Investigation of blackheart in stored potatoes

The project had two components: a PhD studentship project at Cranfield University (CU) and trials at Sutton Bridge Crop Storage Research (SBCSR). The trials led to the development of a method to induce blackheart which can be used on a commercial scale to assess the likelihood that stocks will develop blackheart symptoms. The method was also used to select stocks for more detailed biochemical and physiological studies (as part of the PhD studentship). Not all tubers within a stock designated as blackheart susceptible will ultimately develop symptoms of the condition and the number of tubers which can be studied using the detailed techniques is limited. As a result, it has not been possible to identify reliable biomarkers which could be used to predict the risk of blackheart developing. The techniques have highlighted the variation in the occurrence of metabolites between different stocks and have provided the first indication of the pathways and particular molecules that may warrant further study.

Risk factors 

Blackheart is associated with oxygen depletion so it can be linked to factors across a range of a growing, storing and processing conditions. Any that increase the respiration rate, or limit gas movement through the potato tuber, should be avoided. Here are some high risk factors:

• Very low storage temperature. Avoid storage conditions below 3°C. But don’t forget, even at an average storage temperature of 3.5°C, parts of the store may be significantly colder.

• Condensation. Avoid rapid changes in temperature that create a condensation layer. This can limit the rate of gas movement in and out of the potatoes (as well as encourage disease).

• Ethylene. If ethylene is used, always ensure its initial introduction is very gradual (ramped) and in accordance with recommendations.

• Variety. Susceptibility to blackheart varies between varieties. Recent experimental work focused on Maris Piper and Marfona. Both were susceptible. No data is available for other varieties so further testing is needed to establish their susceptibility.