Potential Molecular Markers Associated with Tuber Calcium Content in Wild Potato Germplasm

High tuber Ca is associated with a reduced incidence of disease and physiological disorders in potato (Solanum tuberosum L.). However, genetic variation for tuber Ca content in cultivated potato is low, limiting opportunities to study the genetic basis of this trait. We used wild germplasm to develop a population segregating for tuber Ca concentration. The high-Ca-accumulating potato wild relative S. microdontum Bitter (clone M15) was crossed to low-Ca-accumulating S. kurtzianum Bitter & Wittm. (clone K12) and 12 F-1 individuals were intercrossed to create a segregating population. Significant variation in tuber Ca content was found in this population, and simple sequence repeats (SSRs) were tested for association with tuber Ca content. Twelve of 42 SSRs tested were associated with tuber Ca content. SSR4743 on chromosome 7 was found to be linked to a cation exchanger-like (CAX3-like) gene known to be involved with Ca uptake in plants. This SSR may be used to develop a molecular marker to identify tubers with high Ca levels.