Rebuilt HTML — PaddleOCR-VL (Baidu)

Introduction: What is Pawpaw?

Pawpaw: Asimina triloba (L.) Dunal.

Native tree fruit in the southeastern U.S.

Tropical-like flavor

mixture of banana, mango, and pineapple.

Early stages of commercial production.

Pawpaw Flowering and Harvest

Flower on 1 year old wood

Cross-pollinate

Pollinated by flies and beetles

Ripe fruit should yield when squeezed and give way with a gentle tug

Color change not a reliable indicator of ripeness

Fruit may be harvested from the same tree over several weeks

Pawpaw Pests

Organic production possible?

Some Past Problems

Japanese beetles

Zebra swallowtail butterfly-not necessarily a pest

Talponia plummeriana - pawpaw peduncle borer

New Pawpaw Diseases and Pests?

Leaf and fruit spot (Phyllosticta)

New Pawpaw Diseases and Pests?

Asian Ambrosia Beetle Xylosandrus crassiusculus

The Kentucky State University Pawpaw Research Program

Program Leaders: Brett Callaway (1990-1993), Desmond Layne (1994-1997), and Kirk Pomper (1998-Present)

USDA National Clonal Germplasm Repository for Pawpaw (1994)

The orchards at KSU contain more than 2000 accessions sampled from native stands from 17 different states in the papaw's native range.

Pomper et al., 2003. J. Amer. Soc. Hort. Sci. 128:521-525.

Pawpaw Regional Variety Trial

Collections

Neal Peterson and Dr. Harry Swartz began collecting pawpaw germplasm in 1981

They assembled a germplasm collection of about 1500 accessions

Open pollinated seedlings from the historic collections of Buckman, Zimmerman, Hershey, Allard, the Blandy Experimental Farm, Ray Schlaanstine, and some modern cultivars

Some Desirable Pawpaw Tree characteristics

Small tree size, easier harvest

Precocious bearing, 4 years or less

Vigorous growth with low to medium inputs

Open branching with strong crotch angles

High flower density

High fruit set under natural pollination

Consistently high fruit yields

Cold hardiness and drought tolerance

Some Desirable Pawpaw Fruit Characteristics

Some Desirable Characteristics FRUITFULNESS over 40 fruit per tree FLAVOR sweet, firm texture, delicate blend of flavors, rich but not cloying, no bitter aftertaste FLESHINESS visually: mostly flesh. By weight: less than 5% of the fruit is seed FRUIT SIZE over 10 ounces

SEEDS

over 45 seeds per oz., av. seeds as small as 3/4" (2 cm) long APPEARANCE bright clear colors, no brown mottling (ripe); even, symmetrical PECULIARITIES SKIN: waxy/ fuzzy/ thick and hard/ yellow/ bluish. FLESH (ripe): white/ pink/ red. SEEDS: in a single row. RIPENING TIME: early / late KEEPING ABILITY: 2+ in refriger.

PEARLY bright clear colors, no brown mottling (ripe); even, symmetrical PECULIARITIES

Materials and methods

28 selections, 10 named varieties, 224 total grafted trees on PPF seedling rootstock (half-sib seed)

■ Spacing 2 m (6.5 ft) between trees, 5.5 m (18 ft) between rows

Princeton, KY (1995) and Frankfort, KY (1998)

Commercially Available Cultivars

Seedlings of Commercially Available Cultivars

Seedlings from Collections

BEF = Blandy Experimental Farm Collection, Boyce Va.

GAZ = George A. Zimmerman Collection., Linglestown, Pa.

RS = Ray Schlaanstine Collection, West Chester, Pa.

Fruit Production on Mature Trees 2004-2006 in Frankfort

Clone	Average fruit weight (g)	Average number of fruit per tree
3-11	137 efgh	68 ef
7-90	135 fghi	74 def
1-23	126 ghij	90 cde
11-13	124 hij	75 def
Taytwo	121 hijk	73 def
2-54	121 hijk	73 def
3-21	115 ijkl	60 fghi
Mitchell	112 jkl	58 fghi
PA-Golden	108 jklm	118 ab
Taylor	106 jklm	68 efg
Wells	104 klm	64 fgh
9-47	100 lm	74 def
Rappahannock
Wilson
Middletown

What cultivars should I plant?

NC-1

Fruit weight: 167 g

Number of fruit/tree: 36

Good flavor

Available from many commercial nurseries

NC-1

Overleese

Fruit weight: 157 g

Number of fruit/tree: 40

Good flavor (melon)

Available from many commercial nurseries

Sunflower

Fruit weight: 165 g

Number of fruit/tree: 63

Mild flavor

Available from many commercial nurseries

Sunflower

Potomac

Fruit weight: 244 g

Number of fruit/tree: 31

Good flavor

Fruit cracking?

Peterson Pawpaws Limited availability

Potomac

Shenandoah

Fruit weight: 157 g

Number of fruit/tree: 61

Mild flavor

Peterson Pawpaws

Limited availability

Wabash

Fruit weight: 183 g

Number of fruit/tree: 51

Dark flesh

Cracking issues

Peterson Pawpaws

Limited availability

Wabash

Pawpaw RVT Overview

There is great variation in fruit size, yield, and quality among the pawpaw selections examined

About 4 to 5 years to come into production

A number of pawpaw selections in the trial show promise for production in Kentucky [Potomac, Wabash, Overleese, Shenandoah, NC-1, and Sunflower] can be recommended.

Rootstock and Training System Trial

Pawpaw Propagation and the Nursery Industry

High tree prices are limiting development of an industry

Seedlings $5-$10

Grafted trees $15-$30

Our goal is to identify seedling rootstocks that would enhance scion growth, improve tree establishment, and promote precocity.

Pawpaw Training and Pruning

Tend to form narrow-angled weak branches at the trunk.

Therefore, pawpaws are prone to wind damage.

A central leader training system would develop a strong framework and a desirable form for harvesting.

Will pruning dwarf a young tree and delay bearing in pawpaw?

Will fruit suffer sunburn?

Objective

To determine if cultivar, rootstock, and training method would influence early flower bud production in pawpaw

Materials and Methods

The rootstock trial was planted on May 10, 2004.

Rootstocks: 5 seedling rootstocks

Scions: 'Sunflower' and 'Susquehanna'

Two pruning systems: minimal pruning versus central leader

8 replicate blocks with each treatment combination for a total of 160 trees (2 x 5 x 2 x 8 = 160).

Why Did We Choose These Selections?

Scions:

Sunflower

Noted to flower and produce fruit in 4^{th} year in Princeton, KY trial.

Susquehanna'

Slow to flower and to come into production.

Seedling rootstocks:

Cultivars vigorous: Sunflower and PA-Golden

Cultivars lack vigor: Susquehanna and K8-2

Commercial mixed seed: RVT

Studies with seedlings in containers

Seed size and genetic background important

2008 Growing Season

Scion Percent of Trees Number of

Flowering Survival TCA Flower Density Clusters

Susquehanna 94% 68% 14.3 1.6 3.7

Sunflower 100% 82% 14.3 6.0 7.0

P-value 0.04* 0.06 NS 0.64 NS 0.0000*** 0.011*

Rootstock Percent of Trees Number of

Flowering Survival TCA Flower Density Clusters

RVT 96% 77% a 13.8 3.8 4.1

Sunflower 96% 90% a 14.0 4.2 5.6

PA-Golden 100% 84% a 15.7 4.1 6.3

K8-2 95% 73% a 14.0 3.5 3.4

Susquehanna 100% 52% b 13.7 4.7 7.1

P-value 0.63 NS 0.005** 0.32 NS 0.13 NS 0.2041 ns

2008 Growing Season

No evidence of sun scald on fruit

Rootstock and Training System Conclusions

Genetic background of seedling rootstock did not influence scion precocity or growth.

Survival of Susquehanna seedling rootstock was poor.

Sunflower was more precocious than Susquehanna.

Central leader training tended to reduce vigor (TCA) and the number of flowers/tree.

KENTUCKY STATE UNIVERSITY

pawpaw.kysu

Welcome

Personnel

Growing Information

Recipes and Uses

Reports and Presentations

Other KSU Information and Links

Calendar of Events

FAQ and Contact Information

KSU Home Page

Photograph of pawpaw flower taken on May 5, 2009. Photo by Jeremy Lowe.

pawpaw.kysu provides information on how to grow and use fruit from the North American pawpaw tree.

Over 200,000 visitors since 2003!

Google™ Custom Search Search Site

Pawpaws Gain Standing as Kentucky Crop (6/28/09)

Pomper and Crabtree win Shepard Award for Pawpaw Research (6/18/09)

From Novel Fruits (pawpaw), a Lush Landscape in NY Times (5/20/09)

Pawpaw article in Northern Nut Growers Association Nutshell Newsletter (5/13/09)

Summaries of recent KSU pawpaw research projects (5/06/09)

KSU Student wins award for pawpaw research project (see page 7) (5/06/09)