Phenotypic performance of nine genotypes of Cry1A.105/Cry2Ab2 dual-gene resistant fall armyworm on non-Bt and MON 89034 maize.

The fitness of individual resistant genes on pyramided Bt plants varied in the dual-gene resistance system. Genotypes containing more Cry1A.105 RAs performed better than those possessing more Cry2Ab2 RAs. The functional dominance level of an individual resistant gene in this system is related to the DML level in its corresponding single-gene system. Data generated from this study should fill gaps in understanding dual-/multiple-gene Bt resistance, as well as providing useful information for refining resistance modeling, improving resistance risk assessment, and developing management strategies for the sustainable use of pyramided Bt maize technology. © 2019 Society of Chemical Industry.