Resource allocation in kiwifruit (Actinidia chinensis)

302 Pages·2013·5.57 MB·English

by  Boyd, Linda

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RESOURCE ALLOCATION IN KIWIFRUIT (Actinidia
chinensis)

A thesis presented in partial fulfilment of the requirements
for the degree Doctor of Philosophy
in
Plant Physiology
at
Massey University, Albany, New Zealand

Linda Boyd
2012
ABSTRACT

Kiwifruit growers in New Zealand receive financial incentives to produce high yields of fruit
with high individual dry matter concentrations (DMCs). Several vine management techniques
are available to growers to enable them to direct more resources into production of fruit rather
than into other sinks such as root growth and shoot extension. The long term consequences of
these management techniques are not well understood. The overall objective of the work
described in this thesis was to investigate how manipulating whole vine source-sink
relationships affects fruit quality, long-term vine health and productivity in ‘Hort16A’
kiwifruit vines.

A compensatory reduction in flower numbers occurred as a result of whole vine carbohydrate
depletion (famine treatment) and producing high crop loads of high DMC fruit with reduced
leaf area (minimal pruning, standard nitrogen). Keeping crop loads low did not result in
increased productivity, instead additional resources were allocated to root growth (feast
treatment). Isolating the canopy from the roots by extended trunk girdling was the technique
that enabled high flower numbers to be maintained across seasons.

Increasing individual fruit DMC generally enabled fruit to be harvested earlier than fruit with
lower DMC. This was because flesh colour change, the main harvest criterion, occurred
earlier in fruit from treatments where DMC was increased. Fruit softening behaviour was less
affected by changes in DMC than flesh colour change, meaning that low DMC fruit could be
softer at commercial harvest that more mature high DM fruit. The implications of this finding
for storage performance were discussed.

Vines showed few of the common responses to carbohydrate depletion. There was no
evidence of increased individual leaf area, reduced specific leaf weight, upregulated leaf
photosynthesis or increased shoot growth. Uptake and allocation of some mineral nutrients
within the vines was affected, but few visible signs of leaf nutrient deficiencies were seen.
The results suggest that vines respond to carbon depletion primarily be altering resource
allocation between flowering and root growth, rather than by altering its ability to capture
carbon.
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ACKNOWLEDGMENTS

Many people were involved in helping me produce this thesis.

Firstly I would like to thank my supervisors Errol Hewett and Ian Ferguson for sharing their
wisdom with me.

Many of my workmates helped in one way or another, talked things through, read my chapters
and discussed my results. In particular I’d like to acknowledge Peter Alspach, Andrew
Barnett, Nihal De Silva, Ross Ferguson, Nagin Lallu, Peter Minchin, Warick Nelson, Kevin
Patterson, Mary Petley, Bill Snelgar and Anne White.

Numerous people helped with the practical side of things, including the vine excavations, in
often cold and wet conditions. Special thanks go to Dave Billing, Peter Blattmann, Michael
Blattmann, Helen Boldingh, Chen Goh, Carol Jaeglio, John May, Phil Martin, Craig Maxwell,
Ella Maxwell, Sam Ong, Steve Owen, Nui Tibble and Diane Weber, plus all the casual staff,
summer students and other people who have helped.

ZESPRI International funded some of the work in this thesis and I’d particularly like to thank
Jayne Chamberlain, Shane Max and Alistair Mowat for this.

For the past few years my employer Plant & Food Research allowed me a generous
proportion of my time to complete this thesis, Mike Currie, Bruce Cambell and Michelle
Williams were instrumental in making this happen.

Final thanks go to Andy, Anne, Henry, Lisa and Sue for providing friendship, humour and a
welcome distraction or two.

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CONTENTS
Page
Abstract ................................................................................................................................... i
Acknowledgments .................................................................................................................. ii
List of Figures ..................................................................................................................... viii
List of Tables ........................................................................................................................ xv
List of Appendices .............................................................................................................. xix
List of Abbreviations and Terms Used ................................................................................ xx
1 INTRODUCTION ................................................................................................................... 1
1.1 Vine productivity .............................................................................................................. 3
1.1.1 Fruit dry matter concentration ................................................................................... 3
1.1.2 Harvest criteria for ‘Hort16A’ kiwifruit .................................................................... 4
1.1.3 Fruit storage performance ......................................................................................... 5
1.1.4 Flowering and yield ................................................................................................... 7
1.2 Source-sink manipulations ............................................................................................... 9
1.2.1 Summer pruning and crop load adjustment ............................................................... 9
1.2.2 Trunk girdling ......................................................................................................... 11
1.2.3 Modified nitrogen input .......................................................................................... 15
1.3 Problem statement and objectives .................................................................................. 18
1.4 References ...................................................................................................................... 19
2 GENERAL MATERIALS AND METHODS ...................................................................... 28
2.1 Vines ............................................................................................................................... 28
2.1.1 Plant material ........................................................................................................... 28
2.1.2 Canopy management techniques ............................................................................. 28
2.1.3 Components of yield ............................................................................................... 31
2.1.4 Flowering date ......................................................................................................... 31
2.1.5 Canopy development and architecture .................................................................... 33
2.1.6 Leaf sampling .......................................................................................................... 33
2.1.7 Leaf gas exchange measurements ........................................................................... 33
2.1.8 Fruit sampling ......................................................................................................... 34
2.2 Analysis .......................................................................................................................... 34
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2.2.1 Fruit quality at harvest ............................................................................................. 34
2.2.2 Fruit storage quality ................................................................................................ 34
2.2.3 Analysis of mineral nutrients .................................................................................. 35
2.2.4 Analysis of carbohydrates ....................................................................................... 35
2.2.5 Analysis of chlorophyll ........................................................................................... 36
2.2.6 Canopy and whole-vine biomass ............................................................................. 36
2.2.7 Data analysis ........................................................................................................... 37
2.3 References ...................................................................................................................... 39
3 FRUIT SUB-SAMPLING ..................................................................................................... 40
3.1 Introduction .................................................................................................................... 40
3.2 Materials and methods ................................................................................................... 44
3.2.1 Fruit harvest and sampling ...................................................................................... 44
3.2.2 Data analysis ........................................................................................................... 45
3.3 Results ............................................................................................................................ 46
3.3.1 Longitudinal gradients in developing fruit .............................................................. 46
3.3.2 Comparison of plugs and equatorial slices with whole fruit ................................... 50
3.4 Discussion ...................................................................................................................... 56
3.4.1 Developing fruit ...................................................................................................... 56
3.4.2 Mature fruit ............................................................................................................. 56
3.5 Conclusions .................................................................................................................... 59
3.6 References ...................................................................................................................... 60
3.7 Appendix ........................................................................................................................ 63
3.7.1 Regression analysis ................................................................................................. 63
4 WHOLE VINE CARBOHYDRATE STATUS .................................................................... 65
4.1 Introduction .................................................................................................................... 65
4.2 Materials and methods ................................................................................................... 69
4.2.1 Vines and treatment application .............................................................................. 69
4.2.2 General measurements ............................................................................................ 71
4.2.3 Statistical analysis ................................................................................................... 73
4.3 Results ............................................................................................................................ 74
4.3.1 Canopy composition ................................................................................................ 74
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4.3.2 Leaf attributes .......................................................................................................... 78
4.3.3 Fruit attributes ......................................................................................................... 90
4.3.4 Whole-vine resource allocation ............................................................................. 103
4.4 Discussion .................................................................................................................... 112
4.4.1 Vegetative/reproductive balance ........................................................................... 112
4.4.2 Shoot architecture .................................................................................................. 113
4.4.3 Leaf function ......................................................................................................... 114
4.4.4 Leaf plasticity ........................................................................................................ 115
4.4.5 Leaf senescence ..................................................................................................... 117
4.4.6 Generation of alternative sinks .............................................................................. 118
4.4.7 Perennial reserves .................................................................................................. 119
4.4.8 Fruit attributes ....................................................................................................... 120
4.5 Conclusions .................................................................................................................. 121
4.6 References .................................................................................................................... 122
4.7 Appendices ................................................................................................................... 127
Appendix 4.7.1 Estimating change in hue angle ............................................................ 127
Appendix 4.7.2 Carbohydrate concentrations in perennial vine parts ........................... 127
Appendix 4.7.3 Whole vine mineral nutrient composition ............................................ 128
Appendix 4.7.4 Mineral nutrient concentrations in perennial parts of the vine ............. 129
5 EXTENDED SUMMER TRUNK GIRDLING .............................................................. 130
5.1 Introduction .................................................................................................................. 130
5.2 Materials and methods ................................................................................................. 132
5.2.1 Vines and treatment application ............................................................................ 132
5.2.2 Measurements ..................................................................................................... 134
5.2.3 Statistics ............................................................................................................... 136
5.3 Results .......................................................................................................................... 137
5.3.1 Canopy composition ............................................................................................ 137
5.3.2 Leaf attributes ...................................................................................................... 141
5.3.3 Fruit attributes..................................................................................................... 155
5.3.4 Resource allocation ............................................................................................... 168
5.4 Discussion .................................................................................................................... 179
5.4.1 Vegetative/reproductive balance ........................................................................... 179
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5.4.2 Shoot architecture ............................................................................................... 181
5.4.3 Leaf plasticity ........................................................................................................ 184
5.4.4 Leaf function ......................................................................................................... 185
5.4.5 Leaf senescence ..................................................................................................... 187
5.4.6 Generation of alternative sinks .............................................................................. 187
5.4.7 Perennial reserves .................................................................................................. 188
5.4.8 Fruit attributes ....................................................................................................... 192
5.5 Conclusions .................................................................................................................. 195
5.6 References .................................................................................................................... 196
5.7 Appendices ................................................................................................................... 203
Appendix 5.7.1 Canopy composition ............................................................................. 203
Appendix 5.7.2 Within-canopy resource allocation ....................................................... 204
6 EFFECTS OF PRUNING AND NITROGEN APPLICATION ..................................... 205
6.1 Introduction .................................................................................................................. 205
6.2 Materials and methods ................................................................................................. 207
6.2.1 Vines and treatment application ............................................................................ 207
6.2.2 General measurements .......................................................................................... 209
6.2.3 Statistical analysis ................................................................................................. 210
6.3 Results .......................................................................................................................... 211
6.3.1 Pruning/nitrogen interaction. ................................................................................. 211
6.3.2 Effect of Nitrogen input ........................................................................................ 221
6.4 Discussion .................................................................................................................... 232
6.4.1 Pruning/nitrogen interactions ................................................................................ 232
6.4.2 Nitrogen management and vine productivity. ....................................................... 235
6.5 Conclusions .................................................................................................................. 244
6.7 References .................................................................................................................... 245
6.7 Appendices ................................................................................................................... 252
Appendix 6.7.1 Effect of pruning on leaf mineral nutrient concentrations .................... 252
Appendix 6.7.2 Leaf mineral nutrient concentrations – effects of nitrogen .................. 254
Appendix 6.7.3 Calculating leaf area from pruning weight ........................................... 255
7. GENERAL DISCUSSION ................................................................................................. 256
7.1 Thesis objectives .......................................................................................................... 256
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7.2 Long-term vine productivity ........................................................................................ 257
7.3 Fruit maturity attributes ................................................................................................ 262
7.4 Fruit storage performance ............................................................................................ 266
7.5 Vine canopy responses ................................................................................................. 268
7.6 Reserve depletion ......................................................................................................... 270
7.7 Conclusions .................................................................................................................. 275
7.8 References .................................................................................................................... 277

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LIST OF FIGURES
Chapter 1 Page
1.1 Canopy of A) ‘Hort16A’ and B) ‘Hayward’ kiwifruit vines 1
1.2 ‘Hort16A’ kiwifruit stored at 1.5ºC for 20 weeks and affected by low temperature 6
breakdown showing A) external rots and B) water-soaked tissue at the beak end of
the fruit
1.3 ‘Hort16A’ canopy photographed in December 2007, about 2 months after bud 9
break showing the vigorous growth of long shoots
1.4 Growth curve from A) ‘Hayward’ and B) ‘Hort16A’ kiwifruit showing the double- 12
sigmoidal pattern of fresh weight accumulation
Chapter 2
2.1 ‘Hort16A’ vine canopy showing the leader zone, fruiting zone and edge zones and 28
the male vines which occupy a small proportion of the canopy area.
2.2 A) a vigorous fruiting shoot is cut back directly above the last fruit, B) a healed
zero-leafed shoot, showing the lack of regrowth, and C) regrowth from an 29
incorrectly zero-leafed shoot
2.3 A) Regrowth from a stubbed (cut) shoot, and B) The tip of a vigorous shoot is 30
squeezed so as to stop further growth but without generating new regrowths
2.4 Fruitlets originating from the central king flower and two lateral or side flowers 31
2.5 The same part of a ‘Hort16A’ kiwifruit canopy photographed on A) 1 October, 32
and B) 15 October 2008 when 0 % and 45 % of flowers were open respectively
2.6 A sigmoid curve fitted through flowering data from an individual ‘Hort16A’ 32
kiwifruit vine, illustrating the days when A) 10 %, B) 50 % and C) 90 % of
flowers had opened
2.7 A) A section of the canopy immediately before it was separated into its various 38
components: fruit, live leaves, abscised leaves, senesced leaves, shoots and canes,
B) the canopy being dismantled, C) the leader is cut into sections before being
chopped and passed through a chipper, D) once the canopy and leader have been
removed, the trunk, crown and some of the roots are pulled out, E) the remaining
roots were exposed by digging, or by applying a stream of high-pressure water
Chapter 3
3.1 A) ‘Hayward’ fruit with both ends removed for soluble solids concentration 41
determination, two 1-mm deep skin slices have been removed showing puncture
marks from firmness measurement, and B) an equatorial slice being removed to
measure dry matter concentration
3.2 The three sample types used to compare sampling procedure: longitudinal quarter 42
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