Graduate Student: Sarah Turner, Department of Horticulture, University of Wisconsin-Madison, [email protected]
Faculty Advisor: Dr. Erin Silva, Department of Plant Pathology, University of Wisconsin-Madison, [email protected]
Project Period: 2015-2016
Carrots are an important crop for many organic vegetable growers, but weed control remains a major challenge due to slow emergence and delayed canopy closure. The growth habit of carrots results in an extended critical weed free period, during which intensive and costly manual weeding is necessary for successful crop establishment. Varieties with rapid seedling growth and reduced time to canopy closure offer a potential solution to mitigate weed control in organic carrot production. However, little is known about shoot growth in carrots and additional research is needed to inform selection strategies and future breeding efforts. This project aimed to elucidate competitive responses in diverse carrot lines by observing emergence, canopy growth, and postharvest quality at different planting densities (50, 120, and 200 seeds/linear meter). Canopy height and width significantly increased with planting density, suggesting that higher planting densities may encourage competitive shoot growth in carrots and may be helpful for weed management. Although higher planting density significantly reduced emergence, the impact was negligible as the number of marketable roots at harvest was still higher than for low planting density. Results will be used to facilitate breeding efforts for improved growth habit in carrots.