PURPLE CORN GENERALLY SIGNIFIES SOMETHING RESTRICTING NORMAL ROOT DEVELOPMENT
Anything that restricts normal root cell divison can cause a hybrid to cast a purplish flourescence
in its upper canopy.Cold soils, wet soils, compacted soils, root pruning from insects, fertilzer burn or anything else that can restrict a plants root development
can cause a hybrid to express PURPLE CORN SYNDROME.
The corn in the above photo is expressing a purplish fluorescence because of all the wet weather we've been experiencing in the last 3 weeks and the side-hill seep that is occurring because of it.Side-hill seep will keep soils much cooler and wetter than other areas of a field and the plants root growth and development will be slowed.As a consequence the anthocyanin genes that a hybrid carries will cause the accumulated sugars in the above ground tissue to trigger a purplish florescence to be cast.
The amount of purplish florescence cast is a result of the number of anthocyanin genes a hybrid carries.Hybrids can carry anywhere from 2 to 8 genes.Those that carry more will cast more purplish florescence than those that carry fewer.
When growing 2 hybrids side x side it is possible to have one hybrid express a lot of purplish florescence and the other one to express very little.When you see this don't get caught up into thinking that the hybrid expressing less puplish pigment is not being hurt by whatever soil stress is causing the slower root growth.Labratory work has shown that hybrids that don't express much purplish florescence in their canopy under the prescence of root restrictions are slowed in their above ground cell divison to the same degree as hybrids that express a lot of purple anthocyanin expression.The key is to assess what factors are causing the corn to purple in the first place.Once you resolve those factors you will be on your way to producing higher yielding better performing crops.