Impacts of <i>S</i>-Metolachlor Application Timing on Sweetpotato Growth and Development
Impacts of <i>S</i>-Metolachlor Application Timing on Sweetpotato Growth and Development作者机构：Department of Plant and Soil Sciences 117 Dorman Hall Mississippi State University Mississippi State MS USA Pontotoc Ridge-Flatwoods Branch Experiment Station North Mississippi Research and Extension Center Pontotoc MS USA USDA UVB Monitoring and Research Program Natural Resource Ecology Laboratory and Department of Ecosystem Science and Sustainability Colorado State University Fort Collins CO USA
出 版 物：《American Journal of Plant Sciences》 (美国植物学期刊（英文）)
年 卷 期：2019年第10卷第5期
页 面：780-795页
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
主 题：Adventitious Root Development Growth Herbicide Phytotoxicity Injury Marketable Storage Roots Sweetpotato
摘 要：S-metolachlor is used to control/suppress yellow nutsedge, annual grasses and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when excessive rainfall occurs within 24-h after application. A greenhouse study was conducted to determine the effect of S-metolachlor application timing on sweetpotato growth and development. S-metolachlor treatments (0 and 1 kg·ha-1) were applied over-the-top at 0, 5 and ten days after transplanting (DAT) and a simulated rainfall treatment delivered 25 mm of rain, 51 mm·h-1 intensity, immediately after herbicide application. Plants were harvested at 5, 10, 15, 20 and 80 DAT. During the first four harvests, roots were scanned and analyzed with WinRHIZO-Pro image analysis system to estimate root number, length, volume, and surface area along with aboveground growth parameters. At the final harvest, plant growth and biomass components, and quality of storage roots were recorded. Plants treated with S-metolachlor on day 0 and 5 DAT were significantly less than those of 10 DAT and untreated control for all measured parameters for the initial 20 days of plant growth. Even though vine length, leaf number, stem biomass, and total storage roots were not different among the treatments at 80 DAT, all other plant components and total biomass production and leaf area development for plants treated at 0 and 5 DAT were significantly (P 0.05) less than from those of 10 DAT and the untreated control. Marketable storage root conversion efficiency declined by 18% and 16% for plants treated at 0 and 5 DAT, respectively, relative to the untreated check. These results indicate that delaying S-metolachlor application to 10 DAT will be less damaging to sweetpotato growth and development, particularly marketable storage roots and yield.
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