Winter wheat can germinate in spring

There are reports circulating of agronomists telling producers to reseed winter wheat fields that have just germinated this spring. As I understand, it is related to the process of vernalization and whether it has occurred or not.

Last fall I wrote a Crops eNews article titled “What Happens if My Winter Wheat Didn’t Emerge?” – see link

The key points related to vernalization were:

  • Neither fall seedling growth nor tillering is required for vernalization to occur. This process can begin in seeds as soon as they absorb water and swell. Hence, late-planted wheat that has not emerged prior to winter should be adequately vernalized.
  • Vernalization may also occur under cool spring conditions.

No guarantees, but experience counts

In talking with Brian Fowler of the University of Saskatchewan, who has 40 years of experience with winter wheat production in Canada, he has never seen a fall-seeded winter wheat crop that did not head the next year.

This includes situations where the seed supposedly did not germinate in the fall. Here in Manitoba, the long spring we have had with the spells of cool weather (average daily temperature 10 C or lower) is ideal for vernalization.

No guarantees can be made in regards to spring-germinated winter wheat and vernalization. However, based on what we know about winter wheat physiology and the recent spring weather, vernalization concerns shouldn’t be the reason to reseed in 2012. If you are considering reseeding and before destroying any wheat fields, contact your local MASC insurance agent.

There are a few key points to keep in mind when managing a crop that only germinated in the spring. The crop may not be as competitive so early weed control and nitrogen fertilizer application will be very important. Maturity may also be delayed so scout for disease pressure, including rust and fusarium head blight.

If reseeding

If plant stands are determined to be unacceptable and the decision is made to reseed, remember that winter wheat is hard to kill. Tillage and/or burn-down herbicides will likely not control all plants, especially if some are suffering injury and slow spring regrowth. In-crop volunteer cereal herbicides may also be required.

Wheat streak mosaic may also carry over from infected winter wheat fields into spring seeded cereals. Try to avoid replanting to cereals, especially wheat. If you do decide to replant to a spring cereal, it is recommended that there be two weeks with no living green material to try and mitigate the risk of infection to the reseeded crop. And remember to factor in crop reseed choice if nitrogen fertilizer has already been applied.

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