uses a variant Bt Cry3Bb1 insecticidal protein (Donovan et al., 1992). Cry3Bb1 is known to be biologically active The corn rootworm (CRW; Diabrotica spp.) is one of the most against several species within the Coleopteran family serious pests of corn in the USA. Chemical insecticides and crop rotation have been the only two options available to growers for Chrysomelidae, including the western corn rootworm, managing CRW. Unfortunately, both of these tactics can be ineffective Diabrotica virgifera virgifera LeConte (Rupar et al., as a result of either resistance or behavioral modifications. In this 1991). The biological activity of this protein against D. paper, we describe transgenic maize (Zea mays L.) hybrids that control virgifera virgifera suggested its potential use in creating CRW. These hybrids were created with a Cry3Bb1 Bacillus thurintransgenic plants expressing Cry3Bb1 that would confer giensis (Bt) variant that is approximately eight times more lethal to protection to corn root tissue from larval feeding damcorn rootworm larvae than the wild-type protein. A DNA vector age. To further augment protection of the root system containing the modified cry3Bb1 gene was placed under control of a from larval feeding damage, modifications were introroot-enhanced promoter (4-AS1) and was introduced into embryonic duced in the cry3Bb1 gene that gave rise to an amino acid maize cells by microprojectile bombardment. Described here is the variant Cry3Bb1 protein with an eight-fold increase in molecular genetic characterization, protein expression levels, and field performance of the recently commercialized MON863 hybrids.

Fumonisins were monitored in corn grain collected from Bt hybrids grown in 107 locations across the United States in 2000-2002. Bt corn hybrids contain the Cry1Ab protein from Bacillus thuringiensis that controls European corn borers and other stalk-boring pests. Fumonisin levels were frequently lower in grain from Bt hybrids grown in field trials under conditions of natural (FACT trials) or manual insect infestation (university trials). Over three years of FACT trials, there were 126/210 comparisons when fumonisin levels in grain from control hybrids were >2 ppm, exceeding U.S. FDA guidance levels of 2 ppm for human food. Grain from Bt hybrids was at or below 2 ppm of fumonisins for 58 of the 126 comparisons. The use of Bt hybrids can increase the percentage of corn grain that would be suitable for use in food and feed.

This chapter examines the current management strategies and their limitations in USA maize production and the potential benefits of managing these pests with a developed corn rootworm (Diabrotica spp.)-protected maize. The topics covered include development of a genetic solution for corn rootworm management, characterization of YieldGard rootworm maize, food and feed safety of YieldGard rootworm maize, environmental safety of YieldGard rootworm maize, performance of YieldGard rootworm maize, and benefits of YieldGard rootworm maize.

No abstract

No abstract

No abstract

No abstract

No abstract