Author
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Hammerschlag, Freddi |
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GARCES, SANDRA - PONTIFICA UNIV ECUADOR |
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KOCH-DEAN, MARGERY - VOLCANI CENTER ISRAEL |
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Ray, Stephanie |
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Lewers, Kimberly |
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MAAS, JOHN - RETIRED ARS |
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Smith, Barbara |
Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/16/2005 Publication Date: 5/4/2006 Citation: Hammerschlag, F.A., Garces, S., Koch-Dean, M.K., Ray, S.A., Lewers, K.S., Maas, J.L., Smith, B.J. 2006. In vitro response of strawberry cultivars and somaclones to colletotrichum acutatum. Plant Cell Tissue And Organ Culture. 84:255-261. Interpretive Summary: A major constraint to strawberry production is the loss caused by diseases, and one of the most serious diseases of strawberry worldwide is anthracnose caused by the fungal species Colletotrichum acutatum. Tissue-culture-induced (somaclonal) variation provides us with a strategy for generating disease resistant genotypes. As part of a program to generate strawberry germplasm resistant to anthracnose, a tissue culture (in vitro) screening system to evaluate resistance to C. acutatum was used to evaluate several commercial strawberry cultivars, Chandler, Delmarvel, Honeoye, Latestar, Pelican and Sweet Charlie, and shoots regenerated from leaves of these cultivars. The amount of infection observed on the cultivars in vitro was similar to that reported for their response under field conditions. Tissue-culture induced variants (somaclones) with significantly higher levels of resistance were identified for all the cultivars. Somaclones of commercially important, anthracnose susceptible cultivar Chandler exhibited from 1.6- to 6.2-fold increases in anthracnose resistance. The highest levels of anthracnose resistance (2 to 6 % leaf necrosis) were exhibited by somaclones of cultivars Pelican and Sweet Charlie. These studies suggest that generating somaclonal variation may be a viable approach to obtaining strawberry plants with increased levels of anthracnose resistance, and thus, this approach should be of value to strawberry breeders and scientists interested in alternative methods for strawberry improvement. Technical Abstract: Diseases affecting strawberry (Fragaria x ananassa Duch.) have been of major concern in recent years because of their widespread occurrence and potential for yield loss. Anthracnose, caused by the fungus Colletotrichum acutatum, is one of the most serious diseases of strawberry worldwide. Tissue-culture induced (somaclonal) variation provides one strategy for generating disease resistant genotypes. As part of a program to generate strawberry germplasm resistant to anthracnose, an in vitro screening system was used to evaluate several commercial cultivars, Chandler, Delmarvel, Honeoye, Latestar, Pelican and Sweet Charlie, and shoots regenerated from leaf explants of these cultivars for resistance to C. acutatum Goff (highly virulent). Somaclones with increased levels of resistance were identified for all the cultivars. The greatest increases in disease resistance were observed for somaclones of cultivars Pelican and Chandler that exhibited 17.5- and 6.2-fold increases in resistance, respectively. The highest levels of anthracnose resistance (2 to 6 % leaf necrosis) were exhibited by somaclones of cultivars Pelican and Sweet Charlie. These studies suggest that generating somaclonal variation may be a viable approach to obtaining strawberry plants with increased levels of anthracnose resistance. |