This bulletin summarizes results of 1994-1997 performance trials of commercial dent corn hybrids being sold in Indiana. The participating seed companies selected the hybrids for testing and mailed samples of seed taken from commercial seed lots to Purdue University for planting and evaluation.
This information, protected by copyright by the Purdue Research Foundation, is presented under authority granted the Indiana Agricultural Research Programs to conduct performance trials, including interpretation of data to the public, and does not imply endorsement or recommendation by Purdue University. Performance information may be used in following ways. 1) Permission is granted to reproduce the tables in their entirety provided the source is referenced and the data are not manipulated or reinterpreted. A conspicuous disclaimer which states "endorsement or recommendation by Purdue University is not implied" must accompany any information reproduced. 2) Advertising statements by an individual company about the performance of its entries can be made as long as they are accurate statements about the data as published, with no reference to other companies' hybrids. A statement similar to "See the official Purdue University bulletin 'Performance of Commercial Dent Corn Hybrids in Indiana, 1994-1997', B-757, for details." must be included in the ad.
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Sincere appreciation is extended to Tom Boyd, Paul DeVries, Ed Ripberger, Tom Ripberger and Tom Smith for their assistance with establishing and carrying out the performance tests on their private farms. Appreciation is also extended to Jim Beaty, Don Biehle, Jon Leuck and their supporting staff for their assistance with the performance trials at the regional Purdue Agricultural Research Centers.
Excessive rain during February and March left most fields saturated in early April. By mid-month, corn planting was underway in scattered fields around the state. Colder than normal temperatures slowed drying of the soil. Corn planting picked up, with 5 percent of the intended corn acreage planted by April 20th. Dry weather in late April allowed planting and tillage operations to advance at a record pace. Soil conditions in many areas were ideal for tillage and planting operations. The best progress occurred in the northern two-thirds of Indiana, but progress slowed in early May as rain fell across much of the state.
By the first week of May, corn planting had increased to 60 percent complete, well ahead of 8 percent last year and the five-year average of 17 percent. This matched the record progress achieved in 1988 for this date. Regionally, corn planting was 62 percent complete in the north, 74 percent complete in the central, and 27 percent complete in the south. Planting slowly progressed over the first half of May as widespread rain hindered field operations. By May 18, corn planting increased to 86 percent complete, greatly ahead of 13 percent last year and the average of 57 percent. Intended corn acreage was more than 90 percent planted in the north and central regions, and 60 percent planted in the south. Emergence and growth were slow due to below-normal temperatures and soil crusting, resulting in poor stands and replanting of some areas. Many farmers were finished planting corn by mid-May, and with the exception of replanting, planting essentially finished in the state by the end of May, exceeding 56 percent complete last year and the average of 83 percent complete for this date. Much of the state experienced light frosts in late May, however very little crop damage was reported.
Rain and wet field conditions halted field operations in late May and early June. Some heavy rainfall resulted in ponding and flooding. Corn emergence and growth remained slow because of below-normal temperatures and lack of sunshine. Weeds also became more of a problem as wet field conditions prevented the application of needed herbicides. Corn rootworm larvae caused root damage in many fields as insecticides lost effectiveness over the extended cool, wet spring. Favorable weather that arrived in mid-June allowed farmers to apply herbicides and nitrogen. Replanting of corn continued as soil moisture allowed. The greatest need for replanting was in the southern region of the state, particularly along the Ohio and Wabash Rivers.
Toward the end of June and into early July, corn grew rapidly as hot, sunny conditions combined with ample soil moisture. The weather allowed fieldwork that included side dressing corn, applying herbicides and cultivating. Corn condition ratings increased over this period, with 70 percent rated good to excellent on July 13. As July continued, hot and dry weather began to stress fields, and soil moisture conditions declined. Some areas in the southwest received no precipitation in July. Corn maturity as of July 27, was still behind the five-year average. Forty percent of the corn acreage was reported silking, ahead of 32 percent last year, but behind 62 percent for the average.
Widespread rains in late July provided much needed relief. Rainfall was widely varied, missing some areas while dumping up to 6 inches in others. Rains were heavy in the northern region. Crop conditions remained good in areas that received timely rains, however some areas were not as fortunate. The southern region as well as the west central and east central districts appeared to be the driest, where about a third of the crops were rated poor to very poor on August 10. Topsoil moisture was more than 90 percent short to very short in these areas. Soil moisture conditions rapidly declined statewide, with 82 percent of the topsoil and 72 percent of the subsoil rated as short to very short.
At the end of August, crop conditions remained good, however, fewer than normal growing degree days left the corn about a week behind in maturity. Thirty-seven percent of the corn was in the dent stage, ahead of 28 percent last year, but behind the 42 percent average for this date.
Low overnight temperatures in early September kept crop development at a slow pace. At the end of the first week of the month, 8 percent of the corn was mature, equal to last year, but behind the five-year average of 10 percent. Warm, sunny conditions that returned mid-month helped crops advance toward maturity. Seed corn harvest and cutting of silage also made good progress. By September 21, 86 percent of the corn acreage has reached the dent stage, ahead of 80 percent last year, but behind the 93 percent average for this date. One-third of the corn crop was mature compared with 35 percent mature last year, but behind the five-year average of 47 percent. By month's end, 4 percent of the corn acreage had been harvested. Moisture content of harvested corn remained around 30 percent. Scattered showers across much of the state slowed operations. Fifty-two percent of the corn crop was mature, slightly ahead of last year, but behind the five-year average of 67 percent.
Most farmers spent early October harvesting soybeans. While soybean harvest advanced at a record pace, corn harvest made only modest progress as most farmers tried to finish with soybeans first. Moisture content of harvested corn remained around 29 percent. Heavy winds reportedly caused lodging in some corn fields. According to the Indiana Agricultural Statistics Service, most areas of the state reported a killing frost in mid-October. By October 19, 98 percent of the corn crop was mature, equal to the five-year average. Twenty-five percent of the corn acreage had been harvested, behind the 33 percent average. Good harvest weather continued through the end of October. Many farmers delayed corn harvest in order to reduce drying costs. By the end of October, corn harvest advanced to 59 percent complete, as scattered showers slowed field operations. This was the first break many farmers had since harvest began, as conditions had been ideal. Average harvest moisture for corn grain had dropped to 21.7 percent.
November harvest progress in many areas was controlled by drier capacity, as rain and snow kept corn moisture content fairly high. The percentage of corn acreage harvested was ahead of the five-year average throughout the month, reaching 92 percent by November 23. Moisture content of harvested corn remained around 21 percent.
To summarize the 1997 season, corn planting progressed rapidly in late-April. Rain events were frequent into early-June. Temperatures averaged below normal and overcast conditions prevailed. Crops planted received little heat or sun, further slowing crop progress. Crop development remained two weeks behind average. This contributed to later harvests and higher moistures at harvest. Growing Degree Day accumulations through the end of the season were below normal statewide. Cool conditions also contributed to keeping insect and disease pressure light in most areas. Parts of the southern region and west central and east central districts were hard hit by dry weather, while rainfall was generally timely and abundant in the north. On November 23, the Indiana Agricultural Statistics Service estimated Indiana's 1997 corn yield at 120 bushels per acre, below the 123 bushel per acre yield in 1996.
Predominant soil types or production levels commonly found in northern, central, and southern Indiana were represented by two sub- locations in each region. At each sub-location, each hybrid was replicated four times within a randomized complete block design with hybrids of similar height randomly assigned adjoining plots. Participating companies supplied estimated height data, as well as relative maturity data reported in the index as days from emergence to kernel black layer. The plots were planted from pre-counted packets of seed using a plot research air planter, and harvested with a self-propelled harvester without gleaning. Stand counts for each individual plot were recorded during the month of June. The percent stand is determined based on the number of kernels planted and the number of plants emerged, and therefore, indicates only germination and emergence losses.
Average harvest moisture is presented for each hybrid, and yield data are calculated in bushels of shelled grain per acre, adjusted to 15.5% moisture. No yield adjustment was made for stand except for continuous skips which are determined to be of mechanical origin. Lodged plants (root lodged or stalk broken below the ear) were counted just prior to harvest. Test weight data were adjusted to 15.5% moisture.
Each farm cooperator prepared the seedbed using conventional tillage practices and applied herbicides at labeled rates. Fertilizer application was based upon the management program of each cooperator and the desired plant population of each test.
The performance data for each production The performance data for each production level within a region are reported in four tables. For example, Table 1A presents four-year averages, Table 1B presents three-year averages, Table 1C presents two- year averages, and Table 1D presents 1997 data only, for location 1. Similarly, Tables 2A, 2B, 2C, and 2D present the data for location 2, etc. Hybrids in each table are listed by yield in descending order. Comparisons can be made only between hybrids within a table. Comparing two hybrids from different tables (i.e. different environments and/or production levels) would likely lead to an erroneous conclusion.
With the use of statistical analysis, it is possible to determine whether a difference in performance between two hybrids is real or due to chance, at a chosen level of confidence. The least significant difference (LSD) listed at the bottom of each table for each column of data should be used to distinguish such differences. This bulletin presents data with an LSD of 10%. If the difference between two hybrids is equal to or greater than the LSD, the difference would be attributable to hybrid differences and not random chance in 18 out of 20 (90%) instances when the two hybrids are evaluated under conditions like those of the test. A difference which is less than the LSD is likely due to chance, rather than true hybrid performance. When no significant difference for a given parameter is found among hybrids, "ns" (nonsignificant) replaces an LSD value.
While much care is exercised to keep experimental error to a minimum, variation in data among any given hybrid's replications can and does occur. For example, very rarely is a hybrid's yield exactly the same for all replicates, although relatively small amounts of variation are certainly considered "normal". A relatively large amount of variation for many of the hybrids in a test can render the data useless for determining real, instead of chance, differences in performance. Plot replication is carried out in order to sample the uncontrollable variation within a test site which has been chosen for its uniformity of soil type and slope. Other factors which may introduce error, but which can be reasonably controlled, include uniformity of tillage, herbicide and fertilizer application, timeliness of planting and harvesting, and the condition of equipment used to perform the research. Ideally, all hybrids within a test should have an equal chance to perform.
Relative performance of hybrids changes with different growing conditions from year to year. Therefore, caution is necessary in using data from one year as a guide. Future hybrid performance can best be estimated by observing past performance in several environments over at least two or three years if possible.
Trials were conducted at seven locations throughout the state. Following is information about each location.
RAINFALL (Departure) KENTLAND FORT WAYNE
WANATAH W. LAFAYETTE
APRIL 1.25 (-2.66) 1.02 (-2.98) 1.5 (-2.41) 1.62 (-3.40)
MAY 4.54 (+1.16) 5.19 (+2.08) 5.3 (+2.19) 5.06 (+1.65)
JUNE 4.73 (+0.93) 3.46 (+0.17) 5 (+1.15) 5.86 (+2.25)
JULY 2.39 (-2.41) 5.8 (+1.89) 4.39 (-0.02) 2.08 (-2.97)
AUGUST 2.68 (-0.74) 6.31 (+3.37) 3.68 (+0.06) 2.71 (-0.62)
SEPTEMBER 1.2 (-2.44) 5.1 (+2.73) 1.84 (-1.89) 1.16 (-1.41)
OCTOBER 0.38 (-1.57) 0.95 (-1.37) 0.35 (-2.99) 0.39 (-1.86)
TOTAL 17.17 (-7.73) 27.83 (+5.89) 22.06 (-3.91) 18.88 (-6.36)
Growing Degree Days (Departure)
APRIL 145 (-34) 134 (+10) 111 (-18) 151 (-28)
MAY 286 (-45) 249 (-126) 244 (-136) 286 (-162)
JUNE 577 (+5) 570 (+26) 542 (+20) 589 (-5)
JULY 711 (-11) 675 (-126) 652 (-117) 704 (-147)
AUGUST 603 (-2) 580 (-10) 533 (-36) 599 (-32)
SEPTEMBER 474 (-17) 444 (+34) 413 (-62) 505 (+47)
OCTOBER 280 (+39) 268 (+55) 264 +40) 303 (+41)
TOTAL 3076 (-65) 2920 (-137) 2759 (-309) 3137 (-286)
RAINFALL (Departure) TIPTON VINCENNES
BUTLERVILLE
APRIL 1.23 (-3.07) 2.56 (-2.22) 2.42 (-1.60)
MAY 5.19 (+1.16) 4.22 (+0.63) 6.87 (+2.41)
JUNE 5.1 (+1.35) 8.73 (+5.03) 7.08 (+3.53)
JULY 3.28 (-1.47) 3.33 (-1.65) 1.88 (-2.74)
AUGUST 2.38 (-0.79) 2.71 (-0.89) 5.6 (+1.91)
SEPTEMBER 2.16 (-0.64) 2.37 (-0.29) 0.77 (-1.86)
OCTOBER 0.23 (-2.24) 0.64 (-1.60) 0.42 (-2.69)
TOTAL 19.57 (-5.70) 24.56 (-0.99) 25.04 (-1.04)
Growing Degree Days (Departure)
APRIL 130 (-8) 184 (-27) 165 (-40)
MAY 260 (-132) 385 (-112) 320 (-100)
JUNE 528 (-14) 646 (-2) 582 (-74)
JULY 670 (-127) 774 (-126) 749 (-35)
AUGUST 562 (-11) 688 (+110) 640 (-89)
SEPTEMBER 468 (+56) 554 (+34) 487 (-49)
OCTOBER 258 (+17) 344 (+45) 301 (+63)
TOTAL 2876 (-219) 3575 (-78) 3244 (-324)
Kentland is the nearest weather station to Demotte test location.
Fort Wayne is the nearest weather station to Auburn test location.
Tipton is the nearest weather station to Windfall test location.
Vincennes is the nearest weather station to Washington test location.
Growing Degree Days (Modified 86/50 Method) = daily mean temperature - 50