• Korean journal of applied entomology
• /
• v.25 no.1 s.66
• /
• pp.27-32
• /
• 1986

To establish a method for measuring varietal resistance against rice stem maggot in field and pot, 20 varieties were used in $1981{\sim}1983$. The degree of injured stems by the 1st generation larvae was significantly correlated with that of injured panicles by the 2nd ($r=0.864^{**}$). There was no ovipositional preference in rice stem maggot. The larval mortality after artificial infestation varied widly from 5.6 to 100% in varieties and that of the resistant varieties was high after boring. There was a negative correlation between number of injured leaves and larval mortality after artificial infestation ($'81:r=-0.833^{**},\;'82:r=-0.918^{**}$). It is considered that larval mortality mainly caused by antibiosis and larval mortality 20 days after infestation on rice seedlings is ideal for evaluating the varietal resistance to rice stem maggot. Resistant varieties are Nagdongbyeo, Jinjubyeo and Chucheongbyeo susceptible varieties, Keumgangbyeo, Milyang 23, Baigyangbyeo and Milyang 30.

• Korean journal of applied entomology
• /
• v.17 no.3 s.36
• /
• pp.149-154
• /
• 1978

Varietal resistance of 49 strawberry varieties to two isolates of Mycosphaerella fragariae was investigated by incoulation experiments and its chemical control was also studied. 1. The susceptibility of varieties and pathogenecity of the isolates were significantly different. 2. in most instances isolate $S_3$ and the reactions of varieties to the isolates were different. 3. Among the varieties tested, Tioga, Donner, Marhall, Northwest, Red star, Senga, sengana, Shasta, Torrey, Hokowase and Daehak No. 1 were found highly susceptible to isolate $K_2$, and America, Dabreak, Takanae, Kurumae No. 103, Horida's wander, Benizuru, Hukuba and Himiko were found as highly resistant. 4. It was apparent that America, Morioka No. 17, Takanae, Kurumae No. 13, Horida's wander, Benizuru and Hukuba were resistant to isolate $S_3$ and Marshall, Tioga were very susceptible to it. 5. As for the susceptibility of varieties by old End new leaf to isolate $K_2$, old leaves were evaluated as highly resistant. 6. Under the conditions of artificial infection Captan was the most effective in controlling for the leafspot and followed by Zineb and Difolatan.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.41 no.3
• /
• pp.308-317
• /
• 1996

These experiments were conducted to investigate variation of physical characteristics of the culm related to lodging resistance by nitrogen levels under direct seeding on flooded paddy surface. The number of seedling per m$^2$ were from 103 to 110 plants, and seedling ratios were ranged from 66.7% to 71.2%. The lodging occurrence were increased in order to the nitrogen levels 15 kg, 10 kg, 5 kg /10a, and the lodging resistant varieties ; Dongjinbyeo and Cheongmyungbyeo showed less values of field lodging than those of lodging susceptible varieties ; Daecheongbyeo, Palgongbyeo and H waseongbyeo. The lodging resistance was decreased in semidwarf varieties compare with long culm varieties, but Dongjinbyeo, long culm variety has lodging resistance. The occurrence of lodging decreased with lower values in top moment, but with higher values in the breaking moment with leaf sheath. The root dry weight positively correlated with weight of culm base, but modulus of section was negatively correlated with bending curvature, respectively.

• 한국균학회소식:학술대회논문집
• /
• 2015.05a
• /
• pp.28-28
• /
• 2015

Clubroot disease caused by Plasmodiophora brassicae induces severe losses of cruciferous vegetables worldwide. To control clubroot of Chinese cabbage, many CR (clubroot resistance) F1 hybrid cultivars have been bred and released in Korea, China and Japan. In this study, we determined the race of P. brassicae 12 field isolates, which collected from 10 regions in Korea, using Williams' differential varieties including two cabbage ('Jersey Queen', 'Badger Shipper') and two rutabaga ('Laurentian', 'Whilhelmsburger'). By Williams' differential varieties, 12 clubroot pathogens were assigned into one (GN2), two (HS and YC), two (HN1 and HN2), three (DJ, KS and SS) and four (GS, GN1, JS and PC) isolates for races 1, 2, 4, 5 and 9, respectively. In addition, the degree of resistance of 45 CR cultivars that were from Korea, China and Japan was tested with the 12 isolates. The 45 CR cultivars of Chinese cabbage were differentiated into three genotypes according to their resistance responses. Even though the 12 P. brassicae isolates were same race by Williams' differential varieties, three CR genotypes showed different resistance response to the isolates. These results indicate that races of P. brassicae by Williams' differentials were not related with resistance of CR cultivars, and three CR genotypes represented qualitative resistance to the P. brassicae isolates. CR genotype I including 'CR-Cheongrok' showed resistance to GN1, GN2, JS, GS, HS, DJ and KS isolates and susceptibility to YC, PC, HN1, HN2 and SS isolates. And CR genotype II such as 'Hangkunjongbyungdaebaekchae' was resistant to GN1, GN2, JS, GS, HS, YC, PC and HN1 and susceptible to DJ, KS, SS and HN2. CR genotype III including 'Chunhajangkun' and 'Akimeki' represented resistance to 10 isolates except for SS and HN2 isolates. Based on these results, we selected 'CR-Cheongrok', 'Hangkunjongbyungdaebaekchae', and 'Chunhajangkun' as a representative cultivar of three CR genotypes and 'Norangkimjang' as a susceptible cultivar. Furthermore, we investigated the resistance of 15 lines of Chinese cabbage, which were provided by seed companies, to 11 isolates except for HN1 of P. brassicae. The results showed that three lines were susceptible to all the tested isolates, whereas five, four, and three lines represented the similar responses corresponding to the CR genotypes I, II, and III, respectively; there is no line of Chinese cabbage showing different resistance patterns compared to three CR genotypes. In particular, line 'SS001' showing resistance responses of CR genotype II was a parent of 'Saerona' that have been commercialized as a CR $F_1$ cultivar of Chinese cabbage. Together, we divided 12 isolates of P. brassicae into 4 races, designated by wild type, mutant type 1, mutant type 2, and mutant type 3. Wild type including GN1, GN2, JS, GS, and HS isolates of P. brassicae was not able to infect all the cultivars of three CR genotypes, whereas, mutant type 3 such as SS and HN2 isolates developed severe clubroot disease on all the CR genotype cultivars. To mutant type 1 including DJ and KS isolates, CR genotypes I, II and III were resistant, susceptible and resistant, respectively. In contrast, to mutant type 2 including YC, PS, and HN1 isolates, CR genotypes I, II and III showed susceptibility, resistance and resistance, respectively. Taken together, our results provide the extended knowledge of classification of P. brassicae races, which is useful information for the breeding of resistant crops, with a suggestion that 'Norangkimjang', 'CR-Cheongrok', 'Saerona' and 'Chunhajangkun' cultivars of Chinese cabbage could be used as new race differentials of P. brassicae for clubroot disease assay.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.145-145
• /
• 2017

Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative genes to foxglove aphid resistance in wild soybean, PI 366121 (Glycine soja Sieb. and Zucc.). One hundred and forty-one F4:8 recombinant inbred lines developed from a cross between susceptible variety, Williams 82 and foxglove aphid resistance wild soybean, PI 366121 were used. The two type of resistance response, antibiosis and antixenosis resistance were evaluated through choice and no-choice test, graded by the degree of total plant damage and primary infestation leaf damage; a genome-wide molecular linkage map was constructed with 29,898 single-nucleotide polymorphism markers utilizing a Axiom(R) 180K soyaSNP array. Using inclusive composite interval mapping analysis for foxglove aphid resistance, one major candidate QTL on chromosome 7 was identified. The major QTL on chromosome 7 showed both antixenosis and antibiosis resistance responses. The newly identified major QTL was consistent with previously reported QTL, Raso2, which showed around 5 times narrow down interval range with 8 candidate genes. Furthermore, total 1,115 soybean varieties including Glycine soja and Glycine max were exposed to germplasm screening, and 31 varieties, which showed significant antibiosis type foxglove aphid resistance were identified. This result could be useful in breeding for new foxglove aphid resistant soybean cultivars and developing novel insecticides.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.4
• /
• pp.336-342
• /
• 1993

To obtain the basic information necessary for the development of soybean varieties well adaptable to upland-paddy field rotational croppings, the difference of growth characteristics between upland and paddy-field including yield potentials of current recommending soybean varieties were evaluated. The growth characteristics, both above and under-ground, which were measured at flowering stage were generally greater in paddy-field but the number of root nodules was much greater in upland, thus the artificial inoculation was practically recommended for soybean growing in paddy-fields. Mean seed yield was generally higher in paddy-fields than in upland. All soybean varieties showed higher seed yield in the early planting date, April 20, were somewhat susceptible to soybean mosaic virus(SMV), thus they could be escaped from the disasterous endemic necrotic soybean mosaic virus(SMV-N). Soybean varieties showed over 4.0 tons/ha seed yield in the paddy-field were Williams 79, Union, SS77053, and Namhaekong. At the same time, Jangyeobkong and Danyeobkong were the most stable soybean varieties among the tested soybean varieties with less than 10% of coefficient variation values in all planting dates in paddy fields. Compared with Hwangkeumkong which is most widely being cultivated on farmer's fields, soybean varieties showed high yields in paddy-field were higher in plant height, less in the number of branches, and more in the number of nodes on main stem. At the same time, they had medium seed size which would bring the good germination and stands. Disease resistance especially for necrotic soybean mosaic virus was also one of the most decisive factors in seed yields for the early planted soybeans.

• Korean Journal Plant Pathology
• /
• v.13 no.2
• /
• pp.95-99
• /
• 1997

To obtain a basic information of breeding for resistance to clubroot in Chinese cabbage, disease incidence, pathogenicity, and varietal response to the pathogen were studied. Incidence of clubroot was observed at 3 districts in Gyeonggi-Do, 2 districts in Kangwon-Do, and 1 district each in Gyeongnam, Geongbuk and Jeonbuk, respectively. Disease infection rate and diseased ara were most severe in northern part of Gyeonggi-Do. The isolates of clubroot collected from 8 different districts were not different in their virulence one another in view of their infection rate and disease severity in Chinese cabbage. The clubroot fungus had a wide host range for the cruciferous vegetables. Disease severity was high in rape, turnip and mustard, moderate in Chinese cabbage and broccoli, and low in kale and cauliflower. All of Korean hybrids of Chinese cabbage tested were highly susceptible to clubroot, but Japanese varieties were resistant to the highly pathogenic isolate (EJ-93) which was isolated from the Chinese cabbage in Korea. The hybrid(F1) between clubroot resistant line(930WG) and the susceptible line(332MS) showed completely resistant reaction, which indicated that clubroot resistance was governed by a dominant gene.

• The Plant Pathology Journal
• /
• v.25 no.4
• /
• pp.422-428
• /
• 2009

Studies were conducted to identify the sources of resistance in mungbean recombinant inbred lines (RILs) in Thailand against mungbean yellow mosaic disease (MYMD). 146 mungbean RILs in $F_8$ series were evaluated in a field including resistant parent NM-10-12-1 and susceptible parent KPS 2 during summer 2008 under high inoculum pressure. The RILs were subsequently scored for disease symptom severity ratings (DSSR) using a new scale. Observations regarding DSSR and % disease index (%DI) showed that the tested RILs responded differently to the disease. A large number of RILs (132) were found highly susceptible, 12 were susceptible, 3 were tolerant and one was resistant. Overall screening results showed that three RILs, viz. line no. 30, 100 and 101 had minimum DSSR and % disease index thus they are good source of resistance to MYMD in spite of high disease pressure and can therefore be used directly as varieties to manage the disease in Thailand.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.1
• /
• pp.57-63
• /
• 2001

Barley Yellow Dwarf Virus (BYDV) has been a major disease causing a severe loss of yield in winter cereals worldwide. It has been recently reported that BYDV occurs frequently in wheat field and also causes serious yield reduction in Korea. This study was performed to investigate the regional distributions of BYDV strains in Korea and to identify the resistant cultivars or lines of wheat to the predominant BYDV strains, providing basic information for the breeding of BYDV-resistant wheat varieties. Using RT-PCR and EcoRI digestion methods, the regional distribution of BYDV strains in Korea from 1999 to 2000 showed that PAV strain was mainly detected about 65% (Vic-PAV 52.6% ; CN-PAV 47.4%) and MAV strain about 3%. Using ELISA test for the examination of BYDV resistance with 17 cultivars and 4 lines among Korean wheat, three cultivars, Gurumil, Topdongmil, and Olgurumil, were susceptible to BYDV and the others were resistant. In plant growth and yield component responses to BYDV infection, Gurumil showed significant difference between the uninfected and the infected, suggesting the most susceptible to BYDV among Korean wheat, but Eun-pamil and Seohae118 did no difference, an indication that they have the highest resistance.

• Korean Journal of Organic Agriculture
• /
• v.23 no.3
• /
• pp.497-507
• /
• 2015

It is necessary to evaluate the resistance to disease among genetic resources for development of disease resistant grapes. This study was conducted to screen the resistance to crown gall in muscadine and Florida hybrid bunch grapes by pathogen inoculation. In order to compare the responses to infection with different pathogen strains, muscadine and Florida hybrid grapes were inoculated with 3 strains of Agrobacterium vitis. Although there were different levels crown gall formation among grape cultivars, there little variation in response to inoculated strains. Among 29 muscadine cultivars tested by inoculation of A. vitis 'C4612', most of them were shown to be susceptible, and 'Gold Isle' and 'Africa Queen' were highly susceptible, and two cultivars, 'Welder' and 'Jumbo' were found to be resistant to crown gall disease. Among Florida hybrid grapes, 'Daytona', 'Stover', and 'Swanee' were susceptible and 'Blanc du Bois' was moderately susceptible to crown gall. Because muscadine grapes have been actively utilized as useful genetic resources for development of new grape varieties by intersub-genus cross, this result from the screening of resistance among muscadine grapes can provide valuable information in breeding programs of grape resistant to crown gall.