At harvest prediction of the susceptibility of potato varieties to blackspot after impact over long-term storage

The paper presents a prediction method of the susceptibility blackspot damage after impact of potato varieties for three- and seven-month storage of potato tubers at a temperature of 4 °C based on the geometric parameter of the microstructure of tuber parenchyma determined at harvest. Similar sized and shaped potato tubers of twenty eight cultivars harvested in 2012 and 2013 were analysed. Analyses of the tuber parenchyma microstructure were carried out using an optical confocal microscope for ten tubers of each variety. Cylindrical samples with a thickness of 1 mm and a diameter of 10 mm were collected from the perimedullary zone. Microscopic images of the structure were analysed. The size parameter of the cell cross-section surface area was determined two days after harvest, and the susceptibility of each variety to blackspot after impact was assessed after three and seven months of storage. The mean post-harvest size of the tuber parenchyma cells and the susceptibility to blackspot during storage are related. Tubers of varieties with smaller cells of the perimedullary zone tissue exhibited greater blackspot susceptibility during storage.