Why am I seeing Tillers in my Corn?

I have been receiving a few calls over the season regarding tillering in corn. So I figured a Crop Chatter post based on an article I wrote back in 2005 would be good to answer some questions. Is it only due to plant populations? What could be other causes? What effect will tillering have on crop growth and yield potential?

What are Tillers? And What Causes Them?  Tillers are lateral branches that form at below ground nodes. Although tiller buds form at each below ground node, the number of tillers that develop is determined by plant population and spacing, soil fertility, early season growing conditions, and the genetic background of the hybrid.

  • Plant Population: Many hybrids will take advantage of available soil nutrients and moisture by forming one or more tillers where stands are thin in the row or at the ends of rows. However, excessive tillering may indicate problems with stand density and distribution. If tillering is associated with row gaps and less than optimal plant populations, these are the conditions which need to be corrected to ensure optimal yields.
  • Soil Fertility: Tillers are most likely to develop when soil fertility and moisture supplies are ample during the first few weeks of the growing season. They are usually visible by the 6-leaf stage of development.
  • Genetics: Hybrids with a strong tillering trait may form one or more tillers on every plant even at relatively high populations if the environment is favorable early in the growing season. If a particular hybrid shows excellent yield potential and also produces extensive tillering under some growing conditions, it should not be avoided.
  • Weather Conditions: Hail, frost, and flooding injury that destroy or damage the growing point early in the growing season can also result in tiller development and non-productive plants.

What is the Effect on Yield Potential? When farmers see extensive tillering in their corn hybrids, they often express concern that the tillering will have a detrimental effect of crop performance (that the tillers will “suck” nutrients from the main plant and thereby reduce yields). As a result, tillers are often referred to a “suckers”. However, research has shown that tillers usually have little influence on grain yields and what effects they do have are generally beneficial. Recent studies have found that there is little movement of plant sugars between the main plant and tillers before tasselling.

After silking and during grain fill, substantial amounts of plant sugars may move from earless tillers to ears on the main plant. When there are ears on both the tiller (often called ‘tassel-ears’) and the main plant, little movement of plant sugars occurs. The main plant and tillers act independently, each receiving sugars from their own leaves. The ‘tassel-ears’ that tillers may produce, therefore have no impact on the ear development of the main plant as was once thought and don’t contribute to yield.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
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