Susceptibility of Potato Cultivars to Blackspot and Shatter Bruise at Three Impact Heights

Handling potatoes can create opportunities to develop bruise resulting in quality defects that reduce the acceptability for purchase among retailers, processors, and consumers. Understanding cultivar specific bruise susceptibility can aid in developing appropriate bruise management programs. A two-year trial was conducted to examine bruise susceptibility in six commercially grown russet cultivars as affected by impact height. Russet Burbank, Ranger Russet, Clearwater Russet, Dakota Russet, Teton Russet, and Umatilla Russet were impacted using a device that dropped a 100 g steel weight from 8, 18, or 30 cm height to deliver a uniform impact on both the bud and stem end of a stationary tuber. Blackspot bruise incidence, severity and depth, and shatter bruise incidence were evaluated. Blackspot and shatter bruise were significantly influenced by impact height and tuber end in all cultivars. As impact height increased, blackspot bruise incidence, severity, depth, and shatter bruise incidence increased. There were no significant differences among cultivars or tuber ends in shatter bruise at the 8 cm impact height, but differences became evident at 18 and 30 cm impact heights. Overall, the bud end had lower blackspot bruise incidence, severity, and depth compared to the stem end for all cultivars, although the response difference between ends was dependent on cultivar. Clearwater Russet and Dakota Russet had the highest blackspot bruise incidence compared to other cultivars. Teton Russet had the lowest blackspot bruise incidence, severity rating, and depth among the six cultivars but had the highest shatter bruise incidence. This study provided insight on the importance of including more than one impact height to develop robust bruise susceptibility research protocols as well as develop cultivar-specific bruise management recommendations for the industry.