Pawpaw Trees Production Potential

Name and Title:
Patrick O’Malley, Field Specialist Commercial Horticulture, Southeast

Fiscal Year Submitted:
2010

POW Number & Title:
130 Horticulture: Commercial and Consumer

Title:
Pawpaw Trees Production Potential

Issue: 
Many new or existing growers are looking for alternative crops that require minimal inputs.  The pawpaw (Asimina triloba) is the largest tree fruit native to the United States and grows wild in 25 states, including Iowa.  In full sun they grow to about 15’ high and 8’ in width.  In shaded areas they may be taller, but more narrow in spread.  This sweet dessert fruit tastes somewhat like a very sweet creamy banana.  They range in size from a few ounces up to 19 ounces in size.  The fruit primarily ripens in September.

Response: 
Background research on pawpaws was conducted to determine any possible potential for growing them as a commercial crop in the upper Midwest.  Contacts were made with Kentucky State University (KSU) and the Pawpaw Foundation (PF) to learn more about pawpaws and to secure access to both grafted named cultivars and elite germplasm lines.  A replicated trial consisting of 300 total trees and 28 different cultivars or breeding lines were planted in 1999 in Louisa County, IA.  Partners with ISU Extension include: The fore mentioned KSU and PF, Louisa County Conservation, Northwoods Nursery, Red Fern Farm (Iowa), Columbus Junction High School (planting), Trees Forever, Iowans for a Better Future, and the Leopold Center.

Results:
Trees first fruited in 2004.  Trial results indicated that pawpaw fruit can be grown in the upper Midwest and certain accessions were shown to have better potential for production. Some impressive performers in the trial include “Pennsylvania Golden,” an existing cultivar that ripens early and had the largest number of fruit, but each fruit was relatively small (about 6 ounces). A recently released cultivar “Shenandoah”, features midseason ripening, large fruit (many over 10 ounces), and low seed count. A later ripening cultivar recently released as “Susquehanna” bore large fruit (above 10 ounces) and had low seed count. It appears at least 10 years of growth are needed for trees to achieve full production of fruit.  Yields are still being determined but it looks like each tree could produce in excess of 20 pounds of fruit. In general, it appears growth rates and potential yield north of HWY 30 will be less than the more optimum conditions south of HWY 30.

Pawpaw that is unrefrigerated has a shelf life of just a few days, and refrigerated pawpaw will last about two weeks. The biggest hurdle for commercialization is devising a way to handle the processing to produce pulp. Currently the only way to separate the pulp from the seeds and skin is by hand which is uneconomical on a large commercial scale.  I have just begun a new project working with Lester Wilson, ISU Food Scientist on a possible mechanical method for pulp separation.  This project is sponsored in part by a grant from the Leopold Center.

Pawpaw

2010

130 Horticulture: Commercial and Consumer

 

Page last updated: May 5, 2010
Page maintained by Linda Schultz, lschultz@iastate.edu