scholarly journals Identification of Soybean Genotypes Resistant to Cercospora sojina by Field Screening and Molecular Markers

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 408-411 ◽  
Author(s):  
Rouf Mian ◽  
Jason Bond ◽  
Tarek Joobeur ◽  
Alemu Mengistu ◽  
William Wiebold ◽  
...  
Keyword(s):  
United States ◽  
Molecular Markers ◽  
Pathogen Resistance ◽  
Field Trials ◽  
Southern United States ◽  
Cercospora Sojina ◽  
Field Screening ◽  
Production Region ◽  
Soybean Genotypes ◽  
Northern United States

Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina, has been a problem in the southern United States for many years and has recently become a greater problem in the northern United States. Cultivars resistant to FLS have been developed for planting in the southern United States and resistance in many of these cultivars is conditioned by the Rcs3 gene. This gene conditions immunity to all known races and isolates of the pathogen. Resistance to C. sojina in soybean genotypes (cultivars and breeding lines) adapted to north-central U.S. production region is unknown. The objectives of this study were to (i) identify maturity group (MG) III, IV, and V soybean genotypes resistant to C. sojina race 11 by field screening at multiple locations over years and (ii) determine whether FLS resistance in these genotypes is likely to be conditioned by the Rcs3 gene. In total, 1,350 genotypes were evaluated for resistance to race 11 in field trials, and 13 MG III, 45 MG IV, and 15 MG V genotypes did not develop symptoms of FLS. Of these, 54 were subsequently tested for the possible presence of Rcs3 using five molecular markers located within 2 centimorgans (cM) of the gene. None of the MG III genotypes tested had the Rcs3 haplotype of cv. Davis, the source of Rcs3; six of the MG IV genotypes and seven of the MG V genotypes had the Rcs3 haplotype. This is the first report of the presence of the Rcs3 haplotype in LN 97-15076 and S99-2281. The soybean genotypes predicted to have the Rcs3 gene and other genotypes with no FLS symptoms in field trials may be useful in developing soybean cultivars with broad resistance to FLS and adapted to the northern United States.

Resistance to Frogeye Leaf Spot in Selected Soybean Accessions in MG I through MG VI

2012 ◽  
Vol 13 (1) ◽  
pp. 13 ◽  
Author(s):  
Alemu Mengistu ◽  
Jason Bond ◽  
Rouf Mian ◽  
Randall Nelson ◽  
Grover Shannon ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Glycine Max ◽  
Seed Yield ◽  
Leaf Spot ◽  
Yield Loss ◽  
Field Trials ◽  
Maturity Group ◽  
Cercospora Sojina ◽  
Frogeye Leaf Spot ◽  
Glycine Max L

Frogeye leaf spot (FLS) caused by Cercospora sojina Hara is a disease of soybean [Glycine max (L.) Merr.] that causes significant seed yield loss in warm, humid environments worldwide. The Rcs3 gene in soybean has been reported to condition resistance to all known races of C. sojina. The objectives of this study were to: (i) identify maturity group (MG) I to VI accessions resistant to C. sojina race 11 by field screening at two locations; and (ii) determine if the FLS resistance of the symptomless soybean accessions is likely to be conditioned by the Rcs3 allele. A total of 260 accessions including 12 differentials were evaluated for reaction to race 11 in field trials in Missouri and Illinois during 2009, and 20 accessions that did not develop symptoms were retested in 2010 to validate their resistance. The 20 accessions remained resistant and were tested for the potential presence of Rcs3 allele using molecular markers; and none was predicted to carry the Rcs3 allele. These accessions may contain novel loci for FLS resistance and may be used to broaden the base for developing soybean cultivars with frogeye leaf spot resistance. Accepted for publication 16 April 2012. Published 21 May 2012.

scholarly journals Overwintering of Sclerotium rolfsii and S. rolfsii var. delphinii in Different Latitudes of the United States

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Z. Xu ◽  
M. L. Gleason ◽  
D. S. Mueller ◽  
P. D. Esker ◽  
C. A. Bradley ◽  
...  
Keyword(s):  
United States ◽  
North Carolina ◽  
North Dakota ◽  
Southeastern United States ◽  
Sclerotium Rolfsii ◽  
Climate Extremes ◽  
Bare Soil ◽  
The United States ◽  
Southern United States ◽  
Northern United States

Previously known only from the southern United States, hosta petiole rot recently appeared in the northern United States. Sclerotium rolfsii var. delphinii is believed to be the predominant petiole rot pathogen in the northern United States, whereas S. rolfsii is most prevalent in the southern United States. In order to test the hypothesis that different tolerance to climate extremes affects the geographic distribution of these fungi, the survival of S. rolfsii and S. rolfsii var. delphinii in the northern and southeastern United States was investigated. At each of four locations, nylon screen bags containing sclerotia were placed on the surface of bare soil and at 20-cm depth. Sclerotia were recovered six times from November 2005 to July 2006 in North Dakota and Iowa, and from December 2005 to August 2006 in North Carolina and Georgia. Survival was estimated by quantifying percentage of sclerotium survival on carrot agar. Sclerotia of S. rolfsii var. delphinii survived until at least late July in all four states. In contrast, no S. rolfsii sclerotia survived until June in North Dakota or Iowa, whereas 18.5% survived until August in North Carolina and 10.3% survived in Georgia. The results suggest that inability to tolerate low temperature extremes limits the northern range of S. rolfsii.

scholarly journals Response of Canola Cultivars to Sclerotinia sclerotiorum in Controlled and Field Environments

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 215-219 ◽  
Author(s):  
C. A. Bradley ◽  
R. A. Henson ◽  
P. M. Porter ◽  
D. G. LeGare ◽  
L. E. del Río ◽  
...  
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Disease Process ◽  
Field Trials ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Detached Leaf ◽  
Red Lake ◽  
Low Levels ◽  
Northern United States

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, can be a devastating disease of canola (Brassica napus) in the northern United States. No canola cultivars are marketed as having resistance to SSR. Field trials were established in Red Lake Falls, MN (2001, 2003, and 2004) and Carrington, ND (2001, 2002, 2003, and 2004) to evaluate canola cultivars for resistance to SSR. These cultivars also were evaluated for resistance to SSR under controlled conditions using the following methods: petiole inoculation technique (PIT), detached leaf assay (DLA), and oxalic acid assay (OAA). Significant (P ≤ 0.05) differences were detected among cultivars for SSR and yield in the field trials, with SSR levels varying from low to high among years and locations. Cultivars with consistent high levels and low levels of SSR in the field trials were identified. Significant (P ≤ 0.05) differences were detected among cultivars for SSR using the PIT and OAA methods, but not the DLA method. No significant (P ≤ 0.05) correlations between SSR levels in the controlled studies with SSR levels in the field trials were detected; however, significant negative correlations were detected between SSR area under the disease process curve values from the PIT method and yield from Carrington, ND in 2001 and 2002. Although the PIT and OAA methods differentiated cultivars, neither method was able to predict the reaction of cultivars to SSR in the field, indicating that field screening for SSR resistance is still critical for the development of resistant cultivars.

scholarly journals First Description of the Causal Agent of Taproot Decline of Soybean, an Emerging Disease in the Southern United States

2017 ◽  
Vol 18 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Tom Allen ◽  
Burt Bluhm ◽  
Kassie Conner ◽  
Vinson Doyle ◽  
Trey Price ◽  
...  
Keyword(s):  
United States ◽  
Lateral Roots ◽  
Morphological Characters ◽  
Causal Agent ◽  
Southern United States ◽  
Unknown Etiology ◽  
Symptom Expression ◽  
Production Region ◽  
Soybean Plants

Over the past decade, a soybean root issue of unknown etiology has been observed across a widespread geography in the southern United States. Recently, pathologists began referring to the problem as taproot decline of soybean, based on the appearance of root symptoms. Taproot decline has been observed to cause foliar symptoms in vegetative and reproductive soybean plants ranging in maturity from V6 to R6. Symptom expression can appear similar to other notable root-associated diseases except that taproot decline exhibits a progression of symptom expression from subtle to severe interveinal chlorosis during the season. However, one distinct symptom associated with taproot decline is observed as darkened, black stroma on the taproot and, in some cases, the lateral roots of affected plants. Pathogenicity was confirmed by isolating the suspected fungus from naturally-infected soybean roots in multiple states and completing Koch’s postulates. The causal agent was identified, based on morphological characters and multilocus phylogenetic inference, as a member of the Xylaria arbuscula aggregate. At present, research projects are underway to address the role of the newly described disease and extent of the pathogen in the southern soybean production region in addition to developing integrated strategies for managing the disease.

Identification of Soybean Accessions Resistant to Cercospora sojina by Field Screening, Molecular Markers, and Phenotyping

Crop Science ◽  
2011 ◽  
Vol 51 (3) ◽  
pp. 1101-1109 ◽  
Author(s):  
Alemu Mengistu ◽  
Jason Bond ◽  
Rouf Mian ◽  
Randall Nelson ◽  
Grover Shannon ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Cercospora Sojina ◽  
Field Screening

Trends and Variability in Severe Snowstorms East of the Rocky Mountains*

2014 ◽  
Vol 15 (5) ◽  
pp. 1762-1777 ◽  
Author(s):  
Jay Lawrimore ◽  
Thomas R. Karl ◽  
Mike Squires ◽  
David A. Robinson ◽  
Kenneth E. Kunkel
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Strong Influence ◽  
Cold Season ◽  
Southern United States ◽  
Ohio Valley ◽  
Northern Plains ◽  
Seasonal Timing ◽  
Median Date ◽  
Northern United States

Abstract The 100 most severe snowstorms within each of six climate regions east of the Rocky Mountains were analyzed to understand how the frequency of severe snowstorms is associated with seasonal averages of other variables that may be more readily predicted and projected. In particular, temperature, precipitation, and El Niño/La Niña anomalies from 1901 to 2013 were studied. In the southern United States, anomalously cold seasonal temperatures were found to be more closely linked to severe snowstorm development than in the northern United States. The conditional probability of occurrence of one or more severe snowstorms in seasons that are colder than average is 80% or greater in regions of the southern United States, which was found to be statistically significant, while it is as low as 35% when seasonal temperatures are warmer than average. This compares with unconditional probabilities of 55%–60%. For seasons that are wetter (drier) than average, severe snowstorm frequency is significantly greater (less) in the Northern Plains region. An analysis of the seasonal timing of severe snowstorm occurrence found they are not occurring as late in the season in recent decades in the warmest climate regions when compared to the previous 75 years. Since 1977, the median date of occurrence in the last half of the cold season is six or more days earlier in the Southeast, South, and Ohio Valley regions than earlier in the twentieth century. ENSO conditions also were found to have a strong influence on the occurrence of the top 100 snowstorms in the Northeast and Southeast regions.

Responses of soybean genotypes to intercropping with maize in the Southern Guinea Savanna, Nigeria

2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa
Keyword(s):  
Seed Yield ◽  
Block Design ◽  
Field Trials ◽  
Yield Response ◽  
Ecological Zone ◽  
Land Equivalent Ratio ◽  
Guinea Savanna ◽  
Days To Maturity ◽  
Soybean Genotypes ◽  
Location Interaction

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.

The results of field trials of the codling moth pheromone preparations in 2020

2020 ◽  
Author(s):  
S.V. Dmitriyeva ◽  
◽  
I.M. Mityushev
Keyword(s):  
Russian Federation ◽  
Central Region ◽  
Cydia Pomonella ◽  
Codling Moth ◽  
Field Trials ◽  
Field Screening ◽  
Tube Type ◽  
The Russian Federation ◽  
Polyethylene Dispenser

This article presents the results of field screening of pheromone preparations of the codling moth, Cydia pomonella L., conducted in 2020 under conditions of the Central Region of the Russian Federation. The new «Tube» type dispensers were tested vs. standard foil-polyethylene dispenser.

Sign in / Sign up

Export Citation Format

Share Document