Submitted to: International Crop Science Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 26, 2004
Publication Date: September 26, 2004
Citation: Bruns, H.A., Abel, C.A. 2004. Effects of Nitrogen Fertility on BT Endotoxin Levels in BT Hybrid Maize. International Crop Science Congress Handbook and Abstracts. Brisbane, Austrailia, September 26 - October 1, 2004. P.289. Technical Abstract: A study was conducted to determine if Bt endotoxin concentrations during reproductive growth of Bt maize hybrids are affected by different N-fertility rates used to grow the crop. Previous research has shown N-fertility rates positively affect Bt concentrations of young Bt maize plants grown in a glasshouse. Three Bt hybrids, two with Bt event MON-810 (AgriGold brand cv. A 6729Bt and Pioneer brand cv. 33V08Bt), one with Bt event DBT 418 (DeKalb 626Bt) and one non-Bt maize hybrid (DeKalb brand cv. 626) were grown at Stoneville, MS, USA in 2002 and 2003 with N-fertility rates of 0, 112, 224, and 336 kg N/ha. Tissue samples of the outer ear husks and ear leaves were collect at growth stage R3 and analyzed for Bt concentration. Agronomic data were collected at maturity. The concentrations of Bt endotoxin in both sets of tissue were positively correlated with N-fertility rate for the MON-810 Bt hybrids but not the DBT 418 Bt hybrid. Increases in N-fertility increased grain yields. The Bt hybrids had less lodging (0.7%-1.0%) than the non-Bt hybrid. Adequate levels of N-fertility are important to MON-810 Bt hybrids not only for yield, but also to insure sufficient levels of Bt endotoxin for maximum protection from susceptible insect pests.