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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #243066

Title: Heterodera glycines Population Development on Soybean Treated with Glyphosate

Author
item NOEL, GREGORY
item WAX, LOYD

Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2009
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soybean cyst nematode (SCN) is the most yield limiting pest or disease of soybean in the United States. Control of SCN is achieved primarily through the use of crop rotation and planting of cultivars resistant to SCN. Many of these SCN-resistant cultivars also are genetically modified for tolerance to application of glyphosate. There is a dirth of knowledge concerning possible interactions in the incorporation of both resistance to SCN and glyphosate tolerance and application of glyphosate. To better understand potential interactions, field research was done for three seasons. There was indication of increases in SCN numbers due to application of glyphosate on the SCN-susceptible and glyphosate tolerant variety, but not on the SCN-resistant variety. There was no loss of yield associated with the population increase. This research impacts soybean farmers in that they can plant both SCN-susceptible and SCN-resistant varieties tolerant to glyphosate and apply glyphosate without concern of reducing their soybean yields.

Technical Abstract: Soybean cyst nematode (Heterodera glycines) is a major yield limiting pest in all major soybean producing countries. In the last decade genetically modified soybean tolerant to glyphosate has become widely planted and postemergence application of glyphosate has increased exponentially. Genetically modified crops may affect nontarget microorganisms, either directly or indirectly as in the case of glyphosate application to tolerant crops. Glyphosate translocates to soybean roots where it might affect metabolic sinks such as syncytia produced by Heterodera glycines. In 2002 - 2004 glyphosate tolerant soybean DSR 320 susceptible to H. glycines and DSR 327 resistant to H. glycines were grown in three different fields and either sprayed with glyphosate at the recommended rate and time of application or not sprayed. Nematode reproduction and soybean yield were determined. In all three years, Pf and Pf/Pi were significantly greater on DSR 320 when compared with DSR 327. In 2004, when Pi exceeded the damage threshold, there was a cultivar × glyphosate interaction for Pf on DSR 320 with greater numbers of eggs recovered from glyphosate treated DSR 320. In 2002 and 2003 Pi was below the damage threshold and no differences in yield occurred between the resistant and susceptible cultivars. However, in 2003 a significant cultivar × glyphosate interaction was observed for yield of DSR 320. In 2004 a significant difference in yield between DSR 320 and DSR 327 was observed. Glyphosate application affected Pf of H. glycines eggs in 2004, the only year Pi exceeded the damage threshold. However, the increase Pf did not translate into crop loss.