Mechanism of Resistance, Gene Flow, and Integrated Management of Ragweeds (Ambrosia) in Nebraska
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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Theses, Dissertations, and Student Research in Agronomy and Horticulture Agronomy and Horticulture Department 12-2016 Mechanism of Resistance, Gene Flow, and Integrated Management of Ragweeds (Ambrosia) in Nebraska Zahoor Ahmad Ganie University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/agronhortdiss Part of the Agricultural Science Commons, Agriculture Commons, Agronomy and Crop Sciences Commons, Botany Commons, Horticulture Commons, Other Plant Sciences Commons, and the Plant Biology Commons Ganie, Zahoor Ahmad, "Mechanism of Resistance, Gene Flow, and Integrated Management of Ragweeds (Ambrosia) in Nebraska" (2016). Theses, Dissertations, and Student Research in Agronomy and Horticulture. 216. https://digitalcommons.unl.edu/agronhortdiss/216 This Article is brought to you for free and open access by the Agronomy and Horticulture Department at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Theses, Dissertations, and Student Research in Agronomy and Horticulture by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. MECHANISM OF RESISTANCE, GENE FLOW, AND INTEGRATED MANAGEMENT OF RAGWEEDS (Ambrosia) IN NEBRASKA by Zahoor Ahmad Ganie A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Agronomy (Weed Science) Under the Supervision of Professor Amit J. Jhala Lincoln, Nebraska December, 2016 MECHANISM OF RESISTANCE, GENE FLOW, AND INTEGRATED MANAGEMENT OF RAGWEEDS (Ambrosia) IN NEBRASKA Zahoor Ganie, Ph.D. University of Nebraska, 2016 Adviser: Amit J. Jhala Common ragweed (Ambrosia artemisiifolia L.) and giant ragweed (Ambrosia trifida L.) are native annual broadleaf weeds in the United States found in diverse agroecosystems, roadsides, and wastelands. They are economically important weed species in the Midwest and sources of pollen allergies. Confirmation of glyphosate-resistant (GR) common and giant ragweed in Nebraska justified the need to determine the mechanism of resistance, dispersal of resistance genes via pollen, and to develop an integrated management program. The objectives of this research were to: 1) determine the mechanism of glyphosate resistance in a common ragweed biotype from Nebraska; 2) evaluate the effect of varying growth temperatures on efficacy, absorption, and translocation of glyphosate or 2,4-D in GR and susceptible (GS) common and giant ragweed biotypes; 3) quantify the pollen-mediated gene flow (PMGF) from GR to GS giant ragweed under field conditions; and 4) evaluate the integrated management of giant ragweed with preplant tillage followed by PRE and/or POST herbicide programs in corn and soybean. Experiments were conducted to determine mutation(s), and amplification of the EPSPS gene (target-site mechanisms), as well as differences in uptake/translocation and the metabolism of glyphosate (non-target site mechanisms) between GR and known GS common ragweed biotypes. The results suggest that a slow rate of glyphosate absorption and translocation likely prevents the build-up of the minimum inhibitory glyphosate concentration required at the target site, resulting in resistance to glyphosate in a common ragweed biotype from Nebraska. Experiments conducted to study the effect of temperature on the efficacy of 2,4-D or glyphosate in common and giant ragweed suggested that control improved at warm temperatures (29/17 0C d/n) compared to cooler temperatures (20/11 0C d/n) due to increased translocation in common ragweed, and increased absorption and/or translocation in giant ragweed biotypes studied. Studies on PMGF from GR to GS giant ragweed were conducted under field conditions using glyphosate resistance as a phenotypic marker. The highest frequency of gene flow (0.43 to 0.68) was detected at closer distances (< 0.5 m) and 50% reduction in gene flow occurred at < 7 m from the pollen source. Field experiments conducted to evaluate the integrated management of GR giant ragweed suggested that integration of preplant tillage would provide an alternate method for early season control of giant ragweed; however, follow-up application of herbicides are needed for season-long control in corn and soybean. iv DEDICATION This thesis is dedicated to my parents, Hajira Begum and Abdul Ahad Ganie, for all their unconditional love, support, and sacrifices to give me the best education they could. v ACKNOWLEDGEMENTS I am beholden to the highly benevolent and merciful almighty ALLAH whose grace and blessings helped me to reach this far in my academic pursuits. My profound regards and sincere gratitude goes to my major adviser, Dr. Amit J. Jhala, for his prudent guidance, knowledge, encouragement, and constant support. His timely advice and inspirational mentorship is honestly appreciated. I also extend my earnest gratitude to the members of my graduate committee, Dr. Mithila Jugulam, Dr. John L. Lindquist, Dr. Greg R. Kruger, and Dr. David B. Marx, for their time and invaluable input in my research and dissertation. I would also like to express my sincere thanks to Irvin Schleufer, Dr. Vijay K. Varanasi, Lowell D. Sandell, and Sharon Hachtel for their constant technical help and support in my Ph.D. research. I would also like to thank Dr. Jatinder S. Aulakh, Joshua Miller and Dr. Rodrigo Werle for their help in preparing for the weed contests. I would like to acknowledge the help and cooperation of Aatif Majeed, Bradley Meusch, Don Treptow, Dr. Aruna Varanasi, Dr. Debalin Sarangi, Ethann Barnes, Ian Rogers, Junjun Ou, Karthik Putta, Luke Baldridge, Mason Adams, Maxwel C. Oliveira, Parminder S. Chahal, Seth Menzer, Simranpreet Kaur, Sridevi Nakka and Umme Kulsoom. I’ve also appreciated the opportunity to meet and work with my fellow graduate students and research technicians at the University of Nebraska-Lincoln. I also owe a great deal of appreciation to my friends Aabid Lone, Bilal Ganie, Farooq Mir, vi Fayaz Sofi, Mohd A. Shah, Mumtaz Ganie, Nadia Lahbass, Roheela Kirmani, and Waseem Hussain for their constant encouragement and moral support. I would like to thank the staff and faculty of the department of Agronomy and Horticulture at the University of Nebraska-Lincoln. My gratitude also goes out to the Indian Council of Agricultural Research, New Delhi, India for partial financial support for this research. Finally, I must thank my parents, my beloved sister (Shagufta Ahad), my dearest brothers (Aijaz Ganie, Danish Ganie), and my other family members for their support, selfless sacrifices, and encouragement throughout my career. vii Table of Contents List of Tables ...................................................................................................................... x List of Figures ................................................................................................................... xii CHAPTER 1: INTRODUCTION AND OBJECTIVES ..................................................... 1 Introduction ..................................................................................................................... 1 Ambrosia species. ....................................................................................................... 3 Common Ragweed Biology. ....................................................................................... 3 Common Ragweed Interference and Yield Loss. ....................................................... 4 Herbicide Resistance in Common Ragweed. .............................................................. 4 Giant Ragweed Biology. ............................................................................................. 5 Giant Ragweed Interference and Yield Loss. ............................................................. 6 Herbicide Resistance in Giant Ragweed. .................................................................... 6 Objectives ....................................................................................................................... 7 Literature Cited ............................................................................................................... 9 CHAPTER 2: INVESTIGATION OF THE MECHANISM OF GLYPHOSATE RESISTANCE IN A COMMON RAGWEED (Ambrosia artemisiifolia) BIOTYPE FROM NEBRASKA ......................................................................................................... 17 Abstract ......................................................................................................................... 17 Introduction ................................................................................................................... 18 Materials and Methods .................................................................................................. 22 Plant Material and Growth Conditions. .................................................................... 22 Shikimate Assay........................................................................................................ 23 EPSPS Gene Sequencing. ......................................................................................... 24 Relative EPSPS Genomic Copy Number. ................................................................ 25 Absorption and Translocation of Glyphosate. .......................................................... 26 Metabolism of Glyphosate. ......................................................................................