No abstract

Annual decreases in soybean (Glycine max L. Merrill) yield caused by diseases were estimated by surveying university-affiliated plant pathologists in 28 soybean-producing states in the United States and in Ontario, Canada, from 2010 through 2014. Estimated yield losses from each disease varied greatly by state or province and year. Over the duration of this survey, soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) was estimated to have caused more than twice as much yield loss than any other disease. Seedling diseases (caused by various pathogens), charcoal rot (caused by Macrophomina phaseolina (Tassi) Goid), and sudden death syndrome (SDS) (caused by Fusarium virguliforme O’Donnell & T. Aoki) caused the next greatest estimated yield losses, in descending order. The estimated mean economic loss due to all soybean diseases, averaged across U.S. states and Ontario from 2010 to 2014, was $60.66 USD per acre. Results from this survey will provide scientists, breeders, governments, and educators with soybean yield-loss estimates to help inform and prioritize research, policy, and educational efforts in soybean pathology and disease management.

No abstract

Planting date is a commonly manipulated management practice in soybean [Glycine max (L.) Merr.] production; however, the impacts of past and ongoing agronomic improvements, such as earlier planting, on genetic yield improvement and associated changes in seed protein and oil have not been evaluated. The objectives of this study were to determine if a 30‐d difference in planting date affected measured rates of genetic improvement in (i) yield, (ii) seed mass, and (iii) seed protein and oil in the midwestern United States. Research was conducted at Arlington, WI, Urbana, IL, and Lafayette, IN, during 2010 and 2011, using 59 Maturity Group (MG) II cultivars (released 1928–2008) at Wisconsin, and 57 MG III cultivars (released 1923–2007) at Illinois and Indiana, with targeted planting dates of 1 May and 1 June. Earlier planting provided higher yields (+3.1 kg ha−1 yr−1) than late planting in MG III soybean. Seed protein concentration decreased linearly over cultivar year of release at a rate of 0.191 (± 0.069) g kg−1 yr−1 for MG II, and 0.242 (± 0.063) g kg−1 yr−1 for MG III. Seed oil concentration increased over year of release at a rate of 0.142 (± 0.037) g kg−1 yr−1 for MG II, and 0.127 (± 0.039) g kg−1 yr−1 for MG III. The interaction between planting date and cultivar year of release for MG III yield suggested that the trend toward earlier planting is one agronomic improvement that, when coupled with genetic improvement, has provided a synergistic increase in on‐farm soybean yields in the midwestern United States.

Soybean (Glycine max L. Merrill) is an economically important commodity for United States agriculture. Nonetheless, the profitability of soybean production has been negatively impacted by soybean diseases. The economic impacts of 23 common soybean diseases were estimated in 28 soybean-producing states in the U.S., from 1996 to 2016 (the entire data set consisted of 13,524 data points). Estimated losses were investigated using a variety of statistical approaches. The main effects of state, year, pre-and post-discovery of soybean rust, region, and zones based on yield, harvest area, and production, were significant on "total economic loss" as a function of diseases. Across states and years, the soybean cyst nematode, charcoal rot, and seedling diseases were the most economically damaging diseases while soybean rust, bacterial blight, and southern blight were the least economically damaging. A significantly greater mean loss (51%) was observed in states/years after the discovery of soybean rust (2004 to 2016) compared to the pre-discovery (1996 to 2003).