2013 WISCONSIN CORN HYBRID PERFORMANCE TRIALS: Grain - Silage - Specialty - Organic

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The UW Hybrid Trial website

Every year, the University of Wisconsin-Extension and the University of Wisconsin-Madison College of Agricultural and Life Sciences conduct a corn evaluation program in cooperation with the Wisconsin Crop Improvement Association. The purpose of this program is to provide unbiased performance comparisons of hybrid seed corn for both grain and silage available in Wisconsin.
In 2013, grain and silage performance trials were planted at 14 locations in four production zones: the southern, south central, north central, and northern zones. Both seed companies and university researchers submitted hybrids.

Table of Contents
Introduction Companies entering hybrids Hybrid index Transgenic technologies Seed treatments Temperature and Precipitation Trial management Hybrid history		Text Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 25
Grain
Southern Zone   Arlington, Janesville, Lancaster	Early Maturity Trial: 105 day or earlier Late Maturity Trial: later than 105 day	Table 7 Table 8
South Central Zone   Fond du Lac, Galesville, Hancock (irrigated)	Early Maturity Trial: 100 day or earlier Late Maturity Trial: later than 100 day	Table 9 Table 10
North Central Zone   Chippewa Falls, Marshfield, Seymour, Valders	Early Maturity Trial: 90 day or earlier Late Maturity Trial: later than 90 day	Table 11 Table 12
Northern Zone    Spooner (three sites), Coleman		Table 13
Silage
Southern Zone   Arlington and Lancaster	Early Maturity Trial: 110 day or earlier Late Maturity Trial: later than 110 day	Table 14 Table 15 Figure 2
South Central Zone   Fond du Lac and Galesville	Early Maturity Trial: 106 day or earlier Late Maturity Trial: later than 104 day	Table 16 Table 17 Figure 3
North Central Zone   Chippewa Falls, Marshfield, Valders	Early Maturity Trial: 99 day or earlier Late Maturity Trial: later than 99 day	Table 18 Table 19 Figure 4
Northern Zone   Spooner (two sites), Coleman		Table 20 Figure 5
Organic
Southern Zone    Arlington, Janesville, Lancaster		Table 21
North Central Zone    Chippewa Falls, Marshfield, Seymour, Valders		Table 22
Specialty - Dryland and Conventional
Central Zone - Dryland    Chippewa Falls, Hancock Deficit Irrigation,    Hancock Full Irrigation		Table 23
Southern Zone - Conventional    Arlington, Janesville, Lancaster		Table 24

OBTAINING DATA ELECTRONICALLY

This report is available in Microsoft Excel and Acrobat PDF formats at the Wisconsin Corn Agronomy website: http://corn.agronomy.wisc.edu. 

The most current version of Wisconsin Corn Hybrid Performance Trials (A3653) is also available to download as a PDF or purchase as a printed booklet at the UW Extension Learning Store: http://learningstore.uwex.edu. 

For more information on the Wisconsin Crop Improvement Association, visit: http://wcia.wisc.edu. 

Copyright © 2013 by the Board of Regents of the University of Wisconsin System doing business as the division of Cooperative Extension of the University of Wisconsin-Extension. All rights reserved. Send copyright inquiries to: Cooperative Extension Publishing, 432 N. Lake St., Rm. 227, Madison, WI 53706, pubs@uwex.edu.

This publication is available from your county UW-Extension office (yourcountyextensionoffice.org), from the University of Wisconsin–Madison Department of Agronomy, 1575 Linden Drive, Madison, WI 53706, phone: (608) 262-1390, or from Cooperative Extension Publishing. To order, call toll-free: 1-877-947-7827 (WIS-PUBS) or visit our website: learningstore.uwex.edu.

Evaluating On-Farm Test Plots

Wisconsin farmers are in the thick of corn harvest. With the delayed frost, some are finishing up silage harvest, while others have begun grain harvest. Early yield indications are good in many areas that had reasonable spring planting dates. Average yields of hybrids gown in the early- and late-trials at Galesville were 221 and 234 bu/A. However, the trials at Marshfield we had to abandon due to June flooding, and the trials at Chippewa Falls will be quite variable due to drought.

This is also the time of year when on-farm strip plots are evaluated. Field variability alone can easily account for differences of 10 to 50 bushels per acre. Be extremely wary of strip plots that are not replicated, or only have "check" or "tester" hybrids inserted between every 5 to 10 hybrids. The best test plots are replicated (with all hybrids replicated at least three times).

Don't put much stock in results from ONE LOCATION AND ONE YEAR, even if the trial is well run and reliable. This is especially important in years with tremendous variability in growing conditions. Years differ and the results from other locations may more closely match your conditions next year. Use data and observations from university trials, local demonstration plots, and then your own on-farm trials to look for consistent trends.

A few suggestions on how to evaluate research test plots:

1. Walk into plots and check plant populations. Hybrids with large ears or two ears per plant may have thin stands.
2. Scout for pest problems. Hybrid differences for pest resistance and tolerance should be monitored and noted all season, but will be most apparent in the fall. Counting dropped ears is a good way to measure hybrid ear retention and tolerance to European corn borers.
3. Check for goose-necked stalks. This is often root pruning caused by corn rootworms. Hybrids differ in their ability to regrow pruned roots.
4. Find out if the seed treatments (seed applied fungicides and insecticides) applied varied among hybrids planted, e.g. were the hybrids treated with the same seed applied insecticide at the same rate? Differences in treatments may affect final stand and injury caused by insects and diseases.
5. Differences in standability will not show up until later in the season and/or until after a wind storm. Pinch or split the lower stalk to see whether the stalk pith is beginning to rot.
6. Break ears in two to check relative kernel development of different hybrids. Hybrids that look most healthy and green may be more immature than others. Don't confuse good late season plant health ("stay green") with late maturity.
7. Visual observation of ear-tip fill, ear length, number of kernel rows, and kernel depth, etc. don't tell you much about actual yield potential. Hybrid differences are common for tip kernel abortion ("tip dieback" or "tip-back") and "zipper ears" (missing kernel rows). Even if corn ear tips are not filled completely, due to poor pollination or kernel abortion, yield potential may not be affected significantly, if at all, because the numbers of kernels per row may still be above normal.
8. Be careful with test plots consisting predominately of one company's hybrids. Odds are stacked in their favor!

Can Yield Maps Predict Future Yields?

To maximize field productivity and profitability, growers are increasingly using site-specific management rather than whole field management practices. Our objective is to describe spatial and temporal yield variability to predict grain yield of specific land cells (parcels of land). The goal is to determine if yield maps allow accurate delineation of management zones for prescription applications.

Grain yield data for twenty-six years of continuous corn (CC), continuous soybean (SS), and corn-soybean rotations (CS) in no-tillage (NT) and conventional tillage (CT) systems were used in the analysis.

Spatial variability is the variation of land cells within a field for a given year (i.e. yield map) and in this example averaged + 12 bu/A (+5 to +24 bu/A). Temporal variability is the variability of a land cell over time and in this example averaged + 42 bu/A (+40 to +43 bu/A).

Within corn systems, spatial variability was +11 to +15 bu/A and temporal variability was +42 to +44 bu/A. Within soybean systems, spatial variability was +4 to +5 bu/A, while temporal variability was +9 to +13 bu/A.

Each land cell was ranked within its rotation x tillage combination; therefore, to incorporate the CS rotation effect, two years are required for one cycle. Our analysis found that land cells are significantly different for grain yield and could be ranked within a tillage x rotation treatment. CC-NT required 2 years (one cycle) before a significant yield difference was first found between land cells, while corn in CS-NT required 20 years (10 cycles). High- and low-yielding land cells were not consistently identified until 16-20 years (8-10 cycles) had passed, with the exception of CC-CT which only required 4 years (2 cycles).

For specific land cells, high corn yield did not always predict high soybean yield and vice-versa. For example, land cell 102 was the lowest yielding cell for corn, while yielding statistically the same as the highest land cell for soybean.

In this uniform field, consistent land cell grain yield patterns were observed for tillage x rotation treatments. These patterns did not consistently predict grain yield between corn and soybean. Since spatial variation is lower than temporal variation, prescription predictions remain challenging.

For a complete report including tables click here.

Pricing Corn Silage

Pricing corn silage is a difficult decision because it often comes at a time when emotions between sellers and buyers are high. The seller has the opportunity to sell a corn field for either silage or grain and incorporate the fertilizer value of the stover back into the field. The buyer has the opportunity to buy a corn field for silage or buy grain from the market and purchase low quality straw (wheat or corn stover aftermath) to formulate rations.

Arriving at a fair price and being able to take into account the markets (grain, straw, milk and silage), fertilizer, harvesting and quality costs is a difficult decision. Somewhere in the middle of the seller and buyer perspectives negotiations should be able to arrive at a fair price. The Sterry et al. spreadsheet (see http://corn.agronomy.wisc.edu/Season/DSS.aspx) accounts for both the seller and buyer perspectives to arrive at a fair price for corn silage. This article performs a sensitivity analysis of this spreadsheet.

The assumptions and initial values typical for the market conditions heading into the 2013 harvest are shown on page 2 of the original article (click here). To produce the sensitivity analysis in Table 1, one input value at a time was changed on the spreadsheet for grain price, milk price, grain yield, starch content, straw price and NDFD. This can lead to somewhat ambiguous conclusions. For example, often the seller receives a lower price than what the buyer must pay for grain, however, in this example the seller and buyer grain prices are held the same. Also, when one quality measure moves in a certain direction (i.e. starch content) other measures (i.e. grain yield or NDFD) are affected as well. In 2013 many corn fields were late late-planted and affected by drought which affects yield, starch content and NDFD.

Table 1. Sensitivity analysis of seller and buyer perspectives using the Sterry et al. spreadsheet for calculating the value of standing corn silage ($/T) with quality adjustments.

Grain prices between $4 and $7 per bushel affect corn silage price from $28 to $51 per Ton wet. Milk price affects the buyer decision much more than the seller. Low grain yields reduce the price of standing corn silage as does lower starch content. Straw price does not affect the seller perspective, but does affect the buyer perspective of a standing corn silage field because he has the option to buy wheat straw. NDFD had little effect on corn silage price in this spreadsheet.

Users of this spreadsheet need to input their own data for the values used in the calculations.

Assessing Hail Damage in Corn

This past Tuesday evening, an intense storm with hail and high winds swept through northern Wisconsin. Some hail damage has been reported in western Wisconsin. Any corn knocked down by wind will likely recover since it is still early enough in the growing season and the stalk and leaves are still green.

Hail affects yields primarily by reducing stands and defoliating the plant. Defoliation causes most of the loses. Knowing how to recognize hail damage and assess probable loss is important for decision making.

The keys to storm related damage of crop fields are to: 1) be patient, 2) determine the crop growth stage, and 3) assess plant health accurately. Go ahead and view the damage, but do not make any assessments until 7-10 days have passed because it is difficult to distinguish living from dead tissue immediately after a storm, It will take that long for the corn plant to begin growing again if it can. For guidelines on assessing hail damage click here.

Hail adjusters use standard tables to calculate compensation for yield loss associated with hail. Four assessments are made on corn when hail occurs after silking (Vorst, 1990) including:

1. Determining yield loss due to stand reduction,
2. Determining yield loss due to defoliation,
3. Determining direct ear damage, and
4. Bruising and stalk damage.

It is important to work with your crop insurance adjuster before any final decisions are made. 

Further Reading

Lauer, J.G., G.W. Roth, and M.G. Bertram. 2004. Impact of Defoliation on Corn Forage Yield. Agron J 96:1459-1463.

Roth, G.W., and J.G. Lauer. 2008. Impact of Defoliation on Corn Forage Quality. Agron J 100:651-657.

Vorst, J.V. 1990. Assessing Hail Damage to Corn. National Corn Handbook NCH-1:4 pp.

Corn Kernel Development During 2009-2012

Due to late-planting dates, the 2013 growing season is shaping up to be one of the most uneven seasons for plant  development. Nearly 30% of our corn was planted during June and many fields were finally planted the week of July 4 (Figure 1). As we near harvest, corn from these fields will likely be sold as silage to dairy farmers. In a previous article we talked about the theory of late planted corn on kernel maturity and the implications for yield and quality. In this article I would like to present field data of kernel development from experiments conducted at Arlington, WI.

Figure 1. Wisconsin corn planting progress (Data source: USDA-NASS).

These experiments had five planting dates involving different maturities of corn. Corn development stages were determined for each plot by noting the first date each reproductive growth stage was achieved (Table 1). Data from the first and last planting date is shown in Table 1. The growing season of 2009 was characterized as cool and wet, while 2012 was hot and dry. The number of days to get from silking (R1) to the denting stage (R5) was 28-45 days depending upon year, planting date and hybrid maturity. For kernels to develop from silking to 50% kernel milk required 45-62 days.

Table 1. Kernel development of full- and shorter-season corn hybrids at Arlington, WI.

	2009	2010	2011	2012
Planting dates	April 10-June 15	April 14-June 18	April 13-June 17	March 28-June 15
GDUs (May 1-July 15)	932	1156	1038	1253
GDUs (July 15-Oct 1)	1069	1327	1264	1309
Full-season Hybrid	Pioneer 35F40	Pioneer 35F40	Pioneer 35F44	Pioneer 35F48AM1
Relative Maturity (days)	105 d RM	105 d RM	105 d RM	105 d RM
R1: Silking date	July 24-Aug 16	July 16-Aug 11	July 20-Aug 9	July 9-Aug 6
R5: Denting date (DAS) †	Sep 3-Sep 28  (41-43)	Aug 16-Sep 21  (31-41)	Aug 18-Sep 14  (29-36)	Aug 10-Sep 9  (32-34)
R5.5: 50% Kernel milk date (DAS)	Sep 20-DNM  (57-DNM‡)	Sep 2- Oct 11  (48-61)	Sep 6-Oct 10  (48-62)	Aug 31-Sep 28  (48-53)
Forage yield (T DM/A)	11.0-7.2	10.0-7.5	10.1-7.2	8.7-7.3
Grain yield (bu/A)	224-118	255-51	224-155	236-106
Grain moisture (%)	24-40	15-40	17-29	19-50
Shorter-season hybrid	Jung 7426VT3	Jung 7426VT3	Dekalb DKC48-37	---
Relative Maturity (days)	96 d RM	96 d RM	98 d RM	---
R1: Silking date	July 25-Aug 17	July 16-Aug 12	July 19-Aug 7	---
R5: Denting date (DAS) †	Aug 31-Oct 1  (38-45)	Aug 18-Sep 18  (33-38)	Aug 20  Sep 12  (28-36)	---
R5.5: 50% Kernel milk date (DAS)	Sep 18-DNM  (54-DNM)	Aug 30-Oct 12  (45-61)	Sep 4-Oct 7  (48-61)	---
Grain yield (bu/A)	271-144	235-138	231-177	---
Grain moisture (%)	20-41	13-39	15-27	---

† DAS= Days after silking; ‡ DNM= Did not measure

As planting date is delayed the number of days required to reach various reproductive stages increased. To predict whether corn will mature before frost note the hybrid maturity, planting date and tasseling (silking) date of the field. For silage planted early, add 42-47 days on to this date to predict 50% kernel milk, while for grain, add 55-60 days to predict maturity. For later planting dates an additional 7-10 days may be required. These dates are guidelines which will require further in-season decisions as the season unfolds.