Some producers may be anxious this year to find out the germination percent of the wheat they harvest, to see if it will make suitable seed. If they do a home germination test too soon after harvest, they will be shocked at the low germination percent. That’s because wheat has a post-harvest dormancy requirement (some varieties more so than others). Even high quality seed will not germinate right after harvest in most cases.
For the first several weeks after harvest, it’s important to make sure the wheat is pre-chilled before taking a germination test. Any reputable seed lab will do that on a routine basis. Producers testing their seed at home should also pre-chill the wheat by putting it in the refrigerator at about 40 degrees for 5 days and then moved to room temperature for an additional 5-7 days. If the seed is not prechilled, producers should wait a month and a half after harvest before testing for germination.
There is some difference among varieties regarding how long their summer dormancy requirement is and even that can vary from year to year. Hard white wheats with poor sprouting tolerance, for example, have almost no summer dormancy requirement. They will germinate almost as soon as the seed is harvested. Other varieties have a relatively long summer dormancy requirement, and may not germinate well for five or six weeks after harvest unless the seed is pre-chilled. Unfortunately, there is no routine testing of varieties for their summer dormancy requirement, so we have no way of knowing which varieties will germinate shortly after harvest and which will take a longer period of rest.
By Labor Day, all varieties will have lost their summer dormancy and should germinate unless the seed is defective in some way. In addition, if seed is tested soon after harvest, it would still be a good idea to test again prior to harvest to be sure the germination has not been compromised due to heating or insect damage.
If there is any question about the viability of the seed, it is well worth the $15 it costs to have the seed tested for germination by a professional seed laboratory. This is especially true in areas where there was freeze damage, severe drought, a rain delay at harvest, or scab. To the untrained eye, seeing some amount of shoot and root development would seem to be sufficient proof that the seed is in good condition. But that alone does not always mean you have a seedling that will develop into a healthy plant. A trained laboratory analyst evaluates each seedling to be sure that all essential parts exist and have sufficient development at the end of the test to, in fact, establish a normal, healthy plant.
(Source – http://www.farms.com/news/conducting-germination-tests-on-this-year-s-wheat-seed-64363.aspx)