Title: Canopy Variation among Three Sweet Corn Hybrids and Implications for Light Competition Authors
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 2, 2006
Publication Date: October 1, 2006
Citation: Williams, M., Boydston, R.A., Davis, A.S. 2006. Canopy variation among three sweet corn hybrids and implications for light competition. HortScience. 41:1449-1454. Interpretive Summary: . Weeds cause serious losses in sweet corn yield and quality despite extensive use of herbicides. A non-chemical approach to reducing the negative affects of weeds on some agronomic crops is to use more competitive cultivars. Few have investigated the potential for competitive cultivars in sweet corn, despite apparent differences among cultivars in canopy architecture. In order to identify competitive sweet corn cultivars, we must first determine the extent to which cultivars vary in canopy properties such as leaf area index, light interception, and height. We found large variation among cultivars in canopy properties, with one hybrid (Spirit) producing a considerably shorter, less dense canopy than other hybrids (WHT2801 and GH2547). Large leaf area index distributed high in the crop canopy will likely confer greater weed suppressive ability relative to low leaf area index or short-stature plants. We hypothesize some sweet corn cultivars are more competitive than others. The impact is that we are one step closer to identifying non-chemical approaches to improving weed management in sweet corn.
Technical Abstract: Research in dent corn has found significant variation in crop/weed competition for light among hybrids. However, little has been published on the extent of variation in sweet corn competitive ability. Field studies were conducted under weed-free conditions to quantify canopy development and light environment among three sweet corn hybrids and to determine associations among canopy characteristics to crop yield. An early-season hybrid (Spirit) and two mid-season hybrids (WHT2801 and GH2547) were grown at experimental sites located near Urbana, Illinois and Prosser, Washington in 2004 and 2005. Maximum leaf area index (LAI) and intercepted photosynthetically active radiation (PAR) was typically highest for GH2547 and lowest for Spirit. Most differences in vertical LAI among hybrids was observed above 60 and 150 cm in Illinois and Washington, respectively, with WHT2801 and GH2547 having leaf area distributed higher in the canopy than Spirit. Both number and mass of marketable ears were positively correlated with maximum relative growth rate (correlation coefficients 0.60 to 0.81), leaf area duration (0.68 to 0.79), total LAI (0.56 to 0.74) at R1, and intercepted PAR (0.74 to 0.83) at R1. Differences in canopy properties and interception of solar radiation among Spirit, WHT2801, and GH2547 lead us to hypothesize that variation in weed suppressive ability exists among hybrids. Future testing of this hypothesis will provide knowledge of interactions specific to sweet corn useful for developing improved weed management systems.