K. M. Day, C.P. Ag., C.S.
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Department of Agronomy
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It is the policy of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, color, sex, religion, national origin, age or handicap.
Soybeans are evaluated annually at several locations in Indiana. These trials are conducted according to the policies and procedures of the Indiana Agricultural Research Programs at Purdue University. In this bulletin, results of the 1997 performance trials are given as well as multiple year averages for those entries tested in the past three test years. Data for experimental entries are not included.
This information is presented under authority granted 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. Also any soybean not included in this bulletin does not imply criticism by Purdue University. This bulletin is protected by copyright by the Purdue Research Foundation. Permission is granted to reproduce the tables only in their entirety provided that this bulletin, "Performance of Public and Private Soybeans in Indiana", is referenced and the data are not edited, manipulated or reinterpreted. The table number, title, heading and footnotes 1 and 2 must be included. Permission is also granted to reproduce a maturity-group sub-table provided that the complete table heading and footnotes are included with the sub-table. A conspicuous disclaimer which states "endorsement or recommendation by Purdue University is not implied" must accompany any information reproduced from this bulletin.
Additional bulletin copies are available from:
Agricultural Media Distribution CenterPerformance results for both private and public entries are presented. Certified seed was used for seeding the public varieties. Private entries, entered voluntarily by the owner, were accepted in the trial after meeting requirements for eligibility and payment of a testing fee. No verification has been made that the seed or the quality of the seed entered in this test is the same as that offered for sale to the public.
Plans and rules for entering this trial are available, upon request, to anyone at any time. Persons wishing to enter the soybean performance test should contact the author by February 1, 1998.
In 1997 trials were planted at five locations. The locations, numbered from north to south are:
In 1997 at each location the trial was divided into an early maturity and a late maturity test. The soybean plots were planted in a randomized complete block design with four replications at each location. Anticipated maturity differences between adjacent plots were restricted to 10 days or less.
Conventional farm equipment was used for seedbed preparation. At locations 1, 2, 3, and 4 the plots were planted with a John Deere 7100 Max-emerge planter, modified and equipped with cone distributors, which dropped a pre-counted number of seeds in each 33 linear feet of row. The planting rate for proprietary entries, selected by the owner, varied from 5 to 8 viable seeds per linear foot of row, with most ranging from 5 to 7. Most public varieties were planted at the rate of 6 viable seeds per linear foot of row (approximately 70 pounds or 157,000 viable seeds per acre). Only high-germinating seed (usually 90 percent or better) was used in the test. At locations 1, 2, 3, and 4 each plot consisted of four rows, 30 feet long. Row spacing within the plot was 20 inches. All plots were treated with herbicides and, when possible, cultivated. Hand weeding was used to remove weeds that emerged late in the season.
All plots were end trimmed prior to harvesting, and all rows were harvested. Locations 1, 2, 3, 4, and 5, were harvested with an Almaco combine. The combine was equipped with a modified John Deere head with a floating cutter bar. Plot width was calculated from plot center to plot center for locations 1, 2, 3, and 4, and was calculated as 75 inches wide at location 5. Other observations such as lodging, plant height and maturity were taken from the center rows.
At Location 5 the maturity group III and maturity group IV soybean tests were planted in a conventionally tilled seedbed (spring chiseled and tilled with a field cultivator). The tests were planted with an Almaco plot drill, equipped with 10 John Deere openers and press wheels, set on 7.5 inch row spacing. The Almaco drill was also equipped with cone distributors, which dropped a pre-counted number of seeds every 33 linear feet of row. The planting rate for proprietary entries, selected by the owner, varied from 3.0 to 4.0 live seeds per linear foot of row. Public entries were seeded at the rate of 3.0 live seeds per linear foot of row, which would be 209,088 live seeds per acre. Assuming 90 percent emergence this should produce a stand of 188,179 plants per acre.
Plots harvested with the Almaco combine were weighed and moisture tested automatically, on the combine, using a Seed Spector II and a Psion HC 110. The equipment was calibrated using a Motomco moisture meter and Chantillon scales, and the calibrations were checked throughout the harvest season. It should be pointed out that this equipment is not the same as equipment used to meet official sampling standards, but is believed to be suitable for field plot work. All yields were adjusted to 13 percent moisture and are reported as bushels per acre.
At location 5, Dr. E. P. Christmas planted the solid-seeded no-till and conventional-till test. Satisfactory stands were not established at the first planting, and both tests were replanted on July 2, 1997. The replanted tests produced good stands. Conditions were favorable for planting a double crop soybean test following wheat harvest, and the test was planted by Dr. Christmas on July 10, 1997.
This year, for the first time, two companies entered a tillage test for transgenic soybeans (Roundup Ready®, which is a trademark of Monsanto Company), the transgenic soybeans were tested, by Dr. Christmas, in conventional tillage and in no-till plots, and one Roundup Ready® entry was included in the double crop test. The results are reported in table 19.
The tillage tests, conducted by Dr. E. P. Christmas, were planted with a Great Plains No-Till Drill, equipped with 11 openers set on 7.5 inch row spacing. The drill was equipped with a belt cone distributor which dropped a pre-counted number of seeds equivalent to 200,000 seeds per acre. For the tillage tests, germination was assumed to be 90 percent for all of the entries. The target population was 165,000 plants per acre assuming that 90 percent of the viable seed emerged. At harvest time the plots were end trimmed and 8 of the 11 rows were harvested with a Wintersteiger Plot Combine. Data from the tillage tests and the double crop test are presented in tables 17, 18 and 20.
Plant height, taken at maturity, is the average length (to the nearest inch) from the soil surface to the tip of the main stem.
Lodging is rated at maturity according to the following scores:
Maturity is the date when more than 90 percent of the pods are ripe (brown). Delayed leaf drop and green stems are not considered when assigning maturity. Seven to ten days of good drying weather may be needed before soybeans are ready to combine after reaching maturity. Varieties chosen for production should mature about two weeks before the average date of the first killing frost, which ranges from approximately October 10 in northern Indiana to October 25 in southern Indiana.
Soybean planting in Indiana in 1997 began earlier than usual. By April 27, 10 percent of the crop was planted, which was well ahead of the 1 percent, which is normal for that date. Planting continued well ahead of the normal pace and by May 4, a record 22 percent were planted. Soybean planting continued at a rapid pace during May and by June 1, 87 percent of the crop was planted compared with 64 percent which is normal for that date. Temperatures were cold during May and June, and some replanting was necessary.
In response to concerns about the impact of below normal temperatures on soybeans, during the reproductive stages of growth, Dr. E. P. Christmas prepared the following information:
Hot , sunny weather the last of June, brought an end to low temperatures. At the end of June, 61 percent of the crop was rated excellent, 31 percent fair and 8 percent poor to very poor. By mid-July soybean planting was virtually complete, and 17 percent of the crop was blooming compared to 24 percent for the 5-year average.
Soybeans developed rapidly during the last half of July. Sixty-five percent were blooming and fifteen percent were setting pods. Dry weather in early August caused the soybean crop condition to decline from a rating of 65 percent good to excellent to a rating of 57 percent.
By August 10, soils were dry in east and west central Indiana as well as in the southern part of the state. Statewide, 82 percent of the top soil, and 72 percent of the sub-soil was rated short to very short. The soybean crop continued to decline until arrival of substantial rainfall in mid-August. Development of the soybean crop was near normal by the end of August, with 97 percent of the crop setting pods, and 5 percent shedding leaves. The crop was rated 62 percent good to excellent.
In mid-September, 5 percent of the crop was mature. Harvest began by the third week of the month, and maturity was progressing faster than normal. The first week of October, soybeans were reported to be 79 percent mature, ahead of the 73 percent average. During the second week of October, record harvesting gains were made when farmers harvested 45 percent of the crop. This was the largest percent harvested in one week on record. The record early harvest for October 12 occurred in 1964, when 87 percent of the crop had been harvested by that date. By the end of October, the crop was 96 percent harvested and by the third week of November harvesting was virtually over.
In summary, most of the soybean crop was planted in a timely manner and developed in cold, and in some instances wet, conditions until mid-June. This early season stress contributed to shorter than normal plant height, and wet conditions promoted phytophthora rot in eastern Indiana. Weather warmed rapidly after mid-June and soils became progressively drier, until drought, by early August, was a major concern in the central and southwestern portions of the state. The crop developed rapidly under hot, dry conditions, and although plants were generally shorter than normal, areas which received mid-August rainfall produced good yields. Except for some replanted or double crop soybeans, most of the crop was mature before killing frosts arrived in mid-October. The excellent weather, which permitted rapid harvesting, was also beneficial for good grain quality.
On November 20, 1997 the Indiana Crop and Livestock Reporting Service reported:
It is not possible to absolutely determine or predict the response of plants to the environment. The results of every field test conducted are influenced by the treatment and by the experimental error. In this test the treatment is the soybean entry (variety, brand, or blend) planted in the test. Experimental error is a composite term to indicate everything which could not be controlled by the person performing the test. It is not intended to include human error. These tests are conducted on the assumption that all the entries in the test are equal until evidence is obtained that they are not equal. In order to obtain this evidence it is necessary to determine whether the test results were influenced most by the entries or by experimental error. To do this an analysis of variance is performed and the relationship of the yielding ability of the entries to experimental error is determined. The analysis of soybean performance tests show that maturity relationships are very predictable whereas yield relationships are the most difficult to predict.
Probability levels have been established to assess the validity of the test. Generally tests should be significant at the 10 percent probability level. This means 1 test in 10 could be a fluke and not be detected. In this bulletin the 1997 tests are significant at the 10 percent probability level except for the maturity group IV test at location 4.
The analysis of variance makes it possible to compute a coefficient of variability (C.V.). The coefficient of variability is a relative term. It is the ratio of the standard deviation to the grand mean of the test, expressed as a percent. On the western side of Indiana a normal C.V. for soybeans is 5 to 10 percent; whereas on the eastern side it is 10 to 15 percent. Whenever the C.V. is larger than normal for a test location it indicates the precision of the test was below normal. When yields are high and the experimental error is small, the C.V. will be small.
Single-year tests, in this report, generally require yield differences of 7 to 10 bushels for significance. A test of significance must be performed to determine if the yield difference between two entries is due to experimental error or due to the yielding ability of the entries. The single-year test only reflects what happened in one year at one location and is generally inadequate for predicting how the soybeans may perform in the future. Data from multiple years, and in some instances multiple locations, when combined and analyzed, provide a superior estimate of how soybeans will perform in the future.
Generally a minimum of three years of testing are needed from a test location to obtain adequate data for predicting performance. An analysis of variance, which includes years, will show that years have a very strong influence on yields. Also, an analysis of variance which includes locations will show that locations also influence the performance of the entries in the test.
Brief periods of favorable or unfavorable weather when the plants are vulnerable to weather stress can change the yield relationship among varieties from year to year. Maturity relationships are influenced by photoperiod and are much less affected by weather from year to year.
Often it is not beneficial or appropriate to combine data across locations from these performance tests. The tests are far enough apart from north to south that the entries in the test may not be adapted to both locations. The test environments from east to west are also very different, especially in regard to the presence and severity of Phytophthora rot. It is important to realize that locations may all provide similar test results one year and produce quite different results the following year.
This year, 1997, data combinations were made for the maturity group II tests at locations 1 and 2, for three years, two years and one year.
Data combinations were made for the maturity group III tests for three years (1995, 1996 and 1997) at locations 1, 2, 4 and 5; and for two years (1996 and 1997) and for one year (1997) at locations 1, 2, 3, 4, and 5.
Results of the maturity group IV tests are combined for locations 4 and 5, for three years, two years and one year. The results for all the combined years and locations are presented in tables 21, 22, and 23.
Soybean data from any source must include years (preferably three), must be analyzed, and must have a test of significance before it has any value as a basis for performance prediction.
Test results are ranked by yield. The Waller-Duncan Bayesian k ratio t test is used for the test of significance. A k ratio of 100:1 was used in computing the Bayesian least significant difference (BLSD) for the test of significance. This ratio may be considered in a loose sense to take the place of the 5% level of significance. The BLSD value may be used to make all possible pair-wise comparisons among varieties. Yield differences smaller than the BLSD value should be considered due to chance (experimental error) and not due to superior performance.
An asterisk (*) is included in the yield column in each sub-table. The asterisk denotes all yields in the sub-table which are not, statistically, significantly different from the top yield. Do not place undue emphasis on yield differences followed by an asterisk. The BLSD value must still be used to determine if the particular yields being compared are significantly different.
At Location 1, April was relatively dry with 1.64 inches of rain for the month, May received 5.30 inches of rain with most of it coming about a week after the plots were planted. June rainfall was 5.0 inches, July 4.39, August 3.68 and September 1.88. This is ideal moisture distribution during the growing season.
Temperatures remained cool until the beginning of the third week of June, then warmed rapidly and remained at or near optimum for soybeans during the rest of the growing season. All plots were mature and harvested before the first killing frosts which arrived at the beginning of the third week in October.
Yields in the maturity group III soybean performance test produced all time record high yields for this performance test. Both tests were, statistically, highly significant and should be useful in making yield comparisons.
At Location 2, April was dry with 1.62 inches of rain, May received 5.06 inches, June 5.86 inches, July 2.08, August 2.71 and September 1.16 inches. Temperatures were cool until mid-June and then warmed rapidly to near optimum levels for soybeans. Growing conditions were excellent during most of July, August and September. All plots were mature, and harvested before the first killing frosts which arrived at the beginning of the third week of October.
Both the maturity group II and III tests produced higher than normal yields, and were, statistically, highly significant. Both tests should be useful for evaluating yield performance.
This year, for the first time, a performance test for transgenic soybeans, (Roundup Ready®, which is a trademark of Monsanto Company), was planted. Two companies entered the test. The precision of the test was good and yields were acceptable. Since this is a first year observation, more data may be needed for making performance decisions.
At Location 3, April was the driest of all the test locations, receiving only 1.19 inches of rain for the month. May rainfall totaled 4.56 inches, June 4.73, July was dry with 1.57 inches, August 3.75 which came about mid-month, and September with 2.70 inches.
Phytophthora rot was present in both tests and appeared to do the most damage during germination and emergence. Many plots had stand reductions of 20 percent. The surviving plants were stunted, but produced branches and pod set which tended to offset the loss of stand.
Temperatures were similar to the other central and northern test locations. April, May and early June were cooler than normal. Temperatures from mid-June through July, August, and September were only slightly below optimum for soybean development. All the plots were mature and harvested before the first killing frosts which arrived at the beginning of the third week of October.
Yields in 1997 were superior to previous years in northeastern Indiana. Although the precision in both tests is not high (note the high coefficients of variability, and the BLSD values), the data indicate how the entries performed in an environment where phytophthora rot was severe enough to cause considerable loss of stand, as well as stunted plants.
At Location 4, weather data come from the Vincennes weather station, which is about 15 miles from the plot area. This makes the weather data, especially rainfall, less representative of the plot area than weather data for the other plot locations. In 1997, July and August rain recorded at Vincennes did not fall at the plot area 15 miles away.
Soils were wet for a month after planting, making it impossible to apply post emergence herbicides. Weeds became well established, and by the time it was possible to spray the plots, the herbicides did not provide a complete weed kill. Weather became progressively drier, and a second spraying only stunted weed growth.
This year, 1997, was the third consecutive year of adverse weather at location 4. Yields were low, plant height short and the precision in the test was not good.
The test results may be used to view performance under extremely dry conditions, but not as an indication of the genetic yield potential of the entries. Data from Jennings Co., location 5, may be much better information for making yield comparisons.
At Location 5, the regular maturity group III and IV tests got off to a good start. April rain totaled 2.42 inches, May 6.86, June 5.14, July 1.88, August 5.09, September 0.77, and October 1.42.
Temperatures were cool from planting in mid-May until the beginning of the second week of June. From that point on, temperatures were generally favorable for soybean growth. Although July was dry, moisture reserves were generally adequate, and mid-August rain of over 3 inches provided excellent moisture.
The tillage tests did not produce acceptable stands at the first planting, and were replanted July 2. The second planting produced uniform, vigorous stands.
This year, 1997, tillage tests were established for transgenic (Roundup Ready®) soybeans. Roundup Ready® is a trademark of Monsanto Company. Two companies entered the transgenic test. Also new, a double crop soybean test was planted following wheat. Entries in the double crop test were the same as the entries in the (regular, i.e. not transgenic) tillage tests.
All of the 1997 tests at location 5 may be considered useful for making yield comparisons if the planting date is taken into consideration. The maturity group III and IV tests were planted near the optimum date of planting and the results may be considered normal. The soybeans were mature and the test harvested, before a killing frost arrived.
The double crop test was also planted near the normal planting date for double crop. The plants were mature about the time of the first killing frosts which occurred at the end of the third week of October. Frost did not have any significant impact on the yields, which were outstanding for double crop soybeans.
The tillage tests and transgenic tests were planted about 6 weeks later than the optimum date of planting, and this could have some impact on the performance results. The soybeans were mature several days before the first killing frosts, which arrived at the end of the third week of October. Since the transgenic tests and the double crop test have only one year data, it might be advisable to view the 1997 results as preliminary data.
Information concerning certified seed may be obtained from the Indiana Crop Improvement Association, which certifies seed from both public and private sources. Publicly developed varieties, presented in this bulletin, are listed under the Indiana Crop Improvement Association, and the Ohio Seed Improvement Association addresses. Private companies have requested that inquiries concerning proprietary entries, presented in this bulletin, be directed to the addresses listed below.
Small case letters preceding the entry name are, v-variety, m-mixture (blend), and b-brand. Other names, associated with the entry name, are brand or company names usually associated, in the trade, with the entry name.