Originally published in Purdue Pest Management & Crop Production Newsletter (7 June 1996)

Corn That's Every Color But Green

R.L. (Bob) Nielsen , Agronomy Department , Purdue University, West Lafayette, IN 47907-1150
Internet address: rnielsen@purdue.edu

Pick your colors.......... Yellow, Purple, Red, and even White. These are the colors that some corn growers see as they walk their corn fields this year. Given the growing season to date, multi-colored corn is not unexpected. Here's why.

As Mother Nature often reminds us, corn grows and develops best with sunny days and warm temperatures. Indiana has simply not had many days like that in 1996. Consequently, many fields are an ugly yellow-green rather than the darker green that we would prefer to see. Warm, sunny days will correct this.

Purpling results from the accumulation of a purple pigment called anthocyanin. Whether or not a corn plant produces anthocyanin is determined by the hybrid's genetics. Some hybrids contain more 'purpling' genes than others.

Purple corn is caused by one of two factors. The first factor is simply a genetic response to cool nights following bright, sunny days. Warmer weather will cause the purpling to slowly disappear. The second factor is restricted root development, coupled with an abundance of plant sugars produced by photosynthesis that triggers the purpling.

If the cause of the root restriction is temporary (e.g., cool temperatures), then the purpling should disappear as the plants develop further and yield losses should be minimal, if any. If the cause of the root restriction continues to affect plant growth all season (e.g., soil compaction), then the purpling may continue for some time and some yield loss may result.

White corn is often blamed on the herbicide clomazone (e.g., Command), but can also be caused by spray drift of glyphosate (Roundup). Single white plants in a field are usually genetic mutants.

Return to the the Chat 'n Chew Cafe.

The Corn Growers Guidebook , a WWW resource for corn management systems in Indiana and the eastern CornBelt.

Purdue University Agronomy Extension WWW Home Page.

Purdue Agronomy On-Line! , Purdue's Agronomy Department WWW Home Page.

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