Paul Price, Waltman, William F., Stephenson, Daniel O., Fromme, Daniel, Buckley, Blair, Brown, Sebe, Purvis, Myra, Padgett, Guy B., Ezell, Dustin, Parvej, Md Rasel, Copes, Josh, Mathews, Marcie
The performance of corn hybrids is evaluated annually in official hybrid trials (OHTs) by LSU AgCenter researchers. The purpose of these trials is to provide Louisiana growers, seedsmen, county agents and consultants with unbiased performance data for commercial corn hybrids submitted for evaluation by private companies. Selection of superior hybrids that are well adapted for a given region is essential for maximizing yield and profit. In 2020, 53 corn hybrids were entered by commercial seed companies. Locations of these trials included the Dean Lee Research and Extension Center, Alexandria; Northeast Research Station, St. Joseph; and Macon Ridge Research Station, Winnsboro (Table 1).
Table 1. Agronomic milestones for corn hybrid trials by location, 2020.
|Location||Soil type||Irrigation||Row spacing||Planting date||Harvest date|
|Alexandria (AX)||Coushatta silt loam||Nonirrigated||38”||3/18/20||8/20/20|
|St. Joseph (SJ-sl)||Commerce silt loam||Furrow||40”||3/17/20||8/13/20|
|St. Joseph (SJ-c)||Sharkey clay||Furrow||40”||3/16/20||8/18/20|
|Winnsboro (WN)||Gigger silt loam||Furrow||40”||3/18/20||8/17/20|
Hybrid selection is one of the most important decisions for producers, and there are many different hybrids available on the market. Soil conditions, irrigation practices and cultural practices vary among growers throughout the state; consequently, hybrid performance also varies based on soil type, irrigation, planting date, environmental conditions and location.
Yield is usually the most important trait considered by producers when selecting hybrids; however, maturity, stay-green, lodging, shuck cover, ear placement, disease and insect resistance also need to be considered. Yield data from multiple locations will offer clues as to hybrid performance consistency.
Hybrid maturity is rated using relative maturity (RM) or growing degree day (GDD) rating systems. These two methods are based on the number of days or degree days required for physiological maturity. Louisiana producers can grow early, mid-, and full-season hybrids, with 112-day to 121-day hybrids producing the best yields. Full-season hybrids do not consistently out-yield mid-season hybrids. It appears there is more variability in yield among hybrids within a given RM rating than there is between maturity groups.
Hybrids that stay green later into their maturity usually retain better stalk strength and have less lodging potential. Shuck cover is important for protecting the ear and kernels from weathering and fungi. When planted late during the recommended window, hybrids will grow taller because of higher day and night temperatures and resulting internode elongation. Therefore, ear placement will be higher when compared to earlier planting dates, which may increase lodging potential. Consider planting a hybrid that has a low ear placement late during the planting season.
Corn hybrids have different insect and herbicide traits conferred by biotechnology and should be chosen based on the best fit for your production system. More information regarding available transgenic traits for insect and weed control are available in the Insect Pest Management Guide and Suggested Chemical Weed Control Guide.
Select several hybrids that are consistently top performers over multiple locations or years within a region. Consistency over multiple environments is important because environmental conditions vary annually.
The experimental design at each location was a randomized complete block design with four to five replications. Measured traits and rating scales are defined in Table 2. Analyses of variance and least significant differences (LSD) were calculated only if differences existed at the 90% confidence level. If differences were significant, an LSD at the 10% probability level was calculated. If the LSD (0.10) for yield in a trial is 10 bushels per acre, there is a 10% chance that two hybrids with a reported yield difference of 10 bushels per acre are genetically equal and a 90% probability they have differences in genetic potential in that particular environment. LSD values are influenced by how well soil fertility, stand establishment, plot length, harvest efficiency, and other variables are controlled and by the number of replications for each hybrid. The letters NS are used in the text and tables to indicate lack of significance (not significantly different) at the 10% probability level. The coefficient of variation (CV) reflects the magnitude of experimental error (random variation not accounted for by hybrids and replications) in relation to the trial mean. A high CV means that relative differences among hybrids were not consistent among replications, which reduces the precision of the test.
Table 2. Corn traits and rating scales used in the LSU AgCenter Official Hybrid Trials, 2020.
|Yield||YLD||Grain yield, bu/a, adjusted to 15.5% moisture|
|Grain moisture||GM||Grain moisture at harvest (%)|
|Test weight||TW||Volume weight of grain (lb/bu)|
|Plant population||PP||Plant population (No./A)|
|Mid-silking date||MS||Silking date of 50% of plants, in days after planting (DAP)|
|Plant height||PH||Height from ground to the flag leaf (in)|
|Ear height||EH||Height from ground to where primary ear attaches to the plant (in)|
|Husk cover||HC||Visual rating of how well kernels are covered, 1=closed and 3=open husk|
|Lodging||LO||Lodging at harvest (%)|
|Northern corn leaf blight||NCLB||Northern corn leaf blight rating; 0=none, 9=severe|
|Southern rust||SR||Southern rust rating; 0=none, 9=severe|
Yield data across locations for 2020 is summarized in Table 3. For individual locations, a summary of agronomic milestones is listed prior to the data (Tables 4-7). Contact information for participating seed companies is detailed in Table 8.