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Corn Illustrated: The tassel develops inside the stalk long before it emerges.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

July 21, 2020

3 Min Read
a piece of cornstalk from a V12 stage plant with 12 leaves
WHERE IS THE TASSEL? Dave Nanda holds a piece of cornstalk from a V12 stage plant with 12 leaves. The tassel is tucked inside, just above the growing point, although it is difficult to see.Tom J. Bechman

You probably know that by the time corn has 12 leaves with fully exposed collars, plants already have made several decisions that will impact final yield. Plants take their cues from their microenvironment, deciding how many rows of kernels to put on each ear, and how many kernels per row. Sure, genetics plays a huge part, but weather conditions, coupled with soil moisture and other factors, help plants tweak their decisions.

What you may not know is that if you dissect a V12 plant, you will find a fully formed tassel, just above the growing point. “It’s actually there before that stage, but you can definitely find it near the end of the grand growth phase, at V12,” says Dave Nanda, director of genetics for Seed Genetics Direct. “There is a lot you can learn from studying tassel formation and understanding how corn plants develop.”

Here are a few observations Nanda made while dissecting a V12 corn plant:

The growing point. If you slice the top of the stalk carefully, you will find the growing point, Nanda says. It’s visible near the top of the stalk, once it’s cut in half.

Location of the tassel. Once you find the growing point, the tassel will be tucked inside the stalk just above it, Nanda says. It may not appear to be fully formed, but if you pick it out carefully with the tip of a knife or tweezers, you’ll find that it’s a complete tassel, already formed inside the stalk. Study the pictures to see how Nanda coaxed the tassel out of the stalk, revealing various branches of the tassel.

corn tassel tucked inside a piece stalk being teased out with a pen

TEASE IT OUT: Dave Nanda begins to expose the tassel, which is developed and tucked inside the stalk, just above the growing point.

Tassel structure. How many branches a tassel has is determined primarily by genetics, Nanda says. Some hybrids have more branches than others. Each plant will have a main tassel shooting straight up. Then the number of additional branches can vary from four to nearly a dozen. Anthers containing pollen develop on the tassel branches.

tassel fully exposed inside piece of stalk

FULLY EXPOSED: Here is the tassel fully exposed, inside the same piece of stalk. It will be ready to go, Dave Nanda notes, once more leaves unfold and the timing is right.

Where pollen shed starts. If environmental conditions are favorable and pollination is on schedule, pollen shed on a fully emerged tassel will begin from the main tassel branch, Nanda explains. Pollen shed starts in the middle of the main branch, then moves up and down the branch until all pollen has been released from the main branch of the tassel.

How pollen shed continues. From the main branch, pollen shed moves to the next set of branches surrounding the main branch within the tassel. It proceeds until all the pollen has been released from the tassel. If everything worked correctly, Nanda says, silks emerged as pollen shed began, and a pollen grain found its way to each individual silk, growing down the silk and fertilizing an ovule. If each fertilized ovule develops, you can expect an ear filled with kernels.

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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