Seed producers can have the genetics for seed quality, harvest at proper seed moisture, use good seed drying processes and still be disappointed with germination test results the following spring. The most prevalent variable is weather during the seed production season. Drought stress after pollination often the primary stress on seed quality, although rain during harvest time can delay harvest, allowing for deterioration in the field.
Seed produced under stressful environments can lead to near normal germinations for a few months after harvest but faster deterioration than normal before planting in the next spring. Standard warm and cold tests done before preparing seed for packaging that is usually adequate to predict the field emergence the next spring may not be correctly identifying seed that is deteriorating this quickly.
Special tests have been devised to predict these types of potential problems but often have some limitations in establishing standards for every genotype. Balancing the demand for early delivery of hybrid seed to growers with need to detect potential late seed quality problems is not easy.
Seed do age but predicting the rate of aging is not easy. Seed production history and conditions are not identical for each individual seed within a seed lot as well. The goal of establishing a uniform plant stand in the corn field is the goal of everyone involved with corn but the realities of multiple environments and biology does produce obstacles to 100% success.
Successful seed production, like most of agriculture, is the result of managing multiple variables with a combination of science, experience and at least a little bit of luck.
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.