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 may be shocked at the low germination percentage – unless the test is done correctly. That’s because wheat has a post-harvest dormancy requirement (some varieties more so than others). Even high-quality seed will not germinate at its maximum capacity right after harvest in most cases. This post-harvest dormancy is important to help decrease the chances of pre-harvest sprouting in case harvest is delayed due to weather conditions or other reasons.
To get around that, 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 planting it and putting it in the refrigerator at about 40 degrees for 5 days. If the seed is not pre-chilled, producers should wait a month and a half after harvest before testing for germination.
There is some difference among varieties regarding how long their post-harvest dormancy requirement is – so much so that some varieties are more prone to pre-harvest sprouting. Hard white wheat varieties 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. By Labor Day, all varieties will have lost their summer dormancy and should germinate unless the seed is defective in some way.
If there is any question about the viability of the seed, it is well worth the cost 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 or heat stresses during grain filling, a rain delay at harvest, or wheat head scab.
Professional lab testing
Having your seed professionally tested for germination is always a good practice, but with the severe drought and heat stress on the wheat crop in many areas this year, it is highly recommended.
To have an official germination test on the seed, send a two-pound sample to:
Kansas Crop Improvement Association
2000 Kimball Ave.
Manhattan, KS 66502
A germination test for non-members of KCIA will cost $20.00 and a sample submittal form can be printed off from the KCIA website: www.kscrop.org/seed-lab.html
Other seed quality tests are also available and are listed on the submittal form. A companion article in this eUpdate discusses the Accelerated Aging test that can help identify weak seed lots beyond the standard germination test.
Home testing: Doing it correctly
If producers want to test their seed for germination at home, it needs to be done correctly to be of value.
Place the roll in a plastic bag. Seal, but not completely, so as to keep moisture in but still allow some air into the bag.
For newly harvested seed:
For carryover seed, or after September 1:
To calculate the germination percentage: divide the number of healthy seedlings by the number of seeds tested and multiply by 100.
Example: 42 healthy seedlings X 100 = 84% germination
50 seeds tested
This may be repeated more times for each sample in order to obtain more accurate results, testing up to 400 seeds. If the seed will be treated with a fungicide seed treatment prior to planting, the test should be performed after the seed treatment is applied because it can increase the germination percentage.
Eric Fabrizius, Kansas Crop Improvement Association, Seed Laboratory Manager
efkcia@kansas.net
Romulo Lollato, Extension Wheat and Forages Specialist
lollato@ksu.edu