It seems apparent that the seed moisture for storage is most critical to maintaining high germination percentage and initial root and shoot growth. Temperature was a factor but moisture content in storage was critical. Seed producers are aware of this concept and use many methods to monitor drying of seed after harvest, applying seed treatments and storing the seed.
Higher moisture content in the seed activates some metabolism but not insufficiently to germinate effectively, causing an aging process. The pericarp does help protect air moisture diffusion into the kernel but genotypes vary in this pericarp feature, potentially complicating the drying and storage of the seed. Each individual kernel being slightly different physiologically and structurally contributes to the difficulty in producing and maintaining high percentage germination quality until planting time. Plant Physiol. 42, 1071-1076) compared seed respiration during imbibition, storage facility conditions, germination % and seedling growth of corn seed. Following table from that publication summarizes the interaction.
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.