Genetic Mapping of Steroidal Glycoalkaloids Using Selective Genotyping in Potato

Steroidal glycoalkaloids (SGAs) are important secondary metabolites in potato which are associated with constitutive host defense mechanism. SGAs like leptines and dehydrocommersonine (DHC) present in wild S. chacoense and S. oplocense, respectively, are known to deter Colorado potato beetle (CPB) feeding. In the current study, LC-MS analysis led to tentative identification of a new SGA with the same molecular mass as α-solanine, solanidenol-chacotriose (SC), which was present in high levels in the CPB susceptible S. tuberosum cv. Shepody, but not in S. oplocense. In a progeny derived from a cross between S. tuberosum, cv. Shepody and S. oplocense derived F1 hybrid, 13213–07, SC was one of the highly variable metabolites along with DHC. Selective genotyping was used for genetic mapping of QTL controlling SC and DHC to chromosome 1. Selective genotyping is dependent on variation between extremes in populations, and it was not effective for QTL mapping of α-solanine and α-chaconine where differences between extremes was low.