INTERNATIONAL MOVEMENTS OF STRAWBERRY GERMPLASM: VIROLOGICAL ASPECTS
Fragaria chiloensis, a plant native to North and South American, has been used frequently for breeding of commercial strawberry (Fragaria × ananassa). Recent attempts to find sources of disease and pest resistance and stress tolerance has resulted in efforts to broaden the genetic diversity of strawberry. An extensive collection of wild Fragaria accessions was made in Chile in 1990. All collected clonal accessions are maintained in the germplasm repository at Corvallis, Oregon and currently are being grown for a 2 year pos-entry quarantine, during which they will be evaluated for horticultural characteristics and inspected for possible disease symptoms. While fungal and bacterial diseases express symptoms on infected Fragaria, virus diseases are usually symptomless but may cause obscure symptoms easily confused with nutritional deficiencies. Thus, such plants are symptomless carriers of viruses that are spread with vegetatively propagated plant material or that could be vectored by insects, mites, nematodes, fungi of through seeds. Multiple virus infections are very common and may cause a drastic reduction in yield and vigor. A new ilarvirus, currently being characterized, was isolated out of two symptomless clones collected from different locations in Chile. The new virus is not related to tobacco streak virus, a pollen-borne virus is strawberry, and its relationship to other ilarviruses is being investigated. This results clearly demonstrates the need to test for viruses in introduced germplasm before it is released to the public. It also emphasizes the need to establish workable virus detection procedures for known and unknown viruses during germplasm evaluation in order to ensure conservation of valuable and sometimes endangered germplasm with minimum phytopathological risk.
Spiegel, S., Martin, R., Leggett, F. and Postman, J. (1993). INTERNATIONAL MOVEMENTS OF STRAWBERRY GERMPLASM: VIROLOGICAL ASPECTS. Acta Hortic. 348, 517-517