bodies. Further molecular biological studies will provide details of the mechanism. This work shows that the chemical mutagenesis approach is highly utilizable in the development of mushroom strains as well as in the generation of resources for molecular genetic studies.

• Mycobiology
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• 제43권1호
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• pp.81-86
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• 2015

To promote the selection of promising monokaryotic strains of button mushroom (Agaricus bisporus) during breeding, 61 progeny strains derived from basidiospores of two different lines of dikaryotic parental strains, ASI1038 and ASI1346, were analyzed by nucleotide sequencing of the intergenic spacer I (IGS I) region in their rDNA and by extracellular enzyme assays. Nineteen different sizes of IGS I, which ranged from 1,301 to 1,348 bp, were present among twenty ASI1346-derived progeny strains, while 15 different sizes of IGS I, which ranged from 700 to 1,347 bp, were present among twenty ASI1038-derived progeny strains. Phylogenetic analysis of the IGS sequences revealed that different clades were present in both the ASI10388- and ASI1346-derived progeny strains. Plating assays of seven kinds of extracellular enzymes (${\beta}$-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease) also revealed apparent variation in the ability to produce extracellular enzymes among the 40 tested progeny strains from both parental A. bisporus strains. Overall, this study demonstrates that characterization of IGS I regions and extracellular enzymes is useful for the assessment of the substrate-degrading ability and heterogenicity of A. bisporus monokaryotic strains.