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| May 22 | |
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Last week I noticed the wheat was losing its pretty green color. So, this morning I thought we had better take a look. As you can see, our area is still green, but it has a subtle reddish color. This is normal because about 15 days after flowering the wheat will start to turn its mature color. Our variety, Jagger, has a reddish, bronze mature chaff color. (When we use the word "chaff" we mean the head parts, such as, the glumes, lemma, and palea.) Other varieties have a white chaff color. This change in chaff color is associated with further kernel development. The kernels should now be in the milk stage, but we will have to wait and see. |
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Here’s a closeup of a head from our area. It looks pretty good to me. The awns or beards are green. What do you think those awns do for the wheat plant? (Click here to find out.) Look closely at the spikelets up and down the head. Do you notice anything different among the spikelets? It seems to me that some of the spikelets in the bottom half of the head look bigger than those at the top. Why do you think they look bigger? Let’s see. |
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Looking at the bottom two spikelets, how many
florets have kernels in them? That’s right, there are four kernels in
each of those two spikelets! That’s a lot of kernels in a small area.
There are more kernels in them, that’s why some spikelets look bigger.
It is very common to see two kernels per spikelet and it is not unusual to see three kernels, but more than that is rare. And you might see spikelets that have two, three, and four kernels in them all in the same head. If you look closely at these spikelets you can see a fifth floret (The fifth floret is high and in the middle of the spikelet–do you see it?) trying to fill a kernel. The third, fourth, and fifth kernels (if they form) are generally smaller than the first two kernels. |
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Now, let’s look at these two kernels. They are about 15 to 17 days old, well formed, and plump. So, we know something is inside them. Right? But what is it? Last week the kernels were in the watery ripe stage because we could see the clear, watery liquid. Let’s smash one to see. |
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There’s still a liquid, but it now has a milky appearance. This is the milk stage of kernel development. What is that milky substance, you ask? That, my friends, is sucrose that was produced by the leaves and it is being transported into the cells of the endosperm. It will be converted to glucose and stored as starch in the endosperm cells (but I’m getting ahead of myself). The milk stage in a single kernel will last for about 5 days, but it will last for more than a week for the whole head. |
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