By Bill Adamsen
Member CT Chapter TACF
The purpose of this report is to present the Connecticut Chapter of the American Chestnut Foundation® summary of breeding orchard success following close of 2012. The Connecticut Chapter currently operates seven orchards widely distributed across Connecticut in which we planted almost four thousand trees. We planted our first back-cross orchards in April of 2006 in the Towns of Woodbridge and Salem. We added at least one new orchard each year through 2010. The majority of trees in those seven orchards are about 92% American and balance Chinese, with the latter representing the opportunity to provide resistance to the Chestnut blight. This successful effort represents a huge milestone for a volunteer-run organization!
(Click table see larger version) shows the total number of trees we’ve grown in our back-cross orchards since those first planting. These include control trees such as pure or open-pollinated American chestnut, in addition to F1 hybrids and pure Chinese chestnuts. The overwhelming majority of trees planted are back-cross American chestnut with predominantly genes of CT origin. The chart shows summary values for the number of trees planted and surviving, as well as values for height and diameter breast height (dbh) for known values. Not all of the orchards have reported values for dbh and height for 2012.
Table 1. CT Program Overview – table of total plantings
(Click table see larger version) details the various types of trees planted in the research orchards and summarizes that data. As mentioned, those types include F1 (Chinese/American hybrid), American chestnut (either of known type or open pollinated) and also pure Chinese chestnut. These non-backcross types are planted to serve as controls for resistance inoculation. In inoculation, trees of a sufficient size are inoculated with a blight inoculum of known virulence. The trees inoculated represent a continuum of expected resistance to the blight from strong – Chinese, F1 Hybrid, Back-cross, and American – to weak. By inoculating at the same time, this range of resistance facilitates evaluating which of the back-cross trees are most resistant, and to what degree. Table 2 shows the different types planted in each orchard, by year and then summarizes by type, year and also orchard. Table 2. CT Program Summary – Summary table of total plantings
(Click table see larger version) details the back-cross lines planted in TACF® CT Orchards. Any resistant trees available for future planting would be bred from progeny of our back-cross orchards. The goal of the TACF® regional diversity program is to plant twenty lines – each line representing the capturing of genes of a local validated American chestnut through pollination of a local mother tree. Since some of the lines were split – planted in two orchards – one must be careful not to double count lines. The records show that we have 24 lines planted, but only seventeen of those are complete … requiring additional pollinations with pollen from the same lines of resistance. Always more work to do!
Table 3. CT Back-cross Trees – table of back-cross plantings
Should you have questions about the program, or have an interest in getting involved, please contact TACF® Regional Science Coordinator Kendra Gurney to start a conversation. And of course we always look forward to meeting new supporters and participants who are interested in returning Chestnut to a position of ecological importance in the forests of CT.