A single-environment QTL analysis of flavor-related volatile compounds in a sweetpotato mapping population

Flavor is an important trait influencing consumer preference for sweetpotato, yet little is known about the genetic mechanisms controlling the volatile organic compounds (VOCs) that may contribute to the flavor of cooked storage roots. In this study, a biparental mapping population consisting of 362 genotypes was used to perform the first genetic study of VOCs in cooked sweetpotato. VOC identification was carried out using headspace solid-phase microextraction and 2-dimensional gas chromatography coupled to time-of-flight mass spectrometry. In total, 176 VOCs were analyzed, including 27 compounds which were previously identified as predictors of different flavor attributes in sweetpotato, and 14 compounds whose identities remain unknown. A high-density phased genetic linkage map including 14,367 single nucleotide polymorphism markers was used for quantitative trait loci (QTL) mapping. A total of 85 QTLs were identified, including 2 monoterpenes and 2 apocarotenoids that have been associated with a “cooked carrot” flavor in sweetpotato. No QTLs were observed for VOCs important in the prediction of “sweetpotato” and “caramel” flavor attributes, suggesting that variation in their precursor substrates or other interacting factors may contribute to these traits. Because the population was evaluated in a single environment, multi-environment validation is required to establish QTL stability before marker development. The identified QTLs nevertheless provide a foundation for future validation and genetic improvement of sweetpotato flavor.