by Emi Kimura, Assistant Prof., Vernon; emi.kimura@tamu.edu and Clark Neely, Assistant Prof., College Station; cneely@tamu.edu

Winter wheat in the 2014-15 crop year endured a wet spring, which caused pre-harvest sprouting and many head diseases (stinking smut, loose smut, and Fusarium head blight or scab infection) throughout the regions in the state. Some areas of the state had less than 30% germination on wheat acres planted for forage due to the low quality wheat seed. The wet conditions in the spring of 2015 lowered the quality of wheat seed intended for planting for the 2015-16 crop year. Examining the seed quality prior to planting is critical for successful stand establishment.

There are several factors to be checked for the seed quality prior to planting.

1. Healthy look and smell
Seeds should look plump with good color and have no unpleasant odor. If seeds are sprouted, swollen, shrunken, or exhibit any other unhealthy traits, then suspect that the seeds have already been infected with seed-borne diseases, damaged by insects, or undergone pre-harvest sprouting. When seed size is compared, use the seed within the same variety because seed size varies by variety. Large and plump seed contains more carbohydrates that will serve as the initial energy source to be used for germination and seedling growth before the plants produce energy through photosynthesis. Healthy seeds are very important in successful stand establishment of the seedling.

2. Test weight
The potential reasons for the low test weight include adverse weather during the seed development, nutrient deficiency, drought stress, insect activity, sprout damage, and diseases such as scab, rots, and fungal diseases. Healthy seeds should have test weights greater than 58 lb/bu. Test weight lower than 58 lb/bu should be investigated for seed quality.

3. Germination percentage
Though Texas does not have an official minimum germination requirement, most certified seed in the state contains 85% or greater germination and generally indicates a good seed source. Germination percentage is always reported on certified seed tags. On the other hand, previous work conducted by Morgan et al. (2007) indicated germination of farmer saved seed could vary from 20% to 100% (Figure 2). This variability suggests that despite good germination for some farmer saved seed, the quality of the seed depends in the seed source and a germination test should be conducted before planting. Certified seeds, by law, have seed quality requirements and must include the percent germination for each bag of seed. Testing germination of saved seed not only gives you piece of mind, but can also reduce risk and allow seeding rate adjustments prior to planting to ensure adequate stands. Seeds infected with head scab and other seed disease usually contain lower germination percentage as well. If seeds with low germination are used for planting, seeding rate should be adjusted to achieve the target plant population; however, this can be risky and not a perfect solution. In short, germination testing is highly recommended. For a list of seed testing laboratories, please refer to the Seed Testing Laboratory Providers for Texas Agriculture.

4. Seed-borne diseases/insect activity
If seeds are infected with stinking smut, loose smut, head scab, or black point, seeds should be treated with an appropriate seed fungicide. For detailed disease and seed treatment decisions, please refer the Seed Treatment Decisions for Use on Winter Wheat.

5. Weed seed contamination
If seed is saved from the previous crop, seed should be saved from a field with low weed contamination. Dollars spent on weed control will be higher than dollars saved by seed collected from weed contaminated fields. Common weed seeds that may contaminate saved wheat seed include bindweed, Italian ryegrass, jointed goatgrass, and other noxious weeds. Careful inspection is necessary to lower the risk of weed contamination.

Cost associated with using saved, low quality seed can be higher than purchasing certified seed. Inspection of seed quality prior to planting is highly recommended.

Acknowledgement

This article was updated version of ‘Selecting Quality Wheat Seed’ prepared by Drs. Gaylon Morgan and Brent Bean.