• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.161-168
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• 2013

Soybean cyst nematode (Heterodera glycines Ichinohe) is one of the serious soybean [Glycine max (L.) Merr.] pests in major soybean producing countries. The objective of this study was to investigate of Heterodera glycines type using the five SCN infested soybean field soils and was to evaluate resistance to the soybean cyst nematode HG 2.5.7 type on soybean varieties and germplasms. The five SCN contaminated soil samples were collected from the three provinces on November 2011 in Korea, and eggs were cultured on early spring season in 2012. For the second study, a total fifty nine soybean varieties and germplasms were tested by infestation of HG type 2.5.7 in the greenhouse. Soybean cyst nematode HG types were investigated from five locations, HG 2 (race 1) type at Donghae, HG 2.5 (race 1) type at Jeongseon and Hapcheon, HG type 2.5.7 (race 1 or 5) at Yeongwol, and HG 1.2.7 (race 5) type at Haenam locations in present study. No Korean soybean varieties and germplasms were observed with SCN resistant trait to the HG type 2.5.7. Average SCN female index were calculated with 82.7% in 59 plant materials. Our results could be provided useful information to develop a SCN resistant cultivar in Korea.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.101-111
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• 2012

Soybean cyst nematode(SCN) (Heterodera glycines Ichinohe) causes the greatest yield loss to soybean compared to any other pest worldwide. Yield loss due to SCN is estimated 7.6 million megagrams in the USA and nearly 9 million worldwide. SCN causes yield reductions by feeding on plant nutrients, retarding root growth, and inhibiting Bradyrhizpbium japonicum(Kirchner) Buchanan nodulation. The primary methods for controlling SCN include planting resistant cultivars and rotation with nonhost crops. Genetically diverse field populations of SCN combined with the limited germplasm base of commercial soybean for resistance could potentially leads to population shifts over time, and this makes controlling H. glycines more difficult. This paper reviewed the importance of soybean, soybean cyst nematode, researches on resistance to SCN, and prospects. Tremendous effort must still be endeavored for elucidating resistance mechanisms and managing H. glycines in the soybean field.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.154-158
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• 2010

Early nematode development and subcellular responses in resistant soybean lines PI 88788 and PI 437654 infected with races 3 (R3) and 14 (R14) of soybean cyst nematode (SCN), Heterodera glycines Ichinohe, were compared. SCN R14 nematodes penetrated and developed significantly more than R3 at 5-6 days after inoculation. Both races also penetrated and developed more in PI 88788 than in PI 437654. Syncytia, characterized by cell wall dissolution and cellular hypertrophy, were developed more in PI 88788 than in PI 437654 and more by R14 than R3, for which less necrotic responses occurred in the former than the latter. This suggests that the latter two may be more resistant and less virulent than the former two, respectively. A common structural feature found in each of PI 437654 and PI 88788 in relation to SCN-resistance was the formation of prominent cell wall appositions and nuclear degeneration prior to cytoplasmic degradation in syncytial cells, respectively. Necrosis and cell wall apposition are types of hypersensitive responses occurring at early stages of the nematode infection so that these structural modifications indicate the inhibition of initial syncytial development related to the early nematode development. As soybean cultivars and lines with identical or similar genotypes have the same types of structural features related to SCN-resistance, the structural modifications induced by SCN infection may result from the expression of inheritable resistance genes, of which the information can be used for breeding soybean cultivars and lines specifically resistant to SCN races.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.83-88
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• 1995

Soybean has been cultivated in China for 5,000 years. The soybean cyst neamtode (SCN), Heterodra glycines, was recongnized in Northeastern China in 1899. Currently, it is known to occur in 12 provinces. The biology of SCN was investigated in several provinces. Six races of SCN were identified (race 1, 2, 3, 4, 5 and 7). About f10,000 soybean germplasm lines were evaluated for their resistance to race 1, 3, 4 and 5 of SCN. At least two black-seeded cultivars are resistant to all four races. Several tolerant soybean cultivars with yellow seed coat were released and are in production. Additional resistant cultivars are being developed. Nematicides were not applied in production Potential biocontrol agents and related aspects are being investigated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.319-322
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• 2002

Soybean cyst nematode (Heterodera glycines Ichinohe; SCN) is an important soybean pest and the use of resistant cultivars is the effective method to reduce or eliminate SCN damage. However, breeding for SCN resistance is difficult and expensive by the oligogenic nature of the resistance and genetic variability in the pathogen. Fortunately, SCN resistance loci, rhg1 and Rhg4 are generally accepted as a necessity for the development of resistant genotypes using any source of resistance. In this study, resistance of 44 Korean soybean cultivars to SCN was tested using two molecular markers. Seonheukkong and Pokwangkong were the homozygous to rhg1 locus. Seven cultivars were susceptible to SCN based on Satt309 marker linked rhg1 locus. All Korean cultivars estimated in this study were recessive homozygous to Rhg4 locus and were susceptible in the PCR reaction using primer 548/563 linked to the Rhg4 locus conferring resistance to SCN race 3. Among 44 cultivars estimated, seven cultivars were susceptible to SCN in both Satt309 and primer 548/563 markers. Based on both Satt309 and primer 548/563 markers, there is no resistant cultivar to SCN in Korea. Therefore, SCN resistant cultivars need to be developed in the future. These two markers can be used for improving SCN resistant cultivars.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.386-392
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• 1998

Reproduction of the soybean cyst nematode (SCN), Heterodera glycines Ichinohe on the susceptible soybean cultivar, Lee 74, was significantly reduced by pre-, post- and simultaneous treatments of acetylsalicylic acid (ASA, aspirin). The control efficiencies were 60%, 64% and 87% for pre-, post- and simultaneous treatments, respectively. ASA had no significant effect on the survival of 2nd stage juveniles and their penetration into the soybean root tissues, but significantly inhibited the early stage nematode growth in the roots. Syncytia were formed 2∼3 days after inoculation in the susceptible soybean without ASA treatment, characterized by dense cytoplasm and increased cellular organelles such as mitochondria and endoplasmic reticulum. The nematode stylet was penetrated into the syncytial cell, and feeding tube was formed at the nematode stylet was penetrated into the syncytial cell, and feeding tube was formed at the nematode stylet entry. However, in the ASA treatments, syncytium was not formed or degenerated, depending on the root tissues. In the pre-treatments of ASA, nematode stylets did not penetrate into cells, showing callose-like cell wall thickening formed at the nematode probing sites, or retracted from the infected cells. The stylet penetration sites of syncytial cells appeared to be sealed off with fibrillar materials. With post-treatment of ASA, syncytia formed by the nematode were degenerated, characterized by degradation of syncytial cytoplasm.

• Research in Plant Disease
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• v.19 no.3
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• pp.216-219
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• 2013

A total of 75 soybean cultivars developed in Korea was screened against soybean cyst nematode (SCN), Heterodera glycines HG type 2.5. Cysts developed on soybean cultivars ranged from 104 to 624 cysts per pot. There was no resistant cultivar but 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' were moderately resistant; 33 cultivars were moderately susceptible and the other cultivars were susceptible. 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' could be recommended for soybean fields infested with SCN until developing SCN resistant soybean.

• The Plant Pathology Journal
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• v.15 no.1
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• pp.1-7
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• 1999

The production of soybean cyst nematode (SCN), Heterodera glycines, including female formation and fecundity was much higher in SCN race 14 (R14) than in race 3 (R3) in susceptible soybean cultivars Bragg (intolerant), Lee74 (moderately tolerant), and PI 97100 (highly tolerant). The nematode body was also significantly larger in R14 than in R3 at 20 days after inoculation, but the further nematode growth appeared to be slower in R14 than in R3, resulting in no significant difference between the two races at 30 days after inoculation. Within each race, no significant difference was observed in the growth and reproduction among the soybean cultivars tested. Syncytial areas near the nematode lip regions (infection sites) were measured for each soybean cultivar-SCN race combination. R14 induced significantly larger syncytia than R3. Bragg had relatively larger syncytia than Lee74 and PI 97100, but the difference among the soybean cultivars was minimal or not significantly different. Syncytium occupation in the stelar region differed only between PI 97100 and the other two cultivars, which may be somewhat, but not exactly, related to tolerance levels. Syncytial cytomplasm was degenerated more with R14 and in Bragg than with R3 and in Lee74 and PI 97100, respectively. In light microscopy, degenerated syncytia were characterized by depleted and loose cytoplasm with less plastids than normal-looking (intact) syncytia which had dense syncytial cytoplasm. Electron microscopy revealed that degenerated syncytia contained highly vacuolated cytoplasm with degenerated plastids. The above results suggest that structural characteristics of syncytia may match the nematode growth and reproduction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.712-721
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• 1997

The objectives of this study were; (1) to identify and localize QTLs for resistance to soybean cyst nematode(SCN) race 5 on RAPD map, (2) to idntify the magnitude and mode of inheritance for each QTL, and (3) to identify the best combinations of QTLs for resistance to SCN race 5. Based on the univariate regression analysis, we detected 26 markers(22 RAPD and 4 RFLP) which showed significant association(P<0.05) with resistance to SCN race 5. From MAPMAKER /QTL analysis, we identified two regions (LGC-20 and Group 2) for resistance to SCN race 5. The QTL that was localized at 8.0 cM from pK418C on LGC-20 showed a recessive mode of inheritance and the QTL that was localized between W03 and E02$^3$ on Group 2 showed a dominant mode of inheritance. Two pairs of flanking markers (E02$^3$ and W03, pK418C and pK418E$_1$) and one unlinked RAPD marker, G10$^1$ were used for multiple regression analysis. Marker combination which was composed of 4 markers, E02$^3$, G10$^1$, W03, and pK418E$_1$, explained the highest amount of phenotypic variation by SCN (35.2％). Further research for the identification of QTLs for resistance to SCN race 5 to explain larger portion of phenotypic variation is needed.

• Plant Resources
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• v.5 no.3
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• pp.169-175
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• 2002

The soybean cyst nematode (Heterodera glycines Inchinoe; SCN) is a devastating pest of soybean and is responsible for significant losses in yield. The use of resistant cultivars is the effective method to reduce or eliminate SCN damage. The objective of this research is to identify AFLP markers linked to the SCN resistant genes. Bulked genomic DNA was made from resistant and susceptible genotypes to SCN and a total of 19 primer combinations were used. About 31 fragments were detected per primer combination. The banding patterns were readily distinguished in resistant and susceptible bulked genotypes. Polymorphic fragments were detected between resistant and susceptible bulked genotypes in the primer combination of CGT/GGC, CAG/GTG and CTC/GAG. In primer combinations of CGT/GGC and CAG/GTG, bulked resistant genotype produced a polymorphic bands. However, in primer of CTC/GAG, bulked susceptible genotype produced a polymorphic fragments. Three AFLP markers identified as a polymorphic fragments between bulked genomic DNA were mapped in 85 F2 population. Among them, only two markers, CGT/GGC and CTC/GAG, was linked and was mapped. Broad application of AFLP marker would be possible for improving resistant cultivars to SCN.