Today, the technology to vary hybrid placement is readily available, making the potential value of this technology for improving yields an important consideration. In addition to potential benefits, growers must also consider potential risks as well as the cost of deploying multi-hybrid planting. Costs include the initial investment in equipment, as well as the increased effort and complexity associated with developing multi-hybrid prescriptions and managing a greater number of seed products during planting season.
Table 2. Corn product designations for each multi-hybrid planting trial location in Pioneer on-farm trials.
Pioneer On-Farm Trial Results
Results showed that, at all eight trial locations, the best outcome would have been achieved by planting one hybrid across the entire field (Table 3). In most cases this was the offensive hybrid. At five of the eight locations, the offensive hybrid was the best yielding across all management zones.
At the two locations where Pioneer® P1197AM™ brand corn was designated as the defensive hybrid, it was higher yielding than the offensive hybrid. The predicted whole-field average yield for the multi-hybrid prescription was usually intermediate between the predicted whole-field average yields for the two individual hybrids. Estimated yield for multi-hybrid planting was 10.8 bu/acre less on average than if the whole field had been planted to the higher yielding hybrid.
Table 3. Predicted whole-field average yield in Pioneer on-farm trials for both individual hybrids and the multi-hybrid prescription, and the difference between multi-hybrid and the better of the two hybrids.
At the three locations where the defensive hybrid had greater yield in portions of the field, the potential benefit of multi-hybrid planting was limited in part by imperfect hybrid placement; i.e., there was not perfect alignment between the zones where the defensive hybrid was assigned and zones where it actually performed better. Had hybrid placement been optimal in these three locations, multi-hybrid planting would have resulted in a whole field average yield between 0.6 and 2.6 bu/acre better than planting the entire field to the best of the two hybrids (Table 4). Lost yield potential due to imperfect hybrid placement at these locations ranged from 2.6 to 8.7 bu/acre.
Table 4. Potential yield advantage with multi-hybrid planting at select locations if hybrid placement had been optimal.
The outcome of the multi-hybrid trials in 2015 was largely driven by the weather conditions experienced during the growing season. Moisture was generally ample, in some cases excessive, in the study area in 2015, which minimized the number and extent of environments in which a more drought tolerant hybrid would provide a yield advantage. This is an example of the first risk/benefit scenario described at the beginning of this article in which multi-hybrid planting can have a downside risk if the stress factor that it is intended to manage is not present. Given that these trials were all conducted in one growing season under similar conditions, the results do not provide much insight on the potential value of multi-hybrid planting across a wider diversity of environments. However, they do provide a very good illustration of a set of conditions under which multi-hybrid planting is unlikely to provide value and could, in fact, carry significant downside risk.
South Dakota State University Research
Researchers at South Dakota State University conducted a four-year study from 2013 to 2016 comparing conventional and variable hybrid planting at several locations in South Dakota (Sexton et al., 2013; 2014; 2015; 2016). This study involved placing hybrids with greater tolerance to wet conditions in low landscape positions where there was likely to be excess moisture early in the season and more drought-tolerant hybrids at upper landscape positions likely to experience drought stress later in the season. Corn products suited to these environments were selected with the input of Pioneer agronomists (Table 5).
Table 5. Pioneer® brand corn products selected for upland and lowland environments in multi-hybrid research conducted by South Dakota State University.
For the first two years of the study, research locations were planted using a modified Monosem twin-row planter capable of switching between two hybrids. The latter two years of the study used a Kinze 4900 multi-hybrid planter. The plots were set up as field length strips and laid out so that each strip included both upland and lowland landscape positions.
Research trials were successfully completed at three locations in 2013, with multi-hybrid planting providing a significant yield benefit at two of the three. At one location, two of the multi-hybrid pairs (Pioneer® P0876AM™ and P1151AM™ brand corn and Pioneer® P0876AM™ and P0987AM1™ brand corn) yielded better than the best individual hybrid, producing overall average yields of 198 bu/acre and 197 bu/acre compared to 190 bu/acre with the whole field planted to Pioneer® P0876AM™ brand corn. This represents an ideal scenario for multi-hybrid planting, since it allowed yields greater than those achieved with any individual hybrid planted across the entire field. Results at this location also demonstrated the importance of optimal hybrid selection, as one of the multi-hybrid pairs (Pioneer® P0533AM1™ and P1151AM™ brand corn) was among the lowest yielding entries in the study. At the second location, the multi-hybrid entries were higher yielding on average, but the highest yielding pair of hybrids did not yield any more than the best individual hybrid. At the third location, multi-hybrid planting did not show a yield benefit.
Research trials were completed at two locations in 2014. Multi-hybrid planting with Pioneer® brand products provided a 6 bu/acre yield advantage at one location but no advantage at the other location. Multi-hybrid planting did not show a yield benefit at any of the four study locations in 2015. This outcome was attributed to the generally favorable growing conditions and lack of drought stress experienced during the 2015 season. Research was only conducted at one location in 2016 and did not show any yield benefit for multi-hybrid planting.
Results of the four-year study showed that multi-hybrid planting can be an effective tool to improve corn yield but that success is dependent upon hybrid selection and placement and the weather conditions experienced during the growing season. Results of trials conducted in 2015 mirrored those of the Pioneer trials in Iowa in which the yield-limiting stress the multi-hybrid prescription was designed to manage did not manifest. Unlike the Pioneer trials, the SDSU study showed little downside risk associated with multi-hybrid planting – it provided a yield benefit in some site years and no yield difference in the majority of site-years, but no instances where the outcome of a multi-hybrid pair was substantially worse than the better of the two hybrids. The risk associated with multi-hybrid planting is likely to be greatly dependent on the profiles of the individual hybrids – the greater the divergence between the two hybrids in top-end yield potential or tolerance to a key yield-limiting stress, the greater the potential to lose yield if conditions during the growing season do not play out as anticipated.
Figure 2. Simplified example showing whole field average yields with a single hybrid and multi-hybrid planting in a field evenly split between high and low productivity zones.
Figure 1A: High Productivity Field
Figure 2A: Drought-Stressed Field
Figure 1B: High Productivity Field
Figure 2B: Drought-Stressed Field
Figure 1C: High Productivity Field
Figure 2C: Drought-Stressed Field
AM - Optimum® AcreMax® Insect Protection system with YGCB, HX1, LL, RR2. Contains a single-bag integrated refuge solution for above-ground insects. In EPA-designated cotton growing counties, a 20% separate refuge must be planted with Optimum AcreMax products. AM1 - Optimum® AcreMax® 1 Insect Protection System with an integrated corn rootworm refuge solution includes HXX, LL, RR2. Optimum AcreMax 1 products contain the LibertyLink® gene and can be sprayed with Liberty® herbicide. The required corn borer refuge can be planted up to half a mile away. AMX - Optimum® AcreMax® Xtra Insect Protection system with YGCB, HXX, LL, RR2. Contains a single-bag integrated refuge solution for above- and below-ground insects. In EPA-designated cotton growing counties, a 20% separate corn borer refuge must be planted with Optimum AcreMax Xtra products.
AMXT (Optimum® AcreMax® XTreme) - Contains a single-bag integrated refuge solution for above- and below-ground insects. The major component contains the Agrisure® RW trait, the YieldGard® Corn Borer gene, and the Herculex® XTRA genes. In EPA-designated cotton growing counties, a 20% separate corn borer refuge must be planted with Optimum AcreMax XTreme products. HXX - Herculex® XTRA contains the Herculex I and Herculex RW genes. YGCB - The YieldGard® Corn Borer gene offers a high level of resistance to European corn borer, southwestern corn borer and southern cornstalk borer; moderate resistance to corn earworm and common stalk borer; and above average resistance to fall armyworm. LL - Contains the LibertyLink® gene for resistance to Liberty® herbicide. RR2 - Contains the Roundup Ready® Corn 2 trait that provides crop safety for over-the-top applications of labeled glyphosate herbicides when applied according to label directions. Liberty®, LibertyLink® and the Water Droplet Design are registered trademarks of Bayer. YieldGard®, the YieldGard Corn Borer design and Roundup Ready® are registered trademarks used under license from Monsanto Company. Herculex® Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred. Herculex® and the HX logo are registered trademarks of Dow AgroSciences LLC. Agrisure® is a registered trademark of, and used under license from, a Syngenta Group Company. Agrisure® technology incorporated into these seeds is commercialized under a license from Syngenta Crop Protection AG.
HX1 – Contains the Herculex® I Insect Protection gene which provides protection against European corn borer, southwestern corn borer, black cutworm, fall armyworm, lesser corn stalk borer, southern corn stalk borer, and sugarcane borer; and suppresses corn earworm. Herculex® I Insect Protection technology by Dow AgroSciences and Pioneer Hi-Bred. Herculex® and the HX logo are registered trademarks of Dow AgroSciences LLC.
All Pioneer products are hybrids unless designated with AM1, AM, AMT, AMRW, AMX and AMXT, in which case they are brands.
PIONEER® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents.
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary.