Frequency of hypersensitive-like reaction and stem infections in a large full-sib family of Pinus monticola
| Authors: | Robert S. Danchok, R.A. Sniezko, S. Long, A. Kegley, D. Savin, J.B. Mayo, J.J. Liu, J. Hill |
| Year: | 2012 |
| Type: | General Technical Report |
| Station: | Pacific Southwest Research Station |
| Source: | In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech. coords. Proceedings of the fourth international workshop on the genetics of host-parasite interactions in forestry: Disease and insect resistance in forest trees. Gen. Tech. Rep. PSW-GTR-240. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp. 281-285 |
Abstract
Western white pine (WWP) (Pinus monticola Douglas ex D. Don) is a long-lived forest tree species with a large native range in western North America. The tree species is highly susceptible to the non-native fungal pathogen, Cronartium ribicola, the causative agent of white pine blister rust (WPBR).
Several types of genetic resistance to WPBR are present in WWP, of which the best documented is a hypersensitive-like reaction (HR) in the needles that conveys complete resistance (generally no stem infection) and is conditioned by a single dominant gene (Cr2). The HR resistance is rare, and its occurrence is geographically limited (Kinloch et al. 1999, 2003). Virulence to Cr2 in the rust (vcr2) is known (Kinloch et al. 2004). Most screening trials examine relatively few seedlings for any one family for HR. We report on the frequency of HR (using needle phenotypes) in a large full-sib family (3,592 individuals) in a cross between two putative Cr2 heterozygotes (this is part of a larger genetic study to map Cr2); the frequency of stem symptoms and mortality in HR and non-HR seedlings; and the number of stem symptoms per seedling for HR and non-HR phenotypes.