Potatoes New Zealand

Seed Potato Certification — Certification Rules

Seed potato certification rules are established by the New Zealand Seed Potato Certification Authority. There have been a number of changes to scheme rules following the 2005 review of the operation of the certification schemes.

A major outcome of the review was that the "Open" and "PT"® schemes have been aligned. There are now common generation numbers and the tolerances for each generation are the same (where these differed between the two schemes, the lower tolerance has been established in the new "pyramid programme".

Pyramid Programme generations and tolerances

Tolerances Permitted	G2	G3 (Pre-Basic, SE)	G4 (Basic, E)	G5 (1st Gen, Open A)	G6 (2nd Gen, Open B)
Maximum Virus PV X, Y, S, PLRV etc	0.05 (1 in 2000)	0.05 (1 in 2000)	0.05 (1 in 2000)	0.1 (1 in 1000)	0.2 (1 in 500)
Maximum Rogues (off types)	0	0	0	0	0.025 (1 in 4000)
Maximum Bolters	0.1 (1 in 1000)	0.1 (1 in 1000)	0.1 (1 in 1000)	0.2 (1 in 500)	0.5 (1 in 200)
Maximum Blackleg E. Carotovora Maximum Wilt Verticillium Wilt	0.1 (1 in 1000)	0.1 (1 in 1000)	0.1 (1 in 1000)	0.1 (1 in 1000)	0.5 (1 in 200)

Prior to the 2006-7 season, the Authority adopted a new rule (Rule 26) requiring that growers "maintain a Quality Assurance system for monitoring the quality and certification standard of seed tubers during grading". To assist with this process the Authority has developed a "Grower guide to seed potato tuber inspection (PDF) ". This guide outlines a procedure that growers can follow to monitor seed quality during grading, take corrective actions, and record results of inspections.

The review also established the competencies required by inspectors and administration staff.