Based on customer orders, a nursery will produce a “batch” of uniformly raised and inoculated tree seedlings ready for eventual testing and evaluation, generally over a period of 18 months.
A uniform batch of tree seedlings will be produced on the same day, grown in the same glasshouse, produced from the same seed batch, using the same inoculum batch, inoculation procedure and growing medium.
Once the seedlings are ready to be evaluated, an independent technician is engaged by ATIA to randomly select 12 seedlings from the batch using a strict sampling protocol.
These selected representative sample seedlings are taken by the independent technician, labelled, packed, and sent to an independent laboratory where the individual seedlings are evaluated, according to prescribed criteria, including but not limited to:
- Plant condition and quality – general health and root architecture of the seedlings.
- Number and percentage of roots colonised by Tuber melanosporum.
- DNA verification of other Tuber mycorrhizae that may also be present on the root system specifically, T. indicum, T. aestivum, T. brumale, T. borchii and T. maculatum.
- Other mycorrhizal fungi found will be noted but may not be identified.
The AVSTEP evaluation results are aggregated to provide an overall assessment of the batch of trees presented for evaluation by the nursery. Once data is available and the nursery operator is satisfied with the results of the batch, the Association allocates serially numbered labels for identification of all the seedlings remaining within the batch that has passed the evaluation process.
As the evaluation procedure involves the complete destruction of the evaluated seedlings, a randomly selected sample from the same production “batch” has been evaluated, but the labelled trees remaining have NOT been evaluated. Accordingly, there remains a degree of statistical error, which is indicated by the level of confidence (confidence Index) in the test results. Purchasers of trees are advised to read their copy of the batch evaluation report and understand the results.
Data on an evaluated batch can be obtained from the nursery but can also be accessed through the Association. It is important to understand that the purchaser is acquiring tree seedlings derived from a ‘batch’ that has been evaluated based on a representative sample.
The individually labelled trees they purchase are therefore not guaranteed by the nursery nor by the Association, but they have been subjected to the AVSTEP process.
AVSTEP will inform truffle growers that for any AVSTEP labelled trees independent assessment information is available for inspection prior to purchase and a copy of this evaluation information should be a requirement of the purchase agreement between the purchaser and the nursery.