Pinking of the cut or, as it is known, "butt" end and of the ribs on lettuces is an ongoing problem for growers because it can lead to quality issues and customer complaints.
It is thought that pre-harvest environmental factors can influence the effects of post- harvest pinking in lettuce and these were investigated in AHDB Horticulture-funded project FV 413a "Lettuce: Predicting high-risk plantings to manage post-harvest pinking".
The project was led by Dr Jim Monaghan of the Fresh Produce Research Centre at Harper Adams University. Lettuce samples from seven commercial businesses were assessed for their post-harvest pinking with the findings of the study showing that butt-end pinking is more marked than rib pinking and that there is a strong correlation between the signs of rib cracking and rib pinking.
There were also significant differences in pinking between the different sites and between years on the same site. Some pinking was also shown to be internal. Work is now underway to look at how the pinking of lettuces from each of the individual sites correlates with meteorological data as well as site-specific inputs and practices.
This information will be used for the purpose of building pinking prediction models that will be used by growers to identify which crops out in the field are more likely to pink after harvest.
The modelling will help to inform harvest and post-harvest decision-making concerning "at risk" lettuce plantings. Dr Monaghan is working with Professor Xiangming Xhou (East Malling Research) to build the models, which will be made available to growers when completed.
The final project report will be made available via the AHDB Horticulture website at horticulture.ahdb.org.uk.
For details on all AHDB Horticulture activity, see horticulture.ahdb.org.uk