Cold test minimum standard
Although it is acknowledged by many that the cold test for corn germination is a good predictor of field emergence, there may be confusion among what the minimum percent germination is acceptable by each company and grower. Part of the problem is range of test methods among labs, difficulty of sampling to represent the lot or even adequate sampling from a bag and characterization of delayed germinating seeds.
Late emergers can have few kernels probably mostly of competition with more vigorous adjacent corn plants. Not only do they tend to become weaker plants with smaller ears but also tend to silk when most pollen in the field has already diminished. There have been numerous studies showing that uniform field emergence is more productive than uneven emergence. This is true whether caused by germination problems or field problems such as compaction.
We are frequently asked for an opinion about the minimum standard. I usually answer that I think the industry standard is about 85% germination but actually each company should be considering the hybrid, the test methods and their own comparisons with field studies. Uniformity of seedling emergence can only be visual factor in customer satisfaction and/or it may be a significant factor in final grain production by a hybrid, depending upon hybrid genetics and field environments of that season. Biology of maize seed is important but only one of the biological contributors to a successful and profitable season of a corn crop.
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About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.