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Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/12/2015 Publication Date: 7/10/2015 Citation: Williams II, M.M. 2015. Stress test: identifying crowding stress-tolerant hybrids in processing sweet corn. Agronomy Journal. 107:1782-1788. Interpretive Summary: Improvement in corn’s ability to maintain per plant yield at ever higher plant populations over the last several decades has played a major role in positioning the U.S. as the global leader of corn production. The U.S. is also the leading producer of sweet corn, and this work developed a method to quantify the extent to which this 'crowding stress tolerance' has been made in modern processing sweet corn hybrids. The method is better than traditional plant population density studies, in that crowding stress tolerance of a larger number of hybrids can be determined.The research showed larger variation in crowding stress tolerance among modern hybrids than reported previously and also identified those hybrids with superior crowding stress tolerance. The impact of this work advances the competitiveness and sustainability of the U.S. sweet corn processing industry, by 1) challenging sweet corn breeding programs to improve crowding stress tolerance in future hybrids, 2) highlighting the economic benefit of crowding stress tolerant hybrids to the vegetable processing industry, and 3) introducing the idea of planting such hybrids at plant populations higher than currently used. Technical Abstract: Improvement in tolerance to intense competition at high plant populations (i.e. crowding stress) is a major genetic driver of corn yield gain the last half-century. Recent research found differences in crowding stress tolerance among a few modern processing sweet corn hybrids; however, a larger assessment would reveal a deeper understanding of crowding stress tolerance in sweet corn. The objectives of this study were to 1) compare yield, recovery, and processor profitability of sweet corn hybrids grown under conditions of crowding stress, and 2) determine if an interaction exists between N fertilization and hybrid on crop response to crowding stress. Twenty-six processing sweet corn hybrids were grown under suboptimal and supraoptimal N fertilization at 72,000 plants ha-1, a level beyond the optimal population of the most crowding stress-tolerant hybrid identified in previous research. Results showed hybrid and N fertilization had no interactive effect on key variables of interest to the sweet corn processing industry, namely green ear mass, recovery, case production, and gross profit margin. Therefore, hybrid rankings were consistent whether the crop was N stressed or not. Relative to the poorest performing hybrid, the highest performing hybrid grown at an elevated population yielded 50% more green ear mass, 61% greater case production, and 71% higher gross profit margin. This work demonstrates a simple method to identify processing sweet corn hybrids with the best tolerance to crowding stress. Significant gains in sweet corn productivity may be realized by growing such hybrids at plant populations higher than currently used. |
