The certification process for growing seed potatoes in Canada is designed to ensure seed stocks remain healthy, pure and true-to-variety. Understanding how the replication process works and investing in an early generation of seed potatoes can make a huge difference to a commercial grower’s success.
Seed potato production starts out in a sterile lab, where disease-free tissue samples of a given variety are cultured to develop the first or ‘nuclear’ generation of seed potatoes. These earliest generation tubers are grown out in fields to produce a pre-elite (PE) generation. From there, each subsequent grow out moves the resulting generations of tubers further down the classification scale. The ‘flush through’ system limits disease build-up and impurities since seed potatoes can never be more than seven generations removed from the nuclear generation.
Throughout the replication process, field inspections and lab testing ensures each generation meets rigorous health and purity requirements. That said, the permitted maximum level of disease increases as the distance from the nuclear generation grows.
Canadian Food Inspection Agency’s Canadian Seed Potato Field Certification Program
|Maximum Tolerance on Final Inspection|
|Seed Class||Total Virus (%)||Total Blackleg and Wilts (%)||Total Varietal Mix (%)|
|Elite I (E1)||0||0.1||0|
|Elite II (E2)||0.1||0.2||0|
|Elite III (E3)||0.2||0.3||0.05|
|Elite IV (E4)||0.3||0.5||0.1|
The risk-reward ratio favours earlier generation seed for both purity and disease risk. Think of each generational replication being like a photocopy of the previous generation. As generations get further removed from the nuclear original, replications become diluted and distorted, decreasing the tubers’ ability to achieve the variety’s true potential for yield, health and consistency.
Currently, our industry is trending towards higher quality, earlier generation seed. Whereas many commercial growers previously purchased E4 or Foundation seed, the majority of growers are now opting instead for E2 or E3 seed. For the long-term success of individual growers and the industry as a whole, we encourage all growers to adopt this best management practice. Given potatoes’ high cost of production, using the best quality seed just makes good economic sense.
We also highly recommend seed growers put effort into educating their buyers about the value of earlier generation seed. After all, customers’ improved success will ultimately translate into direct benefit for the seed grower as well.