Zea Mays L.) a Thesis Presented to the Faculty of Graduate
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PREEMERGENCE AND POSTEMERGENCE INTERACTIONS OF SAFLUFENACIL IN CORN {Zea mays L.) A Thesis Presented to The Faculty of Graduate Studies of The University of Guelph by MEGHAN ELIZABETH MORAN In partial fulfillment of requirements for the degree of Master of Science April, 2010 © Meghan E. Moran, 2010 Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 OttawaONK1A0N4 Canada Canada Your file Voire reference ISBN: 978-0-494-64667-0 Our file Notre reference ISBN: 978-0-494-64667-0 NOTICE: AVIS: The author has granted a non L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduce, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lntemet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. 1+1 Canada ABSTRACT PREEMERGENCE AND POSTEMERGENCE INTERACTIONS OF SAFLUFENACIL IN CORN (Zea mays L.) Meghan Moran Advisors: University of Guelph, 2010 Clarence J. Swanton Peter H. Sikkema Studies were conducted under field and growth room conditions to explore the tolerance of corn to postemergence treatments of saflufenacil and BAS 781 (saflufenacil plus dimethenamid-p), and to determine the safening effect of sodium compounds on saflufenacil applied postemergence. Saflufenacil and BAS 781 applied at the 3-to-4 leaf corn stage caused up to 28 and 65% injury, respectively, resulting in yield loss. The addition of Na-bentazon and baking soda to saflufenacil reduced this injury by decreasing foliar herbicide uptake. Field studies were conducted with BAS 781 applied preemergence to evaluate overall and species specific weed control, as well as the dose required for weed control when followed with glyphosate. The GR95 across locations ranged from 126 to 675 g/ha. Common ragweed was the most difficult weed to control; the GR95 was 933 g/ha. When followed by glyphosate, 46 to 1470 g/ha of BAS 781 resulted in optimum yields. ACKNOWLEDGEMENTS Funding for this project came from BASF Canada, as well as the Ontario Ministry of Agriculture, Food, and Rural Affairs. Thank you for your financial contributions in support of this research. There are a number of people to thank for their guidance, support, and assistance with this research project. I would like to thank my advisors, Clarence J. Swanton and Peter H. Sikkema, for their ideas and suggestions, and assistance during the writing process. Thank you to Nader Soltani and J. Christopher Hall of the University of Guelph, and Trevor Kraus of BASF Canada, for serving on my advisory committee and contributing in various ways to the research project. You have all been very kind and supportive, and have made this a great experience in which I have learned more than I expected to. I would also like to thank those that helped manage my field experiments; Kevin Chandler, Todd Cowan, and Christy Shropshire. All of your help and advice was greatly appreciated. Additionally, I would like to thank all of the members of the Weeds Lab for their friendship and advice, and for lending a hand in the field. You have been an important source of support and entertainment over the past two years, and I will miss spending time working with you. I would also like to thank my family, specifically my mother and grandfather, for taking good care of me and encouraging me along the way. I wouldn't have made it this far without you, and attribute much of my success to you. Thank you to my friends and partner, Chris, for encouraging me when I was overwhelmed, and for keeping me humble. 1 TABLE OF CONTENTS Acknowledgements i Table of Contents ii List of Tables iv List of Figures vi 1.0 Literature Review: Protoporphyrinogen Oxidase Inhibiting Herbicides, and the Use of Herbicide Safeners 1.1 Introduction 1.2 Protoporphyrinogen Oxidase (PPO) and PPO Inhibiting Herbicides 1.3 A New PPO Inhibitor: Saflufenacil 1.4 Herbicide Safeners 1.5 Bentazon as an Herbicide Safener 1.6 The Role of Sodium Ions in the Safening Effect 2.0 Na-Bentazon Safens Saflufenacil Applied Postemergence to Corn 2.1 Abstract 2.2 Introduction 2.3 Materials and Methods 2.3.1 Tolerance of Corn to Saflufenacil and BAS 781 2.3.2 Growth Room 2.3.3 Dose Response of Saflufenacil 2.3.4 Safening Effect of Na-bentazon Under Growth Room Conditions 2.3.5 Safening Effect of Na-bentazon Under Field Conditions 2.3.6 Uptake of 14C-Saflufenacil With and Without Na-bentazon 2.3.7 Safening Effect of Baking Soda Under Growth Room Conditions 2.3.8 Statistical Analysis 2.4 Results and Discussion 2.5 Conclusion 2.6 Sources of Material 3.0 The Role of BAS 781 for Weed Control in Corn 3.1 Abstract 3.2 Introduction n 3.3 Materials and Methods 3.4 Results and Discussion 3.5 Conclusion 3.6 Sources of Material 4.0 General Discussion 4.1 Contributions 4.2 Limitations 4.3 Future Research 5.0 Literature Cited 6.0 Appendix 1: Monthly Rainfall Averages for 2008 and 2009 at Each Field Location in List of Tables Table 2-1. Glyphosate tolerant corn hybrids used in each year at each location 50 Table 2-2. Soil characteristics for each location, including soil type, pH, percent composition of sand, silt and clay, and organic matter content 51 Table 2-3. Nozzle type, spray volume, operating pressure and plot size at each location 52 Table 2-4. Herbicide treatments and application timings for the study of corn tolerance to saflufenacil, dimethenamid-p and BAS 781 53 Table 2-5. Dates of seeding, corn seedling emergence, herbicide application relative to corn growth stage, and corn grain harvest in each year at each location 54 Table 2-6. Dates of seeding, corn seedling emergence, herbicide treatment, and corn grain harvest in 2009, at each location used in the study of the safening effect of bentazon on saflufenacil .55 Table 2-7. Herbicide treatments applied to 4 leaf corn in order to evaluate the safening effect of bentazon applied postemergence with saflufenacil under field conditions near Elora, Exeter, and Woodstock in 2009 56 Table 2-8. Average percent corn injury caused by saflufenacil, dimethenamid-p and BAS 781 (consistent with the order of your treatments) at 3, 7, 14, 21 28 and 56 days after application (DAT) at the preemergence, spike-to-2 leaf and 3-to-4 leaf stages of corn growth at Elora, Exeter, Woodstock and Ridgetown in 2008 and 2009 57 Table 2-9. Variance analysis of the dry weight of corn plants harvested 28 days after final herbicide treatment as a measure of crop injury at Elora, Exeter, Woodstock and Ridgetown in 2008 and 2009 59 Table 2-10. Variance analysis of the corn grain yield from experiments near Elora, Exeter, Woodstock and Ridgetown, ON in 2008 and 2009 60 Table 2-11. Mean corn yield from plots treated with saflufenacil, dimethenamid-p and BAS 781 at the preemergence, spike-to-2 leaf and 3-to-4 leaf stages of corn growth at the lx and 2x doses in Elora, Exeter, Woodstock and Ridgetown, ON in 2008 and 2009 61 Table 2-12. Variance analysis of percent corn collar height and dry weight reduction as compared to the untreated control 28 days after herbicide treatment and corn grain yield at Elora, Woodstock and Exeter, Ontario in 2009. All herbicides were applied at the 4th leaf stage of corn growth 62 IV Table 2-13. Distribution of C-safiufenacil in the leaf wash and parts of the treated leaf as a percent of the total amount recovered at 6 and 24 hours after treatment, with and without bentazon, in a controlled growth room experiment 63 Table 2-14. Variance analysis of plant dry weight following treatment with increasing doses of saflufenacil and baking soda in a controlled growth room, and the linear and quadratic regression coefficients at each dose of saflufenacil 64 Table 3-1. Glyphosate tolerant corn hybrids used in each year at each location 75 Table 3-2. Soil characteristics for each location, including soil type, pH, percent composition of sand, silt and clay, and organic matter content 76 Table 3-3. Nozzle type, spray volume, operating pressure and plot size at each location 77 Table 3-4. Dates of seeding, corn seedling emergence, herbicide application and corn grain harvest in each year at each location for the study of weed control with BAS 781 alone and as a part of a glyphosate program 78 Table 3-5.