Screening of Early Maturing Soybean Accessions for Resistance against HG Type 2.5.7 of Soybean Cyst Nematode, Heterodera glycines

Author(s):  
Krishna Acharya ◽  
Guiping Yan

Soybean cyst nematode (SCN; Heterodera glycines) is one of the devastating soybean pests worldwide, including the United States. Resistant cultivars combined with crop rotation are the primary methods for managing this nematode. SCN is known to have genetically diverse populations and can develop new virulent forms over time due to the continuous planting of cultivars derived from same source of resistance. Thus, identifying novel SCN resistant sources is of paramount importance for soybean breeding for nematode resistance. In this study, we screened 149 early maturity soybean [Glycine max (L.)] accessions for resistance to SCN HG type 2.5.7, which is one of the prevalent virulent SCN populations in North Dakota. SCN white females were extracted from individual plants of each accession after 35 days of growth in greenhouse conditions. The females were counted to determine a female index [FI = (average number of females on a tested accession/average number of females in Barnes, a susceptible soybean check) x 100]. The resistance response of each soybean accession was categorized as resistant, moderately resistant, moderately susceptible, and susceptible. Out of the soybean 149 accessions tested, only 13 were resistant in both runs of the experiments. The majority of screened soybean accessions were susceptible or moderately susceptible to the SCN HG type 2.5.7. The resistant soybean accessions identified in this study have the potential to be used in breeding SCN-resistant cultivars after further elucidation of the resistance genes or loci.

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 615-619 ◽  
Author(s):  
Lawrence D. Young

Several soybean (Glycine max) cropping sequences were planted for 12 years in a field that, at the beginning of the test, was infested with race 14 of the soybean cyst nematode, Heterodera glycines. Continuous soybean cropping sequences included H. glycines-susceptible cultivars Forrest, J82-21, Peking × Centennial breeding line, and moderately resistant cultivars Bedford and J81-116. Forrest treated with aldicarb or pentachloronitrobenzene (PCNB) plus metalaxyl and resistant breeding line JS83-236 followed by resistant cultivars Cordell and Hartwig were additional continuous soybean sequences. Rotations included two sequences each of Bedford with J81-116 or J82-21, and three sequences of Bedford with corn (Zea mays) and susceptible Essex soybean. Rotations of Bedford, corn, and Essex had 12-year mean yields significantly greater than continuous Bedford or Forrest. The female index (FI) of H. glycines on five cultivars and lines was used to bioassay changes in parasitic potential in each cropping sequence. The FI on Bedford bioassay plants increased significantly over time for all field treatments involving Bedford. When J82-21 was the bioassay plant, FI decreased significantly in treatments involving Bedford. There were no significant changes in FI for any treatment when Forrest, J81-16, and Peking were used as bioassays. Rotations of soybean cultivars with different sources of resistance and rotations of resistant and susceptible cultivars with a nonhost crop were not successful practices to manage the nematode's ability to parasitize the resistant cultivar Bedford. However, rotation of resistant and susceptible cultivars with a nonhost crop produced greater mean soybean yields and slowed the shift toward greater parasitism of the resistant cultivar sufficiently to warrant adoption of this practice.


Plant Disease ◽  
2021 ◽  
Author(s):  
Mariola Usovsky ◽  
Robert Robbins ◽  
Juliet Fultz Wilkes ◽  
Devany Crippen ◽  
Vijay Shankar ◽  
...  

Plant parasitic nematodes are a major yield-limiting factor of soybean in the United States and Canada. It has been indicated that soybean cyst nematode (SCN, Heterodera glycines Ichinohe) and reniform nematode (RN, Rotylenchulus reniformis Linford and Oliveira) resistance could be genetically related. For many years fragmentary data has shown this relationship. This report evaluates RN reproduction on 418 plant introductions (PIs) selected from the USDA Soybean Germplasm Collection with reported SCN resistance. The germplasm was divided into two tests of 214 PIs reported as resistant, and 204 PIs moderately resistant to SCN. The defining and reporting of RN resistance changed several times in the last 30 years, causing inconsistencies in RN resistance classification among multiple experiments. Comparison of four RN resistance classification methods was performed: (1) ≤10% as compared to the susceptible check, (2) using normalized reproduction index (RI) values, and transformed data (3) log10 (x) and (4) log10 (x+1), in an optimal univariate k-means clustering analysis. The method of transformed data log10 (x) was selected as the most accurate for classification of RN resistance. Among 418 PIs with reported SCN resistance, the log10 (x) method grouped 59 PIs (15%) as resistant, and 130 PIs (31%) as moderately resistant to RN. Genotyping of a subset of the most resistant PIs to both nematode species revealed their strong correlation with rhg1-a allele. This research identified genotypes with resistance to two nematode species and potential new sources of RN resistance that could be valuable to breeders in developing resistant cultivars.


2021 ◽  
Author(s):  
Intiaz Amin Chowdhury ◽  
Guiping Yan ◽  
Addison Plaisance ◽  
sam markell

Soybean cyst nematode (SCN; Heterodera glycines) continues to be the greatest threat to soybean production in the United States. Since host resistance is the primary strategy used to control SCN, knowledge of SCN virulence phenotypes (HG types) is necessary for choosing sources of resistance for SCN management. To characterize SCN virulence phenotypes in North Dakota (ND), a total of 419 soybean fields across 22 counties were sampled during 2015, 2016, and 2017. SCN was detected in 42% of the fields sampled and population densities in these samples ranged from 30 to 92,800 eggs and juveniles per 100 cm3 of soil. The SCN populations from some of the infested fields were virulence phenotyped with seven soybean indicator lines and a susceptible check (Barnes) using the HG type tests. Overall, 73 SCN field populations were successfully virulence phenotyped. The HG types detected in ND were HG type 0 (frequency rate: 36%), 7 (27%), 2.5.7 (19%), 5.7 (11%), 1.2.5.7 (4%), and 2.7 (2%). However, prior to this study only HG type 0 was detected in ND. The designation of each of the HG types detected was then validated in this study by repeating the HG type tests for thirty-three arbitrarily selected samples. This research for the first time reports several new HG types detected in ND and confirms that the virulence of SCN populations is shifting and overcoming resistance, highlighting the necessity of utilization of different resistance sources, rotation of resistance sources, and identification of novel resistance sources for SCN management in ND.


Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 623-628 ◽  
Author(s):  
J. Wang ◽  
T. L. Niblack ◽  
J. A. Tremain ◽  
W. J. Wiebold ◽  
G. L. Tylka ◽  
...  

Field experiments were conducted at locations in northern and southern Illinois, central Iowa, and central Missouri from 1997 to 1999 to investigate the effects of Heterodera glycines on soybean growth, development, and yield. A wide range of infestation levels was present at all locations. Two locally adapted cultivars, one resistant to H. glycines, were grown at each location. Cultivars were planted in alternating four-row strips with 76 cm between rows. For each cultivar, 20 1-m-long single-row plots were sampled every 2 weeks starting 4 weeks after planting. Infection by H. glycines reduced plant height and leaf and stem weight on the resistant cultivars in the first 12 weeks after planting, and delayed pod and seed development 12 to 14 weeks after planting. Biomass accumulation was not reduced on the susceptible cultivars until 10 weeks after planting; reduction in pod and seed development occurred throughout the reproductive stages. Susceptible cultivars produced significantly lower yields than resistant cultivars, but the yield reductions were not accompanied by visually detectable symptoms.


2017 ◽  
Vol 18 (3) ◽  
pp. 167-168 ◽  
Author(s):  
Gregory L. Tylka ◽  
Christopher C. Marett

The soybean cyst nematode (SCN) is a major yield-reducing pathogen of soybeans in North America. The nematode is an introduced pest and, therefore, knowledge of the distribution of SCN can be helpful in identifying areas where scouting and management efforts should be focused. Such information is especially important because yield-reducing infestations of SCN can occur without obvious above-ground symptoms appearing. In late 2016, nematologists, plant pathologists, and state plant regulatory officials from the soybean-producing states in the United States and provinces in Canada were queried to obtain the latest information on where the nematode had been found. An updated map of the known distribution of SCN in North America was also created. There were 17 states in which SCN was newly found since 2014, when the map was last updated, including the first discovery of SCN in the state of New York. North Dakota was the state with the greatest number of counties, seven, in which SCN had been newly discovered since 2014. This updated information illustrates that the nematode continues to spread throughout the soybean-growing areas of the continent and emphasizes that continued efforts to scout for and manage SCN are warranted.


Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1473-1476 ◽  
Author(s):  
Melissa G. Mitchum ◽  
J. Allen Wrather ◽  
Robert D. Heinz ◽  
J. Grover Shannon ◽  
Gene Danekas

The soybean cyst nematode, Heterodera glycines, is a serious economic threat to soybean producers in Missouri. Periodic monitoring for the presence, population densities, and virulence phenotypes of H. glycines is essential for determining crop losses and devising management strategies implementing the use of resistant cultivars. A survey using area-frame sampling was conducted to determine the distribution and virulence phenotypes of H. glycines in Missouri during 2005. Two samples from each of 125 fields representing eight geographical regions of Missouri were collected; 243 samples were processed for extraction of cysts and eggs. In all, 49% of samples had detectable cyst nematode populations, which ranged from 138 to 85,250 eggs per 250 cm3 of soil. Race and H. glycines type tests were conducted on populations from 45 samples. Nearly 80% of the populations that were tested, irrespective of the region, were virulent on the indicator line plant introduction (PI) 88788, which is the source of resistance for most H. glycines-resistant cultivars. More than 70% of populations could reproduce on the indicator lines PI 88788, PI 209332, and PI 548316 (Cloud), indicating that soybean cultivars with resistance derived from these sources need to be carefully monitored and used only in rotation with nonhost crops and soybean cultivars with resistance from other sources. Approximately one-third of the populations, primarily in the southern regions of Missouri, could reproduce on PI 548402 (Peking), another common source of resistance. Fewer than 10% of the populations could reproduce on PI 90763, PI 437654, PI 89772, or PI 438489B, suggesting that these sources of resistance should be used in soybean breeding programs to develop H. glycines-resistant soybean cultivars.


Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2281-2286 ◽  
Author(s):  
K. Acharya ◽  
C. Tande ◽  
E. Byamukama

The soybean cyst nematode (SCN), Heterodera glycines, is the most important yield-limiting pathogen of soybean in the United States. In South Dakota, SCN has been found in 29 counties, as of 2016, and continues to spread. Determining the virulence phenotypes (HG types) of the SCN populations can reveal the diversity of the SCN populations and the sources of resistance that would be most effective for SCN management. To determine the HG types prevalent in South Dakota, 250 soil samples were collected from at least three arbitrarily selected fields in each of the 28 counties with fields previously found to be infested with SCN. SCN was detected in 82 fields (33%), and combined egg and juvenile counts ranged from 200 to 65,200 per 100 cm3 of soil. Eggs and juveniles were extracted from each soil sample and were used to infest seven SCN HG type test indicator soybean lines and ‘Williams 82’ as the susceptible check. A female index (FI) was calculated based on the number of females found on each indicator line relative to those on the susceptible check. A FI equal to or greater than 10% in any line was assigned as that HG type. Out of 73 SCN populations for which HG type tests were done, 63% had FI ≥10% on PI 548316 (indicator line #7), 25% on PI 88788 (#2), 19% on PI 209332 (#5), 7% on PI 548402 (#1), 4% on PI 90736 (#3), and 4% on PI 89722 (#6). None of the SCN populations had FI ≥10% on PI 437654 (indicator line #4). The most prevalent HG types were 0, 2.5.7, and 7. These accounted for 81% of all the HG types determined for the samples tested. HG types with ≥10% reproduction on indicator lines PI 88788, PI 209332, and PI 548317 were most prevalent in the soil samples tested, suggesting that the use of these sources of resistance for developing SCN resistant cultivars should be avoided. For sustainable SCN management, use of resistant cultivars should be rotated with nonhost crops and cultivars with different sources of resistance.


2008 ◽  
Vol 9 (1) ◽  
pp. 29 ◽  
Author(s):  
T. L. Niblack ◽  
A. L. Colgrove ◽  
K. Colgrove ◽  
J. P. Bond

The soybean cyst nematode (SCN) is the most economically important pathogen of soybean in the United States. Most of the SCN-resistant cultivars being grown in this region have resistance derived from a single source, Plant Introduction (PI) 88788. A survey conducted in 2005 showed that 83% of the soybean hectarage in Illinois is infested with SCN, with average population densities high enough to cause significant yield suppression (2,700 eggs/100 cm3 soil). Further characterization of these populations showed that 70% have adapted to PI 88788 at some level, reducing the effectiveness of using SCN-resistant cultivars as a crop management tool. Rotation with alternative sources of resistance is recommended as a means to slow the adaptation to PI 88788. Accepted for publication 11 October 2007. Published 18 January 2008.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1346
Author(s):  
Cheng-Chun Huang ◽  
Jiue-in Yang ◽  
Kuo-Lung Chou ◽  
Chen-Hsiang Lin ◽  
Hao-Xun Chang

Disease resistance is one of the most successful strategies in crop protection. For example, the implementation of PI 88788 type resistance, which contains high copy numbers of Resistance to Heterodera glycines 1 (rhg1) loci, into the commercial soybean varieties of the United States has significantly reduced the yield losses caused by soybean cyst nematode (SCN, H. glycines). Vegetable soybean, or edamame, has become a major exporting agricultural product in Taiwan with an annual revenue over $80 million USD since 2017. Several local varieties have been developed to fulfill the market needs such as the traits of flavor and sweetness. However, it remains unclear if the historical breeding programs ever incorporated rhg1 resistance into the varieties of Taiwan. This study applied the TaqMan qPCR method to measure the fluorescent signals specific to the rhg1 locus on the chromosome 18 of soybean, and the ratio of VIC and FAM signals were analyzed to predict the rhg1 copy number in the 21 soybean varieties of Taiwan. The results indicated the copy number and the single nucleotide polymorphisms of the 21 soybean varieties were identical to the susceptible soybean variety ‘Williams 82’. As importation of soybean will be continuously needed to fulfill the market and because SCN is absent in the soybean fields of Taiwan, lacking rhg1 resistance in the local soybean varieties may put the edamame industry at risk and early implementation of SCN resistance in the breeding program, alongside the application of quarantine regulations, will be the key to maintain the SCN-free status and to sustain the edamame industry in Taiwan.


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