Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia
American chestnut (Castanea dentata) was once a cultural, ecological, and economic staple of hardwood forests of the Eastern United States; however, chestnut blight caused by Cryphonectria parasitica has severely threatened its significance. The American Chestnut Foundation (TACF) is a non-profit or...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2017-04-01
|
| Series: | Global Ecology and Conservation |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2351989416301408 |
| _version_ | 1831739243336040448 |
|---|---|
| author | Martin Cipollini N. Royce Dingley Patrick Felch Chandler Maddox |
| author_facet | Martin Cipollini N. Royce Dingley Patrick Felch Chandler Maddox |
| author_sort | Martin Cipollini |
| collection | DOAJ |
| description | American chestnut (Castanea dentata) was once a cultural, ecological, and economic staple of hardwood forests of the Eastern United States; however, chestnut blight caused by Cryphonectria parasitica has severely threatened its significance. The American Chestnut Foundation (TACF) is a non-profit organization that has focused on backcross breeding as a means of restoring C. dentata to the wild. A major goal of this breeding program has been to introduce blight resistance from Chinese chestnut [Castanea mollissima ] while recovering “American chestnut” morphology by backcrossing with C. dentata. The Berry College backcross orchard, in northwest Georgia, was the first such orchard established by TACF with the goal of producing advanced hybrids derived from crosses with wild C. dentata from Georgia (part of TACF’s state chapter program). In 2008, three lines of third backcross (BC3) hybrids were planted at the orchard along with F1, C. mollissima, and C. dentata controls. The theoretical model for the backcross breeding program predicts intermediate blight resistance, at best, in BC3 trees, along with an otherwise American chestnut morphology. This paper focuses on the degree to which this combination of desired traits has been found among the first lines of BC3 trees generated in Georgia. Trees were inoculated with blight in May 2013 (at age 4–5 yrs), and blight resistance was evaluated in October 2013 and March 2014 and used to calculate an average blight-susceptibility index (BSI). In September 2013, branch samples were collected and used to evaluate 20 leaf, stem, and bud traits known to differ consistently between C. mollissima and C. dentata. The average of standardized scores for morphological traits was used as an index of species identity (ISI) for each tree. On average, BC3 lines showed significant morphological differences when compared with Chinese chestnut lines, nesting morphologically with American chestnuts. Each BC3 line contained some trees with both intermediate blight resistance and morphological traits similar to C. dentata, supporting the prediction that both sets of traits have been advanced using the backcross methodology. These results are discussed in relationship to currently evolving understanding of the genetics of blight resistance and with respect to other traits needed for successful restoration in the southern United States. |
| first_indexed | 2024-12-21T13:35:29Z |
| format | Article |
| id | doaj.art-bb7b4cb0fdc5422ab038658424f3dc58 |
| institution | Directory Open Access Journal |
| issn | 2351-9894 |
| language | English |
| last_indexed | 2024-12-21T13:35:29Z |
| publishDate | 2017-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Global Ecology and Conservation |
| spelling | doaj.art-bb7b4cb0fdc5422ab038658424f3dc582022-12-21T19:02:10ZengElsevierGlobal Ecology and Conservation2351-98942017-04-0110C1810.1016/j.gecco.2017.01.004Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in GeorgiaMartin Cipollini0N. Royce Dingley1Patrick Felch2Chandler Maddox3Berry College, Department of Biology, Mount Berry, GA 30149, United StatesUnited State Peace Corps, Nueva Guinea, NicaraguaUnited States Peace Corps, Okongwe, Erongo, NamibiaInstitute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA 30602, United StatesAmerican chestnut (Castanea dentata) was once a cultural, ecological, and economic staple of hardwood forests of the Eastern United States; however, chestnut blight caused by Cryphonectria parasitica has severely threatened its significance. The American Chestnut Foundation (TACF) is a non-profit organization that has focused on backcross breeding as a means of restoring C. dentata to the wild. A major goal of this breeding program has been to introduce blight resistance from Chinese chestnut [Castanea mollissima ] while recovering “American chestnut” morphology by backcrossing with C. dentata. The Berry College backcross orchard, in northwest Georgia, was the first such orchard established by TACF with the goal of producing advanced hybrids derived from crosses with wild C. dentata from Georgia (part of TACF’s state chapter program). In 2008, three lines of third backcross (BC3) hybrids were planted at the orchard along with F1, C. mollissima, and C. dentata controls. The theoretical model for the backcross breeding program predicts intermediate blight resistance, at best, in BC3 trees, along with an otherwise American chestnut morphology. This paper focuses on the degree to which this combination of desired traits has been found among the first lines of BC3 trees generated in Georgia. Trees were inoculated with blight in May 2013 (at age 4–5 yrs), and blight resistance was evaluated in October 2013 and March 2014 and used to calculate an average blight-susceptibility index (BSI). In September 2013, branch samples were collected and used to evaluate 20 leaf, stem, and bud traits known to differ consistently between C. mollissima and C. dentata. The average of standardized scores for morphological traits was used as an index of species identity (ISI) for each tree. On average, BC3 lines showed significant morphological differences when compared with Chinese chestnut lines, nesting morphologically with American chestnuts. Each BC3 line contained some trees with both intermediate blight resistance and morphological traits similar to C. dentata, supporting the prediction that both sets of traits have been advanced using the backcross methodology. These results are discussed in relationship to currently evolving understanding of the genetics of blight resistance and with respect to other traits needed for successful restoration in the southern United States.http://www.sciencedirect.com/science/article/pii/S2351989416301408Castanea dentataCastanea mollissimaSpecies restorationBreedingDisease resistanceGenetics |
| spellingShingle | Martin Cipollini N. Royce Dingley Patrick Felch Chandler Maddox Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia Global Ecology and Conservation Castanea dentata Castanea mollissima Species restoration Breeding Disease resistance Genetics |
| title | Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia |
| title_full | Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia |
| title_fullStr | Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia |
| title_full_unstemmed | Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia |
| title_short | Evaluation of phenotypic traits and blight-resistance in an American chestnut backcross orchard in Georgia |
| title_sort | evaluation of phenotypic traits and blight resistance in an american chestnut backcross orchard in georgia |
| topic | Castanea dentata Castanea mollissima Species restoration Breeding Disease resistance Genetics |
| url | http://www.sciencedirect.com/science/article/pii/S2351989416301408 |
| work_keys_str_mv | AT martincipollini evaluationofphenotypictraitsandblightresistanceinanamericanchestnutbackcrossorchardingeorgia AT nroycedingley evaluationofphenotypictraitsandblightresistanceinanamericanchestnutbackcrossorchardingeorgia AT patrickfelch evaluationofphenotypictraitsandblightresistanceinanamericanchestnutbackcrossorchardingeorgia AT chandlermaddox evaluationofphenotypictraitsandblightresistanceinanamericanchestnutbackcrossorchardingeorgia |