CHARACTERIZATION OF GLYPHOSATE RESISTANCE AND MANAGEMENT OF RAGWEED PARTHENIUM (PARTHENIUM HYSTEROPHORUS L.) IN THE EVERGLADES AGRICULTURAL AREA OF FLORIDA By JOSE VENANCIO FERNANDEZ A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2013 © 2013 Jose Venancio Fernandez To my family for all their love, support, and encouragement ACKNOWLEDGMENTS I thank my major professor, Dr. Dennis C. Odero, for giving me the opportunity to join his research program. I am extremely grateful for his friendship, patience, support, and the knowledge he imparted on me. Appreciation is extended to the members of my committee: Drs. Gregory MacDonald, Jason Ferrell and Lyn Gettys for the advice provided during my graduate program. I am indebted to Drs. MacDonald and Ferrell for their constant help and advice during the semesters I lived in Gainesville. I thank Dr. Ferrell for allowing me to make use of the weed shop as place where I could feed my curiosity for plant related experiments. Special thanks to Drs. Peter Ditmar, Brent Sellers, and Ramon Leon who have provided advice and friendship. I also want to thank Nikol Havranek, Mike Durham, Hunter Smith, Sarah Berger, Anna Greis, Daniel Abe, Chris Rouse, and Ryan Miller for the friendship and support they provided to me while conducting my research. I would also like to thank the Agronomy Department faculty, staff and students for the knowledge I gained, for the support I received, and for the good time I had at the department. I owe this achievement to my parents and siblings who with their constant support and encouragement have made me the person I am. I thank my dad for being strict and for showing me the value of respect and hard work. I thank my mom for teaching me to trust in God and for her true friendship. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 ABSTRACT ..................................................................................................................... 9 CHAPTER 1 CONFIRMATION OF GLYPHOSATE-RESISTANT RAGWEED PARTHENIUM (PARTHENIUM HYSTEROPHORUS L.) IN THE EVERGLADES AGRICULTURAL AREA ......................................................................................... 11 Glyphosate Resistance ........................................................................................... 11 Materials and Methods............................................................................................ 13 Plant Material ................................................................................................... 13 Greenhouse Dose-Response Assay ................................................................ 14 Absorption and Translocation ........................................................................... 16 Results and Discussion........................................................................................... 18 Greenhouse Dose-Response Assay ................................................................ 18 Absorption and Translocation ........................................................................... 19 Recovery of 14C-glyphosate ....................................................................... 19 Absorption of 14C-glyphosate ..................................................................... 20 Treated leaf section ................................................................................... 20 Above treated leaf section.......................................................................... 21 Below treated leaf section .......................................................................... 21 Roots ......................................................................................................... 22 Autoradiography ......................................................................................... 22 2 RAGWEED PARTHENIUM (PARTHENIUM HYSTEROPHORUS L.) CONTROL IN NONCROP AREAS IN THE EVERGLADES AGRICULTURAL AREA ............... 27 Herbicide Efficacy ................................................................................................... 27 Materials and Methods............................................................................................ 29 Field Study ....................................................................................................... 29 Greenhouse Study ........................................................................................... 30 Results and Discussion........................................................................................... 32 Field Study ....................................................................................................... 32 Greenhouse Study ........................................................................................... 34 3 ALLELOPATHIC EFFECTS OF PARTHENIUM HYSTEROPHORUS L. EXTRACTS ON GERMINATION OF DIFFERENT CROPS GROWN IN THE EVERGLADES AGRICULTURAL AREA ................................................................ 39 5 Allelopathy .............................................................................................................. 39 Materials and Methods............................................................................................ 41 Whole Plant Aqueous Extraction ...................................................................... 41 Germination Assays ......................................................................................... 42 Statistical Analysis ............................................................................................ 43 Results and Discussion........................................................................................... 44 Seed Germination ............................................................................................ 44 Radicle and Shoot Growth................................................................................ 46 4 SUMMARY ............................................................................................................. 53 LIST OF REFERENCES ............................................................................................... 55 BIOGRAPHICAL SKETCH ............................................................................................ 62 6 LIST OF TABLES Table page 1-1 Parameter estimates and standard errors (in parenthesis) for the three parameter log-logistic model (Equation 2) for ragweed parthenium susceptible and resistance biotypes in response to glyphosate. ........................ 23 1-2 Percent translocation of 14C-glyphosate in resistant (R) and susceptible (S) biotypes of ragweed parthenium hours after treatment (HAT) ............................ 23 2-1 Herbicide treatments, rates, and modes of action. ............................................. 36 2-2 Flowering ragweed parthenium control at locations within the EAA, Belle Glade, FL in 2012. .............................................................................................. 37 2-3 Percent dry weight reduction of greenhouse grown ragweed parthenium in response to herbicide treatments at 21 days after treatment. ............................. 38 3-1 Parameter estimates and standard errors (in parenthesis) for the two- parameter exponential decay model (Equation 1) and the four-parameter Brain-Cousens model (Equation 3). .................................................................... 49 3-2 Parameter estimates and standard errors (in parenthesis) for the linear regression model (Equation 2)............................................................................ 49 7 LIST OF FIGURES Figure page 1-1 Effect of glyphosate on ragweed parthenium fresh weight of resistant (R) and susceptible (S) biotypes for two experimental runs (Run 1 and 2). The x-axis uses a logarithmic scale. .................................................................................... 24 1-2 Effect of glyphosate on ragweed parthenium dry weight of resistant (R) and susceptible (S) biotypes for two experimental runs (Run 1 and 2). The x-axis uses a logarithmic scale. .................................................................................... 25 1-3 Autoradiograph image of susceptible (left) and resistant (right) ragweed parthenium biotypes harvested 168 HAT. .......................................................... 26 3-1 Effect of ragweed parthenium aqueous extract on A) rice germination combined over two experimental runs, and B) shoot length for experimental runs 1 and 2........................................................................................................ 50 3-2 Effect of ragweed parthenium aqueous extract on A) radish germination for experimental runs 1 and 2, and B) radicle length for experimental runs 1 and 2. ........................................................................................................................ 51 3-3 Effect of ragweed parthenium aqueous extract on A) lettuce germination for experimental runs 1 and 2, and B) radicle length for experimental runs 1 and 2. .......................................................................................................................