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A harmful cell mutation has popped up in corn fields in Northwest Missouri, according to Wayne Flanary, regional agronomist for University of Missouri Extension in Holt County.
Last year, several Extension agronomists across the state found corn fields that had the plant leaves dying prematurely. Plants were sent to the diagnostic lab where they were tested for various abiotic problems. Nothing was found. Samples were sent to Kansas State University to be tested for viruses and again nothing was found.
This year, Extension has found more fields exhibiting these symptoms. The death starts on the lower leaves and moves upward in the canopy. This causes the plant to lose leaf area and results in low yields. These are not small areas within the field but the whole field is showing the symptoms of dying cells of the leaves of corn plants.
Extension agents have concluded that the problem is a disease called lesion mimic mutants of maize. These are a class of mutants in plants that spontaneously form patches of dead cells in the absence of any stress, injury or infection in the plants. The mutants have recessive and dominant mutants that result from biological processes. Lesion mimic mutants seem to be widespread within corn plants. A paper summary within the American Phytopathological Society indicates that there are more than 50 positions in the chromosome that may give rise to a lesioned phenotype.
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http://www.stjoenews.net/news/2008/aug/10/corn-plants-exhibiting-harmful-mutations/?businessThought I'd post for those who are interested in genetically modified crops.