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.
|