Late season tuber development and bruise susceptibility

Wednesday, July 28, 2021
1:25 PM - 1:45 PM

There are multiple physiological, agronomic, and environmental factors associated with potato bruise susceptibility. Late season tuber development could impact the risk for bruise development by influencing both specific gravity and maturity. The objective of this study was to examine bruise susceptibility of Russet Burbank potatoes during the latter part of the growing season and at harvest. A 5-plant sample (3 replications) was hand-dug weekly starting 8 weeks (early August) prior to final harvest (late September) in 2019 and 2020. Mechanical vine kill occurred at week 6. A 15-tuber subsample (142 to 510g) was selected from each harvested sample. Specific gravity was measured. Tubers (12.8°C) were impacted with a 100 g steel weight dropped 18 cm to deliver two individual impacts on the stem and bud end of a stationary tuber and assessed for bruise susceptibility (blackspot bruise incidence, severity, depth, and shatter bruise incidence). Blackspot bruise incidence was significantly lower at final harvest (81%) than previous weeks (88 to 99%). Blackspot bruise severity and incidence decreased on the bud end as the plants and tubers matured, whereas the stem end maintained higher severity and incidence levels during this time period. Shatter bruise incidence was higher on the bud end compared to the stem end. Shatter bruise incidence on the bud end decreased from 41% to 9% as the plants and tubers matured, but weekly stem end incidence remained at 1%. Specific gravity remained similar over the 7 weeks prior to harvest (averaging1.076) but was significantly higher than the initial sample in early August (1.069). Late season tuber development reduced bud end shatter bruise susceptibility but had minimal impact on blackspot bruise susceptibility prior to harvest. Physiological factors may have contributed to the decreased shatter and blackspot bruise susceptibility at harvest.
Extension, Production, and Management