The Tennessee Chapter of The American Chestnut Foundation held a very successful one-day pollination workshop on Saturday 10 June 2023 at the beautiful Chestnut Ridge Orchard in Middle Tennessee.
The workshop was a hands-on opportunity to learn and practice the techniques to make controlled crosses for the TACF breeding program. We had more than a dozen participants from Mississippi, North Carolina, and Tennessee come together for a day of chestnut breeding. We covered all the steps in the process from finding and identifying American chestnut trees, the basic biology of the genus Castanea, how to recognize the male and female flowers, emasculation and bagging, pollen collection and handling, labelling and record-keeping, and all the intimate details of hand pollination. More than 100 hand pollinations were made on two trees at the site. The pistillate parents (the moms) (TN-RC09-1-24 and TN-RC09-3-62) were chosen based on evidence of their resistance to chestnut blight. The pollen parents (the dads) (TN-TTU05-A30 and TN-TTU05-A34) were chosen based on their known ability to pass to their offspring resistance to phytophthora root rot disease (PRR). Our hope is that the results of Saturdays workshop will be hybrid trees that combine resistance to blight and PRR.
The Chestnut Ridge Orchard (also known as the Ruth Cochran Orchard) was planted in 2009 by chapter volunteers using the direct seed method. Additional plantings at the site were made using transplants in 2010. It originally included almost 500 trees of TACF backcross hybrids in the F1, B1, B2, B3, and B4 generations, all resulting from hand pollinations, Castanea dentata and C. mollissima (the experimental controls), and C. pumila, C. ozarkensis, C. alabamensis (the Chinquapins). In 2017 the hybrids were screened for blight resistance using Cryphonectria parasitica strains EP155 and SG2-3. The orchard was rogued in 2018, 2019, and 2022.
