Investigation of blackheart in stored potatoes
Blackheart is a physiological disorder resulting in necrosis and cavitation of central tissues of potatoes. It does not occur in crops from the field and is therefore a particular problem for GB where a large proportion of the crop is marketed from store. Blackheart is a particular problem for the fresh potato industry because QC procedures cannot adequately control the defect which is undermining consumer confidence. Blackheart is estimated to account for 25-30% of consumer complaints.
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.
A Grower Guide and the final research reports for the two components of the project are provided below, along with a literature review which was produced at the start of the project.
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.
About this project
To determine the main risk factors of blackheart in order to allow improved management of crops and to minimise blackheart incidence.