Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2002
Publication Date: 7/2/2002
Citation: Ballington, J.R., Shuman, J.L., Smith, B.J., Hokanson, S.C., Gimenez, G. 2002. Breeding strawberries (Fragaria x ananassa) for resistance to anthracnose caused by Colletotrichum acutatum. Acta Horticulturae. 567:89-92 Interpretive Summary: Anthracnose is a major disease of strawberries, especially in warm humid regions around the world. Most commercial cultivars are susceptible to this disease and few fungicides registered for use on strawberries will control it. Therefore cultivars are needed that are resistant to anthracnose. When anthracnose resistant F. x ananassa clones were crossed with susceptible clones, a highly variable percentage of seedlings with resistance to the petiole and runner phases of anthracnose were obtained. These results indicate that quantitative gene action not major gene action is responsible for resistance. Plant and fruit resistance do not seem to be correlated. Cultivar development will need to be an ongoing process as isolates and species of Colletotrichum in a region change. A comprehensive germplasm screening effort needs to be undertaken to identify clones with resistance to various species and races of Colletotrichum. These efforts should result in germplasm with well characterized resistance to each of the three Colletotrichum species and wide resistance to multiple isolates. The work will improve the ability of breeders to make predictive crosses and create the potential to pyramid resistance to multiple species. Subsequently, anthracnose resistant cultivars can be developed for all production regions.
Technical Abstract: In the United States, anthracnose fruit and crown rots of strawberry, incited by the fungal species Colletotrichum acutatum, C. fragariae, and C. gloeosporioides, were initially considered 'southeastern' diseases. These diseases are becoming significant problems in other strawberry production regions in the eastern United States. The rapid shift to the annual plasticulture production system in parts of the eastern U.S. is thought to play an integral part in the increased significance of anthracnose throughout North America. Breeding for genetic-based resistance to the disease is considered to be one of the primary means for reducing economic loses due to anthracnose outbreaks. Studies in the eastern U.S. indicate that resistance to strawberry anthracnose caused by Colletotrichum acutatum appears to be quantitative in nature. A greenhouse screening procedure has been effective in identifying resistant genotypes in seedling progenies, with over $32,000 resistant strawberry seedlings identified between 1998 and 1999.