Your Reading List

Five Considerations For Choosing A Canola Variety

Every year, one of the most common questions for agronomists from farmers is, “What’s the best canola variety?” My usual short answer is, “There is no best canola variety for everyone.”

The best variety for you may be different from that of your neighbour, and is most certainly different from another farmer in a different region. Finding the best canola variety for your farm requires looking at several issues.

Of course, the first is yield potential. However, yield is just one part of the whole canola production package. After all, your main goal should be maximizing your net revenue per acre, not just producing the most bushels per acre. Therefore, you have to look at all the factors that go into producing a crop.

FERTILIZE TO YIELD POTENTIAL

Let’s start with fertility. Research has shown that, in general, hybrid canola varieties are more efficient in utilizing soil nutrients than open pollinated varieties. That is, for a specific amount of fertilizer used, hybrids will usually yield more than open pollinated varieties. As well, to maximize the yield potential of varieties, hybrids generally require a higher fertility level (especially N fertilizer) than open pollinated varieties. The following figures, obtained from a Canola Council of Canada factsheet entitled, Fertilizing hybrids — how much is enough?,illustrate that relationship.

So when attempting to optimize yield produced for a given amount of fertilizer, one should look at and consider hybrid varieties.

WEED CONTROL

Next, let’s consider weed control. Weed control from the most common herbicide tolerant (HT) systems on the market is generally much better than older conventional herbicide tolerant varieties. But you need to look at the cost of the whole weed control package, including extra seed cost associated with the HT trait, herbicide prices, and any associated technology fees.

You need to consider the most prevalent weeds on specific fields, previous herbicide use patterns, and whether any tank mixes are required. The Roundup Ready (RR) and Liberty Link (LL) systems are attractive from the standpoint of limited use on most other rotational crops in Western Canada, and therefore good from the standpoint of herbicide rotation. However, the use of glyphosate extensively in pre-seed burn-offs and pre-harvest applications complicates the issue because overuse of glyphosate is a concern. Conversely, Liberty use is more limited in Western Canada for other use patterns other than in LL canola. However, if one needs to commonly add a Group 1 herbicide to Liberty for control of grassy weeds, then the rotational benefit of Liberty on Group 1 weeds is diminished. And the Clearfield system relies primarily on Group 2 herbicides, which are often used in other crops. You need to be careful — over-reliance on any one herbicide tolerant system is not a good thing because it can lead to weed resistance.

DISEASE RESISTANCE

Then there’s disease control. Canola is affected by a number of diseases, but the ones I want to highlight are blackleg, sclerotinia and clubroot. There are a range of tolerance levels to blackleg in varieties currently on the market, ranging from MS (moderately susceptible) to R (resistant). However, even a variety with an R rating can get up to 29 per cent blackleg infection. Also, there are currently numerous strains of blackleg present in Western Canada, with more strains likely to continue to develop in the future due to the sexual recombinant nature of the disease. Although we don’t know, in most cases, which strains affect which varieties, it is a good idea to rotate varieties from different seed companies, especially with tighter rotations. There is no guarantee this will increase disease resistance to specific strains, but the chances for greater diversity are probably better between different companies.

The next disease to look at is sclerotinia. Until recently, there were no significant differences in sclerotinia tolerance among varieties and the primary method of control was applying a preventative fungicide. However, in recent years, Pioneer Hi-Bred has introduced a couple of varieties with improved sclerotinia tolerance. These varieties have a moderate level of tolerance or resistance, but are not immune to the disease. They just develop lower levels of incidence and severity than other varieties. Under severe sclerotinia pressure, a fungicide application may still be warranted. However, under lower to moderate levels of sclerotinia pressure, where it can be a headache to determine whether fungicide spraying is justified, then the use of a sclerotinia tolerant variety may be attractive.

Clubroot is the next disease to be considered. Although it is currently only a problem in certain areas of central and southern Alberta, there is the potential for this disease to establish itself in all traditional canola growing areas. In the last two years, new varieties with much improved resistance have come on the market. In most areas where clubroot is present, the use of these resistant varieties should be considered, even if clubroot has not been found in a specific field. The use of clubroot resistant varieties in these areas should reduce the overall level of clubroot spores within the region and reduce the chances of a significant clubroot infection developing in fields not currently infected.

MATURITY AND HARVESTABILITY

Maturity is another factor that needs to be considered in most areas of Western Canada. Varieties with differing maturities can help in a number of ways. For a grower with many acres, harvest timing can be a consideration. The use of an earlier maturing variety seeded earlier can help to smooth the harvest because you don’t have to take off everything at once. Harvesting earlier gives you the option of seeding winter wheat in the resulting stubble. Conversely, if seeding is delayed for any reason, the use of an earlier maturing variety can reduce the chances of green seed becoming a problem at harvest, thereby reducing the grade and subsequent value of the resulting crop. Although yield potential of earlier maturing varieties is often lower than later maturing ones, the value of a slightly lower yielding crop that grades No. 1, may be greater than that of a slightly higher yielding crop that ends up grading a No. 3 or sample.

The next factor to consider is harvestablity, or the ease in taking off a crop. It’s a subjective matter. You might look at the way a crop cuts and flows down the swather drapers and the swath opening. Almost everyone who has grown and swathed canola has dealt with the mounds or “beaver huts” of “beaver huts” of bunched swaths that develop when swathing is interrupted because of plugging. Harvestability can also refer to the ease with which the crop enters and is processed by the combine feeder and threshing cylinder or rotor. Harvestability is often influenced by the height of a variety and the thickness or coarseness of the stems. It can also be influenced by other production factors, such as plant density, fertility level used, and the amount and pattern of in-season precipitation.

A variety with poor harvestablity can lead to delays at harvest, which then increases your harvesting time and costs, and reduces your eventual net returns. Because it is a subjective factor, there are generally no published numbers for comparing harvestablity of different varieties, but one can ask company representatives how their new varieties compare to their older ones. Their comments and your experience allows you to compare harvestablity of different varieties.

SPECIALTY OILS

The last thing to consider is use of a specialty oil canola variety, such as Dow AgroSciences’s Nexera varieties, the Cargill Victory line, the InVigor Health varieties or other commodity varieties that have specific attributes such as high oil content or non-GMO. These varieties usually cost more, but can increase net returns per acre. However, there are also some limitations in terms of the need to keep the production from these varieties separate from your other commodity type varieties and certain limitations on when you can sell and/or deliver these varieties.

So what’s the best canola variety? It depends on the specific circumstances for each field. There is no one variety that has all the specific attributes needed to maximize returns for every field. You need to determine the specific production challenges and opportunities for each field, and target your variety choice accordingly.

Good luck in your variety decision making this spring!

JohnMaykofarmswithhisfamilynear Mundare,Alta.,andhasspentthelast20years workinginthecanolaproductionindustry

Comments

explore

Stories from our other publications