Experimental Procedures: 

AgResearch and Education Center Tests: All corn hybrid trials were conducted in each of the physiographic regions of the state. Tests were conducted at the East TN (Knoxville), Northeast Tennessee (Greeneville), Highland Rim (Springfield), Milan (Milan) and West TN (Jackson) AgResearch and Education Centers (REC). The early and medium-season tests were also planted at the Agricenter International Research Center (Memphis). Duplicate plantings of the early-, medium- and full-season tests were made at the Milan and Highland Rim REC for performance testing with and without irrigation. 

The corn hybrids were placed in either the early-, medium-, or full-season tests based on the maturity as reported by the company providing the hybrid. The early season test contained hybrids that had maturity <114 days after planting (DAP); the medium season test contained hybrids with maturity of 114-116 DAP; and the full season test contained hybrids with maturities >116 DAP. All corn hybrid trials were planted to uniform populations per acre at each location using a precision seeding planter. Trials were planted with a goal of 36,000 plants per acre for irrigated plots and 34,000 plants per acre for non-irrigated plots, although final populations varied by location (Table 1). Tests were conducted using 30-inch row spacing. The tests were fertilized with approximately 230 lbs N/a. A portion of the nitrogen was applied prior to planting (e.g. 80 lbs/a) and the remainder was applied as a side-dress (e.g. 150 lbs/a). The plot size was two, 30-ft. rows. Plots were replicated three times at each location. An incomplete block design was used at each location in order to reduce the within replication variation. 

County Standard Tests: The County Standard Corn Tests were conducted in 19 counties in Tennessee and one county in Kentucky. The number of counties varied by test. The County Standard Tests were divided into early-, medium-, and full-season glyphosate resistant and Bt stacked trait tests (same DAP criteria as listed above). Each hybrid was evaluated in a large strip-plot at each location, thus each county test was considered as one replication of the test in calculating the overall average yield and in conducting the statistical analysis to determine significant differences. At each location, plots were planted, sprayed, fertilized, and harvested with the equipment used in the cooperating producer’s farming operation. The width and length of strip-plots were different in each county; however, within a location in a county, the strips were trimmed on the ends so that the lengths were the same for each variety, or if the lengths were different then the harvested length was measured for each variety and appropriate harvested area adjustments were made to determine the yield per acre. 

Growing Season: Corn grain official variety trials were planted between mid-April and mid-May at the University of Tennessee AgResearch and Education Center (REC) locations. Early season rains delayed corn planting throughout the state in April. The weather remained mixed throughout planting, allowing for a large amount of planting to take place in short bursts in mid-May. Statewide corn planting caught up to the five-year average by mid-May, with 84 percent of corn planted in Tennessee. Drought conditions prevailed across the state from mid-June to mid-July, stressing young corn during critical growing periods. Rains in the end of July and early August came too late to aid in corn development. By late August, 29 percent of the crop was rated good to excellent. By early September, farmers were concerned about their yields, with corn yields coming in at about half of the expected yields from previous years. Dry weather in September and early October allowed for on time harvest, with 64% of corn being harvested by the first week of October. Quality continued to remain low, with only 25% of the crop being rated good to excellent by the first week of October. According to the National Agricultural Statistics Service, yield is projected to be 130 bu/ac in Tennessee, which is down 40 bu/ac from 2021. Acres for grain harvest are estimated at 920,000 in Tennessee for 2022. 

Interpretation of Data: 

The tables on the following pages have been prepared with the entries listed in order of yield performance, the highest-yielding entry being listed first. Mean separation was performed using the Fisher’s Protected LSD (Least Significant Difference) test. The mean trait value of any two entries being compared must differ by at least the LSD amount shown to be considered significantly different at the 5% level of probability. Tests with an LSD value of N.S. indicate there were no significant differences in entry performance within that test. To simplify interpretation, Mean Separation Letters have been listed next to traits evaluated across locations. Hybrids that have any letter in common are not significantly different at the 5% level of probability based on the LSD test. Hybrids with performance statistically equivalent to the top performing hybrid will have an “A” included in the list of mean separation letters next to that entry. 

The coefficient of variation (C.V.) values are also shown at the bottom of each table. This value is a measure of the error variability found within each experiment. It is calculated as the ratio of the square root of error variance to the mean yield. For example, a C.V. of 10% indicates that the size of the error variation is about 10% of the size of the test mean. Similarly, a C.V. of 30% indicates that the size of the error variation is nearly one-third as large as the test mean. A goal in conducting each yield test is to keep the C.V. as low as possible, preferably below 20 percent. 

Results 

Yield and Agronomic Traits. Sixty corn hybrids were evaluated in the 2022 AgResearch and Education Center (REC) tests in Tennessee. There were 21 hybrids in the early- (Tables 4-5), 24 hybrids in the medium- (Tables 8-9), and 15 hybrids in the full-season (Tables 12-13) tests. These hybrids represent 11 different brands (Table 17). The County Standard (CS) tests consisted of an early-season glyphosate resistant and Bt stacked trait test (19 hybrids at 13 locations, Table 6), a medium-season glyphosate resistant and Bt stacked trait test (17 hybrids at 17 locations, Table 10), and a full-season glyphosate resistant and Bt stacked trait test (14 hybrids at 13 locations, Table 14) for a total of 50 hybrids. Common to both the REC and CS tests were 15 early-season, 9 medium-season, and 10 full-season hybrids (Tables 7, 11, 15). Similar to the REC tests, all hybrids in the CS tests were placed in the maturity test for which they fit, regardless of other traits associated with each entry. 

All 63 hybrids evaluated were transgenic, containing genetic modification for a combination of herbicide tolerance (RR, RR2, LL) and insect tolerance (A4, CB, HX1, Q, SS, TRE, VIP 3330, VR, VT2P, VZ, YGCB) (see table 17 for full descriptions of abbreviated traits). The majority of entries had glyphosate herbicide tolerance and VT2P insect tolerance. The breakdown of traits by entry are listed below: 

Irrigated vs. Non-irrigated Yields. Duplicate tests were conducted with and without irrigation at Milan and Springfield. At the Milan locations, irrigated tests far out-yielded non-irrigated tests. Irrigated yields exceeded non-irrigated yields by 131, 123, and 145 bu/ac in the Early, Medium, and Full test, respectively. At Springfield, yields were higher in the irrigated Early corn test, exhibiting a 21 bu/ac advantage. However, in both the Medium and Full corn test, yields were higher in the non-irrigated test by 20 and 35 bu/ac, respectively.