Improved Varieties of Pawpaws for Virginia — a new fruit crop well-suited to organic agriculture

• Virginia Association for Biological Farming, 14th Annual Conference, Feb. 8-9, 2013

PAWPAW

A NEW TREE CROP

FOR THE EAST

• R. Neal Peterson – The PawPaw Foundation

WHAT

IS A

PAWPAW

?

The Pawpaw Is

• Asimina triloba – Annonaceae (custard apple family)

• North America’s largest native edible fruit

• Native to 26 states in the East, Midwest & South

• Not a papaya – Brits often call papaya ‘paw paw’

• A delicious and nutritious fruit – lots of personality

• Popular once upon a time – many places named for it

• Nowadays very little known by Americans

• Recently domesticated with superior cultivars

• Is becoming a new fruit crop

Botany: belongs to the Annonaceae family

cousin to the cherimoya and the guanabana

which are popular fruits throughout the tropics

Native Range – Eaten by the Indians

and white settlers, too,

who named towns

and creeks after it,

… and they even sang

a song about them

“Way Down Yonder in

the Paw Paw Patch”

The Paw Paw Bends of the Potomac River

Food Qualities

• Unusual tropical flavor for a temperate fruit.

Tastes similar to cherimoya and guanabana.

Like a combination of banana, mango, pear, pineapple.

Not hard – a soft texture, custardy, avocado-like.

• Possesses great nutritional value (better than apple).

• High in calories (similar to banana).

High in minerals – K, Ca, Fe, Cu, Zn, Mn, Mg.

Protein level about 2% – high for a fruit.

A very good balance of the essential amino acids.

• High in antioxidants

ORCHARD INFO

Cultural Requirements

• Humid temperate climate, zones 5-7

• Moderately acid soils, pH 5.5 – 7.0

• Full sun for optimal yields

• Well-drained soils – no hard pan

• Ideally deep fertile soil with good organic matter

• Freedom from competing vegetation

Orchard Layout

• Flexible spacing

• 10 ft centers (approx)

• 18-22 ft row widths

• Machinery dictates width

• North-south rows (usually)

• Windy sites a problem

• Wind breaks and barriers

Fertilization

• Similar to other fruit trees

• N important in early years

• Roughly 50 lbs of N/acre

• Extra K during harvest years

• Foliar tests for micronutrients

• Requirements probably higher for S and Mg

• Necessary on ALL but

the most favorable sites

• Not necessary in normal

rainfall growing season

• Vital in drought (obvious)

Irrigation

Pruning

• Minimal

• Central leader

• Control height

No Ladders. Pick from

the ground level only

• Open access on sides

• Maintain shade for fruit

Orchard Floor

• Weed control is essential Mulching and cultivation for organic farming.

There are no herbicides listed for pawpaw.

In practice we find that Surflan is well

tolerated. Weed control a must.

• Clean floor management Clean up windfalls after harvest.

Old fruit harbors fungus attacking skin.

Old fruit can be used for seed to be sold to seed companies or as biomass for acetogenins.

• Pawpaw root suckers Control by mowing and pruning

Insect Pests

• Zebra Swallowtail Butterfly Larvae feed on young leaves, cause

slight damage, not an economic pest

• Japanese Beetles Problem only some years, younger leaves

• Pawpaw Peduncle Borer Larvae consume inner flower parts

and burrow down stem. The adult is

small (5-7 mm). Native w/ predators.

• Pawpaw Leaf Roller Webs, rolls & eats leaves in late summer

• Fruit damage extremely rare

Fruit Pests —

Fungal & Physical

• Various fungi involved

• All superficial

• Do not penetrate flesh

• Can cause fruit cracking

• Fruit cracking / cultural Caused by a long dry spell followed by plentiful rain

• Sun scald a problem But shade protects the fruit

the terraced

rice paddies of

southern Appalachia

are often lined or

intercropped with

pawpaws

Well, after global warming!

very compatible

for intercropping

HARVEST INFO

Flowering &

Pollination

• Flowers are perfect

male & female parts in each

• Fly & beetle pollinated

• Usually not self fertile

• Two or more cultivars required for pollination

Fruit Thinning

• Some cultivars overbear. Allegheny you must thin

• Thin to maintain size and fleshiness.

• Thin out weak clusters.

Within a strong cluster, thin to 1, 2 or 3 fruits.

• A few cultivars tend to 1 or 2 fruits per cluster and require little thinning. Shenandoah for example

Yields at Maturity

300 trees/acre, ~ 30 lbs/tree, ~ 4 tons/acre

The Harvest Season

• Ripening season in Virginia is roughly Aug.25 - Oct.1

• Length of picking from each tree is about 12-20 days

• Length varies by cultivar, some shorter, some longer.

• Cultivars are either early, middle, or late. Those with

the best fruit quality are middle and late.

Harvest Issues

Subtle unreliable color breaks

Each tree ripens over 2-3 weeks

• Fragile and perishable

• Picked largely by feel

• Daily picking advised

• Labor intensive

Packing

& Storing

• Refrigeration required

• 33º to 35ºF optimal

• Fruits packed in single layer flats with proper cushioning

• Picked a few days under ripe, fruit can be stored about 21 days and then still finish ripening properly at room temperature

CULTIVAR INFO

Overview

• Too many inferior cultivars are advertised that never should have been named and propagated

• Low quality ones are ‘Wilson’, ‘Wells’, ‘Mitchell’ … many others. They are not worth buying. One cannot trust catalog descriptions.

• Best of the old ones are

‘Overleese’

‘Sunflower’

‘NC-1’

‘Pennsylvania Golden’ (for earliness)

My Breeding Program

• Started in 1981. Ended about 1998.

• 2 orchards at the University of

Maryland experiment stations

• Orchards were planted 2 years apart

• Each orchard was roughly 750 trees

• Trees were O.P. seedlings from five

historic collections, circa 1926-1950

• Best collection turned out to be the

Blandy Experimental Farm, in VA

Breeding (continued)

• Seedlings took about 7 years to fruit.

• Being trees, evaluation over multiple

years is necessary. Ten years maybe?

But do I have time? I went for 3 years.

• None of the trees that looked best in

year-1 were in the top by year-3.

• Selected top 9 trees from each orchard.

• Worked with 10 universities to conduct

a RVT evaluation of pawpaw – this had

never been done – my 18 advanced

selections plus 10 known cultivars.

Pawpaw Regional Variety Trial

Preview – Best of the new

• Peterson Pawpaws ‘Wabash’, ‘Shenandoah’, ‘Allegheny’, ‘Susquehanna’,

‘Potomac’, #10-35, and others (‘Rappahannock’ not consistent however)

• Kentucky State University ‘KSU Atwood” and several selections under observation

• Possibly ‘Mango’ ‘Green River Belle’ ‘Shawnee Trail’

Shenandoah

• Good yields

• Sweet mild flavor

• Fleshy - S:F ratio 6%

• Succulent, custardy texture

• Most popular at DC farmers

market

• Responds well to pruning

TM

Susquehanna

• Very fleshy - S:F ratio 3%

• Very sweet, rich flavor

• Firm, buttery texture

• Fruit size very large

• Moderate yields

• Responds well to pruning

TM

Sources of Peterson Pawpaws

• Nolin River Nut Nursery (KY)

• Forrest Keeling Nursery (MO)

• One Green World (OR)

• Heritage Seedlings (OR)

• Edible Landscaping Nursery (VA)

• Don Shadow Nursery (TN)

• I Have A Handout On These Nurseries With Contact Info

MARKET INFO

Approaches to marketing pawpaws

• Absolutely vital for the commercial grower

• Pawpaws are unknown to 98% of US consumers

• Education is basic to gaining a customer following

• At this time best outlets are farmers markets – urban or at the farm itself

• Restaurants are another possibility (w/ problems)

• Some processed products have real potential

Pricing

• Must be high to cover harvest costs

• In San Francisco they sell for $5/lb and they aren’t even named varieties

• When I sold in DC for 3 years at the Dupont Circle Farmers Market, I sold my named varieties for $5/lb

• In smaller town farmers markets, price about $3/lb

Consumer Education

• Consumer education is a must in order to sell this new fruit.

• Samples! Few people know pawpaw, are fearful, hesitate to buy.

• Also, information sheets and recipes

Market Outlets …………….……

Farmers markets, gourmet restaurants, etc

Mechanized Processing ? Very important to extend the market season.

Makes excellent ice cream. Processing not yet realized.

ORGANIZATIONS

• The PawPaw Foundation – since 1988

Public outreach, education, stimulation of interest & research

• Ohio Pawpaw Growers Association – new in 2008

Production & marketing issues, is now national in scope

• Kentucky State University – since 1992

Only full time research program – Dr. Kirk Pomper

• Ohio Pawpaw Festival – since 1998

Held annually near Athens, OH

KSU Research Dr. Kirk Pomper

• Germ plasm repository

• DNA analysis

• Regional variety trials

• Seed propagation

• Root stock trials

• Acetogenin analysis

• Cultivar breeding

• Species hybrids

Primary Research Needs

• Efficient mechanical processing methods

• Cultivars with thicker skins, less perishable

• Breeding for reliable color break

• Identify superior root stock

• Tissue culture propagation

• Acetogenins as possible anti-cancer compound

• Acetogenins as possible health risk (Parkinsonism)

Primary development needs

• More growers to meet demand

• Mail order fruit from one orchard is sent nationwide

• A few wineries need source of fruit

• Creameries making ice cream need pulp

• People in DC and elsewhere are calling to ask what

market carries the fruit

We Need Growers – Contact Me

• The End