Development of Organic Production Practices for Pawpaw on Selected Rootstocks

Development of Organic Production Practices for Pawpaw on Selected Rootstocks

Summary

Pawpaw is a unique native tree fruit that is resistant to many diseases and insect pests, making this crop attractive to organic farmers. However, little information concerning organic production of pawpaw is available. Pawpaw cultivars with excellent fruit quality are usually propagated commercially by grafting cultivar buds (scions) onto common seedling rootstock of diverse genetic origin. In regional variety trials, the pawpaw cultivars PA-Golden and Sunflower have produced fruit earlier than other cultivars. Rootstocks produced from open pollinated seed from these cultivars could promote early bearing of grafted scions (cultivars) and result in early fruit production for farmers. The goal of this project is to develop organic horticultural practices with selected pawpaw rootstocks in an effort to promote earlier bearing and consistent tree performance, and longer tree life for organic and limited resource farmers.

Objectives/Performance Targets

Objective 1. To determine the optimal application rate of organic nitrogen (fish emulsion) that enhances tree establishment, growth, early flowering, and fruit production in the orchard.

Objective 2. To determine if flame cultivation can be used effectively compared to glyphosate (RoundUp) application, for weed control to promote pawpaw tree establishment and growth in orchards.

Objective 3. To determine if seedling rootstocks derived from two pawpaw cultivars (‘PA-Golden’ and ‘Sunflower’) will enhance tree survival, growth, flowering, fruit set, and fruit size of four pawpaw cultivars (PA-Golden, Sunflower, Shenandoah, and K8-2) compared to rootstock produced from commercially available mixed seed. Plantings for this objective will be established at six sites in three states (KY, VA, and NC), including sites at KSU, UK, and four farms. All sites will serve as demonstration orchards in the future for pawpaw production for limited resource and organic farmers.

Accomplishments/Milestones

In 2003, all project participants were contacted and informed that the grant had been funded. The Research Assistant position to be hired by project funds was also advertised. Nursery containers, potting substrate, tags, and other research supplies were ordered for use in 2004. In September 2003, seed was collected from fruit of the pawpaw cultivars PA-Golden, Sunflower, and K8-2 for later production of seedling rootstocks. The seed was cleaned and stratified, and will be planted in containers in the greenhouse in February, 2004. Plans were initiated for onsite visits to each planting site in February or March, 2004 to layout orchard designs, collect soil samples, and take digital photographs of each site. A web site describing the project was constructed and can be found at: http://www.pawpaw.kysu.edu/sare.htm

Impacts and Contributions/Outcomes

The long-term economic viability of small family farmers, who currently rely heavily on tobacco in the southeastern United States, may be achieved by crop diversification. Pawpaw has great potential for farmers in this region as an alternative high-value fruit crop for processing and fresh market sales. Pawpaw fruit have a unique flavor and were sold in 2003 at the Farmer’s Market in Lexington, Kentucky, for $3.00 per pound. Little information concerning organic production of pawpaw is currently available. Development of organic production recommendations would allow growers to facilitate fruit production and assist in the development of pawpaw as a niche organic crop. Many pawpaw cultivars on seedling rootstock of diverse origin will not produce harvestable crops for 4 to 5 years after planting, this compared to apple where production can begin 3 years after planting. Development of organic orchard management methods and rootstocks which promote early pawpaw fruit production will allow farmers to adopt these economically viable, environmentally sound and socially responsible practices.

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