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Tillers in wheat: Good or bad?

Opinions vary on the question of whether you should shoot for more main stems or more tillers for profit wheat yields.

November 29, 2018

2 Min Read
MAIN HEADS: Wheat heads on main stems are bigger than wheat heads on tillers, but if the stand is poor you’ll need more tillers to fill in and reduce weed pressure.

Should you shoot for more main stems or more tillers in wheat this year?

Opinions vary as to whether or not more tillers are beneficial to grain yields, says Jonathan Kleinjan, South Dakota State University Extension agronomist.

One the one hand, tillers can be beneficial. They help a wheat plant to “fill-in” areas with a poor stand and thus provide weed suppression. More tillers can also result in more heads at harvest, although most research has shown that, regardless of the number of tillers produced, 85% to 100% of hard red spring wheat grain yield is produced by the main stem and the T1 and T2 tillers.

A review of intensive wheat management studies suggest that increased yields are the result of more primary spikes with heavier kernels, instead of increased tiller counts.

If a you want to reduce the number of tiller you might consider:

Planting date. Late planting will generally result in fewer tillers due to a reduction in vegetative growth. However, wheat is a cool-season grass and is most productive when planted early. This management practice is not recommended.

Plant genetics. There is genotypic variation for tillering capacity among cultivars. While environmental factors are typically more important than variety selection, low-tillering varieties may respond differently to other management practices than high-tillering varieties.

Nitrogen management. In general, more N will result in more vegetative growth and more tillers. However, tiller formation can be affected by the timing of N and can be increased when application occurs before planting or during the tillering process. To reduce tillers, the bulk of N should be applied after tillering, just prior to stem elongation. A drawback to this approach is another trip across the field and the risk of having N application delayed by weather events.

Seeding rates. Optimum seeding rates to achieve high yields can vary greatly across variety and environment. However, increasing the seeding rate seems to have the largest impact on reducing the number of tillers without negatively influencing yield. Studies involving intensive management of hard red spring wheat usually increase the seeding rate by about 50%.

Combining practices. In a summary of intensive management research conducted on hard red spring wheat in the upper Great Plains, Joel Ransom, North Dakota State University Extension agronomist, writes: “It has been hypothesized that, by delaying the N application until tillering has ceased combined with a higher seeding rate, there will be more main stems, greater yield potential, and more uniformity in the flowering of the spikes.” Ransom has more recently noted that this approach was developed for winter wheat producing regions that have a long spring growing season and research with spring wheat has been less promising. Furthermore, timely rainfall, to allow for the incorporation of surface applied nitrogen, is critical with this technique and poses a risk of reducing the effectiveness of the in-season applied nitrogen in dryer seasons. 

Source: SDSU, NDSU

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