Effect of Tiller Removal on Corn Yield

by Emerson D. Nafziger, Crop Sciences Department

• Problem Description
• Study Description
• Research Questions and Answers
• Acknowledgement

Problem Description:

Fifty years ago corn tiller ("sucker") removal by hand was common, presumably because it was believed that tillers reduced yield. While the standard response to questions about tillers in corn is that they do not affect yield, the availability of commercial hybrids with strong genetic propensity to tiller continues to raise some concern among producers about this phenomenon. The objective of this study is to assess the effect of tiller removal on the grain yield of a corn hybrid (Pioneer Brand 3335), a hybrid that tends to tiller to a high degree.

Study Description:

The corn hybrid Pioneer 3335 was planted in April in 1997 and 1998 in productive Drummer silty clay loam soil under high management at Urbana, Illinois. Seeding rate was about 35,000 per acre, and after emergence, plant populations of 20,000, 25,000, and 30,000 plants per acre were established in main plots 21 feet long by 12 (30-inch) rows wide, with four replications. Three subplots were assigned within each main plot: 1) tillers allowed to grow; 2) tillers removed by cutting at the 7-leaf stage (mid-June); and 3) tillers removed by cutting at the 7-leaf stage and again at about the 16-leaf stage (mid-July). In 1998, a fourth treatment consisted of cutting tillers only at the V-16 stage. Tiller counts were made at the time of the first tiller removal, and again at the time of the second removal. Tillers were virtually impossible to find prior to harvest, and so counts and size of surviving tillers were not taken. The center two rows of each 4-row subplot will be combine-harvested for yield.

Research Questions and Answers:

1. Did cutting tillers change grain yield?

No. Tillers were unexpectedly scarce in 1997, when only about 19 percent of the plants formed tillers. In 1998, about 35 percent of the plants formed tillers. In neither year did cutting tillers change yield. Averaged over plant populations, cutting tillers 0, 1, or 2 times produced grain yields of 161, 161, and 163 bushels per acre, with the differences not even close to statistically significant (i.e., the two-bushel "difference" was almost certainly due to random chance).

2. Did plant population affect tiller formation, yield, or the response to tiller removal?

Tiller formed slightly more often at lower populations -- plants at populations of 20,000, 25,000, and 30,000 produced tillers on 29, 29, and 21 percent of the plants. Yields responded slightly to increasing plant population in 1997, but not in the drier year of 1998. Tiller removal did not affect yield regardless of plant population in either year.

3. Did tillers regrow after being cut?

Where tillers had been cut at V-7, we found tillers on about 6 percent of plants about a month later, at V-16. Perhaps cutting tillers early may have freed up some sugars in the lower stalk and encouraged another tiller to grow, or original tillers may have regrown. In general, though, tillers at the second cutting date were not much larger than at the first cutting date, due to shading.

4. Is there any reason to be concerned if a hybrid produces a lot of tillers in the field?

No. I would be concerned about tillers only if they were still green and growing at mid-season, especially if they produced ears. That would indicate that they received too much light, probably indicating that the plant population was too low for best yields.

Acknowledgment: This research was supported by a grant from Pioneer Hi-Bred International, Inc..