S | (1) The seed potatoes must be derived from— (a) a stock of pre-basic seed potatoes or a stock which was graded as [GB grade S or equivalent grade] of field generation four or less in the year preceding the planting of the crop; or | (i) Deviations from variety and type or different variety, including groundkeepers - 0.1% |
| (b) such other seed potatoes as are notified in writing by the Secretary of State as being acceptable to the Secretary of State. | (ii) Potato viruses Y, A and leaf roll either individually or in combination - 0.02% |
| (2) The maximum number of field generations, including previous generations at pre-basic grade, is five. | (iii) Total virus including other mosaic viruses and potato viruses Y, A and leaf roll - 0.2% |
| | (iv) Blackleg - 0.1% |
SE | (1) The seed potatoes must be derived from—
(a) a stock of pre-basic seed potatoes or a stock which was graded [[GB] grade S, [GB] grade SE or [equivalent grade]] field generation five or less in the year preceding the planting of the crop; or
| (i) Deviations from variety and type or different variety, including groundkeepers -0.1% |
| (b) such other seed potatoes as are notified in writing by the Secretary of State as being acceptable to the Secretary of State. | (ii) Potato viruses Y, A and leaf roll either individually or in combination - 0.1% |
| (2) The maximum field generations, including previous generations at pre-basic or basic grade, is six. | (iii) total virus including other mosaic viruses and potato viruses Y, A and leaf roll - 0.5% |
| | (iv) Blackleg - 0.5% |
E | (1) The seed potatoes must be derived from—
(a) inside the protected region, a stock of pre-basic seed potatoes or a stock which was graded as [[GB] grade S, [GB] grade SE or [equivalent grade]] in the year preceding the planting of the crop;
| (i) Deviations from variety and type or different variety, including groundkeepers - 0.1% |
| (b) outside the protected region, a stock of pre-basic seed potatoes or a stock which was graded as [[GB] grade S, [GB] grade SE, [GB] grade E or [equivalent grade]] field generation six or less in the year preceding the planting of the crop; or | (ii) Potato viruses Y, A and leaf roll either individually or in combination - 0.4% |
| (c) such other seed potatoes as are notified in writing by the Secretary of State as being acceptable to the Secretary of State. | (iii) Total virus including other mosaic viruses and potato viruses Y, A and leaf roll - 0.8% |
| (2) The maximum field generations, including previous generations at pre-basic or basic grade, is seven. | (iv) Blackleg - 1.0% |