Tennessee News

An Update On Our Ongoing Work at the Tennessee Tech TACF Backcross Orchard

The orchard was planted in 2005 using the direct seed method.  And as you remember, we inoculated all of the trees in the orchard in 2010 as part of the blight-resistance screening.  We evaluated blight cankers and rated the trees on their American morphological traits in 2010 and 2011.  There are three different family lines in the orchard, and we made some preliminary selections in each of the families and began making intercrosses between them in 2011 and 2012. The 2011 F2s were planted in a seed orchard design in Knox County in April of this year.  The 2012 crop is growing in containers in the nursery at UTC.  This is a very exciting result!

I would like to make another round of selections this year and begin to rogue the orchard.  The plan is to mark the selected individuals with flagging and remove all of the other trees.  We can cut the trees to be removed at their bases and spray the cut stumps with glyphosate to kill them.  If we had access to a back-hoe, we could dig up the stumps.  One advantage to physically removing stumps is that it may help to shorten the time to re-plant.

I am excited about the opportunity to continue the relationship between TACF and Tennessee Tech.  I would like to work with you on a proposal to convert the backcross orchard into a seed orchard where we can plant the F2 progenies of the Tennessee Chapter backcross selections.

Hill Craddock

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The 2024 Tennessee Chapter Pollination Workshop was held on June 8 to great success, bringing together 22 enthusiastic volunteers for a day of hands-on learning at the Tennessee Tech Orchard. Established in 2005 using the direct seed planting method, the TTU backcross orchard includes a row of robust, blight resistant F1 hybrids, resulting from a 2004 cross between a naturally occurring Clay County, TN American chestnut, and the Chinese cultivar ‘Gideon.’ These F1s (originally planted as controls in the 2005 backcross orchard), in addition to their blight resistance, exhibit promising resistance to Phytophthora cinnamomi (causal agent of the phytophthora root rot disease, PRR), which has been validated through progeny tests and PRR-screening (Perkins et al., 2019). They were chosen to be the female parents this year in crosses designed to move PRR resistance into the best selections of the southern TACF chapters.

During the 2024 workshop, participants heard a short lecture from Dr. Craddock on the pollination biology of Castanea species and saw an active demonstration of emasculation and bagging of chestnut flowers. They learned about the importance of proper labelling and the labelling conventions of the TACF chapter breeders. They were then engaged directly in hand the pollination techniques used to create hybrid chestnut trees using pollen provided by colleagues in the Georgia, Carolinas, and Alabama chapters ladders and bucket lifts to access the crowns of the trees, successfully performing hundreds of pollinations.
The workshop's outcome was exceptional. The volunteers completed 27 distinct crosses. Fruit set was excellent despite the late summer drought. The burs were harvested in September yielding 2,553 hand pollinated seeds! These efforts advance the TACF breeding program's goal of stacking resistance to both Phytophthora cinnamomi and Cryphonectria parasitica, ensuring future generations of resilient chestnut trees well adapted to conditions here in the South. Volunteers left with hands-on experience, new knowledge, and a sense of accomplishment, with many eager to apply their skills in their own orchards.

Perkins, M.T., Robinson, A.C., Cipollini, M, and Craddock, J.H.. (2019) Identifying host resistance to Phytophthora cinnamomi in hybrid progeny of Castanea dentata and Castanea mollissima. HortScience 54(2): 221-225. doi.org/10.21273/HORTSCI13657-18
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The 2024 Tennessee Chapter Pollination Workshop was held on June 8 to great success, bringing together 22 enthusiastic volunteers for a day of hands-on learning at the Tennessee Tech Orchard. Established in 2005 using the direct seed planting method, the TTU backcross orchard includes a row of robust, blight resistant F1 hybrids, resulting from a 2004 cross between a naturally occurring Clay County, TN American chestnut, and the Chinese cultivar ‘Gideon.’ These F1s (originally planted as controls in the 2005 backcross orchard), in addition to their blight resistance, exhibit promising resistance to Phytophthora cinnamomi (causal agent of the phytophthora root rot disease, PRR), which has been validated through progeny tests and PRR-screening (Perkins et al., 2019). They were chosen to be the female parents this year in crosses designed to move PRR resistance into the best selections of the southern TACF chapters.

During the 2024 workshop, participants heard a short lecture from Dr. Craddock on the pollination biology of Castanea species and saw an active demonstration of emasculation and bagging of chestnut flowers. They learned about the importance of proper labelling and the labelling conventions of the TACF chapter breeders. They were then engaged directly in hand the pollination techniques used to create hybrid chestnut trees using pollen provided by colleagues in the Georgia, Carolinas, and Alabama chapters ladders and bucket lifts to access the crowns of the trees, successfully performing hundreds of pollinations.
The workshops outcome was exceptional. The volunteers completed 27 distinct crosses. Fruit set was excellent despite the late summer drought. The burs were harvested in September yielding 2,553 hand pollinated seeds! These efforts advance the TACF breeding programs goal of stacking resistance to both Phytophthora cinnamomi and Cryphonectria parasitica, ensuring future generations of resilient chestnut trees well adapted to conditions here in the South. Volunteers left with hands-on experience, new knowledge, and a sense of accomplishment, with many eager to apply their skills in their own orchards.

Perkins, M.T., Robinson, A.C., Cipollini, M, and Craddock, J.H.. (2019) Identifying host resistance to Phytophthora cinnamomi in hybrid progeny of Castanea dentata and Castanea mollissima.  HortScience 54(2): 221-225. https://doi.org/10.21273/HORTSCI13657-18Image attachmentImage attachment+1Image attachment

Join us TODAY, Friday, August 16, 2024, from 11:30AM – 1:00PM (ET), for the next LIVE Chestnut Chat.

Special guests Tony D’Amato and Tim Stout will discuss the role of the American chestnut in forest management strategies that address the impacts of climate change and invasive insects and pathogens on eastern forests. Tony will provide an overview of the frameworks and approaches under evaluation and Tim will bring it to a landowner scale by discussing the strategies being tested and applied on his farm in Shrewsbury, Vermont.

To sign up, visit tacf.org/event/chestnut-chat-adaptive-silviculture-for-climate-change/
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Join us for Chestnut Chat's 50th Episode Spectacular next Friday, July 19th at 11:30AM ET.

Click the link to learn more about or sign up for this webinar. tacf.org/event/chestnut-chat-50th-episode-spectacular/
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