scholarly journals Resistance to Brown Stem Rot in Soybean Germ Plasm with Resistance to the Soybean Cyst Nematode

Plant Disease ◽  
2004 ◽  
Vol 88 (7) ◽  
pp. 761-768 ◽  
Author(s):  
T. J. Hughes ◽  
N. C. Kurtzweil ◽  
B. W. Diers ◽  
C. R. Grau
Keyword(s):  
Soybean Cyst Nematode ◽  
Field Experiments ◽  
Germ Plasm ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Brown Stem Rot ◽  
Resistant Cultivars ◽  
Greenhouse Experiments ◽  
Scn Resistance ◽  
Pi 88788

The soybean cyst nematode (SCN) and Phialophora gregata f. sp. sojae, the causal agent of brown stem rot (BSR), are two pathogens of soybean commonly found in the same field throughout the north-central United States. Field experiments designed to study the role of SCN-resistant germ plasm in soybean production have led to data suggesting that some sources of SCN resistance also may provide resistance to BSR. Soybean germ plasm with resistance to SCN was evaluated in greenhouse and field environments for resistance to BSR development based on the percentage of host tissue symptomatic of BSR. Comparison of SCN-resistant cultivars and plant introductions (PI) to standard BSR-resistant and -susceptible checks were conducted in two greenhouse experiments using a root-dip inoculation with a single isolate of P. gregata. For both greenhouse experiments, PI 209332 was the only source of SCN resistance with resistance to BSR similar to standard BSR-resistant checks. Nine other sources of SCN resistance, including PI 88788 and Peking, expressed BSR symptom severity similar to BSR-susceptible checks. Cultivars derived from most SCN-resistant sources, including PI 209332, also were susceptible to BSR development, while four of the five cultivars derived from PI 88788 were highly resistant to BSR development. SCN-resistant cultivars derived from PI 88788, Peking, and PI 209332 were planted along with standard BSR-resistant and -susceptible checks at two field locations naturally infested with P. gregata and SCN or P. gregata alone. As in greenhouse experiments, four of the five cultivars derived from PI 88788 expressed resistance to BSR development equal to or better than standard BSR-resistant checks at both locations. In contrast, cultivars derived from PI 209332 and Peking expressed varying levels of disease development depending on field environment. Yields observed for PI 88788-derived cultivars were higher than BSR-resistant checks regardless of the presence of SCN. Data from both greenhouse and field experiments suggest that cvs. Williams and Williams 82 may contain a gene or genes for BSR resistance that require one or more modifier genes, possibly located in the genome of PI 88788, for complete expression.

Resistance Gene Pyramiding and Rotation to Combat Widespread Soybean Cyst Nematode Virulence

Plant Disease ◽  
2021 ◽  
Author(s):  
Clinton Meinhardt ◽  
Amanda Howland ◽  
Mark Ellersieck ◽  
Andrew Scaboo ◽  
Brian Diers ◽  
...  
Keyword(s):  
Population Density ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Single Type ◽  
Resistant Cultivars ◽  
Scn Resistance ◽  
Pi 88788 ◽  
Selection Of

Soybean cyst nematode (SCN) is an important pathogen of soybean causing more than $1 billion in yield losses annually in the United States. Planting SCN resistant soybean cultivars is the primary management strategy. Resistance genes derived from the plant introductions (PI) 88788 (rhg1-b) and PI 548402 (Peking; rhg1-a and Rhg4) are the main types of resistance available in commercial cultivars. The PI 88788 rhg1-b resistance allele is found in the majority of SCN resistant cultivars in the north central US. The widespread use of PI 88788 rhg1-b has led to limited options for farmers to rotate resistance sources to manage SCN. Consequently, an over reliance on a single type of resistance has resulted in the selection of SCN populations that have adapted to reproduce on these resistant cultivars. Here we evaluated the effectiveness of rotating soybean lines with different combinations of resistance genes to determine the best strategy for combating the widespread increase in virulent SCN and limit future nematode adaptation to resistant cultivars. Eight SCN populations were developed by either continuous selection of a virulent SCN field population (HG type 1.2.5.7) on a single resistance source or in rotation with soybean pyramiding different resistance gene alleles derived from PI 88788 (rhg1-b), PI 437654 (rhg1-a and Rhg4), PI 468916 (cqSCN-006 and cqSCN-007) and PI 567516C (Chr10). SCN population densities were determined for eight generations. HG type tests were conducted after the eighth generation to evaluate population shifts. The continued use of rhg1-b or 006/007 had limited effectiveness for reducing SCN type 1.2.5.7 population density, whereas rotation to the use of rhg1-a/Rhg4 resistance significantly reduced SCN population density, but selected for broader SCN virulence (HG type 1.2.3.5.6.7). A rotation of rhg1-a/Rhg4 with a pyramid of rhg1-b/006/007/Chr10 was the most effective combination at both reducing population density and minimizing selection pressure. Our results provide guidance for implementation of a strategic SCN resistance rotation plan to manage the widespread virulence on PI 88788 and sustain the future durability of SCN resistance genes.

scholarly journals Soybean Cyst Nematode Reduces Soybean Yield Without Causing Obvious Aboveground Symptoms

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 ◽  
...  
Keyword(s):  
Seed Development ◽  
Soybean Cyst Nematode ◽  
Field Experiments ◽  
Heterodera Glycines ◽  
Biomass Accumulation ◽  
Cyst Nematode ◽  
Southern Illinois ◽  
Resistant Cultivars ◽  
Wide Range ◽  
Growth Development

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.

scholarly journals Soybean Stem Colonization by Genotypes A and B of Cadophora gregata Increases with Increasing Population Densities of Heterodera glycines

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1297-1301 ◽  
Author(s):  
G. M. Tabor ◽  
G. L. Tylka ◽  
C. R. Bronson
Keyword(s):  
Population Density ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Population Densities ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Soybean Genotypes ◽  
Genotype A

Growth chamber experiments were conducted to investigate whether parasitism by increasing population densities of Heterodera glycines, the soybean cyst nematode, increases the incidence and severity of stem colonization by the aggressive genotype A and the mild genotype B of Cadophora gregata (Phialophora gregata), causal agents of brown stem rot of soybeans. Soybean genotypes with three combinations of resistance and susceptibility to H. glycines and genotype A of C. gregata were inoculated with each genotype of C. gregata alone or each genotype with two population densities of H. glycines eggs, 1,500 or 10,000 per 100 cm3 of soil. Stems of two H. glycines-susceptible soybeans were more colonized by both aggressive and mild genotypes of C. gregata in the presence of high than in the presence of low H. glycines population density.

scholarly journals Brown Stem Rot and its Interaction with the Soybean Cyst Nematode

2006 ◽  
Author(s):  
G. M. Tabor ◽  
G. L. Tylka ◽  
C. R. Bronson
Keyword(s):  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Brown Stem Rot

Registration of ‘IAR1902 SCN’ Cultivar Resistant to Soybean Cyst Nematode and Brown Stem Rot

2019 ◽  
Vol 13 (3) ◽  
pp. 334-344
Author(s):  
S. R. Cianzio ◽  
P. R. Arelli ◽  
S. Swaminathan ◽  
M. K. Bhattacharyya ◽  
G. Gebhart ◽  
...  
Keyword(s):  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Brown Stem Rot

scholarly journals Increase in Soybean Cyst Nematode Virulence and Reproduction on Resistant Soybean Varieties in Iowa From 2001 to 2015 and the Effects on Soybean Yields

2017 ◽  
Vol 18 (3) ◽  
pp. 146-155 ◽  
Author(s):  
Michael T. McCarville ◽  
Christopher C. Marett ◽  
Mark P. Mullaney ◽  
Gregory D. Gebhart ◽  
Gregory L. Tylka
Keyword(s):  
Soybean Cyst Nematode ◽  
Field Experiments ◽  
Yield Loss ◽  
Plant Introduction ◽  
Cyst Nematode ◽  
Population Densities ◽  
Sources Of Resistance ◽  
Nematode Reproduction ◽  
Soybean Yield ◽  
Pi 88788

Management of the soybean cyst nematode (SCN) relies heavily on use of SCN-resistant soybean varieties to limit nematode reproduction and minimize yield loss. For Iowa, almost all SCN-resistant soybean varieties contain SCN resistance genes from a breeding line named Plant Introduction (PI) 88788. Iowa State University conducts experiments to evaluate numerous SCN-resistant and three to four SCN-susceptible soybean varieties in up to nine field experiments across Iowa each year. Data on SCN population density, virulence (SCN race and HG type), soybean yield, precipitation, and growing degree days from more than 25,000 four-row plots in field experiments conducted from 2001 to 2015 were analyzed to determine how these factors affected SCN reproduction and yield. SCN population densities were positively correlated with temperatures and negatively associated with precipitation during the growing seasons, indicating that SCN reproduction was greatest in hot, dry years. Over the years, virulence of SCN populations on PI 88788 increased in the fields in which the experiments were conducted, resulting in increased end-of-season SCN population densities and reduced yields of SCN-resistant soybean varieties with the PI 88788 source of resistance. These results indicate that soybean yield loss caused by SCN on resistant varieties with the common PI 88788 source of resistance likely will increase as virulence of SCN populations increases unless new sources of resistance become widely available and used in the future.

scholarly journals Variability in Distribution and Virulence Phenotypes of Heterodera glycines in Missouri During 2005

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
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Common Source ◽  
Sources Of Resistance ◽  
Resistant Cultivars ◽  
Soybean Cultivars ◽  
Geographical Regions ◽  
Two Samples ◽  
Pi 88788

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.

scholarly journals Heterodera glycines Infection Increases Incidence and Severity of Brown Stem Rot in Both Resistant and Susceptible Soybean

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 655-661 ◽  
Author(s):  
G. M. Tabor ◽  
G. L. Tylka ◽  
J. E. Behm ◽  
C. R. Bronson
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Growth Chamber ◽  
Susceptible Genotype ◽  
Brown Stem Rot ◽  
Soybean Cultivars ◽  
Phialophora Gregata ◽  
Soybean Genotypes

Growth chamber experiments were conducted to investigate whether parasitism by Heterodera glycines, the soybean cyst nematode, increases incidence and severity of brown stem rot (BSR) of soybean, caused by Phialophora gregata, in both resistant and susceptible soybean cultivars. Soybean genotypes with various combinations of resistance and susceptibility to both pathogens were inoculated with P. gregata alone or P. gregata plus H. glycines. In most tests of H. glycines-susceptible genotypes, incidence and severity of internal stem discoloration, characteristic of BSR, was greater in the presence than in the absence of H. glycines, regardless of susceptibility or resistance to BSR. There was less of an increasing effect of H. glycines on stem symptoms in genotypes resistant to both BSR and H. glycines; however, P. gregata colonization of these genotypes was increased. Stems of both a BSR-resistant and a BSR-susceptible genotype were colonized earlier by P. gregata in the presence than in the absence of H. glycines. Our findings indicate that H. glycines can increase the incidence and severity of BSR in soybean regardless of resistance or susceptibility to either pathogen.

Shift in Virulence of Soybean Cyst Nematode is Associated with Use of Resistance from PI 88788

2008 ◽  
Vol 9 (1) ◽  
pp. 29 ◽  
Author(s):  
T. L. Niblack ◽  
A. L. Colgrove ◽  
K. Colgrove ◽  
J. P. Bond
Keyword(s):  
Soybean Cyst Nematode ◽  
Plant Introduction ◽  
The United States ◽  
Cyst Nematode ◽  
Management Tool ◽  
Sources Of Resistance ◽  
Resistant Cultivars ◽  
Significant Yield ◽  
Pi 88788 ◽  
Alternative Sources

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.

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