Discovery of QTLs Controlling Flavor Compounds in a Sweetpotato Mapping Population

Abstract 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 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 14,364 single nucleotide polymorphism markers was used for quantitative trait loci (QTL) mapping. A total of 86 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 substrates for those VOCs vary across the population, and may be influenced by multiple interacting factors. This study provides a foundation for the genetic dissection of flavor in sweetpotato and offers new opportunities for incorporating desirable VOC profiles into breeding programs to enhance consumer appeal of new varieties.