Evaluation of Soybean Varieties Resistant to Soybean Cyst Nematode in Iowa 2017

Transcription

1 A supplement to Iowa Farmer Today. Evaluation of Soybean Varieties Resistant to Soybean Cyst Nematode in Iowa 2017 View of the northeast Iowa location. Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett, and Mark P. Mullaney Department of Plant Pathology and Microbiology Iowa State University This report is available online at IPM 52 Revised December 2017

2 Evaluation of Soybean Varieties Resistant to Soybean Cyst Nematode in Iowa in 2017 Gregory L. Tylka, Gregory D. Gebhart, Christopher C. Marett, and Mark P. Mullaney Department of Plant Pathology and Microbiology Introduction Use of resistant soybean varieties is a very effective strategy for managing soybean cyst nematode (SCN), and numerous SCN-resistant soybean varieties are available for Iowa soybean farmers. Each year, SCNresistant soybean varieties are evaluated in SCN-infested fields throughout Iowa by Iowa State University personnel. The research described in this report was performed to assess the agronomic performance of maturity group (MG) I, II, and III SCN-resistant soybean varieties and to determine the effects of the varieties on SCN numbers or population densities. Materials and Methods SCN-resistant soybeans were studied in northern, central, and southern Iowa based upon maturity group. The northern trials were located near Newell (northwest Iowa), Mason City (north central Iowa) and Lawler (northeast Iowa). The central trials were located near Moorhead (west central Iowa), Ames (central Iowa), and Urbana (east central Iowa). The southern trials were located near Glenwood (southwest Iowa), Leighton, (south central Iowa), and Fruitland (southeast Iowa). Location-specific details. Initial SCN Location Population HG Type 1 Planting Date Harvest Date (eggs / 100 cc soil) Newell (NW) May 30 th October 17 th Mason City (NC) May 12 th October 20 th Lawler (NE) 2, May 15 th October 19 th Moorhead (WC) 1, May 8 th October 23 rd Ames (C) 1, May 31 st October 26 th Urbana (EC) May 16 th October 18 th Glenwood (SW) May 8 th October 24 th Leighton (SC) May 5 th October 25 th Fruitland (SE) May 3 rd October 3 rd 1 In the SCN HG type test results, 1 indicates >10% reproduction on Peking (PI ), and 2 indicates >10% reproduction on PI indicates an incomplete HG type test; populations were tested only on Peking, PI 88788, PI 90763, and PI SCN-susceptible varieties also were planted in the experiments for comparison purposes. All plots were four 17-foot-long rows spaced 30 inches apart and were planted at 10 seeds per foot, with four replications per variety. Seed companies were encouraged to treat their seed with fungicide and insecticide. Seeds that were received untreated were treated with CruiserMaxx by Iowa State University personnel. A complete list of the seed treatments used on the varieties tested is included at the end of the report. Pre-plant herbicides were applied to each location. Soybean varieties resistant/tolerant to glyphosate or glyphosate + dicamba were sprayed with glyphosate and Flexstar to control weeds during the growing season. Varieties with glufosinate resistance/tolerance were sprayed with Flexstar, FirstRate, and Select Max to control weeds during the growing season. The Moorhead and Lawler locations were planted using notill methods. At all other locations, the seed bed was tilled prior to planting. 2

3 Herbicide resistance/tolerance of the SCN-resistant varieties tested. District Glyphosate Glyphosate + dicamba Glufosinate Total North Central South At growth stage R6 all locations were scouted for foliar symptoms of sudden death syndrome (SDS). None of the locations had sufficient foliar disease to warrant rating the plots. All plots were end trimmed to a length of 14 feet during September. For each location, the center two rows of each four-row plot were harvested with a plot combine, total seed weight per plot and seed moisture were determined, and total plot seed weights subsequently were converted to bushels per acre. Resistant varieties and susceptible check varieties are grouped separately and are listed in the report in order of descending yield. At the beginning of the growing season, plots were sampled for the presence of SCN. Soil samples, consisting of 10 one-inch-diameter, six- to eight-inch-deep soil cores were collected from the center 14 feet of the center two rows of each plot immediately after planting. SCN cysts were extracted from each soil sample, and SCN eggs were extracted from the cysts and counted. SCN egg population densities also were determined for each plot at the end of the growing season in an identical manner. Because of the consistent relationship between higher soil ph and high SCN population densities, all varieties also were field tested for tolerance to iron deficiency chlorosis (IDC). Each variety was planted in a hill plot consisting of five seeds per hill, with four replications per variety, at two high ph field locations. Notes were taken for IDC symptoms at each location approximately four weeks after planting and again at five weeks after planting. Varieties were rated on a scale of 1 to 5 with a 1 indicating no symptoms of IDC present and a 5 indicating plant death due to IDC. The scores from each location were averaged together and an overall rating was assigned to each variety. One variety highly resistant to IDC and one variety susceptible to IDC also were included in the experiments as checks. The highly resistant variety scored an average of 1.1 and the susceptible variety scored an average of 3.5. The scores from these IDC field tests are listed in each location table in the report for reference. 3

4 Data Presentation In the report, soybean yield and SCN reproduction are displayed graphically in addition to numerically in the tables. Yield is represented by the length of the green bars. SCN reproduction is represented by the length of the blue bars. SCN reproduction was determined by calculating the reproductive factor (RF) for each variety. RF is calculated by dividing the average final SCN population density by the average initial SCN population density for each variety. If a variety has an RF value of 5.0, the SCN population density for those plots was 5 times greater at harvest than it was at planting. And an RF value of 0.5 means the SCN population density for those plots at harvest was one half the population density at planting. The RF value is location specific and may vary substantially under different environmental conditions, soil types, and nematode populations. Summary The results of the experiments illustrate the benefits of growing SCN-resistant soybean varieties for management of this important soybean pest. At locations with the most significant SCN reproduction, many of the soybean varieties with SCN resistance had greater yields than susceptible varieties, although some resistant varieties had greater yields than others. At most locations, end-of-season SCN population densities were significantly greater in plots where susceptible varieties were grown relative to plots planted with resistant varieties. Nematode control is an extremely important aspect of growing SCN-resistant soybean varieties that must be considered when selecting soybean varieties. Growing soybean varieties in SCN-infested fields solely to maximize soybean yields in the short term without any consideration of the effect of the varieties on SCN population densities will seriously reduce the productivity of the land for soybean production in the future. The results of these experiments illustrate that SCN-resistant varieties can suppress SCN reproduction and provide increased soybean yields relative to using susceptible varieties. Currently, there are three main genetic sources for SCN resistance genes in commercial soybean varieties, namely PI 88788, Peking, and PI (also known as Hartwig). Each of these sources of SCN resistance contains several genes that confer resistance to the nematode. Consequently, soybean varieties developed from the various sources of resistance may not all contain the same genes in the same combinations. All of these sources of resistance allow some limited reproduction of SCN. Resistant varieties must be used in an integrated management program, along with the use of nonhost crops, seed treatments, and scouting for early detection of SCN, to maximize yields and minimize reproduction of the pest on a long-term basis. The data presented in this report are from a limited number of locations and should be used only as a beginning point for developing a SCN management program for any specific field. Performance of individual SCN-resistant soybean varieties in SCN-infested fields will vary among locations and years. Growers are encouraged to evaluate several SCN-resistant soybean varieties at their own locations to determine the best varieties for their local conditions. Acknowledgments Appreciation is expressed to the staff of the Iowa State University Research and Demonstration Farms. Gratitude also is expressed to Kermit Grote of Newell, Randy and Jess Lutz of Mason City, Donnie Blazek of Lawler, John Melby of Moorhead, Ed McKinley of Urbana, Matt Biermann of Glenwood, Mark Groenendyk of Leighton, and Ron Shepard of Fruitland for use of land for some of the experiments. Supported, in part, by soybean checkoff funds from the Iowa Soybean Association and also by the Iowa Agriculture and Home Economics Experiment Station. 4

5 Table 1. Newell (NW Iowa) Glyphosate-treated Jacobsen 761NR2X 2.1 PI , Pioneer P21A28X 2.1 Peking Legacy Seeds LS-2037N RR2X 2.0 PI , Stine 21RI PI , Pioneer P19A14X Peking 3.4 1, Dyna-Gro S21XT PI , Pioneer P22T69R 2.2 Peking Cornelius CB22R PI , LG Seeds C2255R2 2.2 PI , Hoegemeyer HPT 2511 NRR 2.5 Peking ASGROW AG20X7 2.0 PI , Cornelius CB20R PI , Merschman Navaho 1820GT 2.0 PI , FS HiSOY 24X PI , ASGROW AG23X8 2.3 PI , NuTech 7198 Peking 2.2 1, Pfister 18R PI , Prairie Brand PB-1947R2 PI , NK S21-W8X 2.1 PI , Dyna-Gro S23XT PI , DAIRYLAND SEED DSR-2330/R2Y 2.3 PI , NuTech Peking 2.8 1, LATHAM L2368R2X 2.3 PI , Stine 19RF32 PI , Mycogen 5N194R2 PI , STAR 3X PI , Stine 20RD PI , LATHAM L2228R2 2.2 PI , NK S20-J5X 2.0 PI , Cornelius CB19R71 PI , Merschman Apache 1823GT 2.3 PI , DAIRYLAND SEED DSR-2110/R2Y 2.1 PI , Prairie Brand PB-2197R2 2.1 PI , Legacy Seeds LS-1838N RR2X 1.8 PI , NK S18-G4X 1.8 PI , LG Seeds C2441R2 2.3 PI , Kruger K2X PI , ASGROW AG19X8 PI , Pioneer P16A35X 1.6 PI , Hoegemeyer HPT 2190 NR 2.1 PI , FS HiSOY 23X Peking 2.7 4, Jacobsen 669NR2 19 PI , ASGROW AG17X8 PI , Pfister 20R PI , Wensman W1218NRX 2.1 PI , Dyna-Gro S20XT PI , FS HiSOY 25X PI , Federal Hybrids F2080N R2X 2.0 PI , Kruger K2X-1952 PI , Champion 20X98N 2.0 PI , Federal Hybrids F2280N R2X 2.2 PI , Mean , LSD 3 (P = 0.10) , NK S24-K2 2.4 None , Kruger K None , Dyna-Gro 39RY None , Mean , eggs per 100 cc soil; HG type 2- (30% on PI 88788, 5% on Peking). 5

6 Table 2. Newell (NW Iowa) Non-glyphosate-treated NuTech 3174L PI , Merschman Ute 1821LL 2.1 PI , LATHAM L1958L PI , Merschman Chippewa 1523LL 2.3 PI , Merschman Osage 1824LL 2.4 PI , LATHAM L2358L 2.3 PI , Hoegemeyer HPT LL2300 N 2.3 PI , NuTech 3236L 2.3 PI , NuTech 3205L 2.0 PI , Mean , LSD 3 (P = 0.10) ,122 - NS Dyna-Gro 39RY None , NK S24-K2 2.4 None , Kruger K None , Mean , eggs per 100 cc soil; HG type 2- (30% on PI 88788, 5% on Peking)

7 Table 3. Mason City (NC Iowa) Glyphosate-treated Stine 21RI PI , Jacobsen 669NR2 19 PI Stine 20RD PI , Merschman Navaho 1820GT 2.0 PI , Stine 19RF32 PI , Pfister 18R PI , Legacy Seeds LS-2037N RR2X 2.0 PI , Wensman W1218NRX 2.1 PI , LG Seeds C2255R2 2.2 PI , Mycogen 5N194R2 PI , NK S20-J5X 2.0 PI Prairie Brand PB-1947R2 PI , Prairie Brand PB-2197R2 2.1 PI ,625 FS HiSOY 24X PI , Cornelius CB20R PI , ASGROW AG20X7 2.0 PI ,600 DAIRYLAND SEED DSR-2330/R2Y 2.3 PI , Cornelius CB22R PI , NK S21-W8X 2.1 PI , ASGROW AG23X8 2.3 PI , LATHAM L2228R2 2.2 PI Cornelius CB19R71 PI , LG Seeds C2441R2 2.3 PI , Pfister 20R PI , Pioneer P19A14X Peking Dyna-Gro S21XT PI , Pioneer P21A28X 2.1 Peking ASGROW AG17X8 PI , Champion 20X98N 2.0 PI , Jacobsen 761NR2X 2.1 PI , Pioneer P22T69R 2.2 Peking LATHAM L2368R2X 2.3 PI , NuTech 7198 Peking NuTech Peking Hoegemeyer HPT 2190 NR 2.1 PI ASGROW AG19X8 PI , Dyna-Gro S23XT PI , Legacy Seeds LS-1838N RR2X 1.8 PI , FS HiSOY 25X PI , DAIRYLAND SEED DSR-2110/R2Y 2.1 PI ,125 Hoegemeyer HPT 2511 NRR 2.5 Peking Dyna-Gro S20XT PI ,525 Federal Hybrids F2080N R2X 2.0 PI , Kruger K2X PI , NK S18-G4X 1.8 PI ,900 4 STAR 3X PI , FS HiSOY 23X Peking 2.7 1, Merschman Apache 1823GT 2.3 PI , Pioneer P16A35X 1.6 PI , Federal Hybrids F2280N R2X 2.2 PI , Kruger K2X-1952 PI , Mean , LSD 3 (P = 0.10) Dyna-Gro 39RY None 3.6 3, Kruger K None 3.4 4, NK S24-K2 2.4 None 2.6 4, Mean , eggs per 100 cc soil; HG type 2- (18% on PI 88788, 3% on Peking)

8 Table 4. Mason City (NC Iowa) Non-glyphosate-treated LATHAM L1958L PI NuTech 3174L PI , Merschman Osage 1824LL 2.4 PI , NuTech 3236L 2.3 PI , Hoegemeyer HPT LL2300 N 2.3 PI , NuTech 3205L 2.0 PI , LATHAM L2358L 2.3 PI , Merschman Ute 1821LL 2.1 PI , Merschman Chippewa 1523LL 2.3 PI , Mean , LSD 3 (P = 0.10) NS Kruger K None 3.4 2, Dyna-Gro 39RY None 3.6 5, NK S24-K2 2.4 None 2.6 4, Mean , eggs per 100 cc soil; HG type 2- (18% on PI 88788, 3% on Peking)

9 Table 5. Lawler (NE Iowa) Glyphosate-treated LG Seeds C2255R2 2.2 PI Pfister 18R PI , Pioneer P21A28X 2.1 Peking Prairie Brand PB-1947R2 PI DAIRYLAND SEED DSR-2330/R2Y 2.3 PI Jacobsen 669NR2 19 PI Stine 21RI PI , ASGROW AG23X8 2.3 PI , LATHAM L2228R2 2.2 PI , NK S20-J5X 2.0 PI , Pioneer P22T69R 2.2 Peking Legacy Seeds LS-1838N RR2X 1.8 PI Federal Hybrids F2280N R2X 2.2 PI ,300 NK S21-W8X 2.1 PI , Stine 20RD PI Jacobsen 761NR2X 2.1 PI Stine 19RF32 PI ,000 Legacy Seeds LS-2037N RR2X 2.0 PI , Wensman W1218NRX 2.1 PI , STAR 3X PI ,225 Prairie Brand PB-2197R2 2.1 PI ,425 LG Seeds C2441R2 2.3 PI ,150 Merschman Navaho 1820GT 2.0 PI ,050 Mycogen 5N194R2 PI ASGROW AG19X8 PI Pioneer P16A35X 1.6 PI , NuTech 7198 Peking FS HiSOY 24X PI Pfister 20R PI , Cornelius CB22R PI Champion 20X98N 2.0 PI , Hoegemeyer HPT 2190 NR 2.1 PI LATHAM L2368R2X 2.3 PI , NK S18-G4X 1.8 PI Cornelius CB19R71 PI Cornelius CB20R PI , Hoegemeyer HPT 2511 NRR 2.5 Peking ASGROW AG17X8 PI ,350 Dyna-Gro S20XT PI ASGROW AG20X7 2.0 PI NuTech Peking Federal Hybrids F2080N R2X 2.0 PI ,325 Dyna-Gro S21XT PI ,125 Kruger K2X-1952 PI ,025 Merschman Apache 1823GT 2.3 PI , Kruger K2X PI , Dyna-Gro S23XT PI , FS HiSOY 23X Peking Pioneer P19A14X Peking FS HiSOY 25X PI , DAIRYLAND SEED DSR-2110/R2Y 2.1 PI Mean , LSD 3 (P = 0.10) NS Dyna-Gro 39RY None 3.6 3, Kruger K None 3.4 4,675 NK S24-K2 2.4 None 2.6 2, Mean , ,295 eggs per 100 cc soil; HG type 2- (35% on PI 88788, 1% on Peking)

10 Table 6. Lawler (NE Iowa) Non-glyphosate-treated. Merschman Osage 1824LL 2.4 PI , NuTech 3174L PI NuTech 3236L 2.3 PI , Hoegemeyer HPT LL2300 N 2.3 PI , LATHAM L2358L 2.3 PI , Merschman Chippewa 1523LL 2.3 PI , LATHAM L1958L PI NuTech 3205L 2.0 PI Merschman Ute 1821LL 2.1 PI , Mean , LSD 3 (P = 0.10) NK S24-K2 2.4 None 2.6 2, Kruger K None 3.4 1, Dyna-Gro 39RY None 3.6 4, Mean , ,623 eggs per 100 cc soil; HG type 2- (35% on PI 88788, 1% on Peking). 10

11 Table 7. Moorhead (WC Iowa) Glyphosate-treated Pioneer P25A70R 2.5 Peking NuTech PI , NK S33-T8X 3.3 PI , Federal Hybrids F2480N R2X 2.4 PI , NK S27-M8X 2.7 PI , LG Seeds C2888RX 2.8 PI , Prairie Brand PB-2486R2 2.4 PI , Pioneer P24T93R 2.4 PI ,500 Stine 21RI PI , ASGROW AG26X8 2.6 PI ,475 Champion 24R87N 2.4 PI , Legacy Seeds LS-2638N RR2X 2.6 PI ,000 Cornelius CB22R PI , Dyna-Gro S28XT PI , Hoegemeyer HPT 2721 NR 2.7 PI , FS HiSOY 28X PI , DAIRYLAND SEED DSR-3028/R2Y 3.0 PI , Pfister 24R PI , Mycogen 5N287R2 2.8 PI , Stine 26XB PI Stine 24RH PI , LG Seeds C2520R2 2.5 PI ,900 Cornelius CB24R PI , Hoegemeyer HPT 2811 NR 2.8 PI , Jacobsen 774NR2X 2.4 PI ,000 NuTech Peking NK S29-K3X 2.9 PI ,050 Pioneer P24A99X 2.4 PI , Dyna-Gro S26RS PI , Jacobsen 876NR2X 2.6 PI , Stine 27RIO2 2.7 PI , Kruger K2X PI , Federal Hybrids F2880N R2X 2.8 PI , LATHAM L2682R2X 2.6 PI , LATHAM L3184R2 3.1 PI , Merschman Mohawk 1825GT 2.5 PI ,750 Pfister 26R PI , DAIRYLAND SEED DSR-2909/R2Y 2.9 PI , Pioneer P28T08R 2.8 PI , ASGROW AG29X8 2.9 PI , ASGROW AG24X7 2.4 PI , Merschman Shawnee 1826GT 2.6 PI , NK S21-W8X 2.1 PI ,425 Wensman W1220NRX 2.2 PI , Prairie Brand PB-2876R2 2.8 PI , FS HiSOY 31X PI , ASGROW AG27X7 2.7 PI , Pioneer P31A22X 3.1 PI ,250 FS HiSOY 29X PI , STAR 3X PI , ASGROW AG30X8 3.0 PI ,325 Mean , LSD 3 (P = 0.10) , Dyna-Gro 39RY None , Kruger K None , NK S24-K2 2.4 None , Mean , ,115 eggs per 100 cc soil; HG type 2- (37% on PI 88788, 0% on Peking)

12 Table 8. Moorhead (WC Iowa) Non-glyphosate-treated LATHAM L3187L 3.1 PI , NuTech 3309L 3.0 PI , LATHAM L2684L 2.6 PI , NuTech 3252L 2.5 PI , Champion 26L16N 2.6 PI , Hoegemeyer HPT LL PI ,600 NuTech 3236L 2.3 PI , Hoegemeyer HPT LL PI , Mean , LSD 3 (P = 0.10) , Dyna-Gro 39RY None , Kruger K None , NK S24-K2 2.4 None , Mean , eggs per 100 cc soil; HG type 2- (37% on PI 88788, 0% on Peking)

13 Table 9. Ames (C Iowa) Glyphosate-treated Pioneer P31A22X 3.1 PI , Federal Hybrids F2480N R2X 2.4 PI , Jacobsen 774NR2X 2.4 PI , NK S27-M8X 2.7 PI ,425 Mycogen 5N287R2 2.8 PI , LATHAM L3184R2 3.1 PI , Hoegemeyer HPT 2721 NR 2.7 PI , LG Seeds C2520R2 2.5 PI ,725 Stine 27RIO2 2.7 PI ,000 Stine 21RI PI , Champion 24R87N 2.4 PI ,200 Federal Hybrids F2880N R2X 2.8 PI , Cornelius CB22R PI , Stine 24RH PI ,100 NK S21-W8X 2.1 PI ,800 Pioneer P24T93R 2.4 PI , LG Seeds C2888RX 2.8 PI ,350 Pioneer P28T08R 2.8 PI ,700 Dyna-Gro S28XT PI ,225 NK S33-T8X 3.3 PI ,875 DAIRYLAND SEED DSR-2909/R2Y 2.9 PI , NuTech PI , ASGROW AG29X8 2.9 PI ,625 Stine 26XB PI ,525 Pioneer P25A70R 2.5 Peking 2.5 1,300 NuTech Peking 2.6 1, Prairie Brand PB-2876R2 2.8 PI ,550 Legacy Seeds LS-2638N RR2X 2.6 PI ,625 ASGROW AG30X8 3.0 PI ,550 Pfister 24R PI ,600 ASGROW AG24X7 2.4 PI , Wensman W1220NRX 2.2 PI , FS HiSOY 28X PI , FS HiSOY 31X PI , Prairie Brand PB-2486R2 2.4 PI , Kruger K2X PI ,850 DAIRYLAND SEED DSR-3028/R2Y 3.0 PI ,850 Cornelius CB24R PI , NK S29-K3X 2.9 PI , Jacobsen 876NR2X 2.6 PI ,475 Pioneer P24A99X 2.4 PI , FS HiSOY 29X PI ,450 4 STAR 3X PI ,775 LATHAM L2682R2X 2.6 PI , Merschman Mohawk 1825GT 2.5 PI , Hoegemeyer HPT 2811 NR 2.8 PI , Dyna-Gro S26RS PI , ASGROW AG26X8 2.6 PI , ASGROW AG27X7 2.7 PI , Merschman Shawnee 1826GT 2.6 PI ,375 Pfister 26R PI , Mean , LSD 3 (P = 0.10) , NK S24-K2 2.4 None , Dyna-Gro 39RY None , Kruger K None 3.4 7, Mean , ,974 eggs per 100 cc soil; HG type 2- (33% on PI 88788, 0% on Peking)

14 Table 10. Ames (C Iowa) Non-glyphosate-treated NuTech 3309L 3.0 PI ,400 LATHAM L2684L 2.6 PI , LATHAM L3187L 3.1 PI , Hoegemeyer HPT LL PI , Champion 26L16N 2.6 PI , NuTech 3252L 2.5 PI , Hoegemeyer HPT LL PI , NuTech 3236L 2.3 PI ,025 1 Mean , LSD 3 (P = 0.10) , Dyna-Gro 39RY None , NK S24-K2 2.4 None , Kruger K None , Mean , ,577 eggs per 100 cc soil; HG type 2- (33% on PI 88788, 0% on Peking)

15 Table 11. Urbana (EC Iowa) Glyphosate-treated Jacobsen 774NR2X 2.4 PI , Pfister 24R PI , Cornelius CB24R PI ,550 Federal Hybrids F2480N R2X 2.4 PI , Mycogen 5N287R2 2.8 PI , NK S21-W8X 2.1 PI , Pioneer P24A99X 2.4 PI , Stine 21RI PI , Prairie Brand PB-2486R2 2.4 PI , LG Seeds C2520R2 2.5 PI , Merschman Shawnee 1826GT 2.6 PI , Dyna-Gro S26RS PI , Cornelius CB22R PI , Stine 24RH PI , Stine 27RIO2 2.7 PI , Merschman Mohawk 1825GT 2.5 PI , Hoegemeyer HPT 2721 NR 2.7 PI , ASGROW AG24X7 2.4 PI , NK S27-M8X 2.7 PI , Pioneer P25A70R 2.5 Peking 2.5 2, Legacy Seeds LS-2638N RR2X 2.6 PI , Champion 24R87N 2.4 PI , ASGROW AG26X8 2.6 PI ,375 NuTech Peking 2.6 1, Pioneer P24T93R 2.4 PI , LG Seeds C2888RX 2.8 PI , FS HiSOY 28X PI , Pioneer P28T08R 2.8 PI , Wensman W1220NRX 2.2 PI ,675 Pioneer P31A22X 3.1 PI , LATHAM L2682R2X 2.6 PI , Stine 26XB PI , Hoegemeyer HPT 2811 NR 2.8 PI ,425 Federal Hybrids F2880N R2X 2.8 PI , Jacobsen 876NR2X 2.6 PI ,325 Pfister 26R PI , Dyna-Gro S28XT PI , NuTech PI , DAIRYLAND SEED DSR-2909/R2Y 2.9 PI , ASGROW AG27X7 2.7 PI , NK S33-T8X 3.3 PI , FS HiSOY 31X PI , NK S29-K3X 2.9 PI , Prairie Brand PB-2876R2 2.8 PI , Kruger K2X PI , ASGROW AG30X8 3.0 PI , LATHAM L3184R2 3.1 PI ,725 ASGROW AG29X8 2.9 PI , STAR 3X PI ,600 FS HiSOY 29X PI , DAIRYLAND SEED DSR-3028/R2Y 3.0 PI ,400 Mean , LSD 3 (P = 0.10) NS NK S24-K2 2.4 None , Dyna-Gro 39RY None , Kruger K None ,125 1 Mean , ,052 eggs per 100 cc soil; HG type 2- (33% on PI 88788, 8% on Peking)

16 Table 12. Urbana (EC Iowa) Non-glyphosate-treated LATHAM L2684L 2.6 PI , Champion 26L16N 2.6 PI , NuTech 3309L 3.0 PI , NuTech 3252L 2.5 PI , Hoegemeyer HPT LL PI Hoegemeyer HPT LL PI , NuTech 3236L 2.3 PI , LATHAM L3187L 3.1 PI Mean , LSD 3 (P = 0.10) , Dyna-Gro 39RY None , NK S24-K2 2.4 None , Kruger K None , Mean , eggs per 100 cc soil; HG type 2- (33% on PI 88788, 8% on Peking). 16

17 Table 13. Glenwood (SW Iowa) Glyphosate-treated DAIRYLAND SEED DSR-3630/R2Y 3.6 PI , LG Seeds C3550RX 3.5 PI , Hoegemeyer HPT 3422 NR 3.4 PI , NK S33-T8X 3.3 PI , Pfister 32R PI , ASGROW AG36X6 3.6 PI , Kruger K2X PI , Prairie Brand PB-2917R2 2.9 PI , Federal Hybrids F3080N R2X 3.0 PI , FS HiSOY 34X PI , ASGROW AG33X8 3.3 PI , Pioneer P31T11R 3.1 PI ,450 2 LG Seeds C3489RX 3.4 PI , LATHAM L3448R2X 3.4 PI , NuTech 7352X 3.5 PI , DAIRYLAND SEED DSR-3555/R2Y 3.5 PI , Kruger K2X PI , Dyna-Gro S34XT PI , Cornelius CB28R PI , Merschman Washington 1839GT 3.9 PI , STAR 3X PI , Pioneer P38T20X 3.8 PI , Champion 34R87N 3.4 PI ,975 6 Jacobsen 878NR2X 2.8 PI , FS HiSOY 37X PI , Dyna-Gro S33XT PI , NuTech PI , Stine 38RE PI , Merschman Kennedy 1835GT 3.5 PI ,200 4 Pioneer P36T36X 3.8 PI , Hoegemeyer HPT 3149 NX 3.1 PI , Jacobsen 960NR2X 3.0 PI , Morsoy 3747 RXT 3.7 PI , FS HiSOY 35X PI , NK S35-K9X 3.5 PI , Pioneer P32T16R 3.2 PI , ASGROW AG29X8 2.9 PI , Morsoy 3357 RXT 3.3 PI , NK S29-K3X 2.9 PI , DAIRYLAND SEED DSR-3745/R2Y 3.7 PI , Pioneer P36A18X 3.6 PI , ASGROW AG32X6 3.2 PI , Mycogen 5N327R2 3.2 PI , NK S37-H5X 3.7 PI , Cornelius CB29R PI , Prairie Brand PB-3186R2 3.1 PI , Pfister 34R PI , LATHAM L3278R2X 3.2 PI , Mycogen 5N342R2 3.4 PI , Dyna-Gro S31XT PI , ASGROW AG30X8 3.0 PI , Mean , LSD 3 (P = 0.10) , Kruger K None , Dyna-Gro 39RY None , ASGROW AG None , Mean , eggs per 100 cc soil; HG type 1.2- (59% on PI 88788, 16% on Peking)

18 Table 14. Glenwood (SW Iowa) Non-glyphosate-treated Merschman Grant 1537LL 3.7 PI , Hoegemeyer HPT LL3201 N 3.2 PI , Merschman Monroe 1736LL 3.6 PI , LATHAM L3384L 3.3 PI , Merschman Truman 1438LL 3.8 PI , NuTech 3309L 3.0 PI , Hoegemeyer HPT LL3813 N 3.8 PI , LATHAM L3178L 3.1 PI ,200 2 Mean , LSD 3 (P = 0.10) NS - NS Dyna-Gro 39RY None , Kruger K None , NK S24-K2 2.4 None , Mean , eggs per 100 cc soil; HG type 1.2- (59% on PI 88788, 16% on Peking)

19 Table 15. Leighton (SC Iowa) Glyphosate-treated Pioneer P36A18X 3.6 PI ,300 1 Jacobsen 878NR2X 2.8 PI , Stine 38RE PI , NuTech 7352X 3.5 PI , LATHAM L3448R2X 3.4 PI , NuTech PI , Morsoy 3747 RXT 3.7 PI , DAIRYLAND SEED DSR-3745/R2Y 3.7 PI , ASGROW AG33X8 3.3 PI , Hoegemeyer HPT 3422 NR 3.4 PI , NK S35-K9X 3.5 PI ,400 2 LATHAM L3278R2X 3.2 PI , Pfister 32R PI , Hoegemeyer HPT 3149 NX 3.1 PI , ASGROW AG36X6 3.6 PI , ASGROW AG30X8 3.0 PI , LG Seeds C3550RX 3.5 PI , FS HiSOY 34X PI , Pioneer P31T11R 3.1 PI , DAIRYLAND SEED DSR-3630/R2Y 3.6 PI , Kruger K2X PI , Merschman Washington 1839GT 3.9 PI , FS HiSOY 37X PI , Pioneer P32T16R 3.2 PI , Champion 34R87N 3.4 PI , Pioneer P38T20X 3.8 PI , Kruger K2X PI , DAIRYLAND SEED DSR-3555/R2Y 3.5 PI , Federal Hybrids F3080N R2X 3.0 PI , Prairie Brand PB-3186R2 3.1 PI , Pioneer P36T36X 3.8 PI , Morsoy 3357 RXT 3.3 PI , Pfister 34R PI , Dyna-Gro S31XT PI , NK S29-K3X 2.9 PI , NK S33-T8X 3.3 PI , NK S37-H5X 3.7 PI , Dyna-Gro S33XT PI , Dyna-Gro S34XT PI , ASGROW AG32X6 3.2 PI , Merschman Kennedy 1835GT 3.5 PI , LG Seeds C3489RX 3.4 PI , STAR 3X PI , Mycogen 5N342R2 3.4 PI , Cornelius CB28R PI , Jacobsen 960NR2X 3.0 PI , ASGROW AG29X8 2.9 PI , Mycogen 5N327R2 3.2 PI , Prairie Brand PB-2917R2 2.9 PI , FS HiSOY 35X PI , Cornelius CB29R PI , Mean , LSD 3 (P = 0.10) NS Kruger K None 3.4 9, Dyna-Gro 39RY None 3.6 8, ASGROW AG None 2.4 8, Mean , eggs per 100 cc soil; HG type 1.2- (43% on PI 88788, 19% on Peking)

20 Table 16. Leighton (SC Iowa) Non-glyphosate-treated Merschman Monroe 1736LL 3.6 PI , Hoegemeyer HPT LL3201 N 3.2 PI , Hoegemeyer HPT LL3813 N 3.8 PI , Merschman Grant 1537LL 3.7 PI , Merschman Truman 1438LL 3.8 PI , NuTech 3309L 3.0 PI , LATHAM L3178L 3.1 PI , LATHAM L3384L 3.3 PI ,200 1 Mean , LSD 3 (P = 0.10) , Dyna-Gro 39RY None 2.5 5, NK S24-K2 2.4 None 2.4 9, Kruger K None 2.3 7, Mean , eggs per 100 cc soil; HG type 1.2- (43% on PI 88788, 19% on Peking)

21 Table 17. Fruitland (SE Iowa) Glyphosate-treated Pioneer P31T11R 3.1 PI , Mycogen 5N327R2 3.2 PI , Kruger K2X PI , NK S33-T8X 3.3 PI , Pioneer P32T16R 3.2 PI , Jacobsen 878NR2X 2.8 PI , NuTech PI , FS HiSOY 34X PI , Jacobsen 960NR2X 3.0 PI , Hoegemeyer HPT 3422 NR 3.4 PI , Dyna-Gro S34XT PI , DAIRYLAND SEED DSR-3555/R2Y 3.5 PI , Merschman Kennedy 1835GT 3.5 PI , LG Seeds C3550RX 3.5 PI , NuTech 7352X 3.5 PI , FS HiSOY 35X PI , Pfister 32R PI , ASGROW AG36X6 3.6 PI , ASGROW AG32X6 3.2 PI , Cornelius CB28R PI , LG Seeds C3489RX 3.4 PI , Morsoy 3357 RXT 3.3 PI , LATHAM L3278R2X 3.2 PI , ASGROW AG33X8 3.3 PI , Pioneer P36A18X 3.6 PI , Kruger K2X PI , LATHAM L3448R2X 3.4 PI , DAIRYLAND SEED DSR-3630/R2Y 3.6 PI , Merschman Washington 1839GT 3.9 PI , Dyna-Gro S31XT PI , NK S29-K3X 2.9 PI , NK S37-H5X 3.7 PI , Pioneer P38T20X 3.8 PI , Prairie Brand PB-3186R2 3.1 PI , ASGROW AG30X8 3.0 PI , Prairie Brand PB-2917R2 2.9 PI , Stine 38RE PI , Champion 34R87N 3.4 PI , Pioneer P36T36X 3.8 PI ,525 1 NK S35-K9X 3.5 PI , Mycogen 5N342R2 3.4 PI , ASGROW AG29X8 2.9 PI , Morsoy 3747 RXT 3.7 PI , DAIRYLAND SEED DSR-3745/R2Y 3.7 PI , Pfister 34R PI , FS HiSOY 37X PI , STAR 3X PI , Cornelius CB29R PI , Dyna-Gro S33XT PI , Federal Hybrids F3080N R2X 3.0 PI , Hoegemeyer HPT 3149 NX 3.1 PI , Mean , LSD 3 (P = 0.10) , Kruger K None , Dyna-Gro 39RY None , ASGROW AG None , Mean , eggs per 100 cc soil; HG type 2- (56% on PI 88788, 0% on Peking)

22 Table 18. Fruitland (SE Iowa) Non-glyphosate-treated NuTech 3309L 3.0 PI , Hoegemeyer HPT LL3201 N 3.2 PI , LATHAM L3178L 3.1 PI , Merschman Grant 1537LL 3.7 PI , Hoegemeyer HPT LL3813 N 3.8 PI , Merschman Monroe 1736LL 3.6 PI , Merschman Truman 1438LL 3.8 PI , LATHAM L3384L 3.3 PI , Mean , LSD 3 (P = 0.10) , Kruger K None , Dyna-Gro 39RY None , NK S24-K2 2.4 None , Mean , eggs per 100 cc soil; HG type 2- (56% on PI 88788, 0% on Peking)

23 Table 19. Seed treatments used on varieties evaluated in Brand Seed Treatment Brand Seed Treatment Brand Seed Treatment 4 Star Acceleron Jacobsen Acceleron FI Mycogen CruiserMaxx ASGROW Acceleron FI Hoegemeyer HPT Right Stand NK CruiserMaxx Champion* Acceleron Kruger Acceleron FI NuTech SmartCote Extra Cornelius CruiserMaxx Vibrance LATHAM* SoyShield Plus Pfister CruiserMaxx Dairyland Seed CruiserMaxx Optimize Legacy Seeds L-Coat Total Pioneer PPST 2030 Dyna-Gro Equity VIP LG Seeds CruiserMaxx Prairie Brand CruiserMaxx Federal Hybrids* Maximum ArmourGuard Merschman Bonus Coated + Stine CruiserMaxx FS HiSOY Acceleron FI MorSoy CruiserMaxx Vibrance Wensman* CruiserMaxx *Some varieties were sent untreated. Seeds of those varieties, listed below, were treated with CruiserMaxx by Iowa State University personnel. Federal: F2080N R2X, F2880N R2X, F2280N R2X, F3080N R2X Champion: 20X98N LATHAM: L3448R2X, L2682R2X, L3278R2X, L2368R2X, L3187L Wensman: W1220NRX Table 20. Contact information for companies represented in 2017 variety trials. Champion Seed - Rob Thomas phone: robthomas@championseedofiowa.com website: Cornelius Seed - Will Cornelius phone: cornelius.seed@corneliusseed.com website: Crop Production Services (Dyna-Gro)- Valerie Oberbroeckling phone: valerie.oberbroeckling@cpsagu.com website: Dairyland Seed phone: cs@dairylandseed.com website: Federal Hybrids - Dan Swalla phone: dan.swalla@federalhybrids.com website: Four Star Seed Company - Dennis Kenealy phone: dkenealy@loganet.net website: GROWMARK, Inc. (FS HiSOY) - Eric West phone: ewest@growmark.com website: Hoegemeyer Hybrids - Ryan Spurgeon phone: r.spurgeon@hoegemeyer.com website: Jacobsen Seed Nora Schultz phone: nora@jacobsenseed.com website: Kruger Seed - Neal Borgmeyer phone: neal.borgmeyer@krugerseed.com website: Latham Hi-Tech Seeds -Mark Grundmeier phone: markg@lathamseeds.com website: Legacy Seeds, Inc. - Jim Wold phone: jimwold@legacyseeds.com website: LG Seeds - Greg Peters phone: greg.peters@lgseeds.com website: Merschman Seeds - Brian McKillip phone: bmckillip@merschmanseeds.com website: MFA Incorporated (MorSoy) - Brian Anderson phone: banderson@mfa-inc.com website: Monsanto (ASGROW) - George Kadrmas phone: george.kadrmas@monsanto.com website: Mycogen Seeds - Josh Enderson phone: jtenderson@dow.com website: NuTech Seed, LLC - Steve Sick phone: steve.sick@nutechseed.com website: Pfister Seeds - Brad Johnson phone: bjohnson@pfisterseeds.com website: Pioneer Hi-Bred Int. Inc. - Troy Bauer phone: troy.bauer@pioneer.com website: Prairie Brand Seeds - Mike Carr phone: mike.carr@prairiebrandseed.com website: Stine Seed Company - Brian Hartman phone: bmhartman@stineseed.com website: Syngenta Seeds (NK) - Austin Hively phone: austin.hively@syngenta.com website: Wensman Seed Company - Kyle Kepner phone: kyle.kepner@wensmanseed.com website: and justice for all The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue SW, Washington, DC , or call (voice) or (TDD). USDA is an equal opportunity provider and employer. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Cathann A. Kress, director, Cooperative Extension Service, Iowa State University of Science and Technology, Ames, Iowa. 23