The Road to Productivitycesanluisobispo.ucanr.edu/files/231126.pdf · en paltos var. Hass. Encón,...
Transcript of The Road to Productivitycesanluisobispo.ucanr.edu/files/231126.pdf · en paltos var. Hass. Encón,...
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The Road to Productivity
Mary Lu ArpaiaUniversity of California,
Riverside
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The ultimate crop that one harvests is dependent upon many factors:
• On/Off status• Overall tree health• Conditions during
flowering and fruit set • Conditions during
subsequent fruit development
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This presentation will focus on one small
aspect of productivity -Pollination
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Terminology
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The avocado flower
Stigma
Ovule - Seed Ovary – Fruit Flesh and Peel
StyleAnther/Filament –Source of Pollen
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Pollination Terms:
Pollination – the transfer of pollen from the anther to the stigma.– Cross pollination – the pollen deposited on
the stigma is from another cultivar.– Close pollination – the pollen deposited on
the stigma is from another flower of the same tree or cultivar.
– Self pollination – the pollen deposited on the stigma is from the same flower.
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Pollination Terms:
Pollinator: The agent which transfers pollen from the male to the female floral organ.
Pollinated Tree: A cultivar that receives the pollen (i.e. Hass).
Pollinizer: A cultivar that donates pollen to another cultivar.Common Hass pollinizers: Bacon, Zutano, Ettinger, Edranol, Walter Hole.
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Pollination Terms:Fertilization – the fusion of the male
gamete with the female gamete forming the zygote.
Effective Pollination – pollination which leads to fertilization.
Non effective pollination – pollination which does NOT lead to fertilization.
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Avocado Flower
Behavior
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Avocado flowering characteristics
• Attraction: the whole tree acts like a giant inflorescence with many small flowers.
• Small fertilization percent: thus most flowers do not set fruit.
• Competition: between fruits and growth, as well as among the fruits, which leads to high rate of primary-fruit abscission.
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♀ ♂There are 2 phases to avocado flowering
This is called Synchronous Dichogamy
Source: I. Hormaza
FEMALE PHASE MALE PHASE
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The avocado flower
Female Phase
Male Phase
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Ish Am, PhD. Thesis
FEMALE PHASE
MALE PHASE
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Timing of flowering for “A” and “B” flower types.
DAY 1 DAY 2MORNING AFTERNOON MORNING AFTERNOON
Flow
er-ty
pe c
ultiv
ar
“A”
“B”
DAY 1
DAY 2
MORNING
AFTERNOON
MORNING
AFTERNOON
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The sequence of timing for “A” and “B” flower types under field conditions.
Morning AfternoonFl
ower
-type
cul
tivar “A”
“B”
Morning
Afternoon
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Avocado Flowering Sequence
Type A
Type B
Female flowersMale flowers before dehiscenceMale dehiscing flowers
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Overlap within the tree occurs
Source: I. Hormaza
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Fruit Set
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• Millions of flowers during bloom• Long flower duration
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Are all flowers created equal?
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05
1015202530354045
20 40 60 80 100 120 140 160 180 200 220
Nº F
lore
s
Σ Densidad óptica ( x104)
I2KIN
o. o
f flo
wer
s
Optical density x104
- NO EXTERNAL DIFFERENCES AMONG FLOWERS- GREAT DIFFERENCES IN STARCH CONTENT
Source: I. Hormaza
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02468
1012141618
Caídas Cuajadas
ΣD
ensi
dad
óptic
a (x
104 )
Opt
ical
den
sity
x10
4
Dropped Retained Source: I. Hormaza
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‘Fuerte’ pollen on anther flap ‘Hass’ pollen grain(SEM x2000)
From: G. Ish Am
The avocado pollen grain
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Hand pollinated ‘Hass’ stigmas by ‘Ettinger’ pollen. Four hrs of germination.
Shoval, 1987
1-4 pollen grains
>20 pollen grains
5-19 pollen grains
Percent of pistil length
Perc
ent
of f
lowe
rsPollen tubes
Reach:
Avocado Pollen Germination Rate
Effect of competitionbetween and cooperationamong the pollen grains
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Early dropped Initially retained Fruit set
01020304050607080
Early dropped Initially retained Fruit set
Ger
min
atio
n (%
) ab
b
Hass Flowers/Fuerte Pollen
Pollen germination does not appear to be limiting
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NUMBER OF POLLEN GRAINS ON STIGMA AND FLOWER FATE
05
101520253035
� 0 �1-5 �6-10 �11-15 �16-20 �21-25 �26-30 �31-35 �36-40 �>41
Flow
ers (
%)
Early drop
05
101520253035
� 0 �1-5 �6-10 �11-15 �16-20 �21-25 �26-30 �31-35 �36-40 �>41
Flow
ers (
%)
Initial retention
05
101520253035
� 0 �1-5 �6-10 �11-15 �16-20 �21-25 �26-30 �31-35 �36-40 �>41
Flow
ers (
%)
Final fruit set
1-5
1-5
1-5
1-5
>40
>40
>40
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Temperature and Humidity
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0
20
40
60
15ºC 20ºC 25ºC 30ºC Campo
% G
erm
inac
ión
Temperatura
Femenino Masculino
0
20
40
60
50% 75% 95%
% G
erm
inac
ión
Humedad relativa
Femenino MasculinoSource: I. Hormaza
Temperature and Relative Humidity Impacts Pollen Germination
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Sedgley and Annells, 1981• Kept trees at 3 temperature regimes
(Day/Night): 91/82; 77/68; 63/54• Flowering cycle: At 63/54 prolonged from 36
hr to 72 hr• Overlap: most overlap occurred at 77/68• Fertilization: occurred at all temps but lowest
at 63/54• Embryo development: occurred at all
temperatures but fruitlets abscised at high temps and growth very slow at low temp
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Temperature fluctuations during floweringIrvine, CA
TEMP
RH
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0 2 4 6 8 10 12 14 16 18 20 22 24
Time of Day (hr), PST
Male Stages
New Male Stages
Female Stages
Female Stages
Hot Day/ Moderately Cool NightTemp. Max. 31.9°CTemp. Min. 8.2°C
Cool Day/Cool NightTemp. Max. 20.9°CTemp. Min. 6.2°C
23 April 2004
14 April 2004
Stages from previous day
87F Day/47F Night
68F Day/43F Night
Temperature influences the timing of the female and male stages
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Do You Need Pollinizers?
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Survival of cross vs. self progenies
Source: Degani, Goldring and Gazit. 1989. J. Amer. Soc. Hort. Sci. 114:106-111 Via www.avocadosource.com
Percent of crossed ‘Hass’ fruits by both ‘Ettinger’ or ‘Fuerte’ according to time after fruit set.
0102030405060708090
May 5 Sept 10 Oct 22
Sampling Date
% o
ut-c
ross
ing
Chart3
May 5
Sept 10
Oct 22
Sampling Date
% out-crossing
22.8
72.4
83.6
Sheet1
May 522.8
Sept 1072.4
Oct 2283.6
Sheet1
Sampling Date
% out-crossing
Sheet2
Sheet3
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MATERIALES Y MÉTODOS
5 Replicated BlocksEach Net House had Honey Bees
TMTO Descripción0 Control, No Net House, 5,5% Edranol
1 Net House, 12 Hass + 0 Edranol
2 Net House, 11 Hass + 1 Edranol
3 Net House, 10 Hass + 2 Edranol
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Resultados
TMTO Frutos 2012 Frutos 2013 Frutos 2014 ∑ 2012-2014
0 50,51 ± 57,88 a -- -- --
1 19,30 ± 43,97 c 138,90 ± 67,62 ab 49,25 ± 59,70 b 207,45 ± 85,58 b
2 22,89 ± 42,21 bc 151,98 ± 70,06 a 79,25 ± 62,82 a 254,13 ± 89,35 a
3 41,48 ± 50,30 ab 121,52 ± 67,28 b 74,70 ± 77,96 ab 237,70 ± 106,05 ab
Cuadro 1. Efecto de los distintos tratamientos en el promedio de número de frutos obtenidosen paltos var. Hass. Encón, Panquehue.
Letras distintas indican que existen diferencias significativas. (Test de Tukey, P ≤ 0,10).
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Hass yields decrease significantlywith increasing distance from ‘Ettinger’
Source: Guil et al. 1986. Alon Hanotea 40:443-455
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Pollinizer Varieties: 8Field trial replicates: 6Pollinizers interset with Hass
DeBusschere Pollinizer Trial – Coastal Ventura County
Does distance play a role?
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Debusschere Pollination Project – 2001 – 2008Cumulative fruit count as a function of distance from pollinizer
0
200
400
600
800
1000
1200
Within Row 27 ft 54 ftDistance from Pollinizer
Cumulative count
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Debusschere Pollination Project – 2001 – 2008Cumulative fruit count as a function of Pollinizer variety and distance from pollinizer
0
200
400
600
800
1000
1200
1400
Fuerte Zutano Ettinger Bacon Sirprize BL667 BL516 HarvestNearest Pollinizer Variety
With-in Row 27 feet 54 feet “A” flower type
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Multiple pollinizers
Bacon + Ettinger + Zutano
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Flowering periods – Oxnard, 2002
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BL516
BL667
Sir Prize
Harvest
GEM
Lamb Hass
Hass
0 20 40 60 80 100 120 140 160 180Julian Date
2005200420032002
Duration of bloom over 4 years
Irvine, CA
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How do you get the pollen to the flower?
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ACW Trial – 2010M. Hoddle, M.L. Arpaia, R. Hofshi
4 Treatments:1) Outside control2) Net House with Bees3) Net House Small insects4) Net House where all trees sprayed to eliminate insects
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ACW Trial – 2010M. Hoddle, M.L. Arpaia, R. Hofshi
0
10
20
30
40
50
60
70
Small Insects Insecticide Bees Control Water control
Avg
. Fr
uit
Num
ber
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0
50
100
150
b b a a
SmallInsects
Insecticide Honeybees ControlAve
rage
Fru
it N
umbe
r
Encon Trial – 2011R. Hofshi, J. Schmidt, F. Mena, F. Gardiazabal, M. L. Arpaia
4 Treatments:1) Outside control2) Net House with Bees3) Net House Small insects4) Net House where all trees
sprayed to eliminate insects
5 Field Replications14 trees per net house
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To maximize yield one needs:
Sufficient cross pollination
Effective pollination
Efficient pollinator(many honey bees)
Pollinizers in close proximity
The Road to ProductivityThe ultimate crop that one harvests is dependent upon many factors:Slide Number 4TerminologySlide Number 7Slide Number 8Pollination Terms:Pollination Terms:Pollination Terms:Avocado Flower BehaviorAvocado flowering characteristicsSlide Number 14Slide Number 15Slide Number 16Timing of flowering for “A” and “B” flower types. The sequence of timing for “A” and “B” flower types under field conditions.Avocado Flowering SequenceSlide Number 20Fruit Set�Slide Number 24Slide Number 25Slide Number 27Slide Number 28Slide Number 29Avocado Pollen Germination RateSlide Number 31Slide Number 32Temperature and HumiditySlide Number 34Sedgley and Annells, 1981Temperature fluctuations during flowering�Irvine, CASlide Number 39 Do You Need Pollinizers?Survival of cross vs. self progeniesSlide Number 42Materiales y MétodosResultadosHass yields decrease significantly with increasing distance from ‘Ettinger’Slide Number 46Debusschere Pollination Project – 2001 – 2008�Cumulative fruit count as a function of distance from pollinizerDebusschere Pollination Project – 2001 – 2008�Cumulative fruit count as a function of Pollinizer variety and distance from pollinizerMultiple pollinizersFlowering periods – Oxnard, 2002Slide Number 51Slide Number 52Slide Number 53Slide Number 54Slide Number 55Slide Number 56Slide Number 57To maximize yield one needs: