Amanda de Oliveira Silva, Small Grains Extension Specialist, Oklahoma State University

The Oklahoma wheat harvest was delayed in many areas this year due to frequent rainfall events. I have received several questions about sprouted wheat seeds and potential issues with post-harvest dormancy, especially when using that grain for seed this fall. So, I would like to share a few considerations.

Pre-harvest sprouting

Pre-harvest sprouting refers to wheat grains that begin to germinate while still on the wheat head, before harvest. Once wheat reaches physiological maturity, it can begin to germinate if exposed to ideal moisture and warm temperatures for just a few days. That is what happened in some locations in northcentral OK this season.

The risk of sprouting depends on both genetics and environmental conditions. Wheat varieties differ in their resistance to sprouting (i.e., some are more prone to sprouting than others).

Can I use sprout-damaged wheat for seed?

It depends, especially on the level of sprouting.

• If wheat kernels appear swollen or with a cracked seed coat, but with no visible root or shoot emerging from the seed, they might still be viable to be used as seed. In this case, run a germination test to assess seed quality before planting.
• However, if you see visible roots or a developing coleoptile emerging from the seed (see Picture 1), those seeds should not be used. They will likely have poor viability and may fail to emerge.

Will pre-harvest sprouting damage affect wheat quality?

Yes. As wheat starts to sprout (i.e., begins to germinate), it produces alpha-amylase and other enzymes that break down starch and protein in the grain. Increased enzyme activity can reduce flour and baking quality, affecting dough strength, loaf volume, and crumb structure. The more severe the sprouting, the greater the loss in marketability and end-use quality.

Post-harvest seed dormancy

Since harvest was late this year, will post-harvest dormancy affect planting this fall?

It is possible. Wheat seed is considered dormant when it fails to germinate even under favorable conditions or take so long that emergence is delayed, thus causing poor stands. Dormancy can be worsened when planting in warm soil (above 70F), which is typical during early sowing of graze-out or dual-purpose systems in Oklahoma.

Some level of seed dormancy is beneficial as it helps prevent pre-harvest sprouting as previously discussed. Dormancy is highest right before harvest and gradually decreases over time. But the rate at which it decreases depends on genetics and several other factors, including:

• Seed coat properties: Inhibitory compounds in the seed coat of hard red winter wheat varieties can extend post-harvest dormancy.
• Storage conditions: Seed stored at extreme temperatures (hot or cold) tend to lose dormancy faster than those stored at ambient air temperatures. This is why placing seed samples in a refrigerator for a day or two before conducting germination tests is a common practice.
• Grain-fill environment: Cooler and wetter conditions during grain fill result in stronger dormancy than hot and dry conditions during this period. This means that the same wheat variety may exhibit different germination behavior depending on the environment in which the seed was produced.

For most hard red winter wheat varieties, dormancy naturally dissipates by October. However, early sowing shortens the interval between harvest and planting, which increases the risk of planting dormant seed, leading to delayed emergence and poor stands.

Dormancy can be mistaken by other problems like dead or damaged seeds. Running a germination test can help to identify what is going on.

What to check before planting saved seed:

1. Germination Test

Even if the grain didn’t visibly sprout in the head, it may have undergone internal changes (like enzyme activity) that reduce vigor. A standard germination test is the best way to assess viability.

The Oklahoma Department of Agriculture, Food and Forestry offers this service. Click here for more information.

2. Fungal infections and seed quality:

Prolonged wet conditions during grain filling and harvest can lead to seed-borne fungal diseases. These can reduce seed quality and emergence. Consider using a fungicide seed treatment to reduce this risk.  

3. Test weight and shrunken kernels

Low test weight and shriveled seeds often indicate poor grain fill. These seeds might have reduced starch reserves, which weakens seedling growth.

Aim for test weight above 58 lb/bu for seed use.

Summary

• Delayed harvest increases the risk of pre-harvest sprouting.
• Both can impact seed viability and plant emergence this fall.
• Before using your own grain as seed, be sure to run a germination test and assess overall seed quality.

Resources:

• If you have questions about testing, seed treatment, or variety selection, feel free to reach out to your local Extension office or to me.
• Oklahoma Department of Agriculture Germination Tests Lab services: Click here for more information.
• Storage and Use of Low Test Weight and Sprouted Wheat –  Factsheet BAE-1109