SCREENING THE UNITED-STATES POTATO COLLECTION FOR FROST HARDINESS

Potato is one of the most important world vegetables with respect to v alue of production and nutritional impact. Frost susceptibility reduce s or precludes production on millions of hectares worldwide. In contra st to disease and pest problems, cultural or chemical treatments are n ot likely to be helpful in combating frost, so genetic improvement mus t be sought. Fortunately, wild relatives of the cultivated potato have been shown to exhibit frost tolerance far superior to that of cultiva ted species. In this research, over 2,600 accessions representing 101 species in the US potato collection at Sturgeon Bay, Wisconsin were vi sually screened after natural frosts in a uniform field in 1992. This provided a more comprehensive survey of germplasm accessions, further characterized species' hardiness and intraspecific variation. The most hardy species were Solanum acaule, S. albicans, S. commersonii, and S . demissum. An additional previously unreported extremely frost hardy species (Solanum paucissectum) was discovered. This information should expand the insights and germplasm options available to those intent o n breeding desirable varieties with high levels of frost hardiness.