California Avocado Varieties: Past, Present and …...B. O. Bergh oversaw an active program from the 1950’s through 1994. Based on industry input he set out to develop a “green-skinned”

California Avocado Varieties:Past, Present and Future (?)

Mary Lu Arpaia, Eric Focht, Rodrigo Iturrieta

The UC Riverside team working to develop new varieties and understand avocado genetics

Eric Focht Rodrigo Iturrieta

Mary Lu Arpaia

The past and current challengesdo we need additional varieties?

Mary Lu ArpaiaBotany and Plant Sciences, UCR

The industry has been dominated by 2 varieties over the last 100 years

Fuerte (1920 – 1970’s)Hass (1970’s – present)

FUERTE

Popenoe, CAS, 1919

Brought from Atlixco, Mexico in 1911

Alejandro Le Blanc

• The leading variety from 1920’s to 1970’s

• Adapted to a wide variety of climates, especially cold

• Known for high fruit quality (Winter-Spring)

• Large spreading tree• Recognized to have erratic

or severe alternate bearing

FUERTE

The rise of Hass

It took a long time

Facts about Hass Chance find in La Habra Heights in 1926 and

patented in 1935 High fruit quality when harvested at proper

maturity Considered interesting but black skin

considered a flaw as compared to leading variety Fuerte

Did not overtake Fuerte in importance until the planting boom of the mid-1970’s

Now worldwide leading variety and major variety marketed in US

Rudolph and Elizabeth Hass

Other varieties….

Pinkerton, Reed, Zutano, Bacon, Sharwil etc….

The contributions of

B. O. Bergh

B. O. Bergh oversaw an active program from the 1950’s through 1994.

Based on industry input he set out to develop a “green-skinned” Hass. This resulted in the release of ‘Gwen’ in 1984.

In a second wave, ~60,000 seedlings, primarily derived from ‘Gwen’, ‘Whitsell’, ‘Hass’ and ‘Pinkerton’, were planted.

This effort yielded ‘Lamb Hass’, ‘Sir Prize’, ‘Harvest’, and ‘GEM’.

B.O. Bergh

GWEN Late 1960’s – early 70’s seedling from the UC, Riverside breeding programPatented 1984Most successful commercial release

from its 1980s cohort (Esther, Whitsell)Specifically bred to be a green-skinned

‘Hass’ Slightly smaller tree than Hass, slightly

less alternate bearing, very similar season and appearance other than color

Griswold on Hass, 1945:“Its single disadvantage is its black color which has been associated in the minds of the public with poor quality fruits.”

Bergh & Martin on Gwen, 1988:“A second drawback of the green Gwen skin is that 80% of our production is now the black Hass, and so black is the standard and preferred in most of our markets.”

GWEN

The progeny of

Gwen….

Released - 1996

Released - 2003

Differences between Hass and Lamb Hass Lamb Hass maturity season – mid to late summer

NOT A SUBSTITUTE BUT SUPPLEMENT TO HASS Fruit shape and size – more “square” but larger Lamb Hass has more upright growth habit Flexible wood – fruit borne interior of tree; tends to set fruit in

clusters Lamb Hass is more “tolerant” to Persea mite and other pests (?) Photosynthetic rate approximately 30% higher than Hass and

higher chlorophyll content

Hass Lamb Hass

Growth habit differences between Hass and Lamb Hass

Differences between Hass and GEM Maturity seasons overlap; GEM slightly later - COULD BE A

SUBSTITUTE TO HASS Can accumulate very high levels of dry matter Fruit shape – more “tear drop” GEM growth habit more vaselike and compact Flexible wood – interior fruiting; tends to set fruit in clusters Pest tolerance (?) Less Alternate Bearing Tends to be more productive under most conditions

Gem is a more compact tree than Hass, very similar to GwenBears fruit on the inside of the tree

Comparing Hass, GEM and Lamb HassUC South Coast, Irvine 1999 - 2005

0

50

100

150

200

250

300

350

400

Hass Lamb Hass GEM

Yield (kg/tree)

2005

2004

2003

2002

2001

2000

1999

0 0.2 0.4 0.6 0.8 1

Hass

Lamb Hass

GEM Alternate Bearing Index

0 50 100 150 200 250 300

Hass

Lamb Hass

GEM

Average Fruit Size (g)

We had other varieties in these trials. In all trials the cumulative yield of Gem and Lamb Hass was typically higher than Hass. Alternate bearing was least in GEM at all sites.

We have noted that climate can greatly influence fruit shape (as in all varieties); in very hot climates GEM can be very elongated.

Anecdotal observations following 2007 Freeze was that GEM did best in return bloom

Canopy Volume by VarietyButler Trial, Ventura county

05

10152025

2013 2014 2016 2017 2019

CarmenGEMHassLamb HassReed

Dry weight changes compared to HassGEM

LAMB HASS

10

15

20

25

30

35

40

10/24 12/6 1/9 2/5 3/1 3/20 4/10 5/1 5/23 6/12 7/1 7/22 8/13

HassGEM

10

15

20

25

30

35

10/24 12/6 1/9 2/5 3/1 3/20 4/10 5/1 5/23 6/12 7/1 7/22 8/13

Hass Lamb Hass

Minimum dry weight for both varieties is 22.8%

Data from 2001, De Luz, CA

GEM Maturity Release Date Project

In year 2/32019 data by regionThe difference between the South and the North is similar to the 2018 – 2019 results. In both years, the South trends slightly higher as shown in the graph. The San Joaquin Valley is much earlier than the other 2 regions.

We are focusing on size 40 and 48.

15

20

25

30

35

28-Oct 28-Nov 28-Dec 28-Jan 28-Feb 28-Mar 28-Apr

North South San Joaquin Minimum

Maluma Hass (PBR)

Photo of fruit and tree by Edrean Ernst, Allesbeste Nursery, https://commons.wikimedia.org/w/index.php?curid=38351359

Maluma Hass• Originated in South Africa; currently grown in several countries, • Patented in the USA, 2010• Released from USDA-APHIS quarantine in CA, 2019

• Upright tree, growth similar to Lamb Hass• Slightly earlier than Hass• Minimum Dry Weight (SA) is 20%• Adaptable to high density, trellising• Appears to be higher yielding and more stress tolerant than Hass

Is there life beyond Hass (or Maluma, GEM, or anything else we may

release in the future)?

Or should we be content with what we

currently have?

Tree size and structure Bearing habit Alternate bearing Stress tolerance (Cold, Heat, Salinity) Disease and pest tolerance Productivity Seasonality

It is dangerous to have an industry based on one variety

Our leading cultivar, ‘Hass’ CAN BE improved:

From a grower perspective we need to go from

Here

There

Production Efficiency Stress Tolerance

Finding new varieties……

How difficult is it?

The challenge of finding new avocado varieties

• Long process – 15 to 25 years from seed to commercialization

• “Looking for a needle in a haystack” –success is low

• Finding both the horticultural and fruit traits in a single selection is challenging

• Defining what traits are the most important

The challenge of finding new avocado varieties

• Long seasonality• Fruit must be ripened in order to

evaluate; ripening time depends on maturity

• Eating quality changes throughout the season; it takes a lot of work to find optimum maturity window for selection

• Industry standard ‘Hass’ sets a high standard for postharvest and eating quality

Program Goal is to develop new varieties that:• Expand environmental adaptability• Enhance yield potential• Minimize grower inputs• Deliver consistent high-quality fruit• Grow consumer demand

Breeding objectives:• Precocious and low AB varieties with high fruit

quality• Upright, slender tree architecture for HD

plantings• High fruit quality and postharvest shelf life

Enhanced productivity and production efficiency

Satisfied consumers and increased consumption

THE ULTIMATE GOAL

The FutureIs it just one endless bowl of guacamole?

We hope so but… We need to enhance industryviabilityWe need to offer increasingly sophisticated consumers CHOICE

What we will soon releaseaimed at addressing needs of industry

Eric FochtBotany and Plant Sciences, UCR

UC, Riverside and Eurosemillashave entered into a partnership to sponsor the variety and rootstock programs

For the variety program we anticipate the release of 4 new varieties within the next 2 years.

THE BIG PICTUREHave a range of both dark skin and green skin varieties that are comparable to ‘Hass’ in terms of eating qualityWe HAVE material that potentially can

• Provide 12-month market coverage• Improved tree architecture• Precocious• Greater yield efficiency

UCR-03 UCR-02 HASS UCR-04 UCR-01

Early Early Middle Middle Late

Breeding Information

Year seed collected

Year planted (Irvine)

Year selected to Tier 2 (Irvine)

Year planted to Tier 3 Selector(s)

UCR‐01 1999 2000 2004 2011 Stottlemyer, Focht, Arpaia



UCR‐04 1983 1986 (Camarillo, CA) 1991 2013

Martin, Bergh, Stottlemyer, Arpaia, Focht

UCR-01Late season

‘A’ flower typeRipens dark-green to black

Picture taken January 2019; pole is 1.5m

Planted 2011 in Irvine, CADusa rootstock

UCR‐01

Fruit from Irvine, CA

Fruit Characteristics

Projected Harvest Seasonz

Fruit ShapeRipe Peel Color

Peel Texture

Peel Thickness

PeelabilityRelative Seed Size

UCR‐01Late

Spring/SummerPear Black

Somewhat pebbly

MediumVery good to excellent

Medium

Hass Spring/Summer Pear Black PebblyMedium thick

Excellent Medium

Footnotes:zHarvest Season: Depends on where in California the variety is grown. What is provided is an estimate of the statewide harvesting window.

Tree Characteristics

Tree Growth

Tree ShapeFlower Type

Heat Tolerance

Cold Tolerance

Alternate Bearing

High Density Potentialz

Fruit Bearing

Production Potential

(w/ optimized spacing)y

UCR‐01Medium to Large

Upright A Unknown Unknown Consistent High InsideGreater than Hass

Hass Large Spreading AModerately sensitive

Moderately sensitive

Susceptible ModerateMostly outside

Footnotes:zHigh Density Potential includes adaptability to heavy pruning.yProduction Potential: Based on data from Irvine Tier 3 site and Tier 2 site. Data collected on a per tree basis and ultimate tree spacing not yet optimized. Production potential needs to be assessed further.

Postharvest and Eating Quality

Storage QualityzFlavor and Texture

Eating QualityyFruit Size (oz)x

Fruit Size (g)x

Pulp content (%)

Dry Matter Rangew

UCR‐01Limited, appears

promising

Rich, smooth,

yielding flesh

Very good to excellent

6.3 179 63.6 22‐24%

Hass

Excellent, 3 ‐ 4 weeks without Controlled Atmosphere

Nutty, rich, creamy


7.0 198 71.6 22‐38%

Footnotes:zStorage Quality: "Limited" is observational only.yBased on consumer tasting at UCR.xFruit Size & Pulp content %: Data is accumulation from all Tier 3 sites in combination with Tier 2 site in Irvine. Not optimized.wDry Matter: Data is accumulation from all Tier 3 sites in combination with Tier 2 site in Irvine and reflects values during expected harvest season across all site; not optimized.

UCR-02Early Season

‘A’ Flower TypeRipens Reddish Black to Black


Picture taken January 2019; pole is 1.5 m


UCR‐02




Peel Texture

Peel Thickness


UCR‐02 Winter/Spring PearReddish black to black

Rough Medium Excellent Small


Excellent Medium



Tree Growth


Heat Tolerance

Cold Tolerance

Alternate Bearing


Fruit Bearing



UCR‐02 Medium‐Large

Rangy somewhat upright, sprawling

A Unknown Unknown Moderately consistent Moderate Mostly

outsideGreater than

Hass








Fruit Size (g)x

Pulp content (%)

Dry Matter Rangew

UCR‐02 Limited, appears promising

Clean smooth taste, firm flesh for slicing

Very good to excellent 6.2 176 73.5 20‐25%

Hass


Nutty, rich, creamy


7.0 198 71.6 22‐38%




UCR-03Early Season

‘A’ Flower TypeRipens Dark Green to Reddish

Black


UCR‐03




Peel Texture

Peel Thickness


UCR‐03 Winter/Early Spring Round

Dark green to Reddish

Black

Somewhat pebbly Medium Very good to

excellent Medium


Excellent Medium



Tree Growth


Heat Tolerance

Cold Tolerance

Alternate Bearing


Fruit Bearing



UCR‐03 Medium‐Large

Weeping, mounding sprawling

A Unknown Unknown Consistent Moderate InsideSlightly

greater than Hass








Fruit Size (g)x

Pulp content (%)

Dry Matter Rangew

UCR‐03 Limited, appears promising Rich, smooth Very good to

excellent 4.1 116 70.7 19‐38%

Hass


Nutty, rich, creamy


7.0 198 71.6 22‐38%




UCR-04Mid to Late Season

‘B’ Flower TypeRipens Black

UCR‐04





Peel Texture

Peel Thickness


UCR‐04 Late Spring/Summer Pear Black Somewhat

pebbly Medium Excellent Medium


Excellent Medium



Tree Growth


Heat Tolerance

Cold Tolerance

Alternate Bearing


Fruit Bearing



UCR‐04 Small to medium

Weeping, upright B Somewhat

SensitiveSomewhat Sensitive Consistent High Inside

Equal to or slightly less than Hass








Fruit Size (g)x

Pulp content (%)

Dry Matter Rangew

UCR‐04

Some work, appears

comparable to Hass

Rich, smooth Very good to excellent 6.6 187 71.3 24‐34%

Hass


Nutty, rich, creamy


7.0 198 71.6 22‐38%


UCR‐03 UCR‐02 HASS UCR‐04 UCR‐01

Early Early Middle Middle Late

Enhanced productivity and production efficiency

Satisfied consumers and increased consumption

THE ULTIMATE GOAL

Selection Process

Fruit qualities ‐>Tree qualities

Therefore: diversity in tree architecture

Understanding tree growthto “design” the tree of the future

Rodrigo IturrietaBotany and Plant Sciences, UCR

What should be the ideal tree architecture for the future?

The exciting point is that we do have opportunities for selection of tree architecture in new varieties

‘LAMB HASS’‘HASS’ ‘REED’

WHAT SHOULD BE THE IDEAL TREE ARCHITECTURE OF THE FUTURE




LOWDENSITY

HIGHDENSITY



‘HASS’


• MANAGEMENT

• GENETICS

THE FUTURE WILL BEA COMBINATION OF:

‘HASS’ ‘HASS’



LATERALBRANCHING BIAS



SO WHAT IS THE POINT?

THAT THE GROWTHCHARACTERISTICS OF

SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE



SHOOTSINFLUENCE

TREESHAPE

‘CARMEN’‘HASS’

‘MALUMA’

GENETICS

GENOTYPES

GENOTYPES

ENVIRONMENT

PHENOTYPES

GENOTYPES

ENVIRONMENT

“HOW SHOOTS GROW”

GENOTYPES

HOW DO YOU “BROWSE” GENOTYPESFOR

PHENOTYPES OF INTEREST ?

GENOTYPES

• PRESERVE COLLECTIONS

• ESTABLISH AMAPPING POPULATION

BL516 (‘Marvel’) X GEM

SO WHAT NOW ?

“WHAT GROWTH HABITARE YOU LOOKING FOR”

THIS IS WHEN KNOWINGYOUR PHENOTYPE(S) OFINTEREST PLAYS A ROLE

Increasingrigidity

‘GEM’ as maternal parent‘BL516’ as maternal parent

Flexible

Somewhatflexible

Intermediate

Somewhatrigid

Rigid

14012010080604020

Increasingrigidity

Progeny members within category

‘CARMEN’‘HASS’

‘MALUMA’

‘HASS’


• MANAGEMENT

• GENETICS

THE FUTURE WILL BEA COMBINATION OF:

TRELLISING

PRELIMINARY DATA SHOW THATTRELLISING INCREASES

SHOOT VEGETATIVE COMPLEXITY :

MORE FLUSHES and MORE LATERALS

WHY DO YOU WANT COMPLEXITY?

HASS: 12 %MALUMA:10 %MALUMA TRELLIS:

22.5 %

2 FRUITS PER SHOOT

Pictures by Zander ErnstPictures by Zander Ernst

ORCHARD PROFILE

HD TRELLISING HD SELF‐STANDING


MANAGEMENT


MANAGEMENT

GENOTYPES (varieties)

MANAGEMENT

GENOTYPES (varieties)

YOUR INPUT IS EXTREMELY USEFULTO OUR BREEDING PROGRAM !

What traits do you think are most important in anavocado variety (pick 3)?

Documents

California Avocado Varieties: Past, Present and …...B. O. Bergh oversaw an active program from the 1950’s through 1994. Based on industry input he set out to develop a “green-skinned”