Submitted to: Proceedings Washington State Potato Conference
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2005
Publication Date: July 15, 2005
Citation: Brown, C.R., Moore, M., Alva, A.K., Boge, W.L., Yang, C. 2005. Genetic variation of mineral content in potato and nutritional considerations. 44th Annual Washington State Potato Conference, Feb 1-3, 2005, Moses Lake, WA. p. 5-8. Technical Abstract: Potatoes are generally recognized as good sources of vitamin C and potassium. Potatoes may contain around 20 mg per 100 grams fresh weight of vitamin C. However, they can easily contain 700 micrograms per gram dry weight of potassium. This is as much as a banana, a food often recommended by dieticians to people who need to supplement potassium consumption. Lesser known are the concentrations of other minerals. Nevertheless, potato is listed as providing 6 percent of the Required Daily Allowance of iron, phosphorus and magnesium and 2 percent of calcium and zinc. Although at first glance these values are low, little is known about the genetic variation in potato for mineral composition and whether it would be possible to select new varieties with higher levels. In examining the mineral content of breeding lines in trial in the Northwest, some surprisingly broad ranges of expression were found. For instance, potato breeding lines varied four-fold for iron and manganese contents. Nonheme ( plant source) iron absorption is often subject to inhibitors of availability. Manganese and vitamin C are auxiliary compounds for iron absorption. It was also found that manganese and iron contents were closely correlated ( r = 0.85). Zinc content showed a two-fold range as did potassium. Approximately one-third of the world's population suffers iron deficiency. Iron from vegetable sources is inhibited by phytic acid, a common constituent of small grains, and polyphenols, which are usually highest in food legumes. Potato has negligible amounts of these inhibitors and is abundant in vitamin C, the most effective absorption promoter in most diet matrices. These findings promote the idea of evaluating the genetic potential of new varieties of potato to play a greater role in iron nutrition in the world.