Sources of TACF Blight Resistance
Sources of TACF Blight Resistance
Some Information on 'Clapper', 'Graves', and 'Nanking'
provided by Sara Fern Fitzsimmons at TACF
The Clapper Tree. This is a BC1 ([C x A] x A) tree named after R.B. Clapper of the USDA Bureau of Plant Industry and was from a test planting in the Crab Orchard Wildlife Refuge, Carterville, Illinois (Burnham et al., 1986, p. 378). It was a good forest type tree, and although it eventually died from blight, grafted progeny are still living at the Lockwood Farm of the Connecticut Agricultural Experiment Station. Clapper is partially inbred, since the same American tree (Forest Pathology 555 at Glendale, MD) was used in both the initial cross and the backcross. Its Chinese parent is listed as PI 34517, M16 tree, Bell, MD, collected in Tientsin, China, in 1912. This Chinese parent is no longer available, as far as we know. The full pedigree of the Clapper Tree is ([PI 34517 x FP 555] x FP 555). McKay and Jaynes describe its origin and characteristics as follows:
[The Clapper Tree] was the outstanding planting of nearly 2,000 planted in 15 cooperative test plantings. The Clapper variety averaged 2.6 feet of height growth the first 17 years and the trunk was 7.3 inches in diameter 4.5 feet from the ground. (McKay and Jaynes, Chestnuts, Chapter 19 in R.A. Jaynes, ed., Handbook of North American Nut Trees, North Nut Growers Association, 1969).
The Graves Tree. This is a BC1 ([C x A] x A) tree named after Arthur Graves of the Connecticut Agricultural Experiment Station (CAES). The full pedigree of Graves is ([Mahogany Chinese x FP 551] x Bowman Tree, Clinton Corner, NY). FP 551, like the FP 555 parent of the Clapper Tree, was a wild American chestnut tree growing near the Glendale, MD, USDA breeding station. The Graves tree is located at the CAES SGSP West Red Pine Lot R13T1. Its F1 parent was also at the CAES -- SLotR2T8. Graves is from cross 37-53 made in 1953 and was selected from 9 nuts. The Mahogany Chinese grandparent of Graves is available and was used as the parent of a genetic mapping population at the Meadowview Farm.
Nanking Chinese. Fred Hebard chose Nanking as the most highly resistant graft-propagated Chinese cultivar based on previous work by Gary Griffin (VA Tech) and his students, as well as by Hebard’s own studies (Hebard et al., 1984, Phytopathology 74:140). According to Jaynes:
Nanking, perhaps the most widely planted of all Chinese chestnut cultivars, originated from seed collected by Peter Liu at Hang Chow, China, and [was] imported in 1935. . . After propagation and testing [as Seedling No. 7930] Nanking was named and released by the USDA in 1949. Nanking is second only to Crane in precocity, grafted trees frequently bearing nuts in their second year. The tree bears heavy crops annually. The Chinese cultivar Kuling, also released by the USDA in 1949, was from the same seed lot. (Chestnuts, Chapter 9 in R. Jaynes, ed., Nut Tree Culture in North America, Northern Nut Growers Assoc., 1979)
Sara Fern Fitzsimmons
Northern Appalachian Regional Science Coordinator
The American Chestnut Foundation
The Pennsylvania State University
206 Forest Resources Lab
University Park, PA 16802
e-mail: sara@acf.org
phone (office): 814-863-7192
phone (cell): 814-404-6013
fax: 814-863-3600