Fighting Potato Diseases by Enhancing Germplasm


This was an article published in the 2010 May/June issue of Agricultural Research - a magazine highlighting research done by USDA/ARS scientists.  I’m pictured with Shelley Jansky while looking at late blight inoculated plants.

Geneticists Dennis Halterman and Shelley Jansky, with ARS’s Vegetable Crops Research Unit in Madison, Wisconsin, are hunting for wild potatoes that contain resistance to important diseases plaguing potato growers nationwide.

One wild potato Halterman has identified, Solanum verrucosum, contains a gene with resistance to late blight. Efforts are under way to cross S. verrucosum with cultivated potato and integrate the late blight resistance gene.

The researchers are looking to produce germplasm useful for develop- ing a potato cultivar with resistance to both late blight and early blight, which also affects tomatoes. Early blight, a fungal disease, mainly affects the potato plant’s leaves and stems but, if left uncontrolled, can also reduce yield. To create the multi-disease-resistant cultivar, the scientists crossed S. verrucosum with another wild potato species that has resistance to early blight, and then crossed the resulting wild potato hybrid with cultivated potato. They currently have seedlings in the greenhouse waiting to be field tested.

Halterman and Jansky are also looking for resistance to Verticillium wilt, another fungal disease that can remain in the soil for up to 10 years. Halterman developed a molecular marker to screen germplasm for resistance to this disease, saving the scientists time and effort. They found resistance in the wild potato species S. chacoense and produced cultivated potato hybrids that contain the important gene. According to Halterman, this is a good, durable gene that should hold up in the long term.

The scientists are also targeting the potato diseases potato virus Y and common scab.—By Stephanie Yao, ARS.