Soybean yield and heterodera glycines response to rotation, tillage, and genetic resistance

Heterodera glycines continues to be the number one yield limiting factor in soybean [Glycine max (L.) Merr.] across the Midwest. Several genetic and agronomic practices are available to assist growers in maximizing yield in a H. glycines environment. The objectives of this research were to (i) measure yield response to rotation and tillage systems and evaluate whether presence of H. glycines and reaction of cultivars to H. glycines modified this response, and (ii) determine if H. glycines population dynamics were related to source of resistance to H. glycines, rotation, or tillage systems. Field research trials were conducted during 3 yr (2006-2008) near Arlington, WI and Ames, IA. Main plots were no-tillage and conventional tillage systems. Subplots consisted of 10 rotation sequences involving corn (Zea mays L.) and soybean. Sub-subplots were three sources of H. glycines resistance. Crop rotation and source of genetic resistance were the most important factors to consider in maximizing seed yield and managing H. glycines across locations, whereas tillage was the least valuable tool in H. glycines management. Extended rotations decreased H. glycines populations, however this benefit was overcome by first or second year soybean. Results also show that continued reliance on one source of genetic resistance can lead to reproduction of H. glycines, regardless of source. Our results suggest that an integrated approach to H. glycines management that considers rotation, tillage, knowledge of H. glycines (HG)- type, and source of genetic resistance is needed to maximize seed yield and decrease H. glycines populations.