Seed orchards are the next major phase of the breeding program and we are actively pursuing locations that could support the seed orchards. A seed orchard is the required next step in producing trees for reforestation in CT that have 50% of their DNA from persisting native CT American Chestnut trees that flowered, allowing pollination and collection of nuts. This DNA reflects the native gene pool that is associated with CT’s soils, light periodicity, disease resistance, rainfall patterns, temperature extremes, etc. These factors differ throughout the native chestnut range in the US and even within CT itself. Capturing this diversity is the goal of the CT program, and seed orchards are our organizational focus, and the primary use of our volunteer efforts.
In a seed orchard we plant 3000 nuts representing crosses between the twenty lines of trees we pollinated and grew in our backcross orchards. We monitor them for resistance and remove the trees until only those very resistant and American chestnut looking trees remain. These trees are 15/16ths “American” in character, morphologically indistinguishable from native American chestnut trees. The key difference is that the resistance to the blight has been bred into them from the Chinese chestnut. Those few trees (twenty) remaining will intercross and produce seed that is expected to grow trees with high resistance to the chestnut blight and the ability to breed true to resistance.
Following the TACF plan. we need to find and establish up to nine seed orchards in Connecticut over the next three years. Seed orchards can be as little as one acre and likely not larger than two. The soils should be chestnut appropriate, the conditions superb for growing trees, the site should be accessible and available to fence. The key requirement is that the orchard land should have either a long-term (30-45 years) easement for growing or be under permanent conservation. Orchards typically need minimal care – similar to our backcross orchards and would be expected to provide the same benefits to the landowner our backcross orchards provide.
Land Trusts would be the ideal arrangement since the land, access, and purpose is traditionally already established. Three of our current eight back-cross orchards have Land Trust ties.
Further Reading to Assess Expectations
Interested parties should contact Bill Adamsen for more details.