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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #258111
Title: Stabilization of Heterodera Glycines Hg Type 0 During a 20-year Rotation Utilizing Resistant and Susceptible Soybean

Author
item Noel, Gregory
item ATIBALETJA, N - University Of Illinois
item BAUER, S - University Of Illinois

Submitted to: Nematropica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2010
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soybean cyst nematode (SCN) is an important pest of soybean and causes several hundred million dollars in crop loss each year. Planting of nematode resistant varieties is a major control method, but there is concern because of reliance on one particular source of resistance, which is in the pedigree of about 97% of all SCN resistant varieties grown in the U.S. This resistance was obtained from a soybean (PI88788) collected in China about 80 years ago. Frequent use of any resistance or pesticide will exert selection pressure leading to adaptation of pests to the resistance or pesticide being used against them. A crop rotation utilizing soybean susceptible to SCN was proposed in the 1980's as a way to eliminate or reduce the effects of selection pressure on sources of resistance to SCN. For various reasons, including lack of long-term studies, the rotation utilizing SCN susceptible varieties was not widely adopted. In Illinois populations of SCN that can reproduce on PI88788 resistance have increased from 30% in 1989, to 60% in 2006. The 20-year-long, on-farm study reported herein documents the effectiveness of the rotation in eliminating selection pressure on the PI88788 source of resistance. SCN never adapted to the PI88788 source of resistance, and the farmer in his last two plantings of soybean obtained exceptional yields, averaging 59.7 bu/acre when the resistant soybean was planted in 2007 and 61.2 bu/acre when the susceptible soybean was planted in 2009. Those who will benefit most from this research are soybean producers and agricultural advisors.

Technical Abstract: In 1989, Heterodera glycines was found in a soybean field near Bellflower, Illinois, and the population was identified as a race 3. The farmer initiated a management program utilizing crop rotation and genetic resistance by planting maize in 1990 and in even years thereafter, and alternating soybean cultivars carrying PI88788 resistance with H. glycines-susceptible cultivars every other production year for soybean. In 2009, a sample was collected from the same location in the field as the original sample. The Hg Type of the 2009 population was determined simultaneously with the original population, which had been cultured on H. glycines-susceptible cv. Williams 82 for 20 years. Both populations were identified as Hg Type 7 (Race 3). The female index ((FI) where FI = no. of females on differential line/no. of females on susceptible × 100) for PI88788 was 2 for the original field population, 6 for the 1989 population grown in culture, and 7 for the 2009 population. The FI for the other differential lines was similar except for PI548316 (cv. Cloud), which was 46 for the population cultured for 20 years and 16 for the 2000 population. This study demonstrated that planting an H. glycines-susceptible soybean in the rotation established balancing selection, which maintained the durability of the PI88788 source of resistance.