Cercospora leaf blight of soybean: pathogen vegetative compatibility groups, population structure, and host resistance

Nitrogen nonutilizing mutants were used to assess vegetative compatibility of 58 isolates of Cercospora kikuchii, 55 of which were isolated from soybean plants in Louisiana. Only 16 of 56 self-compatible isolates were assigned to six multi-member vegetative compatibility groups (VCGs), 01-06, with two or three isolates in each VCG. The other 40 isolates were not vegetatively compatible with any isolates other than themselves. All six multi-member VCGs contained isolates from different soybean cultivars, and three included isolates from different locations. Only one VCG included isolates both from soybean leaves and from seeds, while two and three multi-member VCGs included isolates only from leaves or from seeds, respectively. Population structure of C. kikuchii was further examined in 164 isolates, 161 of which were from Louisiana, with random amplified polymorphic DNA (RAPD) and microsatellite-primed PCR (MP-PCR). All isolates in the VCG study were included. Based on analysis of molecular variances, isolates from different host cultivars or different locations in Louisiana were not significantly different, but the Louisiana population was significantly different from isolates collected outside the state. Leaf and seed populations were significantly different. In the clustering analysis, isolates from Louisiana were grouped into four lineages, clades A-D. Clades A-C were further grouped into a large clade (ABC) with moderately strong bootstrap support. Clade B was the most dominant lineage in Louisiana. Only seven isolates from Louisiana were in the lineage, clade D, that included all three isolates from outside sources. Multilocus gametic disequilibrium tests did not reject the null hypothesis of random mating in clade B, but it was rejected in Clades A and D and the total collection. Some isolates within a VCG were closely related, but isolates within a VCG were not clustered together according to VCG in general. Representive isolates in clades A, B, and D were used to screen six commercial soybean cultivars, HBK R5588, AG5701, DP 5806 RR, TV59R85, SS RT 6299N and DP 6880 RR. Cultivars AG5701 and TV59R85 were significantly more resistant than other cultivars, and cultivar DP 6880 RR was most susceptible. Clade D was significantly more virulent than the other two lineages

The Uniform Soybean Tests: Northern Region 2020

The purpose of The Uniform Soybean Tests is to critically evaluate the best of the experimental soybean lines developed by federal and state research personnel in the U.S. and Canada, for their potential release as new varieties. A test is established for each of ten maturity groups. Uniform Test 00 includes maturity Group 00 strains adapted to production in the northern fringe of the present area of soybean production. Uniform Tests 0 through IV include later maturing strains adapted to locations progressively further south in the North Central States and areas of similar latitude. Each year new selections are added and others that have been sufficiently tested are dropped from the tests. The summary of performance of strains in Uniform Tests 00 through IV in the northern region is included in this report. The USDA-ARS Soybean Production Research Unit, P.O. BOX 345, STONEVILLE, MS 38776, issues the report on Uniform Tests IVS through VIII in the southern states. Data from the Uniform Soybean Tests are the basis for decisions on the regional release of soybean varieties. Preliminary Tests are grown at a limited number of locations throughout the region to evaluate the experimental strains for one year before they are dropped or advanced in the Uniform Tests. Uniform Tests are grown at more locations with more replications than Preliminary Tests. The Uniform Soybean Test Report is a progress report containing statements, which may or may not be verified by subsequent experiments. Statements or data in the report, therefore, should not be published unless those concerned have obtained permission previously. The USDA-Agricultural Research Service does not vouch for the authenticity of either the parentage or ancestry of entries in the Uniform Soybean Tests. This agency is not responsible for the accuracy of data submitted to and included in The Uniform Test Report. Germplasm exchange among breeding programs is the foundation of breeding progress. The purpose of the Uniform Soybean Test is to facilitate the free exchange of germplasm to maximize genetic diversity and provide well-adapted, stable breeding lines and varieties in the pursuit of breeding progress. Participants are encouraged to exchange germplasm within the legal guidelines pertaining to transgenic strains

The Uniform Soybean Tests: Northern Region 2021

The purpose of The Uniform Soybean Tests is to critically evaluate the best of the experimental soybean lines developed by federal and state research personnel in the U.S. and Canada, for their potential release as new varieties. A test is established for each of ten maturity groups. Uniform Test 00 includes maturity Group 00 strains adapted to production in the northern fringe of the present area of soybean production. Uniform Tests 0 through IV include later maturing strains adapted to locations progressively further south in the North Central States and areas of similar latitude. Each year new selections are added and others that have been sufficiently tested are dropped from the tests. The summary of performance of strains in Uniform Tests 00 through IV in the northern region is included in this report. The USDA-ARS Soybean Production Research Unit, P.O. BOX 345, STONEVILLE, MS 38776, issues the report on Uniform Tests IVS through VIII in the southern states. Data from the Uniform Soybean Tests are the basis for decisions on the regional release of soybean varieties. Preliminary Tests are grown at a limited number of locations throughout the region to evaluate the experimental strains for one year before they are dropped or advanced in the Uniform Tests. Uniform Tests are grown at more locations with more replications than Preliminary Tests. The Uniform Soybean Test Report is a progress report containing statements, which may or may not be verified by subsequent experiments. Statements or data in the report, therefore, should not be published unless those concerned have obtained permission previously. The USDA-Agricultural Research Service does not vouch for the authenticity of either the parentage or ancestry of entries in the Uniform Soybean Tests. This agency is not responsible for the accuracy of data submitted to and included in The Uniform Test Report. Germplasm exchange among breeding programs is the foundation of breeding progress. The purpose of the Uniform Soybean Test is to facilitate the free exchange of germplasm to maximize genetic diversity and provide well-adapted, stable breeding lines and varieties in the pursuit of breeding progress. Participants are encouraged to exchange germplasm within the legal guidelines pertaining to transgenic strains

The Uniform Soybean Tests: Northern Region 2017

United States Department of Agriculture Agricultural Research Service, West Lafayette, Indiana, Cooperating with State Agricultural Experiment Stations, Northern States

The Uniform Soybean Tests: Northern Region 2016

United States Department of Agriculture Agricultural Research Service, West Lafayette, Indiana, Cooperating with State Agricultural Experiment Stations, Northern States

Plasmons in Pb nanowire arrays on Si(557): Between one and two dimensions

The plasmon dispersion in arrays of nanowires of Pb close to an average Pb coverage of one monolayer was determined on the Si(557) surface using electron energy loss spectroscopy with both high energy and momentum resolution. While we find purely one-dimensional (1D) plasmon losses at a Pb concentration of 1.31 monolayers (ML), measured with respect to the Si(111) surface concentration, the 1.2 and 1.4 ML coverages exhibit wavelength-dependent transitions from 1D to anisotropic 2D properties. However, due to the high anisotropy in the system at all coverages, the dispersion curves exhibit 1D characteristics in both directions. This behavior seems to be related to the Pb-induced refacetting of the Si(557) surface, which depends on Pb coverage. It changes both effective system sizes and coupling strength between miniterraces. © 2011 American Physical Society.Ministry of Education, Culture, Sports, Science, and Technology, Japa