M A Y J U N E 2 0 1 6 POTATO GROWER 11 Seed Potato Certification Service were edited at the meeting in Kimberley and will be submitted to the UNECE Seed Potato Sections annual meeting in September in Geneva Switzerland. A version of a draft of each of the two guides can be found at httpwww.unece.org index.phpid41760. Considering US seed potato certifi- cation standards with respect to the UNECE Seed Potato Standard US standards are generally within the tolerances of the UNECE Standard. There is an exception. Registration and listing of varieties for certifica- tion is a requirement in the UNECE Standard and all countries but not in the US which is why the US still has a derogation. The certification guide describes that only varieties accepted by the inspection service may be certified including the ones still under registration or from other countries. The first applicant of any new variety must have a ref- erence sample and a description available to the inspection service possibly through the variety rights office. Another issue in international trade is that seed sizes are described in millimetres of a square sizer with a maximum difference of 20 mm unless the buyer and seller agree to deviate from this requirement. The definitions of minimum and maxi- mum size differ from the US size requirements. The tuber inspection guide defines minimum and maxi- mum as A tuber is within the maximum size when the inspector can drop the potato through the sizer when the longitudinal axis is at right angles to the sizer. A tuber is considered above the minimum size when the tuber is held by the sizer regardless of the position of the tuber. The US requirements mention diameter in the defini- tion of sizes and for minimum size do not recognize that a potato is held by the sizer when lying flat on it. The definitions are close but are said to create disadvantages. Risk-based inspections The Dutch industry and certifica- tion service held discussions to see where a more or less frequent inten- sity or frequency can be applied to field and tuber inspections accord- ing to the estimated risk. Inspection should be carried out in higher frequency and intensity where it has been established that there is higher risk that lots will not be within tolerance. Developing the standards for identifying the level of risk is the greatest chal- lenge. True Potato Seed Listing and marketing of potential varieties derived from true potato seed are under discussion in the European Union because no regu- lations covering the marketing of true potato seed and its progeny are in place. Without the requirement to list varieties for certification that Large greenhouses of Wesgrow in Christiana South Africa.