Published in the Chat 'n Chew Café (23 Aug 1999). Also published in the Purdue Pest Management & Crop Production Newsletter (3 Sept 1999).

What A MESS!
(aka Multiple Ears on a Single Ear Shank)

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

Author's note: Originally published in August 1998, but relevant to similar reports being received in August 1999.


The annual Dog Days of August always bring out the odd stories down at the Chat 'n Chew Café. The latest one originated with Dan who claimed he was in a corn field the other day checking out the condition of the developing ears (for which he receives a gold star considering how hot and muggy it's been lately!). Seems that he was finding multiple-eared plants along the edges of the field.

Now, multiple-eared plants in and of themselves are not an oddity. Low plant-to-plant competition (edges of fields, thin populations, etc.) often results in successful ear development at more than one stalk node (joint). This characteristic is often termed "prolificacy" and some prolific hybrids exist that routinely produce more than one harvestable ear at respectable plant populations.

However, Dan claims that the multiple ears were occurring on a single ear shank, rather than their usual occurrence at individual stalk nodes (joints). The primary ear was at its usual position at the end of the ear shank, but one or more additional ears were developing farther down the same shank.

This multiple-eared oddity, let's call it the MESS Syndrome (Multiple Ears on a Single Shank), does not occur very frequently but raises questions when it does show up. Is it a fertility imbalance? Was it caused by your #@$%! herbicide? Was the seed genetically-challenged? Will it affect grain yield?

Well, first of all, let's remember a few things about an ear shank. Basically, an ear shank is a modified stalk. The husk leaves originate from individual nodes (joints) on the shank, similar to the plant's regular leaves originating from individual nodes on the main stalk. Instead of a male flower (tassel) developing at the end of this modified stalk, a female flower (ear shoot) develops.

Similar to the nodes of the main stalk, it is physiologically possible for ear shoots to develop at any of the nodes of the ear shank. Typically, none actually occur. Once in a great while, some do form.

I suspect that the appearance of the MESS Syndrome simply tells us that the plants had ample energy and resources during the initiation and development of the ear shoots earlier in the season, enough that there was extra resources available for the plant to "invest" in the development of these additional ear shoots. Many of these "affected" plants also exhibit the more typical second ear development at the node below the primary ear that is associated with low plant-to-plant competition. As such, therefore, there is likely nothing negative about the existence of the MESS Syndrome.

Bottom Line: If you haven't seen this phenomenon before, take some time this week to walk your fields and look for it along the edges. You will probably find some. They make good desk ornaments and also make for good conversation at your next social event.


Corn Growers GuidebookFor other information about corn, take a look at the Corn Growers Guidebook on the World Wide Web at http://www.kingcorn.org


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