Wheat School: High head counts deliver high yield


Wheat yield is made up of many yield components ranging from thousand kernel weight to head size and kernels per head. But when it comes to driving higher yields, all those components take a back seat to the number of heads per square metre.

It’s the big data point emerging from three years of data from growers participating in the Great Lakes Yield Enhancement Network (YEN), says Michigan State University wheat systems specialist Dennis Pennington.  “That is the biggest thing that’s different between those high yield growers and the lower yield growers.”

On this episode of RealAgriculture’s Wheat School, Pennington and host Peter Johnson dissect the data, which indicates that growers in the top 20 per cent for yield in the 2023 YEN program averaged 870 heads/m2 while growers in the bottom 20 per cent averaged 553 heads/m2.

How do those top growers get those high head numbers? Pennington says the common denominator is early planting or what he often refers to as planting on time. “The only way to get those high head numbers is to get planted in the fall early enough so you can get that fall tillering to occur. That planting date is probably the very most important thing that you can do to drive higher yield potential. We see it in our research trials, we’re seeing it in the YEN, we’re seeing it everywhere,” he stresses.

Johnson notes that, on average, in 2022, there was only six day difference between the planting date for the YEN’s high yield growers and the low yield growers but those days really count.

In the video, Pennington shares research that looks at the impact delayed planting can have on tiller development and head numbers. In the trials, wheat was planted every 15 days beginning September 15 up until November 15. (Story continues below.)

“If you dig a plant in December, and you look at how much fall development there is on that plant, the difference between the October 1 and the October 15 planting — only 15 days difference —  is huge.

“The October 15 planting had no tillers at all and the October 1 had three tillers so that’s a fairly narrow window where you’ve got to get on the front end if you’re going to get that tiller development in the fall,” says Pennington. “If you miss that window, and it’s not very many days, then you just don’t have that number of tillers and number of heads per metre squared that’s going to be so important for your yield potential the following harvest.”

Click here for more Wheat School videos.

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