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Seed quality highly variable

A tough growing year has translated into seed that can have lower germ levels

Seed quality in Manitoba for the upcoming growing season is a mixed bag depending on the crop, according to Holly Gelech, manager of business development for BioVision Seed Labs in Winnipeg.

The average germination of wheat seed tested from the 2016 crop is 86.3 per cent, down six per cent from the five-year high of around 92 per cent in 2012.

“We are definitely seeing poor seed quality in our lab,” said Gelech. “We have had a lot of (germination) results in the 70s and low 80s but some samples are carry-over from the 2015 crop, which is bringing this number up a bit.” Germination in barley samples to date is similar, averaging 87.9 per cent compared to 2012’s high of around 93 per cent.

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Disease challenges

In her presentation to the Manitoba Agronomists Conference in December, Gelech said the biggest challenge that Manitoba cereal seed growers faced in 2016 was in-crop disease, and the lab has also seen some pre-sprouting and high moisture content samples in cereals.

Reflecting the high level of fusarium head blight seen in Manitoba fields this year, lots of wheat seed samples are showing high levels of infection with seed-borne fungus, primarily Fusarium graminearum. Of the 2016 wheat samples tested so far, the average fusarium infection rate is 18.5 per cent compared to just three per cent in 2012.

Fusarium fungus spores germinate in the seed and form pink mycelium which covers the seed and may kill it. As observed in the germination test, some seedlings may start to grow but the roots and shoots will brown and die back. In some cases, germination may only be around 50 per cent of these infected seeds.

“We even saw an oat sample that was infected at 34.5 per cent and oats are rarely susceptible to Fusarium graminearum,” said Gelech. “It’s a really bad year for seed-borne pathogens in Manitoba.”

Gelech says the lab is also seeing some frost-damaged seeds from northern areas of the province, as well as some chemical damage from pre-harvest herbicide applications. Chemical-damaged seeds may sprout but the shoots and roots stop growing soon after.

The news is better for Manitoba soybean growers. Soybean average germination has been trending upwards over the past five years from 82 per cent in 2012 to just over 94 per cent for 2016 samples. Soybeans in 2016 did not face some of the challenges of the last few years, such as hot ambient temperatures which resulted in very dry seed.

Now what?

So what are seed growers — and producers — to do with this poor-quality seed? There are a number of things they can do to assess the usability of their seed, said Gelech.

The first thing to do is test seed in the fall for germination, seed-borne disease diagnosis and trait testing. It’s important to understand how the germination test results stack up against the minimum germination ratings for pedigree seed in the Canada Seeds Act Grain Tables. “For cereals like wheat and barley it’s 85 per cent germination, durum wheat is 80 per cent and soybean is 85 per cent,” said Gelech. “It’s important to understand where you fit in the whole ballpark. At 50 per cent germination, are you even in the game? At 84 per cent you are close.”

Each province has different tolerances for Fusarium graminearum, so growers need to know where their disease results put them in terms of the salability of their seed. In Alberta seed may not be sold that has any level of Fusarium graminearum, whereas in Saskatchewan the maximum fusarium content is region dependent. Due to the high prevalence of FHB in Manitoba, the province recommends producers employ best management practices when growing infected seed.

Talking to seed retailers and agronomists can help growers check the quality of seed that is available in their region.

Storage considerations

Growers should try and achieve optimal seed temperature and moisture levels going into the bin to ensure that the seed will store through the winter months. The Canadian Grain Commission has safe storage guidelines on its website. Any measures growers can take in-season to ensure crop uniformity at harvest will help prevent issues in storage down the road. “This year there is a lot of green seed going into bins which can cause premature spoilage,” said Gelech.

There is some discussion that fusarium spores will eventually die off in storage, but much of the information about this has come from areas with warmer winters. “Fusarium spores will not die off in extreme cold temperatures like -10° to -20°‚” said Gelech. “Under our winter conditions it is going to be very rare that you will see a sizable reduction in the pathogen in the course of one winter.”

Another germination test in March will reconfirm seed quality, and if growers plan to plant in cool soil conditions a cool stress test will provide an indication of how the seed is likely to perform under those conditions. Knowing seed size is important so growers can target a seeding rate that will ensure good crop establishment.

Finally, when it’s time to plant, protecting the seed with a seed treatment will help hold down the growth of any seed-borne fungus and improve germination. “If you have a low germination because of frost damage or something else the seed treatment isn’t going to bring the germination up, but it will help control any seed-borne fungus during that critical first week of sprouting,” said Gelech.

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