Packing More Nutritional Punch into the Already Powerful Potato
The humble spud, already a nutritional powerhouse, is set to get a major health-benefiting boost due to research being conducted by horticultural scientists at Washington State University.
Jacob Blauer, a doctoral student in the Molecular Plant Science program and research assistant in the lab of WSU professor of horticulture Richard Knowles, is investigating how and why potatoes lose their vitamin C after being harvested. The research may lead to ways to improve vitamin C retention after harvest.
One of the inspirations for the research was a comment made by researchers at Harvard University, who claimed that potatoes were unhealthy, Blauer said. Potatoes are actually very nutrient dense, and Blauer and his colleagues would like to promote that fact.
Potatoes are a rich source of vitamin C, with a medium-sized potato supplying about 45 percent of our daily requirement. Potatoes are also rich sources of antioxidants, potassium, high-quality protein, and many other essential nutrients, Blauer said. But, vitamin C, in particular, decreases rapidly after potatoes are harvested.
Blauer is studying the metabolic changes that regulate the transition between the synthesis and accumulation of vitamin C during tuber development and the deterioration that begins soon after harvest. His main goal is to identify regulatory genes governing vitamin C metabolism that can be manipulated to either instill higher initial vitamin C content or to delay its loss. According to Blauer and Knowles, things are looking good so far.
Genes and biosynthetic pathways are at the heart of Blauer’s research. Plant growth, ripening, and other life functions occur in complex networks of interactions called biosynthetic pathways. Blauer compared the role of an individual gene in a biosynthetic pathway to that of particular ingredient in a recipe. The end result — a great lasagna, for instance — is a result of the pathway that combines the ingredients with the way they are cooked.
In the case of potatoes, the ingredients are specific proteins governed by genes that control levels of the end product, vitamin C. The hope is that over the next ten to fifteen years, the coordinate genes that regulate vitamin C levels will be identified, leading to breeding strategies for improving vitamin C content and retention in potatoes.
The Pacific Northwest Potato Variety Development Program has a successful track record of breeding new cultivars with a higher vitamin C content than that of the existing mainstream varieties. The challenge now is to understand, at the molecular level, the metabolism responsible for loss of this essential nutrient and to breed new varieties that take advantage of that new knowledge.
New potato varieties will only be successful if accepted by producers and consumers, though, so researchers in Knowles’ lab conduct regular storage, processing, and culinary evaluations of new potato varieties that come from the development program.
Taste testers are recruited to evaluate french fries made from selected new varieties of potatoes. These evaluators fill out surveys in which they rate each potato on taste and other sensory qualities. The results are then analyzed to determine the best tasting potato selections.
Potato selections that score low on the processing and culinary evaluations are thrown out, Blauer said. The highest rated selections are advanced and have a good chance of becoming a variety available for commercial production. Testing continues on the potatoes, both in the field and in the kitchen, in order to produce a new variety that will be as delicious and profitable as it is nutritious.
By Tessa Rawie, CAHNRS MNEC intern
Learn more about WSU’s graduate program in Molecular Plant Sciences by visiting http://bit.ly/fHIniv.
Learn more about WSU’s collaboration in developing potato varieties for the Pacific Northwest by visiting http://bit.ly/nLyHq.
Diversifying Dryland Organic Farming
The challenge of finding alternative organic cropping systems is what inspires Patrick Fuerst. Fuerst is an assistant research professor in the Department of Crop and Soil Sciences at WSU, conducting research on dryland organic farming.
Fuerst has worked in weed sciences at WSU since 1988 and took over an organic farming research project in 2006. The project’s goal is to master techniques of organic farming in dryland regions, such as the Palouse.
Finding effective ways to grow and sustain organic crops in dryland conditions is a long and difficult process. One difficulty is presented by the pernicious weed species in the region, such as bindweed.
There are few organic farming methods to eliminate weeds without the use of herbicides. Instead, rotary harrows and hoes can be used to till and plow, both of which are time-honored methods of weed control. The use of “under-cutters” can mutilate weed roots without harming crops.
In Fuerst’s research on organic farming techniques, a three-year rotation involves winter peas, winter wheat, and spring wheat.
Fuerst said his goal is to “diversify” organic crop options to more than just conventional wheat. Winter wheat, winter peas, and alfalfa have been the most successful so far, and some new rotation crops have been introduced as well, such as winter triticale, a hybrid of wheat and rye.
Once effective methods of organic farming are found for particular crops, farmers will be able to convert their farms to organic production of those crops, if they so choose. However, Fuerst said there is no question that large farms with thousands of acres take time to convert, beginning with small patches of land and then expanding.
The research project received a $1 million federal grant in 2009, allowing the research to be expanded with a multistate Extension component across Washington, Oregon and Idaho. The main research component of the project is based at WSU, while field trials are located on co-operating farms in all three states. Field trials are investigating certifiably organic methods of increasing fertility and the use of legumes to add nitrogen to soil.
An advisory council meets once a year to review results from the on-farm trials and to determine which methods work so the research can remain targeted on its goal: a system of dryland organic farming that is economically sustainable for the region’s growers.
By Tessa Rawie, CAHNRS MNEC intern
Learn more about organic cropping systems research at WSU by visiting http://bit.ly/gP8rJd.
With this issue, On Solid Ground enters its annual hibernation period. We’ll be back in the new year with a new issue. Until then, happy holidays!