Seed is a living biological product and its behaviour cannot be predicted with the certainty that characterises the testing of inert or non-biological material. The methods used must be based on scientific knowledge of seed and on the accumulated experience of seed analysts; the accuracy and reproducibility required depend on the purpose of the test. The text that follows provides standardised definitions and methods to be used in evaluating seed for transactions in international trade. For this purpose a high degree of accuracy and reproducibility is necessary. As seed moves across international frontiers, it may be tested in the laboratories of different states; it is important therefore that all laboratories should use standard methods designet to give universally the same result within an acceptable range. The text in two parts - Rules and Annexes. The Rules prescribe the objects and principles of each test, the definitions to be applied and, in general terms, the procedures and methods to be used. The Annexes amplify the definitions and describle in more detail the procedures and methods prescribed in the Rules. If the result of a test covered by the Rules is to be reported on the Association's International Seed Analysis Certificate, it is mandatory that the rules be strictly followed; any interpretation of a rule must be consistent with any amplification in the Annexe to the Chapter concerned. It is recommended that these Rules and Annexes be used as far as possible in the evaluation of seed for trade transactions within one state and for the enforcement of national laws for the control of seed quality. For these purposes International Seed Analysis Certificates are not necessary; nevertheless it should be understood that any deviation from this internationally accepted text may obstruct the free movement of seed to and from other countries. Advisory tests may be requested to assess the value of a seed lot for the particular purposes of the owner, taking into account such factors as the season, soil type and altitude in which the seed is to be sown. For such tests these Rules and Annexes provide a basis, which may be supplemented by other techniques described in the literature. The Rules and Annexes are designed for the principal crop species of the world, but apply, in principle if not in every detail, to any species of crop plant not mentioned in the text.
