Anthony W. Whiley.  1994.  ECOPHYSIOLOGICAL STUDIES AND TREE MANIPULATION FOR MAXIMISATION OF YIELD POTENTIAL IN AVOCADO (Persea americana Mill.).  PhD. Thesis.  Department of Horticultural Science.  University of Natal.  Pietermaritzburg, South Africa.  175 pages.

 

 

TABLE OF CONTENTS

 

ABSTRACT

i

DECLARATION

iii

ACKNOWLEDGMENTS

iv

INTRODUCTION

1

UNIT ABBREVIATIONS

4

 

CHAPTER

 

1. LITERATURE REVIEW

5

 

1. 1  ENVIRONMENTAL PHYSIOLOGY

5

 

1. 1. 1 Irradiance

6

 

1. 1. 2 Temperature

9

 

1. 2  CARBOHYDRATE CYCLING IN TREE FRUIT CROPS

12

 

1. 3  AVOCADO AND TRUNK-INJECTED PHOSPHONATES

14

 

2. PHENO/PHYSIOLOGICAL MODELS

 

18

 

2. 1  AVOCADO PHENOLOGY

19

 

2. 2  INTEGRATION OF PHYSIOLOGY WITH PHENOLOGY MODELS

22

 

2. 2. 1 Introduction

22

 

2. 2. 2 Methods and Materials

22

 

2. 2. 3 Results and Discussion

28

 

3. LEAF AND SHOOT PHYSIOLOGY IN RELATION TO CO2 ASSIMILATION AND FRUIT RETENTION

 

42

 

3. 1  DYNAMICS OF GROWTH AND CO2 ASSIMILATION OF THE FRUITING SPRING SHOOT

42

 

3. 1. 1 Introduction

42

 

3. 1. 2 Materials and Methods

43

 

3. 1. 3 Results

44

 

3. 2  CO2 ASSIMILATION OF CV. HASS LEAVES IN RELATION TO IRRADIANCE, CO2 PARTIAL PRESSURES AND TEMPERATURES

48

 

3. 2. 1 Introduction

48

 

3. 2. 2 Materials and Methods

50

 

3. 2. 3 Results

52

 

3. 3  EFFECT OF PRE-ANTHESIS DEFOLIATION OF TREES AND THE INFLUENCE OF INDETERMINATE INFLORESCENCES ON FRUIT RETENTION

58

 

3. 3. 1 Introduction

58

 

3. 3. 2 Materials and Methods

59

 

3. 3. 3 Results

60

 

3. 3. 4 Discussion

63

 

4. GAS EXCHANGE OF DEVELOPING FRUIT

 

72

 

4. 1  CARBON DIOXIDE EXCHANGE OF DEVELOPING FRUIT

72

 

4. 1. 1 Introduction

72

 

4. 1. 2 Materials and Methods

73

 

4. 1. 3 Results

75

 

4. 1. 4 Discussion

79

 

4. 1. 5 Conclusion

81

 

5. CARBON PARTITIONING IN CONTAINER-GROWN AVOCADO TREES

 

83

 

5. 1 14C-PHOTOSYNTHATE PARTITIONING IN AVOCADO TREES AS INFLUENCED BY SHOOT DEVELOPMENT

83

 

5. 1. 1 Introduction

83

 

5. 1. 2 Materials and Methods

84

 

5. 1. 3 Results and Discussion

86

 

5. 1. 4 Conclusions

88

 

6. FRUIT SIZE, YIELD AND STARCH CYCLING IN RELATION TO DELAYED HARVEST OF EARLY AND LATE MATURING AVOCADO CULTIVARS

 

90

 

6. 1  EFFECT OF DELAYED HARVEST ON SUBSEQUENT AND FRUIT SIZE OF EARLY (‘Fuerte’) AND LATE (‘Hass’)YIELD MATURING AVOCADO CULTIVARS

90

 

6. 1. 1 Introduction

90

 

6. 1. 2 Materials and Methods

91

 

6. 1. 3 Results

94

 

6. 1. 4 Discussion

108

 

6. 1. 5 Conclusions

113

 

7. TRANSLATION OF PHENO/PHYSIOLOGICAL RESEARCH INTO MANAGEMENT STRATEGIES

 

114

 

7. 1  CONTROL OF PHYTOPHTHORA ROOT ROT WITH TRUNK-INJECTED PHOSPHONATE

114

 

7. 1. 1 Introduction

114

 

7. 1. 2 Materials and Methods

116

 

7. 1. 3 Results and Discussion

119

 

7. 1. 4 Conclusions

128

 

7. 2  EFFECT OF SPRING APPLIED NITROGEN AND PACLOBUTRAZOL ON ‘HASS’ YIELD AND FRUIT SIZE

129

 

7. 2. 1 Introduction

129

 

7. 2. 2 Materials and Methods

130

 

7. 2. 3 Results and Discussion

134

 

7. 2. 4 Conclusions

141

 

GENERAL DISCUSSION AND CONCLUSION

 

142

SUMMARY

150

LITERATURE CITED

157

APPENDICES

175