The same technology and equipment used to nab drunk drivers may soon be able to tell you the vigour potential of your canola seed. New tools for measuring seed vigour in canola have been developed at Agriculture and Agri- Food Canada’s (AAFC) Brandon Research Centre.
“We have developed several new methods of testing the seed for vigour and we have evaluated these methods by growing seeds of various qualities out in the fields,” says biochemistry research scientist Wayne Buckley.
“We looked at the rate of emergence, the rate of early growth of the seedlings, and the rate of expansion of the leaf area. And we found that we get a pretty good correlation with our new procedures and these measurements of vigour that occur in the fields.”
At Crop Production Week in Saskatoon and Ag Days in Brandon recently, some farmers got a chance to take home a sample, field screening kit (developed by AAFC) to try out. The Vigorcheck is an on-farm test kit, and contains a small two-ounce bottle, a syringe of testing solution and a measuring scoop. Farmers measure a sample of seed into the bottle, add the solution, cap the bottle and shake well. After 24 hours, if the indicator tab on the bottle cap has turned blue, seed quality has deteriorated.
“These are kits that farmers can use on the farm to check the quality of their seed before they plant it so hopefully they might be able to identify a problem before it happens,” says Buckley.
A BREATHALYZER FOR CANOLA
The Vigorcheck screening test is a good first indicator that a farmer’s seed may have lost some of its potential vigour. A more sophisticated instrumentation test developed by Buckley and his team, the Vigorscore, will provide with a further step to determine the severity of the problem. This test (which will eventually be available through seed testing companies) uses breathalyzers modified to measure the amount of alcohol that appears above the seed as it starts to imbibe moisture. The amount of alcohol produced gives a good measure of the seed quality, as seeds that are deteriorating will emit increasing amounts of alcohol.
“It happens that the amount of alcohol that is coming off the seed is the same range of alcohol that is used in breath analysis,” says Buckley. “So we were able to use these breathalyzers to develop a rapid instrumental method for measuring seed vigour. The method is quantitative (so it gives a better idea of the degree of seed vigour deterioration) and only takes 24 hours.”
Many factors affect canola seed vigour, including excess heat and humidity in storage, pesticide treatments and agronomic history. Seed stored at too high a moisture level will heat up and cause rapid deterioration. Seed at five per cent moisture or less is the most stable for optimal storage. The longer seed is stored after pesticides have been applied, the greater the risk of vigour loss because pesticide treatment accelerates the rate of aging of the seeds. And seeds that may have been harvested green or not fully mature also tend to lose vigour more rapidly.
“We can basically attribute all these things to aging of the seed,” says Buckley. “Older seed has more chance of having lost vigour than fresher seed.”
DOES VARIETY MATTER?
The variety of canola, however, doesn’t appear to be a factor.
“There’s not much difference between different genetic types in terms of their susceptibility to vigour loss,” says Buckley. “Vigour loss, however, is sometimes confused with hybrid vigour. Hybrids tend to have more vigour than open pollinated types, they simply grow faster and more vigorously. That is a genetic affect. But what we are measuring is a seed quality effect and the hybrids can lose their vigour, and the seed can deteriorate, just as open pollinated seed can.”
Plants with less vigour struggle to emerge and grow as quickly, and are more vulnerable to disease and pest pressure as the season wears on, in some cases leading to significant yield losses.
AAFC is currently working with the International Seed Testing Association to try and validate the breathalyzer test method for general use and provide a standardised procedure that seed laboratories in Canada and around the world can use.
While there is nothing farmers can do to improve seed vigour once lost, results from tests such as these can help identify the problem, so they can find ways to compensate, such as increasing seeding rates.