DIVERSITY, DISEASE REACTION, HETEROSIS AND COMBINING ABILITY IN HOT PEPPER ...

196 Pages·2004·2.55 MB·English

DIVERSITY, DISEASE REACTION, HETEROSIS AND
COMBINING ABILITY IN HOT PEPPER (Capsicum annum L.)
GENOTYPES FOR AGRO-MORPHOLOGICAL AND QUALITY
TRAITS IN ETHIOPIA

Ph. D. BY RESEARCH DISSERTATION

SHIMELES AKLILU ALEMU

SUPERVISORS:
BEKELE ABEBIE (Ph. D.)
DAGNE WEGARY (Ph. D.)
ADEFRIS TEKLEWOLD (Ph. D.)
GETACHEW AYANA (Ph. D.)

JANUARY, 2018
ASELLA, ETHIOPIA
Diversity, Disease Reaction, Heterosis and Combining Ability in Hot
Pepper (Capsicum annum L.) Genotypes for Agro-morphological and
Quality Traits in Ethiopia

A Dissertation Submitted to Arsi University, College of
Agriculture and Environmental Sciences for the Requirements of
Ph.D. by Research in Plant Breeding

Shimeles Aklilu Alemu

Supervisors: Bekele Abebie (Ph. D.)
Dagne Wegary (Ph. D.)
Adefris Teklewold (Ph. D.)
Getachew Ayana (Ph. D.)

January, 2018, Asella, Ethiopia

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DECLARATION

I, Shimeles Aklilu, declare that the thesis hereby submitted by me for the degree of
Philosophiae Doctor (Ph.D.) in plant breeding at Arsi University, College of
Agriculture and Environmental Sciences is my own independent work and has not
previously been submitted to any other University. Moreover, this thesis does not
contain other persons’ data, pictures, graphs or other information, unless specifically
acknowledged as being sourced from other persons.
………………………………………………………………………………………..
Shimeles Aklilu Alemu
As the candidate’s supervisor, we agreed to the submission of this Thesis:
Bekele Abebie (Supervisor):
Dagne Wagari (Co-Supervisor) : ______ ______________
Adeferis Teklewold
(Co-Supervisor): ______ ________
Getachew Ayana (Co-Supervisor):

As member of the Board of examiners of the Ph.D. Thesis Open Defense
Examination, we certify that we have read, evaluated the thesis prepared by Shimeles
Aklilu and examined the candidate. We recommended that the Thesis be accepted as
fulfilling the thesis requirement for the degree of Ph.D. by research in plant breeding.

Chairman Signature Date

Internal Examiner Signature Date

External Examiner Signature Date

External Examiner Signature Date

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ACKNOWLEDGEMENTS

First of all, I would like to praise the Almighty God for his blessings and allowing me
to advance my study to this level. Though it was not an easy trip, thanks God for
giving me, patience, strength and endurance to withstand those shaky situations in all
the way during the study period and finally enabling me to successfully achieve my
goal.

I greatly acknowledge my supervisors for their thoughtful guidance and creative
suggestions throughout my study period and during the thesis write up. It is my
pleasure to express my heartfelt appreciation and special gratitude and indebtedness to
my major supervisor Dr. Bekele Abebie for his moral and technical support all the
way to make this study fruitful. I have also benefited quiet a lot from his concern and
enthusiasm to do things in different ways. I am also thankful to my co-supervisors
Drs. Dagne Wegary, Adefris Teklewold and Getachew Ayana for their continuous
technical and moral support and constructive comments. Above all, I am glad to
express my sincere appreciation to Dr. Adeferis T/Wold, for his initiation and
encouragement so that I pursue my study in pepper breeding and who made
significant contribution to let me finish my study successfully.

Ethiopian Institute of Agricultural Research (EIAR) deserves my heartfelt gratitude
for sponsoring my study and granting me the study leave. This study could have not
also been possible without the support of MARC management and the finance office.
I am highly grateful to their devotion, positive and timely response and properly
managing issues related to my study. I would greatly acknowledge different
departments of the centre for direct technical support and provision of laboratory
facilities that enabled me to smoothly realize this study. Food Science, Sorghum
Improvement, Crop Protection, Soil and Water management, Farm Management, and
Human Resources for allowing me to use laboratory facilities, analyzing samples,
diseases isolation and above all for their continuous encouragement, cooperation and
genuine support during the execution of the experiment. My special
acknowledgement is due to MARC horticulture section staff members, Tadeg Belihu,
Engida Shiferaw, Etenesh Getahune, Tariqua Hailu, Etagegnhu Gizaw, Tesfaye
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Wondemu for their support during the field trials and data management. Moreover, Dr
Edossa Etissa, Lemma Ayele, Yosef Alemu, Wogayehu Assefa, Abel Debebe, Jibicho
Geleto, Tadele Aytenfisu, Gebyhu Wondemu, Selamawit Ketema, Surafel Shibru and
Tiruworek Assefa deserve my special thanks for their priceless cooperation in
shouldering my responsibilities, moral encouragement and overall support they
rendered to me. I am highly grateful to Shita Belachew, Israeal Neguse and Nestanet
Wondem for their commitment in successfully and carefully accomplishing the
tedious breeding work regardless of the hardship and the workloads they have. The
genuine collaboration of, Mulu Daba, Aysha Abdella and Mohamed Salah for
laboratory analysis are unforgettable. I am highly thankful to Dr. Duguma Adugna,
Dr. Deribew Belew, Mr. Negusie Kassa and Dr. Yehenew Gewtachew for their
continuous encouragement and support. My colleagues Shiferaw Mekonen, from
Hawassa Agricultural Research Centre and Mr. Dessie Getahune from Assossa
Research Center, deserve my heartfelt gratitude for providing me pepper genotypes
with their passport data and for the continuous moral support and encouragement.
Adama Science and Technology University is highly acknowledged for allowing me
to be enrolled for PhD by research program in the then Asella School of Agriculture. I
greatly acknowledge Arsi University, Post Graduate Office and the College of
Agriculture and Environmental Sciences for their kind cooperation for handling
different matters during my study.

I cannot pass without mentioning Dr. Tseteargachew Leggese from Arsi University
for his unreserved support and encouragement and the Human Resource Development
Officer of EIAR, Mr. Girma Tezera for his courageous decision to pave the way to
pursue my study. I will never foregt Mr. Girma’s facilitation and kind cooperation.
My special thanks also go to my friends and colleagues especially my neighbors
Fasika Jeqale and Taddesse Mekuria for their regular good wishes and
encouragement. Acknowledging the encouragement, affection and moral support I
got from my mother, Zewodinesh Assefaw, and all my relatives and their families:
Solomon Alemu, Bitew Neway, Reda Teferi, Alemgena Bitew, Mister Mulatu and all
of my sisters and brothers who have been with me in their regular pray is
indispensable. Finally, I am highly grateful to my wife S/r Biruktawite Redda and our
beloved sons (Eyosias Shimeles and Yafet Shimeles) who are my blessings and
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inspirations. There was no day that I failed to think of you and you were sources of
my strength and enthusiasm to fulfil my dream.

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DEDICATION

This piece of work is dedicated to my father Aklilu Alemu, for his initial support and
continuous encouragement to make me dependable person.
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TABLE OF CONTENTS
DECLARATION ..................................................................................................................... III
ACKNOWLEDGEMENTS ..................................................................................................... IV
DEDICATION ........................................................................................................................ VII
LIST OF TABLES ................................................................................................................... XI
LIST OF TABLES ................................................................................................................. XII
LISTS OF TABLES IN THE APPENDIX ........................................................................... XIII
LIST OF FIGURES ............................................................................................................... XIV
LIST OF ABBREVIATIONS AND ACRONYMS ............................................................... XV
ABSTRACT ........................................................................................................................... XVI
CHAPTER 1: GENERAL INTRODUCTION .......................................................................... 1
1.1. RESEARCH OBJECTIVES ........................................................................................................... 5
1.1.1. General objective ---------------------------------------------------------------------------------------- 5
1.1.2. Specific objectives -------------------------------------------------------------------------------------- 5
1.2. OUTLINE OF THE STUDY .......................................................................................................... 5
1.3. REFERENCES .......................................................................................................................... 7
CHAPTER 2: LITERATURE REVIEW .................................................................................. 9
2.1. THE HOT PEPPER CROP ............................................................................................................ 9
2.2. QUALITIES IN HOT PEPPER GENOTYPES ................................................................................... 10
2.2.1. Nutritional composition ------------------------------------------------------------------------------- 10
2.2.2. Fruit pungency ------------------------------------------------------------------------------------------ 10
2.2.3. Fruit oleoresine ----------------------------------------------------------------------------------------- 11
2.3. LANDRACES AND GENETIC DIVERSITY ................................................................................... 12
2.4. COMBINING ABILITY ............................................................................................................. 14
2.5. VARIABILITY, GENETIC ADVANCE, HERITABILITY AND CHARACTER ASSOCIATIONS ................. 16
2.5.1. Variability ----------------------------------------------------------------------------------------------- 16
2.5.2. Heritability and genetic advance --------------------------------------------------------------------- 17
2.5.3. Character associations --------------------------------------------------------------------------------- 18
2.6. HETEROSIS AND HYBRID PERFORMANCE ................................................................................ 20
2.7. WILT DISEASES OF HOT PEPPER.............................................................................................. 22
2.8. REFERENCES ........................................................................................................................ 24
CHAPTER 3: DIVERSITY OF HOT PEPPER (Capsicum annum L.)
GENOTYPES FOR AGRO-MORPHOLOGICAL TRAITS IN ETHIOPIA ........................ 31
3.1. ABSTRACT ............................................................................................................................ 31
3.2. INTRODUCTION ..................................................................................................................... 32
3.3. MATERIALS AND METHODS ................................................................................................... 33
3.3.1. Experimental materials and field experimentation ------------------------------------------------ 33
3.3.2. Data collected and analysis --------------------------------------------------------------------------- 35
3.4. RESULTS .............................................................................................................................. 37
3.4.1. Analysis of variance ----------------------------------------------------------------------------------- 37
3.4.2. Mean performance of genotypes --------------------------------------------------------------------- 37
3.4.2.1. Phenology and growth characters ----------------------------------------------------------------- 37
3.4.2.2. Yield and fruit characteristics ---------------------------------------------------------------------- 40
3.4.3. Principal component analysis for quantitative traits ---------------------------------------------- 43
3.4.4. Cluster analysis ----------------------------------------------------------------------------------------- 44
3.5. DISCUSSIONS ........................................................................................................................ 48
3.6. CONCLUSION ........................................................................................................................ 50
3.7. REFERENCES ........................................................................................................................ 51
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TABLE OF CONTENTS (Cont...)
CHAPTER 4: DIVERSITY OF HOT PEPPER (Capsicum annum L.)
GENOTYPES IN ETHIOPIA FOR QUALITATIVE AND FRUIT
QUALITY TRAITS ................................................................................................................. 53
4.1. ABSTRACT ............................................................................................................................ 53
4.2. INTRODUCTION ..................................................................................................................... 54
4.3. MATERIALS AND METHODS ................................................................................................... 55
4.2.1. DATA COLLECTION ............................................................................................................ 55
4.4. RESULTS .............................................................................................................................. 57
4.4.1. Frequency distribution of qualitative characters --------------------------------------------------- 57
4.4.2. Frequency distribution of qualitative characters in collection regions ------------------------- 61
4.4.3. Shannon- weaver-diversity analysis of qualitative characters in collection
regions ----------------------------------------------------------------------------------------------------------- 63
4.4.4. Cluster analysis of qualitative characters ----------------------------------------------------------- 65
4.4.5. Bi-Plot analysis of qualitative characters ----------------------------------------------------------- 66
4.4.6. Analaysis of variance and mean performance of genotypes for fruit characters -------------- 68
4.4.7. Principal component analysis for quality fruit characters ---------------------------------------- 71
4.4.8. Cluster analysis for quality fruit characters -------------------------------------------------------- 72
4.5. DISCUSSIONS ........................................................................................................................ 75
4.6. CONCLUSION ........................................................................................................................ 79
4.7 REFERENCES ......................................................................................................................... 81
CHAPTER 5: OLEORESIN AND CAPSAICIN CONTENTS OF HOT
PEPPER GENOTYPES AND RESISTANCE TO FUSARIUM WILT
(Fusarium oxysporium) ............................................................................................................ 84
5.1. ABSTRACT ............................................................................................................................ 84
5.2. INTRODUCTION ..................................................................................................................... 85
5.3. MATERIALS AND METHODS ................................................................................................... 86
5.3.1. Survey and collection of fusarium disease samples ----------------------------------------------- 86
5.3.2. Isolation and identification of the pathogen -------------------------------------------------------- 87
5.3.3. Experimental deign and inoculation procedures --------------------------------------------------- 87
5.3.4. Determination of capsaicin content ------------------------------------------------------------------ 88
5.3.5. Determination of oleoresins content ----------------------------------------------------------------- 88
5.3.6. Data collection procdures and analysis ------------------------------------------------------------- 89
5.4. RESULTS .............................................................................................................................. 90
5.4.1. Isolation and identification of fusarium ------------------------------------------------------------- 90
5.4.2. Reaction of pepper genotypes to fusarium wilt diseases ----------------------------------------- 90
5.4.2.1. Wilt incidence percent ------------------------------------------------------------
5.4.2.2. Disease severity index -------------------------------------------------------------
5.4.2.3. Diseases severity scale ------------------------------------------------------------
5.4.3. Relationship between disease incidence and severity index of Fusarium wilt ---------------- 94
5.4.4. Capsaicin content --------------------------------------------------------------------------------------- 96
5.4.5. Oleoresin content --------------------------------------------------------------------------------------- 97
5.5. DISCUSSIONS ........................................................................................................................ 99
5.6. CONCLUSION ...................................................................................................................... 102
5.7. REFERENCES ...................................................................................................................... 104
CHAPTER 6: GENETIC VARIABILITY AND ASSOCIATION OF
CHARACTERS IN ETHIOPIAN HOT PEPPER (Capsicum annum L.)
GENOTYPES ......................................................................................................................... 107
6.1. ABSTRACT .......................................................................................................................... 107
6.2. INTRODUCTION ................................................................................................................... 108
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TABLE OF CONTENTS (Cont...)
6.3. MATERIALS AND METHODS ................................................................................................ 109
6.3.1. Data collected and analysis ------------------------------------------------------------------------- 110
6.4. RESULTS ............................................................................................................................ 113
6.4.1. Phenotypic and genotypic variability-------------------------------------------------------------- 113
6.4.2. Heritability and genetic advance ------------------------------------------------------------------- 113
6.4.3. Genotypic correlation -------------------------------------------------------------------------------- 115
6.4.4. Path coefficient analysis ----------------------------------------------------------------------------- 118
6.5. DISCUSSIONS ...................................................................................................................... 122
6.6. CONCLUSIONS .................................................................................................................... 125
6.7. REFERENCES ...................................................................................................................... 126
CHAPTER 7: HETROSIS AND COMBINING ABILITY IN DIALLEL
CROSSES OF LOCAL AND EXOTIC HOT PEPPER (Capsicum annum
L.) GENOTYPES ................................................................................................................... 128
7.1. ABSTRACT .......................................................................................................................... 128
7.2. INTRODUCTION ................................................................................................................... 129
7.3. MATERIALS AND METHODS ................................................................................................ 130
7.3.1. Experimental procedure ----------------------------------------------------------------------------- 132
7.3.2. Data collection and method of analysis ----------------------------------------------------------- 132
7. 4. RESULTS ............................................................................................................................ 137
7.4.1. Analysis of variance for morphological and fruit characters ---------------------------------- 137
7.4.2. Combining ability effects --------------------------------------------------------------------------- 137
7.4.4. Analysis of variance ratio --------------------------------------------------------------------------- 147
7.4.6. Heterosis and Heritability Study ------------------------------------------------------------------- 148
7.4.6.1. Heterosis for morphological characters -----------------------------------------
7.4.6.2. Heterosis for fruit yield and quality characters --------------------------------
7.4.6.3. Heritability Study ----------------------------------------------------------------
7.5. DISCUSSIONS ...................................................................................................................... 160
7.6. CONCLUSION ...................................................................................................................... 164
7.7. REFERENCES ...................................................................................................................... 166
CHAPTER 8: GENERAL SUMMARY AND RECOMMENDATIONS ............................. 169
8.1. SUMMARY AND CONCLUSION .............................................................................................. 169
8.2. RECOMMENDATIONS ........................................................................................................... 172
CHAPTER 9. APPENDIX ..................................................................................................... 174
9A. APPENDIX: A; TABLES .................................................................................................. 174
9B. APPENDIX: B; TABLES ................................................................................................... 174

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