# The Seed Potatoes Regulations 1991, Paragraph 5


Seed potatoes shall not be classified as basic seed potatoes unless the immediately succeeding crop produced therefrom is likely to contain–
(a) not more than 0.25% by number of growing plants which deviate from variety and type of which not more than 0.1% shall deviate from variety; and
(b) not more than 4% by number of growing plants which show symptoms of either severe or mild virus diseases attributable to infection in the mother crop.

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Source: https://www.legislation.gov.uk/uksi/1991/2206/schedule/1/paragraph/5 (the official version)
Page: https://openlegislation.uk/seed-potatoes-regulations-1991/schedule-1/paragraph-5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.