Maine Breeding Program
Breeding Program Update for 2009
By Eric Evans, VP and Science Coordinator
This spring we will be making the final planting of third-backcross chestnut trees, thereby completing our goal of planting and growing 20 lines for each of the two sources of blight resistance, called Clapper and Graves. One of these lines will be 25 seeds that Glen Rea collected from his manual pollination of the Alford tree in October last fall. This was his fourth round of competition with squirrels at that tree, and will bring the total for that line already in Harold Mosher’s orchard in Hope up to about 50 trees. Glen is also tending seedlings for two new Graves lines at his house, which we will plant into a new orchard, not yet chosen. These are from trees in Albion and South Bristol that Charlie Hudson, Austin Jones, and Welles Thurber pollinated and harvested in 2008. With these three new lines we will be meeting our original goal of 40 lines of third-backcross hybrid chestnuts for our chapter’s share of TACF’s breeding program, and ensures a high level of genetic diversity in the eventual blight-resistant trees that we produce in the coming decades.
In June of 2007 we inoculated 210 nine-year-old chestnut trees representing four third backcross lines in our Merryspring (Camden) and Groce (Union) breeding orchards with live lab-grown fungus, to test their resistance to Asian chestnut blight. TACF Pathologist Fred Hebard completed the rating of the blight cankers last October. We selected three trees from each of the four lines to save for further breeding –– based both on small canker size and on good American chestnut form, then ME chapter volunteers cut down the losers and piled them for burning. The saved trees will probably outgrow their blight infections, and will be crossed with each other for several years, starting this July, to produce BC3-F2 seeds (first intercrosses of selected third-backcross trees). We will plant the seeds from those crosses –– and similar crosses in the ten other breeding orchards in Maine –– in new “seed orchards”, and some of those new trees will be fully blight-resistant. Preliminary results from Virginia and the Pennsylvania Chapter have verified this hypothesis. We expect to start harvesting fully blight-resistant American chestnuts in Maine about 8-10 years from now.
In June of last year TACF New England Regional Coordinator Kendra Gurney led another team of volunteers in our second “trial by blight”, inoculating four lines of 6-year-old Graves-resistance trees in Clark Granger’s Deer Hill orchard in Weeks Mills (China). Fred and Kendra will do the final ratings and selections of these trees in June, just in time for us to cull the losers before pollination time in July. Then we should be able to collect BC3-F2 seeds from these crosses in October, as in Merryspring, to plant into our new seed orchards in next spring.
Breeding Program Update for 2008
by Eric Evans, VP and Science Coordinator
Here is my best guess for timetable of progress toward blight-resistant Maine-adapted American chestnuts:
* Make third-back-cross seed(BC3) by pollinating ME-natives with BC2 pollen from Meadowview – 1997-2007
* Plant third-back-cross trees in breeding orchards – 1999-2008
* Inoculate BC3 trees to test for blight-resistance – 2007-2015
* Select BC3 trees from test for blight-resistance – 2008-2016
* Cross selected BC3 trees with each other to make first-intercross generation, BC3-F2 – 2009-2020.
* Plant BC3-F2 seeds in “seed orchards” – 2010-2021
* Inoculate BC3-F2 seedlings, then select for full blight-resistance – 2012-2023
* Select and cull –– 2013-2024
* With open pollination, begin BC3-F3 seed production from seed orchards, expected to breed true for full blight-resistance – 2019-2020.
* Formal testing, systematic forest plantings –– 2020-2035
*Limited distribution &/or sale to members –– 2020
That’s Easy to Say!......
In the 10-year history of the Maine Chapter we have been working primarily on the first two items of the time-line shown above. But as we move into the next and final phases of the breeding program, our work demands will increase several-fold. How will we manage and accomplish that? The obvious answer is that we need to double or triple our membership and our lists of committed and enthusiastic volunteers. So, we are asking everyone reading this to picture a future with thriving American chestnuts regaining their place in Maine’s forests. Then fill out and return the volunteer membership form so that we know how and when to call on you to help with this exciting work. If you are already on our volunteer list, please pass this on to a friend with whom you want to share this work.
For starters, here is a description of the major jobs for the coming year. Exact dates depend on Mother Nature. If you send in a volunteer form, you can simply refer to the following letters:
A.In Merryspring orchard in Camden, Groce orchard in Union, and Deer Hill orchard in Weeks Mills, prep trees for open pollination: 15-20 people one day in June.
B.Inoculate 100+ trees in Deer Hill orchard in Weeks Mills, China (that’s in Maine!) with live fungus to test for blight resistance: 15 people one day in June.
C.Routine tree care and measurements in 11 breeding orchards in Monmouth, Camden, Hope, Union, Unity, China, Lovell, Veazie, Morrill, and Bradley: 4-6 people one day in June and October in each location.
D.Manually pollinate several native American chestnut trees: teams of 2-3 people one or two half-days in July in each location to be announced.
E.At the Common Ground Country Fair (MOFGA, Unity) at our booth, spread the word to fair-goers about the return of American chestnuts: 18 people in 3-hour shifts, September 19-21.
F.Harvest BC3-F2 seeds in Merryspring, Groce, and Deer Hill orchards: 15-20 people one half day in October.
G.Publicity committee chair: one person to take responsibility for press releases, media articles, presentation coordination, etc.
H.Volunteer coordinator: one or two people to maintain volunteer lists and assist work team leaders in staffing work parties
I.Other publicity and education-related activities year-round: volunteer-coordination, chapter annual meeting production in October, regional meetings, presentations at fairs and club meetings, chestnut growing and demonstrations for school groups, upgrade slide shows and booth displays, etc.
