Author
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Hammerschlag, Freddi |
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Submitted to: HortScience
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/16/1999 Publication Date: 2/20/2000 Citation: Hammerschlag, F.A. 2000. Resistant responses of peach somaclone 122-1 to xanthomonas campestris pv. pruni and to pseudomonas syringae pv. syringae. Hortscience. 35:141-143 Interpretive Summary: A narrow germplasm base and long generation time have impeded progress in generating peach trees with high levels of disease resistance through conventional breeding. As an alternative approach for obtaining useful genetic variation is to generate somaclonal variants through tissue culture techniques. Previous studies have led to identifying somaclonal variants of peach with high levels of resistance to Xanthomonas campestris pv. pruni (bacterial spot), and other preliminary studies have identified peach variants with increased levels of resistance to Pseudomonas syringae pv. syringae (bacterial canker). This study examines the response of 1) peach somaclone 122-1 to several strains of X. campestris pv. pruni, 2) progeny of somaclone 1221 to X. campestris pv. pruni strain XP1, and 3) somaclone 122-1 to P. syringae pv. syringae over time and following propagation. These studies demonstrate that somaclone 122-1 is a source of bacterial spot resistant germplasm for breeding and a potential source of bacterial canker resistant germplasm. This study should be of interest to peach breeders interested in generating bacterial spot resistant cultivars and other fruit crop breeders interested in alternative approaches to generating disease resistant germplasm. Technical Abstract: A detached-leaf bioassay was used to evaluate peach [Prunus persica (L.) Batsch] somaclone 122-1 (derived from callus produced on an immature embryo of peach cultivar Redhaven) for resistance to several virulent strains of Xanthomonas campestris pv. pruni [E.F. Sm.) Dows] causal agent of bacterial leaf spot, progeny of 122-1 for resistance to X. campestris pv. pruni virulent strain XP1, and 122-1 for resistance to a virulent isolate of Pseudomonas syringae pv. syringae causal agent of bacterial canker. Somaclone 122-1 was significantly more resistant to all strains of X. campestris pv. pruni compared to Redhaven'. All progeny of 122-1 exhibited high levels of resistance to X. campestris pv. pruni strain XP1. Somaclone 122-1 exhibited significantly higher levels of resistance to Pseudomonas syringae pv. syringae compared to Redhaven' and this resistance was retained over time in the greenhouse and following a 2-year cycle of tissue culture propagation. |
