EVALUATION OF AFRICAN EGGPLANT ACCESSIONS FOR PHENOTYPIC TRAITS AND ADAPTATION TO WATER STRESS LAGAT SAMSON KIPCHIRCHIR B.Sc. Agriculture (Hons), University of Nairobi A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF SCIENCE IN AGRONOMY UNIVERSITY OF NAIROBI COLLEGE OF AGRICULTURE AND VETERINARY SCIENCES FACULTY OF AGRICULTURE DEPARTMENT OF PLANT SCIENCE AND CROP PROTECTION ©2016 DECLARATION This thesis is my original work and it has not been presented for award of a degree in any other university. Lagat Samson Kipchirchir Signature: ………………………………………………………. Date: ………………………. This thesis has been submitted with our approval as University supervisors: Prof. George N. Chemining’wa Department of Plant Science and Crop Protection University of Nairobi Signature: ………………………………………………………. Date: ………………………. Dr. Jane L. Ambuko Department of Plant Science and Crop Protection University of Nairobi Signature: ………………………………………………………. Date: ………………………. Prof. Willis O. Owino Department of Food Science and Technology Jomo Kenyatta University of Agriculture and Technology Signature: ………………………………………………………. Date: ………………………. i DEDICATION I dedicate this work to my loving parents Mr. Moses Koech and Mrs. Selly Koech for their continued support in my academic work and guidance in life. ii ACKNOWLEDGEMENTS I am grateful to the Almighty God for His love and undeserved kindness during the entire research period. My sincere gratitude is dedicated to my supervisors; Prof. George N. Chemining’wa, Dr. Jane Ambuko and Prof. Willis Owino for their guidance, helpful critiques and continued support throughout this study. I am thankful to the United States Agency for International Development (USAID) for funding this research work through the Peer Project in Harnessing Genomics of Edible African Solanaceae Plants for Improved Nutritional and Food Security led by Prof. Willis Owino and Dr. Jane Ambuko. My sincere gratitude goes to Mr. Mibei and Mr. Godrefy Anyika for their guidance during field activities. I also thank Mr. Daniel Wasonga for his assistance with the training on the use of analysis software. My sincere gratitude goes to Mr. Kamau who tirelessly assisted me carry out the field work successfully. I appreciate the support in various ways given by all my friends and classmates (Kenneth Tembe and Hillary Otieno) during this study period. My special gratitude goes to my dear parents who sacrificed their resources to support my education and for believing in me. To my cousin Elisha I am grateful for your assistance and encouragement in the course of my study. To my younger siblings Edwin, Judy, Mercy and Kelvin I am eternally grateful for your constant love and encouragement. iii TABLE OF CONTENTS DECLARATION ............................................................................................................................. i DEDICATION ................................................................................................................................ ii ACKNOWLEDGEMENTS ........................................................................................................... iii TABLE OF CONTENTS ............................................................................................................... iv LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ........................................................................................................................ x LIST OF APPENDICES ............................................................................................................... xii LIST OF ABBREVIATIONS AND ACRONYMS .................................................................... xiv GENERAL ABSTRACT .............................................................................................................. xv CHAPTER ONE: INTRODUCTION ............................................................................................. 1 1.1 Background information ....................................................................................................... 1 1.2 Problem statement and justification ...................................................................................... 3 1.3 Objectives .............................................................................................................................. 4 1.4 Hypotheses ............................................................................................................................ 4 CHAPTER TWO: LITERATURE REVIEW ................................................................................. 5 2.1 Botany of eggplant ................................................................................................................ 5 2.2 Ecology and importance of the eggplant ............................................................................... 8 2.3 Nutritional quality of eggplant .............................................................................................. 9 2.4 Constraints to eggplant production ....................................................................................... 9 2.4.1 Drought stress ............................................................................................................... 11 2.5 Methods of assessing phenotypic variation ......................................................................... 12 2.5.1 Pedigree data ................................................................................................................. 13 2.5.2 Agro-morphological characters .................................................................................... 13 2.6 Measures of genetic variation ............................................................................................. 15 2.7 Measures of genetic distance............................................................................................... 16 2.8 Multivariate analysis ........................................................................................................... 17 2.8.1 Cluster analysis ............................................................................................................. 17 2.8.2 Principal component analysis ....................................................................................... 18 2.8.3 Principal coordinate analysis ........................................................................................ 19 2.8.4 Multidimensional scaling ............................................................................................. 19 iv CHAPTER THREE: EVALUATION OF AFRICAN EGGPLANT ACCESSIONS FOR MORPHOLOGICAL AND AGRONOMIC TRAITS.................................................................. 21 3.1 Abstract ............................................................................................................................... 21 3.2 Introduction ......................................................................................................................... 22 3.3 Materials and Methods ........................................................................................................ 24 3.3.1 Site Description ............................................................................................................ 24 3.3.2 Planting materials ......................................................................................................... 25 3.4 Experimental design and crop husbandry ........................................................................... 28 3.4.1 Field experiments ......................................................................................................... 28 3.4.2 Greenhouse experiments............................................................................................... 29 3.5 Data collection..................................................................................................................... 30 3.5.1 Morphological data ....................................................................................................... 30 3.5.2 Agronomic data ............................................................................................................ 30 3.5.2.1 Growth components ............................................................................................... 31 3.5.2.2 Yield and yield components................................................................................... 32 3.6 Data analysis ....................................................................................................................... 32 3.6.1 Qualitative traits ........................................................................................................... 32 3.6.2 Quantitative traits ......................................................................................................... 33 3.7 Results ................................................................................................................................. 34 3.7.1 Qualitative characteristics ............................................................................................. 34 3.7.2 Growth habit ................................................................................................................. 34 3.7.2 Flower colour ................................................................................................................ 35 3.7.3 Leaf characteristics ......................................................................................................