Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2008
Publication Date: 4/1/2009
Citation: So, Y.F., Williams, M.M. II, Pataky, J.K. 2009. Wild-proso Differentially Affects Canopy Architecture and Yield Components of 25 Sweet Corn Hybrids. HortScience. 44:408-412. Interpretive Summary: Crop tolerance (CT) to weed interference is the ability of the crop to endure or avoid competitive stress from weeds without substantial reduction in growth or yield. An increasing prevalence of herbicide resistant weeds and a growing organic market in several crops, including sweet corn, have fueled interest in CT for meeting weed management objectives. Of the 25 hybrids tested for CT, no hybrid escaped yield loss due to weed interference; however, some hybrids endured wild-proso millet interference considerably better than others. The hybrids with the greatest CT were dominated by later-maturing processing-market hybrids. Also, early-maturing hybrids were often less tolerant to wild-proso millet interference than later-maturing hybrids. Wild-proso millet interference had little effect on crop height and leaf angle, suggesting weed interference was insufficient to induce major changes in the crop canopy architecture. The impact of this work is that it shows competitive ability of hybrids would be valuable information in weed management decision making, particularly where weed control options are limited, such as in organic production systems.
Technical Abstract: Knowledge of cultivar-specific information on crop tolerance (CT), the crop’s ability to endure competitive stress from weeds, has garnered recent interest in organic crop production. Twenty-five commercially-available sweet corn hybrids from nine seed companies were grown in the presence and absence of wild-proso millet (Panicum miliaceum L.) to 1) quantify tolerance in crop growth and yield to weed interference, 2) determine associations between tolerance in crop growth and yield, and 3) identify hybrids differing in tolerance to weed interference. Despite large differences in morphology among hybrids, canopy development was minimally affected by weed interference. In contrast, wild-proso millet interference reduced ear number from 11 to 98% and ear mass 24 to 82%, depending on the hybrid. A hybrid’s ability to make small growth adjustments in the presence of wild-proso millet appeared to have no relationship to yield tolerance. Least competitive hybrids were ‘ACX1413’, ‘Quickie’, ‘Spring Treat’, ‘Sugar Buns’, and ‘Optimum’ and most competitive hybrids were ‘Code128’, ‘Coho’, ‘El Toro’, ‘EX 8716622’, and ‘Legacy’. Although some exceptions were observed, in general, the processing/longer-maturity hybrids were more competitive with wild-proso millet than the fresh market/earlier-maturing hybrids.