Project Overview
Information Products
Commodities
- Fruits: mulberry
Practices
- Crop Production: agroforestry, forest farming, forest/woodlot management, grafting
- Education and Training: demonstration, networking, participatory research
- Natural Resources/Environment: afforestation, habitat enhancement
Summary:
Our native red mulberry, Morus rubra—a fruit-producing tree with delicious, nutritious, complex-flavored fruit, high production potential, innate pest/disease resistance, and rapidly growing commercial and home production interest—is slowly fading from its native range due to the rapid spread of the invasive Morus alba. Morus alba was imported in the 1600s and planted by the millions across the eastern seaboard in a failed attempt to create a domestic silk industry. Trees quickly escaped from these orchards and have since naturalized across the country. These invasive trees release large amounts of wind-dispersed pollen that readily pollinate the native trees, producing hybrid offspring that are steadily and irrevocably replacing pure Morus rubra.
In order to address this slow-motion extinction by hybrid replacement, we propose to find, propagate, and establish preserves and breeding orchards of high-quality, fruit-producing Morus rubra specimens with commercial potential. By holding a national mulberry Search and Rescue Contest, we plan to crowdsource the best Morus rubra trees growing wild, in orchards, and nursery rows across the country. Entries will be genetically tested, rated for potential as commercial cultivars, and the winning trees named and made available to farmers, nurseries, researchers, and fruit enthusiasts throughout the North Central region.
Through this project we created a Morus rubra identification guide and helped the public to identify and share samples from mulberry trees suspected of being pure Morus rubra. We received over 100 fresh leaf samples from around the country. Samples were sent to the Ohio University Genomics Facility where they were frozen and then the DNA extracted. Samples were then used to begin constructing a Morus rubra genome by researchers at the Los Alamos National Laboratory (this process is ongoing due to the complexity of the genome). This information was then cross-referenced with the existing Morus alba genome and each individual sample was analyzed and results compiled. Because of the complexity of the project and the lack of an existing complete rubra genome, the results are not necessarily indicative of complete purity of species, but do show with a high degree of accuracy whether a sample is rubra, alba, or a hybrid, as well a good inidcation of the degree of possible hybridization. Results for instance indicate that Illinois Everbearing, a popular mulberry considered a hybrid, has mostly rubra characteristics but does contain a trace of alba. For the results of the study, we classified specimens by the closest obvious fit and marked those with mainly rubra characteristics as "Rubra" and those with obvious high alba influence as "Hybrids". A closer look at the numbers, however, can tell us the degree of hybridization of each specimen.
While imperfect, the results do indicate that many pure or nearly pure rubra trees do still exist in different regions across the country, and while further analysis will be needed to determine complete purity, we are moving in the right direction and have found specimens with good fruit production that can be considered native and are definitely worth growing as food producing trees.
Project objectives:
- Hold a contest to find productive Morus rubra specimens with commercial potential and perform genetic testing of advertised "Morus rubra" cultivars (often mislabeled Morus alba trees that have red fruit) to establish verified native sources.
- Name and release several new Morus rubra cultivars suitable for orchard production.
- Propagate and establish a preserve and breeding orchard in order to provide verified native mulberry plant material to nurseries, farmers, conservation workers, researchers, and landowners throughout the North Central region.
- Promote the value, usefulness, and profitability of growing native mulberry trees through field days, website and social media promotions, and a scholarly journal.