Abstract
Wang, J., P.A. Donald, T.L. Niblack, G.W. Bird, J. Faghihi, J.M. Ferris, D.J. Jardine, C. Grau, P.E. Lipps, A.E. Macguidwin, H. Melakeberhan, G.R. Noel, P. Pierson, R.M. Reidel, P.R. Sellers, W.C. Stienstra, T.C. Todd, G.L. Tylka, and D.S. Wysong. 2000. Soybean cyst nematode reproduction in the north central United States. Plant Disease 84:77-82.
An experiment was conducted in Heterodera glycines - infested fields over forty environments (21 sites in 1994 and 19 sites in 1995) to assess reproduction of the nematode in the 10-state North Central region of the United States. Two resistant and two susceptible soybean cultivars from each of the Maturity Groups (MG) I through IV were grown at each site in 6.1 m by 4 row plots. Soil samples were collected from each plot at planting and harvest for each local growing season at each site to determine H. glycines initial (Pi) and final (Pf) population densities. All samples were processed at Iowa State University for numbers of eggs per 100 cm3 soil. Overall, reproduction (Pf/Pi) of H. glycines on susceptible cultivars in all MG was similar. Reproduction was higher on MG III and IV susceptible cultivars than on those in MG I and II. Resistant MG I and II cultivars reduced nematode population densities more consistently than those in MG III and IV. Reproduction of the nematode was similar among sites within the same maturity zone (MZ), defined as the areas of best adaptation of the corresponding MG. Nonetheless, careful monitoring of nematode population densities is necessary to assess changes that occur over time in individual fields.