Canola acreage has shot up over the past couple of years and with the price right now it can be one of the most profitable crops on the farm. The research that goes into canola is phenomenal and has allowed yield averages to soar in the last few years. But there are still some myths surrounding the flowering period of canola. Some of these include the longer the flowering period the better, and a wide array of sayings related to flowering and yield that aren’t necessarily true. I have had growers come in and say their canola only flowered for 22 days so it is going to be a bad crop, but they don’t realize that isn’t a big concern in the grand scheme of things.
As you can see from the chart pictured above it shows that typically the only flowers that make viable pods are the ones formed in the first 18-21 days from the appearance of the first flower, with significant pod numbers coming from the ones formed within the first 14 days of flowering. This means there are a lot of situations where the extra days of flowering are actually not helping your canola yield at all. In fact these flowers may keep the plant from focusing some of its energy and resources on already formed pods which are the ones that you will gain the most yield from. If conditions are dry you may only see 50% or so of total flowers turn into productive pods, and you will typically see a shortened flowering period. Under higher moisture conditions the flowering period may stretch out longer due to it being a very “plastic” plant, but don’t count on those flowers to add significant yield to your crop.
With that said some of the later flowers can become a viable pod if a plant undergoes significant stress early on in the flowering process. If a plant is dealing with heat stress or insect stress etc. in the early parts of flowering then canola can compensate by focusing more on the later forming flowers. In these situations the canola is working to recover some yield potential lost in the early parts of flowering, so you may see some later flowers contribute to yield.
Flowering length is also very variety dependant as well as your fertility package going down can affect the number of flowers that will become viable pods, so keep those factors in mind.