Evaluation of Disease and Pest Damage on Soybean Cultivars Released from 1923 through 2008 under Field Conditions in Central Illinois

Abstract

Diseases and pests of soybean [Glycine max (L.) Merr.] often reduce soybean yields. Targeted breeding that incorporates known genes for resistance and non‐targeted breeding that eliminates susceptible plants in breeding populations reduces the impact of soybean pathogens and pests. Maturity group (MG) III soybean cultivars released from 1923 through 2008 were grown in three field environments to determine if disease and insect ratings were associated with year of cultivar release. Disease and pest ratings were evaluated on 40 soybean cultivars at one location (Urbana, IL) planted in two rotation treatments in 2010 and on 59 cultivars in two locations (Urbana and Arthur) in 2011. During the season, foliar disease symptoms and insect foliar feeding damage were recorded. At harvest maturity, stem diseases were assessed. In at least one environment, foliar incidence reached 100% for bacterial diseases, brown spot (Septoria glycines Hemmi), and insect foliar feeding damage and 100% incidence for anthracnose [Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore], Cercospora stem blight (Cercospora kikuchii T. Matsumoto & Tomoy.), and charcoal rot [Macrophomina phaseolina (Tassi) Goid.] on stems for all cultivars. For the nine different disease and pest severity assessments in 2010, seven had a significant (P < 0.05) negative correlation to year of cultivar release indicating that cultivars more recently released had lower severity ratings than cultivars with older release dates. This study demonstrated that incidence and severity of diseases were less pronounced on more newly‐released soybean cultivars, showing that decades of breeding has resulted in increased disease resistance in modern soybean cultivars.

Organically Grown Soybean Production in the USA: Constraints and Management of Pathogens and Insect Pests

“…Non-organic growers are able to use synthetic pesticides and transgenic cultivars, while many growers of organic soybeans use cultivars selected for specialty markets. These cultivars may not have the same agronomic traits found in the modern, grain-type cultivars that have benefitted from decades of breeding aimed at increasing yields and disease resistance [18,19].…”

“…The soybean cultivars grown for organic production could theoretically be the same as those grown for grain production, which are generally high-yielding cultivars with resistance to many diseases and pests [19]. However, many commercial grain-types are transgenic and are not permissible in organic production.…”

Effect of Seed Treatment on Early Season Brown Spot Caused by Septoria glycines of Soybean

“…Cultivar differences were not further analyzed and presented since we did not have access to the identity of these proprietary cultivars. While no soybean cultivars are specifically promoted as resistant to brown spot, it has been noted that the incidence and severity of this disease can differ among cultivars (Hartman et al 2015).…”

“…Inoculum from infected soybean residue is splash-dispersed and the disease spreads from the lower to upper leaves during rainy weather (Lim 1980). Although brown spot is not often considered to be an economic threat to soybean production, yield loss can occur when more than 25% of the canopy is defoliated at the R6 growth stage (Cruz et al 2010;Hartman et al 2015;Lim 1980;Wrather et al 2003;Young and Ross 1979).…”

Population genetics of >i<Colletotrichum truncatum>/i< associated with soybean anthracnose

“…The studied isolates were inoculated in the cultivar IPRO 8579 in order to confirm their pathogenicity to the soybean. Pre-germinated seeds were inoculated with conidial suspensions (1x10 6 conidia/mL) of each isolate and incubated into a plant growth chamber at 25°C, in photoperiod of 12 h. The seedlings were evaluated for the presence of symptoms 120 h after inoculation, according to Hartman et al( 2015). The average values were submitted to the analysis of variance (ANOVA) and compared by the Tukey test with P ≤ 0.05.…”