Fragile seed is a concern for Midwest growers

Posted 3/7/01

Fragile seed is a concern for Midwest growers

Seed testing laboratories across the upper Midwest are reporting that seed for planting this yearís crop is low in quality. Seed germination and stress and vigor evaluations have been disappointing, said Lyon County educator Bob Byrnes of the University of Minnesota Extension Service.

ìStandard germinations this year are 85 percent, compared with the normal standard of 90 percent,î says Byrnes. ìSome seed dealers are selling seed with less than 85 percent germination, so checking the tag is crucial.î

Warm, dry conditions during the soybean reproductive stage last summer, and above-normal temperatures in August and September are being blamed. The conditions resulted in rapid seed maturation that was sometimes incomplete as seed passed from green to brown without ripening properly. The seed coats that developed were fragile.

The dry September caused the soybean seed to dry rapidly, down to as low as 8 percent moisture before harvest.

These dry beans were highly susceptible to mechanical damage. This mechanical damage is the major cause of the lower germination of this yearís seed.

Byrnes suggests the following steps producers can take to reduce risk in planting this yearís soybeans:

ïSelect high-yielding varieties that are defensive (resistant or tolerant) to diseases and stress. Where possible, select these varieties with the best possible seed quality.
Even though the average seed quality is low, there is considerable variability in seed quality. Generally, seed that's higher in moisture has higher vigor and germination scores.

ïIn addition to the germination test, consider an accelerated aging test. The accelerated aging test will indicate the potential for ìweakî seed, which may not be reflected in the standard germination test.
The accelerated aging test can help predict the seedís potential to handle weather-related stresses such as cool, damp conditions after planting.

ïHandle seed with care. The seed is drier and more fragile than usual, and any impact will cause greater splitting of seed or damage to the seed coat.
Minimize the drop distance when emptying bagged beans. If using bulk seed, move seed from the bulk containers to the seed hopper gently.
With all systems, running full and at a slower speed will reduce the potential for seed damage.

ïReduce environmental stress at planting. Plant when soil temperatures are near 60 degrees.

This will help plants emerge from the soil as quickly as possible before running out of energy.

It will also reduce the amount of time the germinating seed is exposed to disease infections, herbicide damage, insect feeding, crusting and other stresses.

Depending on the spring weather, this will likely mean planting soybeans a bit later than has been common the past few years.