Seeds come in all shapes and sizes, ranging from the coconut -one of the largest of the plant world, to one of the smallest -tobacco and its close relative the petunia, both having about 500,000 seeds to the ounce! Potato seed is not really a true seed, as it is not the result of pollination and the transfer of pollen. But rather, it is a storage organ of the potato plant, and known as a tuber, filled with starch. Therefore, the potato crop is asexually propagated -or, maybe better understood as being cloned.
While Prince Edward Island is the smallest of Canadian provinces, it is the largest potato-producing province, growing fully 25% of the potatoes in Canada; and the industry, is worth in excess of a billion dollars to the Island economy, each year. Although it exports a great deal of seed potatoes, New Brunswick is Canada’s largest exporter of seed stock.
Not all potatoes are ‘created’ equal. Some farms grow potatoes for the purpose of ‘seed’ production, as opposed to table potatoes. In order to supply the farming community with enough seed -or, planting stock, the supply of seed needs to be ‘bulked-up’, and that means replanting the harvest, repeatedly. And this, must be done with strict attention to phytosanitation (plant health).
Potatoes are a bulky crop to handle and harvest -from start-to-finish. On average, it requires about 1,000 pounds of seed potatoes to plant an acre-field when using 36” row centres, and 12” between plants. The resulting harvest should be about ten fold in yield. A 3-ounce seed piece is ideal, but can easily range between 2-4 oz. as the mechanical cutting procedure of seed potatoes, is imprecise.
Seed potatoes can be planted whole, but more commonly, whole potatoes are cut into pieces containing at least one ‘eye’, or growing point. Each potato seed piece, when planted, will establish a new plant as the eye sprouts and sends up new stems and leaves -and because it is cloned, the seed piece will be ‘true’ to its parent plant, in all its genetic make-up.
The greatest concern in producing potato seed stock, is to ensure that it is disease-free. Insects such as aphids and leaf-hoppers, for example, serve as vectors for disease transmission. Once a plant is infected with virus, it is impossible to eradicate, and yields can suffer, accordingly.
From early days, New Brunswick (N.B.) was settled by Irish, Scotch, and French immigrants, and potatoes were used as an important dietary staple. And, from that time onward, N.B. has continued to develop the seed potato industry. This province has developed strict phytosanitary (plant health) regulations and certification standards. It is a world-leader in research and development, and is recognized world-wide as a system that ensures high quality seed stock.
The Canadian Potato Variety Repository is housed at the Plant Propagation Centre, located in Fredericton, New Brunswick, and consists of an impressive collection of over 400 varieties; it is the go-to source for disease-free potato seed stock, from all over the world.
Located in Kincardine, New Brunswick, the Bon Accord Elite Seed Potato Centre, produces nuclear stock for the Pre-Elite, and Elite classes of seed potatoes. In order to be absolutely sure that potatoes are disease-free from the outset, tissue culture is used, and about 300,000 plantlets are produced every year. From here, they are propagated and planted, and in turn the harvest is replanted for several years to bulk up the crop -in the various classes, for use by commercial potato growers.
Each time a crop is replanted -and it can be done several times in order to create sufficient stock, there is an increased risk of infection from virus and other diseases. The first harvest is referred to Elite 1 seed, followed by Elite II, Elite III, Elite IV, and finally, Foundation Seed ...being the cheapest to plant, but potentially the least desirable given chance of disease.
However, the Canadian Plant Inspection Agency does keep close watch to ensure the highest quality standards.
Like most crops, the first-to-market commands the highest prices. And potatoes are no different. Of course, selecting well-drained land, sandy soils, and a south-facing slope (or aspect) will warm-up the soil faster, and allow potatoes a head-start. Potato seed pieces must become physiologically mature before the eyes begin to sprout -this can be accomplished either before or after planting. However, if in the field, climate conditions can affect the performance of the crop, and retard physiological maturity.
For the small grower, market gardeners can enhance the early development of seed pieces by exposing them to light and warm temperatures (physiological maturation). This is called ‘greening’ (budding or sprouting), and does require some management, but more to be said about that at another time.
In addition, medium-sized potatoes planted whole, will generally give higher, earlier and better quality yields. This process can be further enhanced when the potatoes have been conditioned (physiologically enhanced) before planting -otherwise, this process has to take place in the field, and will largely be dependent upon weather and soil conditions. All seed -either whole or cut, will ‘feed’ off the tuber until it develops its own roots. Whole seed is less likely to rot in cold weather, and not as exposed to soil-borne diseases.
Seed potatoes to be planted whole, should be about the size of a medium-sized chicken egg, but also be selected from a previous crop, that was vigorous to begin with. When planting at 3-foot row centres and 14” apart within the row, about 20 bushels of seed potatoes will be required. Whole seed also gives a more even crop, resulting in smoother and same-sized tubers.
Norfolk County and the surrounding region, has an extensive potato growing industry, and the growers have the production practices fine-tuned to ensure consistent and high-quality yields, all of which should be commended. The potato was once considered to be a ‘lowly’ crop, and only food fit for peasants. But now, given increased demand, potato production is big business, and the grower-community is prospering as a testimony to their hard work and dedication. Or, just maybe, it is because they see ‘eye-to-eye’!