Increasing dietary mineral delivery through potatoes

Potato is the fourth most important crop worldwide after maize, wheat and rice and is a rich source of proteins, carbohydrates, vitamins and minerals. Essential minerals are required in small amounts that enable the human body to produce enzymes, hormones and other substances essential for proper growth and development. In developing countries billions of people suffer from malnutrition caused by mineral micronutrient deficiency. These deficiencies are probably due to the high intake of staple food crops such as maize, wheat and rice that are deficient in essential minerals and low intake of mineral-rich fruits and vegetables (HarvestPlus).

 Among the major food crops, the bioavailability of minerals is potentially high in potatoes because of the presence of high concentrations of the compounds that stimulate micronutrient absorption such as ascorbate (USDA-ARS, 2007). Low concentration of antinutrients (compounds that limit micronutrient absorption) such as phytate (0.11-0.27% DM) (Phillippy et al., 2004) and oxalate (0.03% DM) (Bushway et al., 1984) also improve the bioavailability of minerals in potato. However, there exists limited information on the genetics of micronutrient accumulation in potatoes. Knowledge of the genetics of mineral traits in potatoes will help design strategies for manipulating the candidate genes, and will also permit the selection of desired candidate genes during breeding programs. For this purpose, this project will investigate the opportunities for mineral enhancement in potatoes.

The first element of the project looks at the variation in wild relatives of potato. If appropriate, the resultant variants will be crossed with a self-fertile line of S. tuberosum Group Phureja, a diploid cultivated potato, to generate segregating populations for further studies. The second element will explore some populations that already have genetic marker information to seek variations for mineral traits. The third element will be to investigate the variation in mineral traits in highly diverse tetraploid potato populations, including the neotuberosum population derived from Andean tetraploid potato that is highly suitable for association genetic studies.

Tuber mineral content variation across tubers of the cultivar was determined using ICP-MS to guide tuber sampling strategies and provide information on the mineral variation of different tubers. Preliminary results suggest that mineral variation does exist between skin and flesh samples and also among different portions of the tuber.

References

Bushway, R.J., Bureau, J.L., McGann, D.F. 1984. Determinations of organic acids in potatoes by high performance liquid chromatography. Journal of Food Science 49, 75-81.

Phillippy, B.Q., Lin, M., Rasco, B. 2004. Analysis of phytate in raw and cooked potatoes. Journal of Food Composition and Analysis 17, 217-226.

US Department of Agriculture, Agricultural Research Service (USDA-ARS) 2007. Genetic variation of mineral content in potato and nutritional considerations. (Date visited 18/10/07).                             

Figure : Commonwealth Potato Collection (CPC) accessions in glasshouse 

 Photograph of Commonwealth Potato Collection (CPC) accessions in the glasshouse