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 or Rag2 gene, and a pyramid line containing both genes for their ability to decrease aphid pressure and protect yield, compared with 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 journal 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
2014 Soybean Variety Test Reports Released
Fri, Dec 5, 2014
Variety selection is one of the earliest management decisions farmers make and one of the most important. Fortunately, good information is available to make those decisions. Each year at this time, reports from university and Extension soybean evaluation programs provide you with unbiased comparisons of variety performance. Use these reports together with information from your seed supplier, and your own on-farm comparisons, to select the best adapted and highest yielding varieties for your farm.
Select varieties having stable performance over a range of environmental conditions. Most test reports include two-year or three-year averages. Performance data from a single year or location have a very low predictive value and should not be relied upon for variety selection decisions.
Select a disease resistance package that matches the need for each field. This year, the Wisconsin Soybean Variety Test Results
(Table 8) and Michigan Soybean Performance Report
(Tables 9-12) include data from fields infested with white mold. Iowa State University evaluates soybean performance in the presence of soybean cyst nematode and releases an annual report. See SCN-resistant soybean varieties for Iowa 2015.
Go to University and Extension Soybean Variety Trials,
at this website, for links to all the 2014 soybean evaluation reports in the north-central region.
New Video Series Reports on Charcoal Rot Research
Sat, Oct 25, 2014
Charcoal rot of soybean is a recognized disease in southern U.S. states. More recently, growers and agronomists are noticing an increased incidence of charcoal rot in the north-central region. A multi-state research project, funded by the North Central Soybean Research Program and the United Soybean Board, is underway to determine the effect of charcoal rot on soybean yield, and the best management options for growers in northern states. Soybean pathologists report on their research in this six-part video series. Watch now