1. Department of Biology, Colorado State University, Fort Collins, Colorado 80523‐1878, USA
2. Department of Plant Biology, Cornell University, Ithaca, New York 14853, USA
3. Department of Horticulture and Crop Science, Ohio State University, Wooster, Ohio 44691, USA
4. Quality and Nutrition Laboratory, Centro Internacional de la Papa, Perú Postal 1558, Lima, Peru
5. Department of Horticulture, University of Georgia, Athens, Georgia 30602, USA
6. Department of Biochemistry, University of Missouri–Columbia, Columbia, Missouri 65211, USA
7. Department of Plant Sciences, University of California Davis, Davis, California 95616, USA