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.