There is a lot of diversity in potato production from coast to coast in Canada, be it varieties, markets, planting and harvest dates, and growing conditions.
However, one thing that all growers have in common is the need for high quality seed. There are myriad factors that go into making a high-quality seed lot, too many for one agronomy article. Many of these factors are set before you take possession of your seed, like physiological age, virus level, other diseases and tuber size. Nonetheless, there are many factors to consider after you take possession of your seed that play a significant role in whether your crop will be able to reach its yield and quality potential.
Receiving/Storing Seed:
After taking possession of their seed, take care to ensure that seed is being stored in buildings that have not been previously treated with CIPC. John Walsh, a researcher with McCain Foods in New Brunswick, has shown that even tiny amounts of CIPC residue from storage surfaces can reduce yield potential in seed stored temporarily in those buildings. Steam cleaning can help to reduce CIPC residue, but storing seed in storages with no CIPC history is ideal. In addition, ensure adequate ventilation through your seed after delivery, with lots of air and as low as possible pile heights to reduce the potential for pressure bruising and the spread of tuber diseases like Fusarium dry rot and bacterial soft rot.
Seed Cutting:
Increasingly, we see evidence that larger seed piece size is associated with larger yields. While this may require more cwt of seed per acre at planting, this expense is more than compensated through more even emergence and improved yields on most varieties. The single best thing that a grower can do to improve the yield potential of their seed lot is to eliminate those seed slivers 1.5 ounces and smaller after cutting.
On most varieties, these seed pieces are more likely to have set rot, a lack of viable eyes, and reduced yield potential. Eliminating these small, low-potential pieces will go a long way to tightening the distribution of seed piece size, which in turn will help you land on the right spacing to achieve consistent emergence.
If you are cutting and storing seed ahead of planting, give yourself enough time (10-14 days ideally) for that seed to suberize before heading to the field. Local research in PEI has shown that several varieties respond better to pre-cutting, especially varieties known to be susceptible to soft rot or blackleg; however, this advantage is not universal to all varieties and growing regions.
Regardless of when you cut, ensure that seed is warmed up before cutting and use sharp knives to avoid jagged cut edges, as these are ideal breeding grounds for soft rot bacteria. Keep your knives frequently cleaned and disinfected!
Bruise Reduction:
A fundamental key to seed handling is bruise reduction. Carefully examine all parts of your seed handling system, including the set cutter, treaters, conveyors, elevators, trucks, planter loaders and planters to minimize drop distances and cushion impact surfaces. Previous research in the USA has shown that drops of six inches or more onto hard edges or corners will cause bruising 100% of the time. Ensure that all members of your seed handling team make minimizing drops a priority, as bruises are a great entry point for seed decay pathogens, in addition to the negative physiological effects of bruise.
All my best to Canadian potato growers as they get ready to plant another season’s promise in the ground!
