1a. Objectives (from AD-416)
Improve levels of disease resistance to foliar and soil-borne pathogens in potatoes. Improve processing and nutritional quality in potatoes through breeding and selection of superior germplasm. Evaluate advanced selections through replicated field trials prior to naming and release to stakeholders.
1b. Approach (from AD-416)
Use recurrent selection to improve diploid populations for disease resistances and processing quality. Use parental line breeding to improve tetraploid populations for disease resistances, processing quality, nutritional quality. Transfer these traits from improved diploids to the tetraploid level via 4x-2x crosses. Develop markers to facilitate introgression of desirable genes or deletion of undesirable genes from related species into commercial germplasm.
3. Progress Report
Crosses were made among red skin, purple skin, yellow flesh and purple flesh potatoes and between wild potato species with resistance to late blight and our adapted selections in the fall. Crosses were made among white-skinned late blight resistant potatoes and chipping potatoes in the spring. Crosses were made among specialty market potatoes and between chipping varieties and a haploid inducer in the summer. Crosses were made in the field between chipping varieties and late blight resistant advanced selections. Potato variety collections were screened for resistance to early blight. Yellow-fleshed clones from three families were characterized for carotenoid profiles and quantities. Clones with more carotenoids than available in commercial varieties were identified. Second year field generation germplasm was distributed to five sites for evaluation and selection. In general, ½ of the selections were discarded by the breeder and the other location, ¼ were saved by the breeder but not selected at the other location, 1/8 were saved by both the breeder and the other location, and 1/8 were discarded by the breeder but saved at the other location. Preliminary evaluations suggest that tissue culture may be an effective means to screen wild potato species accessions for root architecture. Increasing root biomass may improve nitrogen uptake efficiency in potatoes and reduce nitrate leaching.
1. Carotenoid content of potatoes differs across environments. Carotenoids have many important human health benefits but little information is available about how growing environment influences potato tuber carotenoid content or if different varieties perform similarly or differently across environments. Nine potato varieties and advanced selections (clones) were grown in Maine and Florida for two years and their tubers were analyzed for the types and amounts of carotenoids. There were no differences in carotenoid content among environments. There were significant differences among clones. As expected, the white-fleshed clones were significantly lower in carotenoids than the yellow-fleshed clones. There are two main branches in the carotenoid biosynthetic pathway: a higher proportion of carotenoids were produced by the lycopene epsilon cyclase branch in white-fleshed than yellow-fleshed tubers. There were significant clone by environment interactions and most of the clones were unstable across environments. With genetic variation for individual and total carotenoid content in potatoes, improving the levels of carotenoids has been and should continue to be feasible; however, concentrations are likely to vary in different environments.
Clough, M.E., Yencho, C.G., Christ, B., Delong, W., Halseth, D., Haynes, K.G., Henninger, M., Hutchinson, C., Kleinhenz, M., Porter, G., Veilleux, R. 2010. An Interactive Online Database for Potato Varieties Evaluated in the Eastern U.S.. HortTechnology. 20:245-249.