Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 5, 2004
Publication Date: February 7, 2005
Citation: Williams, M.M., Boydston, R.A. 2005. Tolerance of three sweet corn hybrids to wild proso millet interference [abstract]. Weed Science Society of America. 45:83. Technical Abstract: Crop phenotypes vary widely in domestic sweet corn (Zea mays L.) production and wild proso millet (Panicum miliaceum L.) is considered one of the most problematic weeds because of herbicide ineffectiveness and crop losses due to interference. Field studies were initiated in 2004 to quantify the variation in tolerance of three morphologically-divergent sweet corn hybrids to wild proso millet interference. To maximize inference space of this work, sites were selected in major domestic sweet corn production regions, including near Prosser, WA and Urbana, IL. A split-plot experimental design was used; with commercially-available hybrids ('Spirit', 'WH2801', 'GH2547') assigned to main plots and four densities of regionally-adapted wild proso millet populations established in subplots. Sweet corn was grown under conventional production practices appropriate to each locale. Ears equal to or greater than 4.4 cm in maximum diameter were hand-picked approximately 3 weeks after silk emergence. Sweet corn yield loss was related to wild proso millet density using a rectangular hyperbola equation and parameter estimates were determined using nonlinear regression analysis. More favorable conditions for sweet corn growth were observed in WA, compared to IL, where weed-free yields averaged 34% higher. 'WH2801' and 'GH2547', both 85-day maturity hybrids, had a taller, more fully developed crop canopy compared to 'Spirit', a 67-day maturity hybrid. Greatest differences in crop tolerance among hybrids were observed in IL, where the crop was less vigorous and wild proso millet grew well. In IL, yield of 'GH2547' was unaffected by wild proso millet, whereas 'WH2801' and 'Spirit' suffered 23 and 64% maximum yield loss. In WA, maximum yield loss was 9, 14, and 16% for 'GH2547', 'WH2801' and 'Spirit', respectively. Initial results suggest selection of commercially available crop cultivars may be a useful tool in elevating the crop's ability to tolerate weed populations in sweet corn.