Wheat Development December 2012 – GS 21-22 Tillering

 

Apologies that its been a while since I last entered much on wheat development, quite simply I lost a bit of oomph and more crucially there has not been much happening. 

Today I took Junior AgronomyMan and AgronomyDog for a walk and took a few shots with the phone, so images aren’t great.

1 main tiller with a coleoptile tiller just visible

The crop is now beginning to tiller, which means that it is producing more shoots on which the ears and then the grain will develop. The tillers form at the base of the first formed leaves of the mainstem and of the coleoptile. A coleoptile tiller bud is present in the dormant seed but the tiller emerges only if the seed is sown deeply. This coleoptile tiller is the very pale yellow shoot that is coming from the seed in the image to the right.  This growth stage is known as GS 2:1, 2 being tillers present and the 1 denoting the number of tillers present.  When another tiller becomes visible it will be GS 2:2, etc. We only count up to maximum of 9 tillers ie GS 29.

                                                                              Tillers in the axils of Leaf 1, Leaf 2 and Leaf 3 emerge first and are usually strong enough to grow to full canopy height and to set grain.  The next image appears courtesy of Wheatbp, and  shows how the crop will develop.  The bottom image shows the crop at GS 23, with 3 tillers being present.

As you can see there are more tillers being formed quite early in the plant’s growth, in fact these tillers will continue to appear through the autumn and early spring period. Not all these tillers will produce viable ears and will eventually die back, and replenish the plants energy reserves. Tillering is vital as not only are these the sites of grain production in the summer, but crucially in the autumn they are covering the soil. Of course this is all used to harness the photosynthetic energy of the sun, but it also has a huge benefit in covering the soil surface and suppressing weed emergence.

As you can see in this image the soil is beginning to be covered by leaves which also means herbicides will need to be applied early to ensure effective control of weeds is present. Herbicides applied to crop leaves will not control the emerging weeds.

It’s interesting to note the growth habit of the crop at this early stage, some varieties are erect in their growth habit and others are more prostrate.  The prostrate varieties will cover the ground earlier and its these varieties that can be used in lower input situations were weed control from cultural (non-chemical) methods could be considered more preferable.

A close-up of erect v prostate varieties in a trial

You can see in the above image that the prostrate variety is still covered in frost whereas the erect variety has warmed up sufficiently to be frost free.

 

I also noticed that some of the varieties were much later in their establishment and were behind in their development. It’s fair to say that these later varieties may have benefitted from a slightly higher seed rate, as they are likely to suffer from higher winter kill.  Unfortunately I did not have the plan of varieties with me at the time.

A slow developing variety close up
 
 
 
 
The next update in this series will be after the Christmas break,  when we will see the crop well into the tillering stages, and we will start to undertake a few plant counts and see if we can estimate the yield of the crop of wheat.
Yes we can do that, all it takes is a ruler, a notepad and a bit of time.
 
Once again  thank you for reading these blogs, if you feel they are useful please tell your fiends, especially if you are a student,  if not – please tell me how i can improve it.

Finally can I take this opportunity to wish you all a Happy and Peaceful Christmas & New Year

 

AgronomySantaMan

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