Degree Name

Master of Science (MS)

Semester of Degree Completion

2002

Thesis Director

Janice Coons

Abstract

Seed companies have transgenic maize (Zea mays L.) hybrids resistant to European corn borer (ECB) [Ostrinia nubilalis (Hübner)]. However, the impact of this Bt (Bacillus thuringiensis) gene on other plant processes is not understood. In 1997 and 1999, a study at Central Golden Harvest Research in Clinton, IL focused on how the Bt gene affects gas exchange and yields of maize with and without ECB infestation. Bt and non-Bt isogenic pairs were planted with or without nets and/or insecticides to eliminate natural infestation of ECB, and with or without manual infestation of ECB. Photosynthesis and transpiration were measured. At harvest, yields and kernel mass were determined. Seed germination percentages and root lengths were measured. Photosynthesis and transpiration were similar for Bt and non-Bt plants regardless of ECB infestation. In 1997 and 1999, yields were not significantly different for Bt and non-Bt plants, but in 1999 yields were significantly higher in plants with nets or insecticides compared to no nets or insecticides. In 1997, kernel mass was significantly higher for Bt than non-Bt plants (28.6 and 26.7 g, respectively). In 1999, kernel mass was not significantly different between Bt and non-Bt plants; however one isogenic pair of hybrids, plants with insecticide had significantly larger kernels and more seed produced than those without insecticide. Seed vigor showed no significant differences for germination percentages or root length. Thus, Bt genes had no significant effects on gas exchange or yields regardless of ECB infestation, but had a significant effect on kernel mass in 1997.

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