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Title: BREEDING FOR RESISTANCES TO POTATO VIRUS Y AND POTATO VIRUS A

Author
item Brown, Charles
item Corsini, Dennis
item Novy, Richard - Rich
item HANE, D - OREGON STATE UNIV

Submitted to: Potato Conference and Trade Fair Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/15/2002
Publication Date: 3/16/2002
Citation: BROWN, C.R., CORSINI, D.L., NOVY, R.G., HANE, D. BREEDING FOR RESISTANCES TO POTATO VIRUS Y AND POTATO VIRUS A. PROCEEDINGS OF THE ANNUAL WASHINGTON STATE POTATO CONFERENCE AND TRADE FAIR, FEB. P 33-39. 2002.

Interpretive Summary: Potato is propagated by taking the vegetative part of the plant, called the tuber and planting it in soil. Pathogens that establish a systemic infection persist in the vegetative parts of the plant and are transmitted generation after generation through the vegetative propagative cycle. Therefore, it is necessary to prevent the infection by these pathogens. The most important pathogens are the viruses. Among the many viruses that infect potato; potato virus Y (PVY) is a very serious one. Recently different variants of this virus have shown up in the Pacific Northwest. One new variant called N-like PVY is relatively mild in the potato. Some of the N-like variants cause brown flecking in the flesh in certain varieties. This would be totally unacceptable to the processing and fresh markets. Therefore measures must be taken to deal with it. Better detection and elimination standards will lower the amount of all forms of PVY in seed potato. Also there is very effective resistance to PVY available for breeding. Several genes from Mexican and South American wild potatoes and primitive cultivars confer immunity to all forms of PVY. They will be components of the resistance package in new varieties of the future.

Technical Abstract: The most important potyvirus of potato is potato virus Y (PVY). PVY is a transitory virus transmitted by aphid vectors, but also easily mechanically transmitted. It appears as two major groups: PVY-O, or the common strain, which is severe in potato, but produces a mild mosaic in tobacco; and 2) PVY-N, or the ¿necrotic¿ strain, which is mild in potato but is severely and systemically necrotic in tobacco, hence the name ¿necrotic.¿ PVY-N has been considered a quarantine virus in the US and Canada, until recently. It still receives special attention, and is the object of extraordinary detection and control plans. Its rarity in certain countries has created a special sensitivity to trade issues. A variant of PVY-N is PVY-NTN, so called because it may cause necrotic flecking in the flesh of some cultivars. This variant seems to the result of recombination between PVY-O and PVY-N. Several distinct variants have recently been found that are not detectable with PVY-N specific antiserum. Fortunately two genes are available that have been shown to be effective, Ry(sto) and Ry(adg), derived from Solanum stoloniferum and Solanum tuberosum ssp andigena, respectively. Breeding clones possessing these genes have been found to be resistant to graft challenge of all types of PVY. They are being incorporated into new varieties through crossing and selection.