Obtaining an expected plant stand in the field has become increasingly significant to final grain production with modern corn hybrids. These hybrids were selected to tolerate high densities partly by producing more, but smaller, ears than those common 20-30 years ago. Highest grain yields are associated with more ears and, thus, more productive plants. Achieving and maintaining high germination quality in corn requires genetics, field techniques, cooperative weather and carefully monitored handling of the seed after harvest.
Genetics of the female parent is a major factor. Kernel pericarp genetics is totally inherited by the female plant. Pericarp vulnerability to cracking in the field, during handling at and after harvest, and from the drying process is largely affected by those genetics. Cytoplasmic genetics for cellular organelles such as mitochondria and ribosomes come from the egg cell of the female plant. Function of these organelles is linked to integrity of their membranes during the stresses of drying, seed imbibition and aging. Deciding which hybrid parent inbred becomes the female in the seed field is an important part of successful seed production.
Production field technique influence seed quality as well. Good timing of pollen supply from male inbred with silking exposure in female plants result in more completely pollinated ears. This includes more seed in the center of ear that tend to have better germination quality. Irrigation timing is important to promote good timing of pollination, as well as maximum silking. Seed of most dent corn genetics begin aging soon after black layer and timing of harvest is critical.
Weather during the growing season can influence pollination by drought stress delaying silking or rain during pollen shed inhibiting dehiscing of anthers resulting in bad pollinations. Rain during silking is often associated with fungal infection of the seed. Drought stress after pollination can be associated with early plant death and poor seed maturation. Weather can also affect meeting the critical harvest timing. I recall witnessing high germinations with a seed field harvested on time but, interrupted by a week of wet weather, the other half of the seed field had very poor germinations.
Dent corn seed must be dried quickly after harvest but without high temperatures to reduced damage to the dehydrating cellular structures in the embryo. Shelling and movement of seed within the seed production facility requires care to minimize damage to corn seed.
The multiple factors involved in obtaining and maintaining corn seed that will result in the expected plant density in the grower’s fields requires experienced management. One of the surprises for people entering the seed corn business is the complexity and significance of seed production on its success. Seed production, like much of agriculture, involves a mix of technology and art.
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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.