EFFECT OF SOIL APPLIED POTASSIUM SILICATE ON PAPAYA (Carica papaya L.) PLANT GROWTH, DEVELOPMENT, YIELDS, PHYSIOLOGY AND, POSTHARVEST FRUIT QUALITY By OCTAVIO A. MENOCAL BARBERENA A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2014 1 © 2014 Octavio A. Menocal Barberena 2 Blessed is the man who finds wisdom, the man who gains understanding (Proverbs 3:13). The man could not step in the same rivers twice, for other waters are ever flowing on (Heraclitus of Ephesus). God our Lord planted many fruit trees in the ‘Garden of Eden’, took man and put him to work and take care of it, and man with all his forces has done it for making a better world (Genesis 2:10-11). God has given to man the most powerful gift: “Hope”. With hope, man work and do research on the land of God and produce the best fruits to feed mankind. Octavio A. Menocal [adapted from Hope International: ‘Hope’ This dissertation is dedicated with all my heart to my lovely wife Norma del Socorro Sandoval-Balladares and our two wonderful children Octavio Augusto and Norman Francisco. My wife always trusted my decisions, supported everything I wanted to do and has inspired me every single day I have spent at the University of Florida in Gainesville and Homestead. In addition, I would like to acknowledge my children’s support whom endured many sacrifices and who have provided me and their mother their continuous love and encouragement during my Ph.D. graduate program. This is also dedicated to my mother Nelcys Barberena-Valladares with all my love for her brave and unwavering support during this difficult time of her life. Last but not least, to Dr. William (Bill) Castle for his teachings and having trained me as a professional. 3 ACKNOWLEDGMENTS First, I would like to thank Almighty God for guiding me and helping, leading, and protecting me and my family. Thank God for his blessings and for everything he did for my family. I would like to thank and express my deep appreciation to my entire committee: Dr. Jonathan H. Crane, Dr. Jeffrey K. Brecht, Dr. Bruce A. Schaffer, Dr. Yuncong Li and Dr. Kati W. Migliaccio for their advice. I want to give very special thanks to my major professor Dr. Jonathan H. Crane for his guidance and support. He also provided me with excellent technical and academic advice. Dr. Crane not only believed in me, but also spent many hours, and much energy and effort, trying to give me the best while showing his true respect, concern, and friendship toward me. I express my deepest gratitude to Dr. Jeffrey K. Brecht for his willingness to participate on my supervisory committee. Dr. Brecht believed in me and encouraged me to develop my research, and provided me his critical advice. He also provided me his friendship, guidance, support, confidence, and illuminated my way during my economical struggles. I also express my gratitude to Dr. Bruce A. Schaffer for his advice and invaluable knowledge and motivation during the process of my statistical analyses. I also thank Dr. Yuncong Li for his friendship, support and his invaluable and critical inputs. I also want to thank Dr. Migliaccio for her advice and guidance in the establishment of and functioning of the irrigation system utilized in my field work. Special thanks to Dr. Wanda Montas for her unconditional support and cooperation during the time I conducted my field research at the Tropical Research and Education Center (TREC-UF), in Homestead, FL. I also want to thank Ms. Ana Vargas for her support and friendship. Special thanks to TREC’s field crew for their work during the time I was conducting my field research. 4 I would also like to thank the Everglades Soil Testing Laboratory, Soil and Water Science Department at the Everglades Research and Education Center of the University of Florida (UF- EREC), Belle Glade, under the direction of Dr. Alan Wright, particularly Dr. Yigang Luo for the arduous and tremendous work he did by analyzing my soil and papaya tissue samples. I am indebted to Ms. María I. Cruz and Ms. Ana Zometa for their support since the beginning of my educational journey, for their friendship, guidance and encouragement during the time I was a student at the University of Florida. I want to express my deepest gratitude for their help and confidence. Special thanks to my very old friend Eng. MSc. Jaime A. Cuadra- Miranda and his wife Ms. Ena for their support, confidence, and friendship. I also want to thank Eng. Armando Bendaña-López and Dr. Leonardo Green for their support and friendship. I also give thanks to my friends: Ms. Adrian Berry and Ms. Kim Cordasco, Walter and Elena (Peruvian), Pavlos, Alexandra and Angelos (Greeks), Xheng-Ke Zhang and Yinyan Guo (Rep. of China), for their friendship at the beginning of my doctoral studies. Thanks to my classmates and very good friends Francisco Loayza (Perú) and Darío Chávez (Ecuador). Thanks to my friends, mentors and excellent professors Eng. Eddy Castellón-Sanabria, Dr. José Ramón Peralta-Videa, Eng. MSc. Miguel López-Guadamuz, Eng. MSc. Aleyda Juárez-Moya, Eng. MSc. Agustín Castillo-Gómez and Eng. MSc. Gerardo Medrano-Morales who believed in me and encouraged me to pursue my doctoral degree, and to my professors Eng. MSc. Ernesto Terán- Hernández and Eng. MSc. Silvio Echaverry-Briceño, In Memoriam (R.I.P). Thanks to my Nicaraguan friends and colleagues: Henner Obregón-Olivas, Dr. Elide Valencia, Carlos and Marthelena Guerrero-Manfut, Rosa Inés Carrillo, Leonardo Omar and Frida Aguilar-Weiss, Marco Pacheco Gómez, William and Adela Chamorro, Nestor and Jaime Bonilla, Matilde Somarriba-Chang, María Lourdes Espinosa, Joel Reyes, Carmen Gutiérrez, Jellin Pavón, 5 Ms. Eva Webster, Martín Mena, José Filipone and Ms. Emilia Sandoval, Eddy and Ms. Martina Thomas, Mario Torres-Molina and Ms. Nidia Gutiérrez-Chamorro for their friendship. Thanks to my family, for all their love and patience, especially to my mother Nelcys Barberena-Valladares and my sister Nelcys Alicia who supported me throughout my graduate studies. Thanks to my sisters Nelcys Evaclemencia and Nelcys René because they cared for my family while I was away. Thanks to my brother Octavio Anastacio because he was the medical doctor for my family and my younger brother Marcos Antonio for his support. To my parents-in-law, my deepest appreciation for taking care of my wife and my kids during the time I was away from home. Special gratitude to my mother-in-law, Ms. Nereyda Sandoval for her support, help, and love for my family. Her love was invaluable and I am in deepest debt to you, as to my father-in-law Mr. Francisco (‘Pancho’) Sandoval. Thanks to my brothers and sisters-in-law Ernesto Espinoza, Julio Delgado, Mario Alvarenga, Ileana Cordero, Marlon-, Victor-, Allan-, Marisol-, and Yessenia Sandoval-Balladares for their support. My highest gratitude is reserved for my wife, Norma del Socorro Sandoval-Balladares, for her support, help, patience, and deepest love which allowed me to complete my doctoral studies. Although, she could not be with me in the U.S. she stood by me and her unconditional support and love throughout my graduate studies at the University of Florida was tremendously valuable for me because without her, I would not be what I am. Thus, all my love goes to my lovely wife because she is everything to me as well as my children Octavio Augusto and Norman Francisco, who are the reasons for my life. Norma, with all my heart I will always love you. 6 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF TABLES .........................................................................................................................11 LIST OF FIGURES .......................................................................................................................18 ABSTRACT ...................................................................................................................................19 CHAPTER 1 INTRODUCTION ..................................................................................................................21 Assumptions ...........................................................................................................................26 Objectives ...............................................................................................................................26 General ............................................................................................................................26 Specific ............................................................................................................................26 2 LITERATURE REVIEW .......................................................................................................27 General Description ................................................................................................................27 Factors Affecting Papaya Production .....................................................................................30 Environmental Conditions ...............................................................................................32 Drought .....................................................................................................................32 Flooding ...................................................................................................................32