Two different lots of the same variety are planted on the same day, in the same field, with identical germination percentages on their labels.

Can the final plant stands of these two fields be different?

Maybe. The germination percent on the label is the percent of healthy seedlings produced in a close to ideal environment in a laboratory. The number is a good indication of the potential of the lot, but may not be a good indicator of how easily the lot can overcome the stress of a field environment. When you place a seed in an environment in which the seed needs to work harder to get that root out, the weaker seed doesn’t always make a plant, when it would make a plant under more favorable conditions.

Less than optimal moisture, temperature, or oxygen levels that can cause stress during seed germination in the field.

Too much water or too little; too high of a temperature or too low; lack of oxygen due to excessive flooding, or compacted soils, can all have a devastating affect on seed performance.

How much of an affect, depends on the strength of your seed.

Most seed lots sold today are relatively strong, and will do well under most environmental conditions. However, there are some situations where it might pay to know the relative strength of the seed that you are planting.

We sometimes have to plant into stressful field conditions such as early planting in cool soils or overly hot conditions, or into fields that have a history of poorer performance.

Using the strongest seed when stress is likely to occur, may increase the likelihood of obtaining a good plant stand under the stress condition.

Sometimes the highest percent germination on the label is also the strongest seed lot, but not always.

The best way to know is to test the seed under stress conditions or measure its growth rate after germination.

Several companies can do these types of tests that are collectively referred to as vigor tests, which is the topic for the next  column.

Keith
k.kubik@hmclause.com