Henry Mascagni | 1/10/2017 3:32:53 PM
Performance of corn hybrids is annually evaluated by Louisiana Agricultural Experiment Station (LAES) researchers in Official Variety Trials (OVT’s). The purpose of these trials is to provide to Louisiana growers, seedsmen, county agents of the Louisiana Cooperative Extension Service (LCES), and other interested individuals and organizations with unbiased performance data for commercial corn hybrids submitted for evaluation by private agencies. The cooperating LAES units in 2016 were: Dean Lee Research Station, Alexandria; Red River Research Station, Bossier City; Northeast Research Station, St. Joseph; and Macon Ridge Research Station, Winnsboro.
In 2016, 43 corn hybrids were entered in the LAES yield trials. Soil type, cultural practices, location summaries, and weather graphs are listed prior to data tables for each location. In weather graphs, maximum and minimum temperatures are weekly averages and rainfall weekly totals. At St. Joseph, trials were conducted both on Commerce silt loam, Commerce sandy loam, and Sharkey silty clay Mississippi River alluvial soils. Bossier City, St. Joseph (Commerce silt loam and Sharkey silty clay trials), and Winnsboro trials were furrow irrigated.
The experimental design at each location was a randomized complete block design with four or five replications. Traits measured and rating scales are listed in Table 1. Traits not listed in Table 1 are footnoted at the base of the respective table. Analysis of variance and least significant differences (LSD) were computed using SAS (Statistical Analysis System). We used the protected F-test, which means LSD’s were calculated only if differences among hybrids existed at the 90% confidence level. If differences were significant, a LSD at the 10% probability level was calculated. If the LSD (0.10) for yield in a trial is 10 bu/acre, there is a 10% chance that two hybrids with a reported yield difference of 10 bu/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 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 a test.
Yield data for 2016 and two-year averages (2015 and 2016) and other agronomic data for each location are presented in Tables 2-8. To be considered for a two-year average, hybrids must have the same seed traits each year (refer to Table 10). Yields for the hybrids in the highest-yielding group for 2016 (yields falling within one LSD value) are in bold print. Hybrids in bold print with a single asterisk are in the highest yielding group for both years, 2015 and 2016. Yield summary across Louisiana for 2016 is presented in Table 9, seed traits and hybrid maturities are listed in Table 10, and participating seed companies are listed in Table 11. Ratings for corn earworm damage have been taken in previous years; however, there was minimal corn earworm damage in 2016. Foliar diseases were also monitored in the trials with ratings taken at Alexandria, St. Joseph (Commerce silt loam trial), and Winnsboro. There was little or no problems with lodging. There were ten seed companies that participated in the 2016 corn hybrid performance trials.