• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.55-60
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• 1987

Fifty eight isolates of R. solani collected from rice plants infected to sheath blight disease at seven different locations through the country were evaluated for their cultural characteristics on media. Degree of resistance of nine rice varieties were tested by the seven isolates representing each culture type from the grouped pathogene-city. Great variation of cultural characterisics on PSA media was observed among isolates, and 58 isolates tested were grouped into 7 culture types. Locational distribution of isolates belong to each culture type was different between types, and only isolate type 'Ia' was distributed in all locations collected. The degree of pathogene-city of each isolate to rice adult plant was different between 7 culture types grouped, and no isolates infected severely on all tester rice varieties. The degree of resistance to the disease showed great variation among 9 tester varieties, and varietal reaction to the disease was varied along with isolates inoculated. An isolate, la, shown strong pathogenecity and distributed through 7 locations was selected for the screening of varietal resistance to rice sheath blight disease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.257-264
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• 2018

The recent global climate change induced the drought, flooding, and insect pest outbreaks. These caused the severe damage to crop yield in the domesticated field and occurrence change of insect pest species. The sap-sucking insect pest, aphids are common in soybean [Glycine max (L.) Merr.] and cause serious yield losses. Thus, developing resistance cultivars is promising and efficient strategy to prevent the significant yield losses by aphid and screening germplasm is the essential procedure to achieve this goal. We tried to establish a resistance test indicator for foxglove aphid, Aulacorthum solani (Kaltenbach), in soybean and found that plant damage degree or infested plant damage is most suitable one. Also we screened around 1,200 of soybean germplasm including wild and cultivated species for its resistance to foxglove aphid from the various origins, and 67 soybeans, including PI 366121, showed antixenosis resistance, 31 germplasms among 67 antixenosis germplasms were showed antibiosis to foxglove aphid with non-choice test. The identified foxglove aphid resistant soybean resources showed significantly low rate in survival test. Furthermore, resistance type, (i.e., antibiosis or antixenosis) of each candidate were varied. In this research, we established the screening index for foxglove aphid resistance in soybean, and identified the resistance varieties. This result could be useful resources in breeding for new foxglove aphid resistance soybean cultivars, and provide fundamental information to investigate the resistance mechanism in soybean.

• Journal of Mushroom
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• v.9 no.3
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• pp.110-115
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• 2011

Trichoderma disease of oyster mushroom has not been effectively detected in the field for testing its resistance against the disease with its varieties. In this study, we investigated the methods to detect its resistance in the laboratory by using media, which enables us to understand the relevant characteristics (e.g., lysis, toxin enzyme, mycelial growth rate). In coculturing with strains of Trichoderma and oyster mushroom, it is possible to observe the difference in the resistance of oyster mushroom against Trichoderma with the phenomena of barrage reaction, overgrowth and lysis. We also observed the inhibition of mycelial growth of oyster mushroom using the dilution method with 48-well plate, but could not observed the inhibition of mycelial growth using the filter paper method of cultural supernatant. In simultaneously culturing both Trichoderma and oyster mushroom, it was possible to detect the inhibition of the mycelial growth of oyster mushroom, but Trichoderma mycelium did not overgrow against oyster mushroom. We found that the pathogenicity was efficient in using solid medium with the phenomena of overgrowth and lysis by inoculating Trichoderma on top of mycelia of oyster mushroom. In conclusion, the methods (e.g., coculture method, dilution method with 48-well plate, post-inoculation method) are recommended to detect the resistance of oyster mushroom against Trichoderma disease.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.34-37
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• 1982

Two species of root-knot nematode, Meloidogyne incognita and M. hapla, were used in tests of soybean cultivars for resistance. Sixteen soybean cultivars were planted in the 20-cm clay pot and inoculated with each of M. incognita and M. hapla. Four soybean cultivars, Eundaedu, Baegcheon, Dongbugtae and Danyeobkong were resistant; Kwangdu, Hwanggeumkong, and Buseog were moderate, and the rest nine cultivars were susceptible to M. incognita. Jangyeobkong only was resistant, Danyeobkong, Hill, Dongbutae, Hamandaerip and Chungbugbaeg were moderate, and the rest ten cultivars were susceptible to M. hapla. There were no cultivars resistant to both nematodes although Dongbugtae and Danyeobkong were resistant to M. incognita and moderately resistant to M. hapla.

• Research in Plant Disease
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• v.10 no.2
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• pp.154-158
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• 2004

To analyze the relationship between CGMMV occurrence and seed contamination by cucumber cultivars, cucumber cultivars of CGMMV infected field and diseased degree were investigated in cucumber main cultivation regions of Jeonnam province from 1999 to 2002. While the diseased degree was different by years and cultivars, CGMMV occurred for 4 years in 'Janghyeongnakhap', for 3 years in 'Jangjukcheongjang', and for 2 years in 'Gyeoulsali' and 'Gyeoulnagi'. CGMMV was detected in seeds of 'Janghyeongnakhap' and 'Jangjukcheongjang' by ELISA test, and seed of 'Jangjukcheongjang' showed positive reaction in bioassay. As a result of resistant test of 34 cultivars to CGMMV, all cultivars showed mosaic symptoms in pot test but only 'Hanboksamcheok' showed mild mosaic symptom in field test.

• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.48-53
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• 2008

This study presents a case study designed to compare the selection efficiency between phenotypic selection (PS) and marker-assisted selection (MAS) in breeding of resistance lines to brown planthopper (BPH). The efficiency between PS and MAS were compared with four population such as the $F_2$, RILs ($F_6$), DH, and backcrosse ($BC_6F_5$) population, derived from a cross 'Samgang / Nagdong'. The resistance lines were selected using two markers, RM28493 and BpE18-3, related to BPH resistance were screened as resistance lines over 95% in PS. The costs required for BPH screening in the MAS system account for approximately 32% of the total costs of PS. The period needed to select the resistance plants was 30 days in PS and 7 days in MAS. Based on the results, we could establish the breeding system for selection of BPH resistance lines by MAS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.173-180
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• 1987

Symptom development and disease severity of Phytophthora blight in the sesame plants varied depending upon age of the plants tested, inoculation method, watering method, and inoculum density in both susceptible Suweon 9 and Suweon 26 and moderately resistant B-67 and IS 103 sesame lines to Phytophthora nicotianae var. parasitica when inoculated. However, successful differentiation of the sesame lines for varietal resistance was possible using 20-day old seedling, inoculation by soil infestation, saturated soil water condition by half immersion of pots in water tank, and 200 sporangia per one ml of inoculum. Spraying or soil inoculation to 70-day old plants also was effective in differentiating the varietal resistance. By the screening method Suwon 26 showed 100％ diseased plants and symptom severity index 9.0, while B-67 showed 20% diseased plants and symptom severity index 1.7. The rating scale given was from 0 through 9. For example, the scale 0 signified no symptom development, 5 signified discoloration of basal part of stem, and 9 signified discoloration of stem more than 10 cm high above the soil surface with blighted leaves. Differentiation in symptom severity also was made by percentage of the lesion area. Results evaluated using both parameters were well corresponded in varietal reaction of sesame to Phytophthora blight.

• Research in Plant Disease
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• v.18 no.2
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• pp.86-92
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• 2012

Clubroot caused by Plasmodiophora brassicae Woron. is one of the most important diseases in Brassica crops worldwide. To establish more simple and reliable screening method for resistant cabbage and broccoli to P. brassicae, the development of clubroot on the plants according to inoculum concentration and incubation period after inoculating with the pathogen was investigated using P. brassicae GN1 isolate (race 9). To facilitate and acquire precise result of resistance screening of cabbage and broccoli to clubroot, 14-day-old seedlings were inoculated by drenching roots with the spore suspension of P. brassicae to give inoculum density of $2.5{\times}10^9$ spores/pot. To develop the disease, the inoculated seedlings were incubated in a growth chamber at $20^{\circ}C$ for 3 days, and then cultivated in a greenhouse ($20{\pm}5^{\circ}C$) for five weeks. Under the optimum conditions, 16 cabbage and 17 broccoli cultivars were tested for resistance to four field isolates (GN1, GN2, GS and YC) of P. brassicae collected from four regions in Korea. Among them, some cabbage and broccoli cultivars showed different resistance response to three isolates (GN1, GN2 and GS) determined as race 9 by using the differential varieties of Williams. On the other hand, all the tested cultivars were highly susceptible to YC isolate (race 2). The results suggest that this method is efficient screening method of cabbage and broccoli for resistance to P. brassicae.

• Korean journal of applied entomology
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• v.5_6
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• pp.47-54
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• 1968

In order to develop an effective control measure for the rice stripe disease, methods of testing for resistance and selection of resistant varieties among the leading varieties were investigated. For use as a parent in breeding for resistant variety to the disease, total of 410 rice varieties were tested. 1. Disease occurrence was higher at group inoculation than that of individual inoculation in comparing the inoculation methods. 2. In both methods, Lacrose responded susceptible; Zenith and St. No. 1 resistant, and the rest moderate. 3. Suseptible symptom type A was prevalant among the susceptible varieties, while resistant symptom type C was abundant among the resistant varieties, There was no difference between the inoculation methods. 4. 410 rice varieties tested could he divided into 3 groups as susceptible (21 varieties), moderate (377 varieties) and resistant (12 varieties). Resistant varieties wers St. No. 1 and 2, Shin-2, Gulfrose Bonnet, Arkrose, Sun Bonnet, Zenith, Yeechunchilichal, Norm-24, Opaikjoke, Yangchubatchal and Nonglimana-1, Nams-97,-149, -159, -216. -265, Iri-243, -265, Kanchuk -5, -7, -8, -10, -41, -43, -47, -50, Suwon-56, -77, Norin-22, Cod-4. Lacrose and Chukna were susceptible. 5. There was slight differance in the disease occurrence in regard to maturing period. However late varieties seem to be more resistant than early or medium varieties. The medium varieties seem to be susceptible. Most of the introduced varieties from foreign countries and the upland cultivated varieties were resistant. 6 Among the leading varieties, Shin-2 in Kangwon-Do was resistant, Kosi in Choongchung-Do, was susceptible, aad the others were moderate.

• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.43-51
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• 2005

Pepper genetic resources consisting of introductions from Mexico and Nepal and susceptible and resistant controls were tested for resistance to gray leaf spot and to bacterial spot by serially inoculating the two disease pathogens, Stemphylium spp. first and Xanthomonas campestris pv. vesicatoria next, with application of fungicide after evaluation of resistance to gray leaf spot first. KC866, KC872, KC902, KC905 were resistant to gray leaf spot in addition to known resistance sources, KC43, KC47, KC220, KC319, KC320, KC380. KC897 was on the top of the resistance sources list, even better than KC177(163192), and was followed by KC889, KC896, KC898, all of which were introductions from Nepal.