Effect of Soybean Cyst Nematode (Heterodera glycines) Resistance Rotation on SCN Population Distribution, Soybean Canopy Reflectance, and Grain Yield

Abstract

The soybean cyst nematode (SCN) is a serious pest that needs to be managed in soybean production. This pest is difficult to detect at its onset, as symptoms deleterious to the plant are not dramatic. This study was conducted to evaluate the effect of SCN resistance rotation on SCN distribution as well as on soybean canopy reflectance and grain yield. A 0.8 ha field was planted with soybeans under eleven resistance rotation treatments. Two sets of SCN counts and three airborne visible-infrared images were obtained during the 2004 season. An analysis of variance (ANOVA) indicated that the resistance rotation treatment explained 59% and 64% of variability in cyst and egg counts at planting, and 55% and 57% of variability in cyst and egg counts at harvest. The yield was lowest in all the plots under cultivar Manokin, and monoculture of Hutcheson or Hutcheson treated with the nematicide Temik, while the highest yields occurred in plots under cultivar Anand. The SCN population densities at planting and harvest and grain yield were correlated to the wide dynamic range vegetation index (WDRVI) at P < 0.1. However, there was no relationship between SCN population densities and normalized difference vegetation index (NDVI) and green NDVI (GNDVI) on any given date in the season. This study indicated that the resistance rotation was effective in managing SCN in the field. Remote sensing showed potential in identifying SCN damage under the low to moderate infestation. This study also elucidates the complex relationship between SCN population density in the soil and potential crop damage, and the difficulty in assessing SCN infestation.