Large-scale Study Focused on Seedling Health
Mon, Apr 6, 2015
Soybean emergence. Photo: S.S. Navi, ISU
Early detection and diagnosis of soybean emergence problems is important to achieving high yields. A team of 15 soybean plant pathologists in 11 states and Canada recently completed a checkoff-funded study on seedling pathogens of soybean, with the goal of helping farmers more accurately detect, diagnose, and prevent soybean emergence problems.
Soil-borne pathogens and other organisms were identified from 3,000 samples collected during this 3-year project. This information guided researchers to refine molecular identification tools that are now available to plant diagnostic clinics. They also produced a step-by-step video on how to take a field sample for seedling blight diagnosis. View video.
The researchers established procedures for soybean germplasm screening, and identified fifteen soybean lines with partial resistance to seedling blight and root rot caused by Rhizoctonia solani.
The members of the research team rated the efficacy of fungicide seed treatments by field-testing the materials over multiple years and locations, and reviewing the national fungicide trials published in Plant Disease Management Reports
by the American Phytopathological Society.
Note that efficacy refers to how well a seed treatment controls a specific seedling disease, and does not necessarily indicate a yield increase. View fungicide ratings.
Soybean Aphid Outreach at the 2015 Commodity Classic Convention and Trade Show
Thu, Mar 5, 2015
Kelley Tilmon, Erin Hodgson, Tom Hunt
Thelma Heidel-Baker, David Voegtlin
Soybean entomologists from South Dakota, Iowa, Illinois, and Nebraska hosted a booth at the recent Commodity Classic convention and trade show, highlighting NCSRP-funded soybean aphid research and outreach.
Visitors to the booth had the opportunity to discuss their soybean aphid questions with the researchers, and receive a print copy of the latest soybean aphid scouting card
or field guide
. Tablets were in place for visitors to browse this Soybean Research & Information Initiative
website or to view the recent webinars on soybean aphid management
, hosted by the Plant Management Network. Almost 8000 people attended the event held in Phoenix this year.
Two-gene pyramids have the potential to increase the efficacy and consistency of soybean aphid control
Fri, Jan 23, 2015
A large-scale checkoff-funded research study conducted in seven states evaluated aphid resistant lines and found that the Rag1+Rag2
gene pyramid suppresses aphids the most, enough to effectively replace insecticides. The study compared near-isolines for the Rag1
gene, and a pyramid line containing both genes, for their ability to decrease aphid pressure and protect yield compared to a susceptible line. The lines were evaluated both with and without a neonicotinoid seed treatment. The genetic relatedness of the test lines, and the large number of locations and aphid pressures present during the 3-year study provided a robust test.
Soybean aphids significantly reduced soybean yield for the susceptible line by 14% and for both single-gene lines by 5%; however, no significant yield decrease due to aphid feeding was observed for the pyramid line. The neonicotinoid seed treatment reduced plant exposure to aphids across all soybean lines, but did not provide significant yield protection for any of the lines.
The results demonstrate that pyramiding resistance genes can provide sufficient and consistent yield protection from soybean aphid in North America. The background and full results of the study have been published in the article One Gene Versus Two: A Regional Study on the Efficacy of Single Gene Versus Pyramided Resistance for Soybean Aphid Management
in the Journal of Economic Entomology. Read the full article
Understanding Soybean Maturity Group Designations
Fri, Jan 9, 2015
Soybean maturity zones
Soybean breeders have developed thirteen maturity group designations, using roman numerals, ranging from 000 to X. In the U.S., maturity groups 00 to VIII are typically planted. Many companies or institutions now use Arabic numbers for maturity groups and divide each maturity group into tenths (for example 2.9 or 5.8).
Dr. Jim Orf, soybean breeding and genetics professor at the University of
Minnesota, explains the significance of soybean
maturity groups, and how maximum yield can be obtained when a crop can use each day of the frost-free season. Watch the webcast on the Plant Management Network