Blackspot bruise susceptibility of potato tubers during growth and storage determined by two different test methods

Blackspot bruise susceptibility of potato tubers of the cultivar Oleva increased during growth but was stable during storage independent of the type of impact method employed. With the pendulum test method, blackspots were observed in the tubers of the cultivar Dali during the final growth period and early in the storage period, whereas no blackspots were observed when they were treated on a shaking table. The relationships between blackspot susceptibility and dry matter content, size of starch granules, concentration of N, K, Mg and Ca, membrane leakiness and turgor pressure in the tuber cortices fluctuated according to cultivar, developmental stage of the tuber and the test method employed. The study underlines the importance of choosing a test method, which closely simulates the impact conditions of commercial situations, since the relationships between blackspot susceptibility and various physiological parameters of the tuber were found to change according to the impact condition employed.