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Arce CC, Theepan V, Schimmel BC, Jaffuel G, Erb M, Machado RA. Plant-associated CO 2 mediates long-distance host location and foraging behaviour of a root herbivore. eLife 2021; 10:65575. [PMID: 33875133 PMCID: PMC8057813 DOI: 10.7554/elife.65575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/08/2021] [Indexed: 11/13/2022] Open
Abstract
Insect herbivores use different cues to locate host plants. The importance of CO2 in this context is not well understood. We manipulated CO2 perception in western corn rootworm (WCR) larvae through RNAi and studied how CO2 perception impacts their interaction with their host plant. The expression of a carbon dioxide receptor, DvvGr2, is specifically required for dose-dependent larval responses to CO2. Silencing CO2 perception or scrubbing plant-associated CO2 has no effect on the ability of WCR larvae to locate host plants at short distances (<9 cm), but impairs host location at greater distances. WCR larvae preferentially orient and prefer plants that grow in well-fertilized soils compared to plants that grow in nutrient-poor soils, a behaviour that has direct consequences for larval growth and depends on the ability of the larvae to perceive root-emitted CO2. This study unravels how CO2 can mediate plant–herbivore interactions by serving as a distance-dependent host location cue. Living deep in the ground and surrounded by darkness, soil insects must rely on the chemicals released by plants to find the roots they feed on. Carbon dioxide, for example, is a by-product of plant respiration, which, above ground, is thought to attract moths to flowers and flies to apples; underground, however, its role is still unclear. This gaseous compound can travel through soil and potentially act as a compass for root-eating insects. Yet, it is also produced by decaying plants or animals, which are not edible. It is therefore possible that insects use this signal as a long-range cue to orient themselves, but then switch to another chemical when closer to their target to narrow in on an actual food source. To test this idea, Arce et al. investigated whether carbon dioxide guides the larvae of Western corn rootworm to maize roots. First, the rootworm genes responsible for sensing carbon dioxide were identified and switched off, making the larvae unable to detect this gas. When the genetically engineered rootworms were further than 9cm from maize roots, they were less able to locate that food source; closer to the roots, however, the insects could orient themselves towards the plant. This suggests that the insects use carbon dioxide at long distances but rely on another chemicals to narrow down their search at close range. To confirm this finding, Arce et al. tried absorbing the carbon dioxide using soda lime, leading to similar effects: carbon dioxide sensitive insects stopped detecting the roots at long but not short distances. Additional experiments then revealed that the compound could help insects find the best roots to feed on. Indeed, eating plants that grow on rich terrain – for instance, fertilized soils – helps insects to grow bigger and faster. These roots also release more carbon dioxide, in turn attracting rootworms more frequently. In the United States and Eastern Europe, Western corn rootworms inflict major damage to crops, highlighting the need to understand and manage the link between fertilization regimes, carbon dioxide release and how these pests find their food.
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Affiliation(s)
- Carla Cm Arce
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Vanitha Theepan
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | - Geoffrey Jaffuel
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Ricardo Ar Machado
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.,Institute of Plant Sciences, University of Bern, Bern, Switzerland
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Bažok R, Lemić D, Chiarini F, Furlan L. Western Corn Rootworm ( Diabrotica virgifera virgifera LeConte) in Europe: Current Status and Sustainable Pest Management. INSECTS 2021; 12:insects12030195. [PMID: 33668906 PMCID: PMC7996541 DOI: 10.3390/insects12030195] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/11/2021] [Accepted: 02/21/2021] [Indexed: 11/18/2022]
Abstract
Simple Summary Diabrotica virgifera virgifera, also known as western corn rootworm (WCR), is a maize-specific pest that has been a serious threat in Europe since the mid-1990s. Between 1995 and 2010, European countries were involved in international projects to plan pest control strategies. However, since 2011, collaborative efforts have declined and the overview of knowledge on WCR is in great need of updating. Therefore, a review of scientific papers published between 2008 and 2020, in addition to direct interviews with experts responsible for WCR management in several European countries, was conducted to (1) summarize the research conducted over the last 12 years and (2) describe the current WCR distribution and population in the EU, and the management strategies implemented. A considerable amount of new knowledge has been gained over the last 12 years, which has contributed to the development of pest management strategies applicable in EU agricultural systems. There is no EU country reporting economic damage on a large scale. In many countries, solutions based on crop rotation are regularly implemented, avoiding insecticide use. Therefore, WCR has not become as serious a pest as was expected when it was discovered in much of Europe. Abstract Western corn rootworm (WCR), or Diabrotica virgifera virgifera LeConte, became a very serious quarantine maize pest in Europe in the mid-1990s. Between 1995 and 2010, European countries were involved in international projects to share information and plan common research for integrated pest management (IPM) implementation. Since 2011, however, common efforts have declined, and an overview of WCR population spread, density, and research is in serious need of update. Therefore, we retained that it was necessary to (1) summarize the research activities carried out in the last 12 years in various countries and the research topics addressed, and analyze how these activities have contributed to IPM for WCR and (2) present the current distribution of WCR in the EU and analyze the current population levels in different European countries, focusing on different management strategies. A review of scientific papers published from 2008 to 2020, in addition to direct interviews with experts in charge of WCR management in a range of European countries, was conducted. Over the past 12 years, scientists in Europe have continued their research activities to investigate various aspects of WCR management by implementing several approaches to WCR control. A considerable amount of new knowledge has been produced, contributing to the development of pest management strategies applicable in EU farming systems. Among the 10 EU countries analyzed, there is no country reporting economic damage on a large scale. Thanks to intensive research leading to specific agricultural practices and the EU Common Agricultural Policy, there are crop-rotation-based solutions that can adequately control this pest avoiding insecticide use.
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Affiliation(s)
- Renata Bažok
- Department for Agricultural Zoology, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 10000 Zagreb, Croatia; (R.B.); (D.L.)
| | - Darija Lemić
- Department for Agricultural Zoology, Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 10000 Zagreb, Croatia; (R.B.); (D.L.)
| | - Francesca Chiarini
- Veneto Agricoltura, Agricultural Research Department, 35020 Legnaro, PD, Italy;
| | - Lorenzo Furlan
- Veneto Agricoltura, Agricultural Research Department, 35020 Legnaro, PD, Italy;
- Correspondence: ; Tel.: +39-049-829-3879
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Agatz A, Schumann MM, French BW, Brown CD, Vidal S. Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests. PEST MANAGEMENT SCIENCE 2018; 74:2450-2459. [PMID: 29575759 DOI: 10.1002/ps.4922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/15/2018] [Accepted: 03/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Characterizing lethal and sublethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here, we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability to strengthen our understanding of mechanisms driving the effectivness of the plant protection product. Experiments were conducted using larvae of the western corn rootworm Diabrotica virgifera LeConte and three pesticide active ingredients: clothianidin (neonicotinoid), chlorpyrifos (organophosphate) and tefluthrin (pyrethroid). RESULTS The order of compound concentrations needed to invoke a specific effect intensity (EC50 values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile, and sublethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots. CONCLUSION Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development, and might be useful tools for assessing resistance development in the future. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Annika Agatz
- Environment Department, University of York, York, UK
| | - Mario M Schumann
- Agricultural Entomology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
| | - Bryan W French
- United States Department of Agriculture, North Central Agricultural Research Laboratory, Agricultural Research Service, Brookings, USA
| | - Colin D Brown
- Environment Department, University of York, York, UK
| | - Stefan Vidal
- Agricultural Entomology, Department of Crop Sciences, University of Göttingen, Göttingen, Germany
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Humbert P, Vemmer M, Mävers F, Schumann M, Vidal S, Patel AV. Development of an attract-and-kill co-formulation containing Saccharomyces cerevisiae and neem extract attractive towards wireworms. PEST MANAGEMENT SCIENCE 2018; 74:1575-1585. [PMID: 29281183 DOI: 10.1002/ps.4842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/12/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Wireworms (Coleoptera: Elateridae) are major insect pests of worldwide relevance. Owing to the progressive phasing-out of chemical insecticides, there is great demand for innovative control options. This study reports on the development of an attract-and-kill co-formulation based on Ca-alginate beads, which release CO2 and contain neem extract as a bioinsecticidal compound. The objectives of this study were to discover: (1) whether neem extract can be immobilized efficiently, (2) whether CO2 -releasing Saccharomyces cerevisiae and neem extract are suitable for co-encapsulation, and (3) whether co-encapsulated neem extract affects the attractiveness of CO2 -releasing beads towards wireworms. RESULTS Neem extract was co-encapsulated together with S. cerevisiae, starch and amyloglucosidase with a high encapsulation efficiency of 98.6% (based on measurement of azadirachtin A as the main active ingredient). Even at enhanced concentrations, neem extract allowed growth of S. cerevisiae, and beads containing neem extract exhibited CO2 -emission comparable with beads without neem extract. When applied to the soil, the beads established a CO2 gradient of >15 cm. The co-formulation containing neem extract showed no repellent effects and was attractive for wireworms within the first 24 h after exposure. CONCLUSION Co-encapsulation of S. cerevisiae and neem extract is a promising approach for the development of attract-and-kill formulations for the control of wireworms. This study offers new options for the application of neem extracts in soil. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Pascal Humbert
- Faculty of Engineering Sciences and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, University of Applied Sciences Bielefeld, Bielefeld, Germany
| | - Marina Vemmer
- Faculty of Engineering Sciences and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, University of Applied Sciences Bielefeld, Bielefeld, Germany
| | - Frauke Mävers
- Department for Crop Sciences, Agricultural Entomology, University of Göttingen, Göttingen, Germany
| | - Mario Schumann
- Department for Crop Sciences, Agricultural Entomology, University of Göttingen, Göttingen, Germany
| | - Stefan Vidal
- Department for Crop Sciences, Agricultural Entomology, University of Göttingen, Göttingen, Germany
| | - Anant V Patel
- Faculty of Engineering Sciences and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, University of Applied Sciences Bielefeld, Bielefeld, Germany
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Humbert P, Vemmer M, Giampà M, Bednarz H, Niehaus K, Patel AV. Co-encapsulation of amyloglucosidase with starch and Saccharomyces cerevisiae as basis for a long-lasting CO 2 release. World J Microbiol Biotechnol 2017; 33:71. [PMID: 28289929 DOI: 10.1007/s11274-017-2237-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 03/01/2017] [Indexed: 12/01/2022]
Abstract
CO2 is known as a major attractant for many arthropod pests which can be exploited for pest control within novel attract-and-kill strategies. This study reports on the development of a slow-release system for CO2 based on calcium alginate beads containing granular corn starch, amyloglucosidase and Saccharomyces cerevisiae. Our aim was to evaluate the conditions which influence the CO2 release and to clarify the biochemical reactions taking place within the beads. The amyloglucosidase was immobilized with a high encapsulation efficiency of 87% in Ca-alginate beads supplemented with corn starch and S. cerevisiae biomass. The CO2 release from the beads was shown to be significantly affected by the concentration of amyloglucosidase and corn starch within the beads as well as by the incubation temperature. Beads prepared with 0.1 amyloglucosidase units/g matrix solution led to a long-lasting CO2 emission at temperatures between 6 and 25 °C. Starch degradation data correlated well with the CO2 release from beads during incubation and scanning electron microscopy micrographs visualized the degradation of corn starch granules by the co-encapsulated amyloglucosidase. By implementing MALDI-ToF mass spectrometry imaging for the analysis of Ca-alginate beads, we verified that the encapsulated amyloglucosidase converts starch into glucose which is immediately consumed by S. cerevisiae cells. When applied into the soil, the beads increased the CO2 concentration in soil significantly. Finally, we demonstrated that dried beads showed a CO2 production in soil comparable to the moist beads. The long-lasting CO2-releasing beads will pave the way towards novel attract-and-kill strategies in pest control.
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Affiliation(s)
- Pascal Humbert
- Faculty of Engineering and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, Bielefeld University of Applied Sciences, Interaktion 1, 33619, Bielefeld, Germany
| | - Marina Vemmer
- Faculty of Engineering and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, Bielefeld University of Applied Sciences, Interaktion 1, 33619, Bielefeld, Germany
| | - Marco Giampà
- Faculty of Biology, Center for Biotechnology (CeBiTec), Proteome and Metabolome Research, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Hanna Bednarz
- Faculty of Biology, Center for Biotechnology (CeBiTec), Proteome and Metabolome Research, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Karsten Niehaus
- Faculty of Biology, Center for Biotechnology (CeBiTec), Proteome and Metabolome Research, Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Anant V Patel
- Faculty of Engineering and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, Bielefeld University of Applied Sciences, Interaktion 1, 33619, Bielefeld, Germany.
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Humbert P, Przyklenk M, Vemmer M, Patel AV. Calcium gluconate as cross-linker improves survival and shelf life of encapsulated and dried Metarhizium brunneum and Saccharomyces cerevisiae for the application as biological control agents. J Microencapsul 2017; 34:47-56. [PMID: 28084135 DOI: 10.1080/02652048.2017.1282550] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Calcium chloride (CC) is the most common cross-linker for the encapsulation of biocontrol microorganisms in alginate beads. The aim of this study was to evaluate if calcium gluconate (CG) can replace CC as cross-linker and at the same time improve viability after drying and rehydration, hygroscopic properties, shelf life and nutrient supply. Hence, the biocontrol fungi Metarhizium brunneum and Saccharomyces cerevisiae were encapsulated in Ca-alginate beads supplemented with starch. Beads were dried and maximum survival was found in beads cross-linked with CG. Beads prepared with CG showed lower hygroscopic properties, but a higher shelf life for encapsulated fungi. Moreover, we demonstrated that gluconate has a nutritive effect on encapsulated fungi, leading to increased mycelium growth of M. brunneum and to enhanced CO2 release from beads containing Saccharomyces cerevisiae. The application of CG as cross-linker will pave the way towards increasing drying survival and shelf life of various, especially drying-sensitive microbes.
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Affiliation(s)
- Pascal Humbert
- a Faculty of Engineering and Mathematics, WG Fermentation and Formulation of Biologicals and Chemicals , Bielefeld University of Applied Sciences , Bielefeld, Germany
| | - Michael Przyklenk
- a Faculty of Engineering and Mathematics, WG Fermentation and Formulation of Biologicals and Chemicals , Bielefeld University of Applied Sciences , Bielefeld, Germany
| | - Marina Vemmer
- a Faculty of Engineering and Mathematics, WG Fermentation and Formulation of Biologicals and Chemicals , Bielefeld University of Applied Sciences , Bielefeld, Germany
| | - Anant V Patel
- a Faculty of Engineering and Mathematics, WG Fermentation and Formulation of Biologicals and Chemicals , Bielefeld University of Applied Sciences , Bielefeld, Germany
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Vemmer M, Schumann M, Beitzen-Heineke W, French BW, Vidal S, Patel AV. Development of a CO 2 -releasing coformulation based on starch, Saccharomyces cerevisiae and Beauveria bassiana attractive towards western corn rootworm larvae. PEST MANAGEMENT SCIENCE 2016; 72:2136-2145. [PMID: 26834068 DOI: 10.1002/ps.4245] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 06/05/2023]
Abstract
BACKGROUND CO2 is known as an attractant for many soil-dwelling pests. To implement an attract-and-kill strategy for soil pest control, CO2 -emitting formulations need to be developed. The aim of the present work was to develop a slow-release bead system in order to bridge the gap between application and hatching of western corn rootworm larvae. RESULTS We compared different Ca-alginate beads containing Saccharomyces cerevisiae for their potential to release CO2 over a period of several weeks. The addition of starch improved CO2 release, resulting in significantly higher CO2 concentrations in soil for at least 4 weeks. The missing amylase activity was compensated for either by microorganisms present in the soil or by coencapsulation of Beauveria bassiana. Formulations containing S. cerevisiae, starch and B. bassiana were attractive for western corn rootworm larvae within the first 4 h following exposure; however, when considering the whole testing period, the maize root systems remained more attractive for the larvae. CONCLUSION Coencapsulation of S. cerevisiae, starch and B. bassiana is a promising approach for the development of attractive formulations for soil applications. For biological control strategies, the attractiveness needs to be increased by phagostimuli to extend contact between larvae and the entomopathogenic fungus growing out of these formulations. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Marina Vemmer
- Fermentation and Formulation of Biologicals and Chemicals, Faculty of Engineering and Mathematics, University of Applied Sciences, Bielefeld, Germany
| | - Mario Schumann
- Agricultural Entomology, Department for Crop Sciences, University of Göttingen, Göttingen, Germany
| | | | - Bryan W French
- North Central Agricultural Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Brookings, SD, USA
| | - Stefan Vidal
- Agricultural Entomology, Department for Crop Sciences, University of Göttingen, Göttingen, Germany
| | - Anant V Patel
- Fermentation and Formulation of Biologicals and Chemicals, Faculty of Engineering and Mathematics, University of Applied Sciences, Bielefeld, Germany.
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Meihls LN, Frank DL, Ellersieck MR, Hibbard BE. Development and Characterization of MIR604 Resistance in a Western Corn Rootworm Population (Coleoptera: Chrysomelidae). ENVIRONMENTAL ENTOMOLOGY 2016; 45:526-536. [PMID: 26834186 DOI: 10.1093/ee/nvv226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/15/2015] [Indexed: 06/05/2023]
Abstract
mCry3A is one of only four proteins licensed for commercial use in Diabrotica control. Utilizing a colony of western corn rootworm, Diabrotica virgifera virgifera LeConte, selected for resistance to mCry3A, we evaluated how mCry3A resistance was inherited and whether fitness costs were associated with mCry3A resistance. Reciprocal crosses between a selected colony and a control colony were performed; resulting progeny along with parent colonies were evaluated in dose toxicity assays, greenhouse assays, and seedling assays. Dose toxicity assay results were inconclusive, as the highest dose of protein tested did not produce sufficient mortality for accurate LC50 calculation. In whole-plant greenhouse assays on mCry3A-expressing corn, larval relative survival of the selected female × control male reciprocal cross was similar to that of the selected colony, while that of the control female × selected male was intermediate between the mCry3-selected colony and the control colony. However, when adult relative survival in whole-plant greenhouse assays was examined, no significant difference between the reciprocal crosses and the two parent colonies was detected. Heritability calculations based on both larval (0.66) and adult (1.03) survival data indicate that resistance to mCry3A is not inherited in a recessive manner. The selected colony was removed from selection pressure and evaluated after three or eight generations of removal. At three generations of removal from selection, a slight decrease in larval relative survival was detected compared with the selected colony. At eight generations of removal from selection, larval relative survival was comparable with that of the selected colony.
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Affiliation(s)
- Lisa N Meihls
- USDA-ARS Plant Genetics Research Unit, 205 Curtis Hall, Columbia, MO 65211 (; ),
| | - Daniel L Frank
- Extension Service, Agriculture and Natural Resources Unit, West Virginia University, Morgantown, WV 26506 , and
| | - Mark R Ellersieck
- Agricultural Experiment Station Statistician, 307E Middlebush, University of Missouri, Columbia, MO 65211
| | - Bruce E Hibbard
- USDA-ARS Plant Genetics Research Unit, 205 Curtis Hall, Columbia, MO 65211 (; )
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