UCR Avocado Rootstock Program Update: Towards Developing ... · In 2006 and 2010 USA was the top 2...

Patricia Manosalva, Peggy Mauk, andMary Lu Arpaia

University of California Riverside

June 10th, 2020

UCR Avocado Rootstock Program Update: Towards Developing Disease

and Salinity Resistant Rootstocks

[email protected]

Natasha Jackson, PhD Student (2021)

Dr. Rodger Belisle (2018)

Brandon (former SRA)

Dr. Guangyuan Xu Former Postdoc (2019)

Aidan ShandsPhD Student (2022)

Dr. Abeysekara, former (2020)

In 2006 and 2010 USA was the top 2 global producer.

Currently, USA is number 8. California produces 90% followed by Florida, and Hawaii.

The market share for USA-produced avocado has decrease!!!

UCR RootstockBreeding Program

George ZentmyerUCR 1943 – 1983

Mike Coffey John MengeGreg Douhan

Dr. Patricia Manosalva (2015)

Borchard Duke7

ToroCanyon

TopaTopa

D9 G755A G755B G755C0

100

200

300

400

500Cumulative yield per tree (kg)

Years after Planting2 3 4 5 6 7 8 9 10

Martin Grande (G755 seedlings)P. schiedeana seedligs (1970s-1980s).

Rootstock influences yield, tree size, nutrient uptake and alternate bearingMickelbart et al, 2007

Mary Lu Arpaia

The evolution of clonal rootstocks

(Past) Duke 7

(Present) Most available at BrokawDusa (SA) Uzi (UCR)Zentmyer (UCR)Steddom (UCR)Tami (VC801), Miriam (VC218), and Ben-Ya’ Acov1(Israel)

Thomas Toro Canyon

G755 (martin grande)G6 Duke 9

Califonia and UCR clonal rootstocks

M = Mexican, G = Guatemalan

Rootstock Race Year Maternal Parent

Origen Flower type Phenotype

Duke M 1912s Unknown UCR, Zentmyer B Good Phytophthora Root Rot (PRR) resistance (moderate resistance, MR) caused by Phytophthora cinnamomi in CA, cold and wind tolerance, vigorous, productive, large trees.

Duke 7 M 1970s Duke UCR, Zentmyer B Good PRR resistance (comparable with Dusa, CA standard), cold and wind tolerance, vigorous, Hass:duke7 is productive, large trees, susceptible to waterlogging. Available at CA, South Africa, Israel, Spain, and Chile.

Duke 9 M 1990s Duke (gamma irradiation)

UCR, Zentmyer B Good PRR resistance (comparable with Dusa, CA standard), vigorous, poor yield (Hass:Duke 9) in CA but similar to Hass:Duke 7 in South Africa, large trees.

Barr Duke M 1990s Duke 6 UCR, Zentmyer B Moderate PRR resistance, susceptible to salinity.

Thomas M 1980s Fuerte UCR, Mike Coffey/Guillemet

B Highly resistant when selected back in the 1980s but currently is susceptible to the new PRR pathogen population in CA, highly susceptible to salinity. Susceptible to P. citricola.

Toro Canyon M x G 1984 Topa Topaseedling

Royden Stauffer B Moderate PRR resistance (CA), tolerant to salinity, vigorous, currently used in CA, good productivity under PRR and high salinity conditions.

Zentmyer M 2011 Thomas UCR, Menge et al A(Menge)/B (Manosalva)

Good PRR resistance in some cases better than Dusa, vigorous, highly sensitive to salinity, good yield under PRR conditions but poor yield under no PRR conditions, good tree for replanting situation under high PRR incidence but no high salinity.

Uzi M 2011 G6 UCR, Menge et al B Good PRR resistance in some cases better than Dusa, extremely vigorous and fast-growing rootstock that is capable of supporting a ‘Hass’ tree growing to 15 ft. in 2 years. It's yields are generally high and consistent. ‘Uzi’ leaves exhibit burn due to salt damage, but this does not seem to affect the growth or yield of the ‘Hass’ variety.

Steddom M x G 2011 Toro Canyon UCR, Menge et al A(Menge)/B (Manosalva)

Good PRR resistance in some cases better than Dusa, it is a slow growing rootstock having a heavy yield, has a high yield/canopy volume ratio. ‘Steddom’ has a small degree of salt tolerance, excellent rootstock with small stature and low vigor, making it desirable for high density or hedge-row avocado plantings.

Rootstock Race Year Maternal Parent

Origen Flower type Phenotype

Duke M 1912s Unknown UCR, Zentmyer B Good Phytophthora Root Rot (PRR) resistance (moderate resistance, MR) caused by Phytophthora cinnamomi in CA, cold and wind tolerance, vigorous, productive, large trees.

Duke 7 M 1970s Duke UCR, Zentmyer B Good PRR resistance (comparable with Dusa, CA standard), cold and wind tolerance, vigorous, Hass:duke7 is productive, large trees, susceptible to waterlogging. Available at CA, South Africa, Israel, Spain, and Chile.

Duke 9 M 1990s Duke (gamma irradiation)

UCR, Zentmyer B Good PRR resistance (comparable with Dusa, CA standard), vigorous, poor yield (Hass:Duke 9) in CA but similar to Hass:Duke 7 in South Africa, large trees.

Barr Duke M 1990s Duke 6 UCR, Zentmyer B Moderate PRR resistance, susceptible to salinity.

Thomas M 1980s Fuerte UCR, Mike Coffey/Guillemet

B Highly resistant when selected back in the 1980s but currently is susceptible to the new PRR pathogen population in CA, highly susceptible to salinity. Susceptible to P. citricola.

Toro Canyon M x G 1984 Topa Topaseedling

Royden Stauffer B Moderate PRR resistance (CA), tolerant to salinity, vigorous, currently used in CA, good productivity under PRR and high salinity conditions.

Zentmyer M 2011 Thomas UCR, Menge et al A(Menge)/B (Manosalva)

Good PRR resistance in some cases better than Dusa, vigorous, highly sensitive to salinity, good yield under PRR conditions but poor yield under no PRR conditions, good tree for replanting situation under high PRR incidence but no high salinity.

Uzi M 2011 G6 UCR, Menge et al B Good PRR resistance in some cases better than Dusa, extremely vigorous and fast-growing rootstock that is capable of supporting a ‘Hass’ tree growing to 15 ft. in 2 years. It's yields are generally high and consistent. ‘Uzi’ leaves exhibit burn due to salt damage, but this does not seem to affect the growth or yield of the ‘Hass’ variety.

Steddom M x G 2011 Toro Canyon UCR, Menge et al A(Menge)/B (Manosalva)

Good PRR resistance in some cases better than Dusa, it is a slow growing rootstock having a heavy yield, has a high yield/canopy volume ratio. ‘Steddom’ has a small degree of salt tolerance, excellent rootstock with small stature and low vigor, making it desirable for high density or hedge-row avocado plantings.

Douhan et al., 2015

Douhan et al., 2011

Tami (WI x M)

Miriam (WI x M)

Ø Rootstock attributes

Phytophthora root rot resistance (Phytophthora cinnamomi)

Salinity tolerance

Drought tolerance

Heat tolerance

Alkalinity & high pH tolerance

Waterlogging/flooding tolerance

Resistance to other pathogens and pest

Cold tolerance

Dwarf phenotypes (For high density planting)

Salinity resistance Drought resistance

PRRresistance

Dwarfism

Heavy soiladaptation

Calcareous soiladaptation

Sandy soiladaptation

Others

0 1 2 3 4 5 6 7 8 General Score

Surveymonkey report for our grower survey conducted in CA. Growers were asked to rate the top priorities for desirable rootstocks traits. From70 surveyed grower from all regions in CA, resistance to salinity, PRR, and drought were the top 3 priorities in CA (*) with scores of 6.3, 6.2, and 5.8 respectively.

“Avocado growers are facing major constrains that affect negatively their profitability and

sustainability”

The UCR rootstock avocado breeding program aimto improve avocado production by reducing yield

losses and production inputs

UCR Rootstock Genetic Diversity

v Genetic diversity is the foundation (Heart) of ANY genetic improvement program.

v Identify genetic sources for different traits that will aid growers face current and future challenges: diseases, pests, environmental, etc.

Mary Lu Arapia

General traits

A1 GROUP I

From avocado and different

hosts from UCR WOC collection

new S/N collections

(2009-2010)& all older

collections (1976-2007)

Only new Southern

collections (2009-2010)

A2 Clade II

A2 Clade I

A1 Clade I

Pagliaccia et al. (2013). Phytopathology 103 (1):91-97

Phenotypic and genetic characterization of P. cinnamomi populations

DelNorte Siskiyou Modoc

Humboldt

San Diego Imperial

OrangeRiverside

San Bernardino

Los AngelesVentura

Santa Barbara

KernSan LuisObispo

Inyo

Tulare

KingsMonterey

FresnoSanBenito

Mono

Madera

Mariposa

TuolumneCalaveras

Amador

El Dorado

Sacra-mento

Alpine

SantaClara

SanJoaquin

ContraCosta

Merced

Marin

NapaYolo

Solano

Sutter

Placer

Nevada

Sierra

Plumas

ButteGlenn

Lake

Mendocino

LassenShasta

Tehama

Trinity

ColusaYuba

Sonoma

StanislausAlameda

Santa Cruz

San Mateo

San Francisco

San Luis Obispo Kern

Santa Barbara

Ventura Los Angeles

San Diego

San Bernardino

Imperial

RiversideOrange

2008-20092010-20112015-201620172018-2019

Collection of 308 isolates isolated from avocado orchards

Copyright ©2020 Patricia Manosalva(university of California, Riverside). All rights reserved

A1 GROUP I

Phenotypic characterization of P. cinnamomi populations in CA

Pagliaccia et al. (2013). Phytopathology 103 (1):91-97

2113$

2114$2110$

2120$

2109$2117$

A2 Clade II

A2 Clade I

A1 Clade Ia) b)

369 - 626 0

3

6

9

Number+of+P.#cinnamomi#

isolates

EC50 (µg/ml)

12.92

Potassium+phosphite

15.41

18.38

21.93

26.16

31.21

37.23

44.42

52.98

63.21

75.40

89.95

107.31

128.01

152.71

182.17

217.32

259.25

309.27

368.94

440.12

525.04

626.3412 - 63 75 - 217

EC50 (μg/ml)

# Is

olat

esc) Mean(Health Tissue) vs. isolate

Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix

Control G1 G10 G13 G2 G5 G6

North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue

All Control G1S G10S G13S G2N G5N G6N North South Mix Mix Mix

Fig.1. Virulence of different P. cinnamomi isolates among different rootstocks. North isolates (N) G2, G5, and G6 correspond to the old Clade A2 I (old population) and south isolates (S) G1, G10, and G13 to the new introduced Clade A2 II (new south population). North mix and south mix refers to the mix of three isolates from North and South respectively and all mix include the 6 isolates in this study. Uninoculated controls are also showing.

% H

ealth

y ro

ot

Mean(Health Tissue) vs. isolate

Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue




Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue



CONTROL CLADE I CLADE II

DUSA

RO.54

UZI

ZENTMYER

STEDDOM

THOMAS

2113$

2114$2110$

2120$

2109$2117$

A2 Clade II

A2 Clade I

A1 Clade Ia) b)

369 - 626 0

3

6

9

Number+of+P.#cinnamomi#

isolates

EC50 (µg/ml)

12.92

Potassium+phosphite

15.41

18.38

21.93

26.16

31.21

37.23

44.42

52.98

63.21

75.40

89.95

107.31

128.01

152.71

182.17

217.32

259.25

309.27

368.94

440.12

525.04

626.3412 - 63 75 - 217

EC50 (μg/ml)

# Is

olat

es

c) Mean(Health Tissue) vs. isolate

Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue



% H

ealth

y ro

ot


Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue




Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mix


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thom

as

Healt

hy R

oot T

issue




DUSA

RO.54

UZI

ZENTMYER

STEDDOM

THOMAS

Belisle et al. 2019. Phytopathology 109:384.

Belisle et al. 2019. Plant Disease 103(8):2024.

A1 GROUP I

Phenotypic characterization of P. cinnamomi populations in CA


Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080

All mixControl G1 G10 G13 G2 G5 G6

North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thomas

Healt

hy R

oot T

issue



% H

ealth

y ro

ot


Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thomas

Healt

hy R

oot T

issue




Health

Tissue

020406080

020406080

020406080

020406080

020406080

020406080


North mix

South mix

isolate

Dusa KB-1

PP14 PP24

PP4 Thomas

Healt

hy R

oot T

issue




DUSA

RO.54

UZI

ZENTMYER

STEDDOM

THOMAS

PS.54

DUSA®

Mixture of A2 Clade II Southernisolates were more aggressive

Phytophthora cinnamomi

Mix South

f)

KB

-1

D

usa

Control T4 T8 T9

Healthy root 100% 3%

Copyright ©2020 Patricia Manosalva (university of California, Riverside). All rights reserved

FungicideAll isolates (n=71) Southern isolates

(n=47)wNorthern isolates

(n=24)x

Southern vs. northern

means

Range Mean Tukey Range Mean Tukey Range Mean Tukey P-Value

Ethaboxam 0.017-0.069 0.035 d 0.018-

0.066 0.034 d A 0.017-0.069 0.037 d A 0.362

Fluopicolide 0.046-0.330 0.133 b 0.046-

0.330 0.131 b A 0.069-0.257 0.135 b A 0.637

Mandipropamid 0.003-0.011 0.005 e 0.003-

0.011 0.005 e A 0.003-0.011 0.006 e A 0.217

Oxathiapiprolin 0.0002-0.0007 0.0004 f 0.0002-

0.0006 0.0003 f A 0.0002-0.0007 0.0004 f A 0.053

Mefenoxam 0.023-0.138 0.061 c 0.026-

0.138 0.061 c A 0.023-0.100 0.062 c A 0.866

Potassium phosphite

12.9-361.2 81.5 a 12.9-

316.2 98.9 a A 16.6-266.2 47.3 a B 0.001

Fungicide EC50 (µg/ml)

Oxathiapiprolin (Orondis) exhibited the best activity against P. cinnamomi isolates


Fungicide efficacy using clonal rootstocks under greenhouse conditions

PS.54 rootstock

Dusa® rootstock

Treatment (gram a. i. / pot)Control

Ethaboxam (0.140)Fluopicolide (0.042)

Mandipropamid (0.029)

Mefenoxam (0.112)

Oxathiapiprolin (0.028)Potassium phosphite (0.469) ab

bab

abab

ab

a

0 10 20 30 40

ce

cd

deb

a

0 25 50 75 100

bbbb

b

b

a

0 10 20 30 40

P. cinnamomi ppg

b

cbcbcbcbc

a

0 25 50 75 100

Avocado PRR incidence (%)

Treatment (gram a. i. / pot)Control

Ethaboxam (0.140)Fluopicolide (0.042)

Mandipropamid (0.029)Mefenoxam (0.112)

Oxathiapiprolin (0.028)Potassium phosphite (0.469)


Re-screen/screen new rootstock for resistance to the current P. cinnamomi population

UCR Advance selection Race PRR Salinity Flower type Years field dataDusa (CA standard) M x G MR T B 4

PP35 M x G MR T B 4PP40 M x G MR T B 4PP80 M x G MR MT B 4PP42 M MR MT B 4PP45 M R S B 4

Dusa

Duke

9

PS.54

PP35

PP40

PP80

PP85

AB20

AB21

AB22

UC20

01To

roCa

nyon

G6

Day

AB15

AB18

AB19

PP22

PP45

PP87

PP4

PP25

PP42

PP84

0"

20"

40"

60"

80"

100"

120"

Dusa" Duke9" R0.54" PP35" PP40" PP80" PP85" VC802" VC803" VC804" UC2001" Toro"Canyon""

G6" VC207" VC218" VC256" VC801" PP22" PP45" PP87" PP4" PP25" PP42" PP84"

Control"

All"Mix""

Pc2109"

100

80

60

40

20

0% H

ealth

y ro

ot

0"

20"

40"

60"

80"

100"

120"

Dusa" Duke9" R0.54" PP35" PP40" PP80" PP85" VC802" VC803" VC804" UC2001" Toro"Canyon""

G6" VC207" VC218" VC256" VC801" PP22" PP45" PP87" PP4" PP25" PP42" PP84"

Control"

All"Mix""

Pc2109"

ControlAll mixS-2109

MR

S

R

• Confirmation of resistance: PRR incidence, PPg/soil, pathogen biomass using qPCR


AgOPs field salinity experiments (Dr. Peggy Mauk) “Evaluation of rootstocks for salinity tolerance”

2015

Field Evaluation for selection of heat resistant rootstock

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Leaf

Bur

n

Rootstocks

G1

G3

0 = 0 - 10 % damage (G1)1 = 11 - 20 % 2 = 21 - 40 % 3 = 41 - 60 % (G3)4 = 61 - 80 %5 = 81 - 100%/dead

Leaf burn rating (August 2018) in Field 7 SCREC. Ratings were done using a score system of 0 = no heat or salinity damage to 5 = Dead. Rating occurred after severe heat spell. Rootstocks were grafted on Dusa.

PP40

G1= UC2001 and seedlings including PP80 and PP35, Duke 9 and seedlings, VC207G3= Spencer, Spencer seedlings, and VC804. PP40 intermediate phenotype


Field Evaluation of rootstocks

Limoneria 3, Santa Paula (2019)

# de

ad tr

ees (

n=20

)

0

5

10

15

20

Dusa

Thomas PP

84PP85

PP86

PP87

PP90

PP91

AB23

AB24

2016 2017 2019

Tree mortality


Field Evaluation of UCR rootstocks (small trials)

• Canopy measurements.• Overall tree health (0 best - 5).• Leaf necrosis: tip burn and heat burn (0 best -5).• Tree mortality.• Individual tree yield data (weight and fruit number).

DelNorte Siskiyou Modoc

Humboldt

San Diego Imperial

OrangeRiverside

San Bernardino

Los AngelesVentura

Santa Barbara

KernSan LuisObispo

Inyo

Tulare

KingsMonterey

FresnoSanBenito

Mono

Madera

Mariposa

TuolumneCalaveras

Amador

El Dorado

Sacra-mento

Alpine

SantaClara

SanJoaquin

ContraCosta

Merced

Marin

NapaYolo

Solano

Sutter

Placer

Nevada

Sierra

Plumas

ButteGlenn

Lake

Mendocino

LassenShasta

Tehama

Trinity

ColusaYuba

Sonoma

StanislausAlameda

Santa Cruz

San Mateo

San Francisco

San Luis Obispo Kern

Santa Barbara

Ventura Los Angeles

San Diego

San Bernardino

Imperial

RiversideOrange

10’ x 10’ planting, organic


Score Overall Health Salinity/Heat0 Perfect looking tree 0 - 5 % damage, perfect/healthy

0.5 Slightly off (less leaves/small leaves, lack of flush) 5 - 10 %

1 Yellow leaves and or small leaves 11 - 20 %

2 Exposed branches, wilting leaves, small yellow leaves 21 - 40 %

3Branch dieback, very few

leaves remaining, starting to die

41 - 60 %

4 Almost dead, won't last long 61 - 80 %5 Dead 81 - 100 %

Overall tree health and leaf necrosis = 0

Overall tree health = 4Leaf necrosis = 0

Overall tree health = 3.5Salinity damage = 4

Fig. 5. Overall tree health and leaf necrosis scoring system developed and used by the UCR avocado

rootstock breeding program.


New selections evaluated in Ramona (2014) . Tom Royden and Kozy

Thanks Tom!!

0.00

0.50

1.00

1.50

2.00

2.50

3.00

Dusa

GD1

GD10

GD11

GD12

GD13

GD14

GD3

GD4

GD6

GD7

GD8

GD9

PP89

PP90

PP91

PP92

PP93

PP94

PP95

PP96

Thom

asAB

3AB

4AB

5AB

6AB

10AB

10AB

2AB

22

0.000.501.001.502.002.503.003.504.004.505.00

Dusa

GD1

GD10

GD11

GD12

GD13

GD14

GD3

GD4

GD6

GD7

GD8

GD9

PP89

PP90

PP91

PP92

PP93

PP94

PP95

PP96

Thom

asAB

3AB

4AB

5AB

6AB

10AB

10AB

2AB

22

Tree health

Salinity

Overall tree health (0 best – 5).Leaf necrosis (salinity), heat damage (0 best – 5)

2018

• No Pc detection• High pH• High CaCO3• E.C 1.74 dS/m• High Chloride (275 mg/L )

2018


New selections evaluated in Ramona Tom Royden and Kozy

Thanks Tom!!

0

5

10

15

20

25

30

Dusa

GD1

GD10

GD11

GD12

GD13

GD14 GD

3GD

4GD

6GD

7GD

8GD

9PP

89PP

90PP

91PP

92PP

93PP

94PP

95PP

96Th

omas

VC15

VC26

VC28

VC31

VC51 VC

6VC

7VC

804

2016 2017 2018

Fig. 68. Cumulative yield (Lb) per rootstock accession in Tom Royden #1 plot, Ramona.

Yield

(lb) p

er ro

otsto

ck

AB3

AB4

AB5

AB6

AB10

AB1

AB2

AB22


Tree health ratings (0 – 5) for both sites in July 2018 following the severe heat event. A score of 0 = healthy and vigorous and 5 = dead

Field Evaluation in Bonsall and Pine Tree_2017

Mary Lu ArpaiaCopyright ©2020 Patricia Manosalva (university of California, Riverside). All rights reserved

Heat/Salinity rating on a 0 – 5 scale for both sites in July 2018 following the severe heat event. A score of 0 = no apparent damage, 3 = moderate leaf damage and some shoot dieback, 5 = moderate to severe leaf damage throughout the tree with extensive shoot tip dieback.

Mary Lu Arpaia


Figure 6C. Bonsall Research Site. Average kg/tree yield for trees harvested on May 16, 2019.

0.0

0.4

0.8

1.2

1.6D

usa

Ste

ddo

mTo

ro C

anyo

nU

ziZe

ntm

yer

PP3

5P

P40

PP4

2P

P45

PP5

0P

P51

PP5

2P

P80

GD

3G

D4

GD

5G

D6

GD

10

GD

11

GD

19

GD

20

R10

6R

O.0

5R

O.0

6R

O.1

5R

O.1

7R

O.1

8R

O.5

4V

C80

2V

C80

4

Average yield per tree (kg/tree)

First harvest at Bonsall (May 2019)

Kg/tree

Mary Lu ArpaiaCopyright ©2020 Patricia Manosalva (university of California, Riverside). All rights reserved

October 2017

Pine Tree, Santa Paula Krnich Plot, Fallbrook

Mary Lu Arpaia


Field Evaluation of PP40,PP35, PP42, PP45, PP80


A

B

0.005.00

10.0015.0020.0025.0030.0035.0040.0045.00

DusaPP18

PP21

ThomasPP22

PP40PP42

PP45PP56

PP58PP63

SA-1

Zutano seedlin

gs

Tree

hea

lth S

core

Perc

enta

ge (%

)

Tree Health and salt burn ratings at Gunderson April 2019

Tree mortality (%) at Gunderson April 2019

0

0.5

1

1.5

2

2.5

3

DusaPP18

PP21

ThomasPP22

PP40PP42

PP45PP56

PP58PP63

SA-1

Zutano seedlin

gs

Tree Health Salt burn

GUNDERSON (2019)* *

* = Significantly different than Dusa

* **

*



GUNDERSON (2019)

0

1

23

4

5

67

8

9

SA-1 KB1 PP58 Zutanosdlng

Thomas PP18 Dusa PP56 PP63 PP40 PP22 PP21 PP45 PP42

Num

ber o

f dea

d tre

es (n

=20) Tree Mortality (Gunderson)

2016 2017 2018

Fig. 58. Tree mortality per rootstock accession in Gunderson, Santa Paula.

0

20

40

60

80

100

120

140

SA-1 KB1PP58

Zutano sdlng

ThomasPP18

DusaPP56

PP63PP40

PP22PP21

PP45PP42

Gunderson

2016 2017 2018 2019

Yiel

d (lb

) per

root

stoc

k





Jim Brown 1 (2019)

0.00

20.00

40.00

60.00

80.00

100.00

ThomasDusa

VC804PP40

PP42PP45

PP35PP80 CTP

NTP

A

B

Tree

hea

lth Sc

ore

Perc

enta

ge (%

)

Tree health and salt burn ratings at Jim Brown 1 March 2019

Tree mortality (%) at Jim Brown 1 March 2019

0

0.5

1

1.5

2

2.5

3

3.5

Thomas Dusa VC804 PP40 PP42 PP45 PP35 PP80


*



Jim Brown 1 (2019)

0

2

4

6

8

10

12

PP80 CTP NTP PP35 PP42 PP45 PP40 VC804 Thomas DusaNum

ber o

f dea

d tr

ees (

n=13

)

Tree Mortality (Jim Brown 1)

2016 2017 2018

Fig. 65. Tree mortality per rootstock accession in Jim Brown #1 field plot,Temecula.

00.51

1.52

2.53

3.54

4.55

Heat

dam

age

Rootstock

Thomas

DusaVC804

PP40PP42

PP45PP35

PP80

AA AB

ABC

BC

ABC

C

AB

Fig. 66. Heat damage rated in July 2018 at Jim Brown ranch in Southern CA.Trees were score from 0 – 5: 0 = 0-10% heat damage, 1 = 11-20%, 2 =21– 40%,3= 41–60%, 4= 61-80%, and 5 = 81–100%. Statistical analyses were done usingANOVA and significantly differences among rootstocks were tested using HSDtest. Levels not connected by the same letter are significant different.



Jim Brown 1 (2019)

0

5

10

15

20

25

PP80 CTP NTP PP35 PP42 PP45 PP40 VC804 Thomas Dusa

2016 2017 2018Fig. 64. Cumulative yield (Lb) per rootstock accession in Jim Brown #1, Temecula.

Yiel

d (lb

) per

root

stoc

k





Jim Brown 2 (2019)

0.00

10.00

20.00

30.00

40.00

50.00

60.00

ThomasDusa

PP40PP70

PP71PP80

PP83PP84

PP86PP88

A

B

Tree

hea

lth Sc

ore

Perc

enta

ge (%

)

Tree health and salt burn ratings at Jim Brown 2 March 2019

Tree mortality (%) at Jim Brown 2 March 2019

00.5

11.5

22.5

33.5

ThomasDusa

PP40PP70

PP71PP80

PP83PP84

PP86PP88


* *


Field Evaluation of PP40,PP35, PP42, PP45, PP80 (old plots)Jim Brown 2 (2018)

0

1

2

3

4

5

6

7

8

PP71 PP88 Thomas PP70 PP86 PP83 PP84 Dusa PP40 PP80

Yiel

d (lb

) per

root

stoc

k


Dusa

PP35

Ventura 2019


RO.05 PP35

Pictures: Peggy Mauk, AgOPs UCR

RO.05 (South African Selection) and PP35 exhibited similar levels of salinity tolerance. PP35 is smaller than RO.05.


Dusa PP45

2019: Santa Paula (Ventura) under PRR, high pH, and high alkalinity as CaCO3 conditions


Dusa PP42

2019: Santa Paula (Ventura) under PRR, high pH, and high alkalinity as CaCO3 conditions


PP80Dusa

2019: Temecula plot under PRR, high salinity, high pH and high alkalinity as CaCO3 conditions

PP80: PRR resistant, salinity and heat tolerant


Semi-commercial trials with 5 most advanced UCR rootstocks (UCR and CAC)

Grower County Year Rootstocks Conditions

Leo McGuire Riverside 2019 PP35, PP40 PRR and high chloride levels

John Lamb Ventura 2019 PP35, PP40 PRR, high chloride and pH

MassodSohaili (Rick and CJ Shade)

Ventura 2020 PP35, PP40,PP45, PP42 (28), PP80 (39)

High PRR (replanting)

Andrew Gabryszak Riverside 2020 PP35, PP40, PP45 PRR and high chloride levels

Pete Miller Santa Barbara

2020 PP35, PP40,PP45, PP42 (28), PP80 (39)

High PRR, high chloride, high EC, clay soils.

Chris Sayer Ventura 2020 PP35, PP40, PP45 High salinity (EC) and high alkalinity

Dr. Lauren Garner (Cal Poly State University, SLO)

San LuisObispo

2020 PP35, PP40, PP45 Pending water analyses and PRR analyses

100 trees/rootstock Hass grafted


Field trials with 5 most advanced UCR rootstocksin other countries

https://news.ucr.edu/articles/2020/06/09/uc-riverside-and-eurosemillas-partner-bring-next-generation-avocados-market

0

5

10

15

20

25

30

35

40

Anita

Brandon

Duke 7

DusaEddie

RO.O6

Steddom Uzi

Zentmye

r

2019

2017

2016

2015

Scion yield by rootstocks

Mary Lu Arpaia

Trees planted 12 x 15 feet

Randomized Complete Block Design

Trees planted June 2012

Zentmyer, Steddom, Uzi, PP35, PP40, and PP45 grafted to

Hass, Carmen, GEM, Lamb, and Reed scions.

PP35

PP

45

Duke 7

Dus

aPP

40RO

.06St

eddo

m UziZe

ntm

yer

ab cd ab bc a abc ab cd d

There is no variety x rootstock interaction for tree size currently

Yiel

d (k

g)


10/01/2019

Laurel Wilt DiseaseAmbrosia beetle-Raffaelea lauricola60% avocado crop lost in FL

http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Agriculture-Industry/Pests-Diseases/Laurel-Wilt-Disease

AVOCADOS IN DANGER!!

DUSA IS SUSCEPTIBLE TO WHITE ROOT ROT

“WE NEED MORE VARIETIES, ROOTSTOCKS, AND SCION X ROOTSTOCK COMBINATIONS FOR A COMPETITIVE AND SUSTAINABLE AVOCADO INDUSTRY”

AcknowledgementsManosalva Lab (UCR) Natasha Jackson (Ph.D Student)Dr. Rodger Belisle (former Ph.D Student)Aidan Shands (Ph.D Student)Dr. Nilwalla Abeysakara (Asst Spec)Brandon McKee (Research Assistant)Angela Buelhman (Undergraduate)Valentina Valencia (Undergraduate)

Pathogen Biology and Genomics James Adaskaveg (UCR)Bruce Schaffer (University of Florida) Liliana Cano (University of Florida)Sylvia Fernandez Pavia (U San Nicolas de Hidalgo)Noelani Van den Berg – University of Pretoria (SA)

California Avocado Society (CAS) Our grower cooperators Brokaw Nursery

Avocado Breeding and GenomicsMary Lu Arpaia – UCR Peggy Mauk – UCRBen Faber – UC ANRDavid Kunh- USDA-ARS FloridaBarbara Freeman-USDA-ARS FloridaAureliano Bombarely - University of Milan (Italy)Noelani Van den Berg – University of Petroria (SA)Antonio Matas -Universidad de Malaga (Spain)

UC MEXUS-CONACYT

Pest and beneficial

UCR CNAS Delfino funds

UCR Avocado Rootstock Program Update: Towards Developing ... · In 2006 and 2010 USA was the top 2...

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