The revision consists of three different parts:  

1. The addition of Section 4.6.4 Assessment of fresh seed. This new section gives a flow chart with step-by-step instruction on the assessment of ungerminated seeds at the end of a germination test.
2. The revision of Appendix 5: Illustrative Standard Operating Procedures (SOP), to include a flow chart that gives step-by-step instructions regarding the calculation of the water-holding capacity of growing media.
3. The addition of an Appendix 6: The 50% rule for the evaluation of foliated cotyledons. This gives guidance on the evaluation of seedlings with damaged, necrotic, decayed and discoloured tissue. Guidance on when actual cotyledon size or estimated cotyledon size should be used when applying the 50% rules is provided, as well as diagrammatic and photographic examples of the application of the 50% rule. This Appendix should be of particular use to those evaluating seedlings with physiological necrosis.

The amendments included in the Handbook are for guidance purposes only. They illustrate procedures that the ISTA Germination Committee considers to meet the requirements of the ISTA Rules and the ISTA Seed Testing Laboratory Accreditation Standard. Accredited laboratories are expected to comply with the requirements and to adopt similar procedures in their own laboratories.