VIETNAM NATIONAL UNIVERSITY OF AGRICULTURE FACULTY OF AGRONOMY UNDERGRADUATE THESIS TITLE OF RESEARCH: “COMBINING ABILITY FOR TRAITS ASSOCIATED WITH YIELD AND QUALITY OF SWEET CORN (ZEA MAYS L. SACCHARATA)” Student : Ngo Thi Nhung Student code : 611712 Class : K61KHCTT Instructor : Prof. PhD Vu Van Liet Department : Plant Genetics and Breeding Ha Noi - 2021 i ACKNOWLEDGEMENTS I would like to express my respect and deep gratitude to Prof. PhD Vu Van Liet, for giving me the opportunity to carry out this work, and his huge efforts, enthusiasm, and support throughout the duration of the undergraduate thesis. I would like to express sincere gratitude to MSc. Tran Thi Thanh Ha and all the members of Research and Technology Development Plant – Crop Research Institute and Plant Development were enthusiastic to help me through the project. I would also like to thank the Directors, Management Training, Department of Genetics - Plant Breeding, Faculty of Agronomy – Vietnam National University of Agriculture (VNUA was dedicated to help me during earning process, to complete the thesis. Finally, I would like to thank my family, those with us and those sadly departed. You provided fantastic support and inspiration throughout the duration of this undergraduate thesis, and without you all, this would never have been possible. Hanoi, 1 st March 2021 Student Ngo Thi Nhung ii CONTENTS ACKNOWLEDGEMENTS .............................................................................................. i CONTENTS...................................................................................................................... ii LIST OF ABBREVIATIONS ......................................................................................... iv LIST OF TABLE...............................................................................................................v LIST OF FIGURES........................................................................................................ vii ABSTRACT................................................................................................................... viii I. INTRODUCTION ....................................................................................................1 1.1. Introduction.................................................................................................................1 1.2. Objectives and requirements......................................................................................3 1.2.1. Objectives ................................................................................................................3 1.2.2. Requirements...........................................................................................................3 II. LITERATURE REVIEW........................................................................................4 2.1. Sweet corn production in the world and in Vietnam.................................................4 2.1.1. Sweet corn production in the world. .......................................................................4 2.1.2. Sweet maize production in Vietnam .......................................................................7 2.2. Origin and classification of sweet maize ...................................................................9 2.3. Genetics of sweet maize .......................................................................................... 12 2.5. Combining ability.................................................................................................... 17 2.5.1. General combining ability.................................................................................... 19 2.5.2. Specific combining ability ................................................................................... 19 III. MATERIALS AND METHODS.......................................................................... 21 3.1. Materials .........................................................................