P1901285: AHDB Research Call - Potato Desiccation: Questions and Answers
A: We expect contractors to devise a suitable mechanical treatment to assess skin set, an example of which can be found at this link: https://potatoes.ahdb.org.uk/sites/default/files/publication_upload/20061%20skin%20set%20and%20bloom%20Final%20Report%20R222.pdf
Rumble barrels are widely used but an applicant can propose an alternative. Use of a grader is not required before assessing skin set.
A: Either machine or hand planting is acceptable, but the approach should be uniform within one site.
A: Shortly before treatment application, take a random sample across the trial and grade with a 5mm riddle. At harvest grade each plot with a 5mm riddle. The size grades of each treatment will be compared with the single pre-treatment sample.
A: Size grading of trials where passive bulking is being assessed (seed trials) will be by 5mm grades. AHDB will consider 10mm grading for the ware trials.
A: Yes. If only one assessment is done, the risk of missing treatment differences in time to skin set is too great.
A: Visual assessment on a per plot basis.
A: The protocol in the call states that vascular browning should be assessed by cutting 50 tubers per plot at harvest. In a change to reduce workload, this cutting of tubers at harvest can be omitted. Vascular browning should be assessed at the same time as rots, after 3 months in store.
A: We have considered the option of a commercial flail and also the use of a hedge cutter / strimmer for the flail treatments. We agree the ideal would be to use a flailer but with the constraints of the trial and to be able to include the number of treatments the use of a strimmer is deemed suitable. We also checked with other agronomists and they agreed that this is a method that would be suitable for simulating flailing.
A: The final application timings have not been fully finalised and are subject to change. It was felt that spraying on the same day as the flail maybe a strong test for the treatments.
A: Treatment 11 on the protocol includes a 3rd application, for the seed crop trials. As with point 2, final timings and treatments have not been finalised and further additional applications may be considered depending on the results seen following earlier applications.
A: The treatment 1 control was designed to reflect current practice. We were advised that such practice does not normally include use of Ranman Top with the first Reglone application. This could be altered to provide uniformity across the trial.
A: We are willing to consider either option with a preference for machine planted. Uniformity at the site is considered an important part of trial set up.
A: The EPPO guideline for potato desiccation this suggests 100 tubers and therefore we are following these guidelines.
A: At this point we haven’t included stolon detachment as an assessment as we were guided that skin set was relevant. Yes I agree stolon detachment would be an interesting characteristic to look at and depending on available budget we may be able to add this to the protocol.
A: Post storage assessments are included to see any effects on the harvested seed which we have been told is of significant interest. As mentioned above there is a third treatment in the seed trial, and the treatment list is still open for potential additions.
A: As the scope of the work depends on the number of trials sites being undertaken by a single contractor, and because there are two aspects to the work i.e. the scientific coordination and the implementation on site, it was not feasible to include an indicative budget on this call. Price and value for money will both be included within the scoring criteria. Potential contractors should consider the part of the project for which they wish to tender, and calculate their costs to achieve the required protocol.