Handle with care Research probes shatter bruise potential of Clearwater Russett By Nora Olsen, Rabecka Hendricks and Jeff Miller Clearwater Russet is a relatively new variety which has good processing characteristics and high proportion of marketable potatoes. However, it has been shown to be highly susceptible to Fusarium dry rot. Fusarium dry rot can be a concern for seed decay and for the commercially stored crop. Some growers have reported the need to increase the planting rate by decreasing seed spacing because of the higher risk of seed decay prior to plant emergence. In addition, storing Clearwater Russet potatoes has been challenging due to the greater risk for dry rot decay. Specific industry-driven questions have centered on management options to minimize seed decay and the need to clarify if there is a relationship between seed decay and harvested tuber decay. There is also a need to establish recommendations for seed handling and postharvest treatment options and to identify the potential impact of plant maturity on shatter bruise susceptibility. Shatter bruises provide entry points for Fusarium dry rot and subsequent decay in storage. The University of Idaho and Miller Research set out to find answers in a two-year study funded by the Northwest Potato Research Consortium with four specific objectives: 1. Identify whether Clearwater Russet seed lots differ in Fusarium dry rot potential and if this will affect seed decay and infection of harvested tubers. 2. Determine if maturity of the crop influences shatter bruise potential. 3. Investigate current seed treatments in the control of Fusarium dry rot seed decay. 4. Explore post-harvest treatments to effectively mitigate dry rot in storage. This article focuses on the second objective and how time after planting can affect the susceptibility to shatter bruise and indirectly affect the risk of Fusarium dry rot decay in storage. Two locations were used for the study: Miller Research in Rupert, Idaho and the University of Idaho Kimberly Research & Extension Center in Kimberly, Idaho. At 22 Spudman * April 2024http://spudman.com/buyersguide