In this project I will continue to assess downy mildew (DM) resistant cucumber seedstocks, with intensified focus on evaluating and advancing the lines I selected in 2018 from Common Wealth Seed Growers’ DMR breeding population. This population performed very well in our 2018 trials, having the highest yield and best foliage ratings in the DM trial, and above average performance in the bacterial wilt (BW) trial. Because I am increasing focus on cucumbers, I am not including melon research in this year’s proposal.

2019 DM variety trials will take place at University of Massachusetts, North Carolina A&T University, University of Mount Olive, and four farms around the Southeast U.S. Trials will evaluate yields in high-DM conditions, rate the impact of DM on foliage, and provide feedback on fruit quality and marketability. On our farm I will conduct a BW-focused trial in early-planted, low-DM conditions. I will conduct a late-season breeding trial of our selected slicing and pickling cucumber lines.

DM is a central limiting factor for cucumber production in the eastern U.S, especially for midseason and late season crops. Organic farmers in particular have limited options for controlling the disease. Development, testing and release of resistant varieties is essential to solving the problem. Controlling BW, and the striped cucumber beetles that transmit it, is also a significant and costly production challenge for organic cucumber growers. While DM resistance is the central focus of my work, I want the DMR lines developed to show well above average BW resistance.