By Harry Brook
As spring approaches, many people have their crop varieties lined up, germination tested and cleaned. For those who are looking for the latest and greatest, it might be a good idea to review the factors that should be considered when choosing a new crop variety.
Front and centre is almost always yield. And why not? That’s how you’re paid. However, don’t be swayed by a 2 to 5% improvement in yield. Those low numbers are not statistically significant unless tested many times. In the variety trials they list the station years a variety has been tested. The greater the number of station years a variety has been tested, the more likely your chosen variety will really be an improvement. You often see a new variety showing much higher yields when first tested, but over time, the yield bump tends to decline. Pay attention to station years.
Maturity rating is important. There is a direct link between length of maturity and yield. However, in the marginal areas around the province where the growing season is short, you can plant yourself a huge headache in the fall with an early frost or poor harvest conditions. Be realistic about the maturity rating. Differences in growing seasons from year to year can be extreme. In the 1930s, we had at least one year with a frost-free growing season of less than 90 days.
If you use a simple, two-crop rotation, you’d better pay attention to disease resistance. Growing the same crop frequently causes greater disease pressure. It becomes important to have good disease packages in the variety. Luckily, our plant breeders always work hard to incorporate multiple genes for resistance to a wide variety of diseases. For clubroot in canola, for example, they first found resistance in several lines of field mustard, black mustard and wild cabbage. The problem with resistant genes is that there is a limited number of sources for resistance. Continued growing of a crop with one or two genes for resistance will quickly lead to those genes being overcome by the disease organism. Resistant genes, like any other tool in variety development, need to be used carefully to prevent resistance.
What the crop is being grown for can have a bearing on the crop variety. With barley, is it grown for feed, forage or malt? If for forage, you want lots of growth and plenty of leaf material. Feed barley is all about high yields and heavy bushel weights. Malt barley needs to have yield and low proteins.
Seed size is a particular concern in peas. In yellow peas CDC Prosper has a thousand kernel weight of 146 grams. Compare that to AAC Delhi at 288 grams. If you seed for a target plant population of 7 to 9 plants per square foot, with germination being identical, you’d have to seed almost twice as many pounds per acre of the Delhi than the Prosper to get the same plant stand. That is a significant cost to buying certified seed! To a lesser extent, this can also affect how many pound or kilos per acre you seed of cereals or canola. Always seed to a target plant population.
Height is an issue in crops as well. Standability in peas is important, especially for harvesting. No one wants to scrape the crop off the ground in fall. In cereals height and standability will affect the risk of lodging, too. In lentils, the location of pods has a big effect on how close to the ground you need to cut.
Ultimately, which variety does best on your farm is a result of genetics, resources available, weather conditions, management and other factors. Use the variety guides as only a guideline. Pick one or two varieties you may want to try, then test them out on your own land. There is no replacement for hands-on experience, but a variety guide can narrow the field of potentials. Use the seed calculators linked below to help with seed estimates.
Cereal seed calculator:
Pulse seed calculator: