Among the fun enigmas of advances in corn knowledge is how to apply new information into practical application. How to take a new understanding of plant function into increased efficiency of producing a crop. Multiple field environments within a few inches of each requiring a resilience affected by many of the 40000 genes is required for reliable field performance.
We are learning more about how to turn on and off genes by new technology. Hopefully the right gene changes still will mean increased productivity within the economics of today’s crop value. Often the single gene changes for herbicide or insect resistance have eventually lost effectiveness as the weeds and insects with single genes to avoid the corn resistance increased. These technological advances served for a time but, at least in some cases, are now not as useful.
This is not really a new phenomenon that is limited to application of a new technology. The Ht1 gene was discovered in the 1960, resulting in most commercial corn research programs integrating the gene into many hybrids beginning in the late 60’s. It was very effective in controlling the northern leaf blight pathogen, Exserohilum (Helminthosporium) turcicum until 1979 when it was apparent in a seed field with the Ht1. After being informed of this occurrence, several more observations were made across the Midwest corn belt in that season. Although occurring at a low frequency within the fungal species, individuals had a gene producing a product that blocked the Ht1 resistance factor and thus allowed normal disease development. These members of the fungal population gained momentum and now are the dominant ‘race’ in the USA, making the Ht1 gene less useful.
We are seeing the same story with weeds, insects and other pathogens. We are dependent upon variability in corn genetics as the crop is grown in a variable environment that includes genetic variability in corn’s pests. It is a continual challenge to decide which new technologies will make meaningful application to corn productivity.
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.