Brief Summary of Minutes of Annual Meeting

Summary of Minutes from the NCERA-200 Business Meeting at Ames October 25, 2005 Agenda: Introduction Steven Slack Secretary election Old business 2005 meeting minutes Review 2005 activities Discussion of future committee activities New NCERA 200 proposal Next meeting Minutes: Introduction. Steven Slack provided an administrative update - overview of the current status of the NCERA 200. Secretary election. Dr. Craig Grau was elected as secretary of NCERA-200 Committee for 2006. Old business. Minutes of the November 2004 meeting were approved. Accomplishments included: assessment of the incidence of soybean-infecting viruses within the North Central Region; evaluation of control strategies virus disease that included host resistance, cultural practices and insecticidal management of virus vector populations; and coordination of research and communication research information to soybean producers through the development of a web-based slide set on soybean virus diseases. Discussion of future committee activities. The rewrite and renewal of NCERA 200 was discussed. The location and date for then NCERA200 meeting next year was set as October 30-31, 2006 in Ames, Iowa. Planning was initiated to host another meeting in 2006 with an attached symposium on virus resistance assessments, homeland security in terms of keeping out exotic viruses, and/or seed certification programs for virus detection. See attachment for individual accomplishments by state.

This project has had major impact to benefit soybean producers in the North Central United States. At the time of its inception, viral disease was epidemic in numerous regions of this area. It was apparent early on that symptoms were generally unreliable for detection and diagnosis. Further, in contrast to previous supposition, green stem does not appear to be strongly associated with infection by virus. Therefore, through extensive survey in various states the project identified BPMV, AMV, SbDV, TRSV, and TSV as present in the region. Distribution and incidence is dependent upon vector population and geographic region; although, BPMV and SMV have historically been most important. Yield suppression, ranging from 15% to as high as 80% was measured. In the case of BPMV, components of yield suppression were studied. Important to detection and identification was the development of diagnostics, which have been shared among cooperators. Nevertheless, severe deficiencies for good diagnostics still exist, primarily for AMV and SbDV in soybean. Extensive effort has been devoted to understanding virus ecology that would lead to disease control. This includes studies of insect vector biology and phenology (especially related to bean leaf beetles and the Asian soybean aphid). An almost two decade monitoring system to predict bean leaf beetle populations has been maintained at Iowa State University. Inoculum sources for BPMV were surveyed for in seed, alternate weed hosts, and overwintering bean leaf beetles. Strains of BPMV were characterized as subgroups I and II with reassortant, recombinant, and partial diploid strains that relate to symptom severity. For the short term, vector management strategies were developed to control disease caused by BPMV. Longer-term strategies for all viruses dictate the development of field tolerance and/or resistance. For BPMV, no resistance genes are known to exist in Glycine max. Research in several states has identified apparent field tolerance using varying techniques. Some field tolerance was identified in already available commercial cultivars. In other cases, it is available in introductions or breeding lines. This remains to be incorporated into commercial cultivars. Further, transgenic resistance was developed and remains to be tested in multiple locations. Previously, AMV has not been commonly isolated from soybean in the north central states. However, with the introduction of the Asian soybean aphid into the region, AMV incidence appears to be increasing significantly. It is unclear what impact this virus has for producers. Apparent resistance has been discovered in one plant introduction. However, because high variability of AMV isolates in soybean has been indicated, it is unclear how sustainable this resistance might be. Also, the first reported resistance to TSV has also been discovered. Previously, naturally occurring resistance genes to SMV had been identified as Rsv1, Rsv3, and Rsv4. Little information, however, was available concerning how they might act and consequently, it was difficult to predict their durability. Studies on how these resistance genes might work suggest durability of Rsv1. Unfortunately; it can be overcome by one SMV strain. Additional molecular studies suggest pyramiding with Rsv3 might be useful. Molecular tools using virus isolates containing marker genes may aid rapid resistance screening as may use of SMV as a transient expression vector. As previously suggested, the introduction of Asian soybean aphid lends additional complexity to the picture. It was shown to efficiently transmit SMV and AMV, both of which appear to be increasing after its introduction. Of major potential impact is the discovery of soybean dwarf virus in soybeans in Wisconsin. This virus, for which there is no resistance in the commonly used soybean germplasm, has potential to be devastating. Results concerning its transmission by the soybean aphid have been conflicting; however, recently it appears that some isolates are transmitted by this aphid species. The virus appears to be prevalent in red clover and less so in white clover in numerous north central states that have conducted surveys. One of the most significant achievements of this project is the bringing together of scientists from different disciplines to work on soybean virus problems. The research results resulting from their interdisciplinary and multi-institutional cooperation have resulted in advances which already have had, and will continue to have in the future, major impacts for soybean producers. Research results generated by this group have been disseminated to soybean growers and industry through extensive extension efforts ranging from meetings, fact sheets, multimedia productions, and web sites. The group has also played a major technical supporting role to the Plant Health Initiative web site developed by the North Central Soybean Research Program.

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