## 2 Results
### Berry Anthocyanin, Acid, and Volatile Analyses  
The total anthocyanins and total mono- and diglucoside anthocyanins concentrations in the F\({}_{2}\) progeny ranged from less than that of 16\(9\)2 (parent of VRS-F\({}_{2}\) population) to a concentration about as great as that of the _V. riparian_ female grandparent (Table S3). Total anthocyanin QTL peak positions on chromosome 2 were close to the berry skin color QTL peak position (Table 3). In contrast, the total mono- and diglucosides QTL peak positions were upstream of the total anthocyanin peak position and only malvidin and petunidin 3-glucoside QTL occurred on chromosome 2 in two years (Table S4). Delphinidin, malvidin and petunidin 3,5-diglucosides QTL were present on chromosome 2 in 2013 only. However, the cyanidin, malvidin, peonidin, and petunidin 3,5 diglucoside QTL were collocated on chromosome 9 in both years (Figure 4 and Table S4). The peak marker for the diglucosides is near the _5-O-GLUCOSYITRANSFERASE_ (Vitvi09g00582) candidate gene at 6.52 Mb in _V. vinifera_ PN40024 12 XV2. _V. riparia_ Manitoba 37' is homozygous for increased diglucoside concentration and 'Seyval blanc', which contains _V. rupestris_ [PERSON] in its pedigree, is heterozygous for the marker rh_9_6523189 at the 5-O-GLUCOSYITRANSFERASE_ gene. Protein alignment of Vitvi09g00582 with the corresponding _V. riparia_ Michx (Accession #XP_034695482.1), _V. amurensis_ Rupr. (Accession #AHL68667.1), and _V. rotundifolia_ (Accession #ALS55360.1) indicate that Vitvi09g000582 has an early truncation; whereas, the three native species contain an additional segment with 51 amino acids (Figure S6). Malic acid concentration ranged from 1.5 to 29.0 g/L across years and generations (Table S3). In the F\({}_{2}\) population, mean malic acid content ranged from 10.6 to 12.0 g/L across years. Correlation analysis showed strong, positive, and significant pairwise correlations for malic acid for most years (Table S5). QTL for malic acid were detected on chromosome 6 in all years and on chromosome 1 for 2016 and 2018 (Tables 3 and S5). Collocated potential malic acid QTL (overlapping confidence intervals) were observed on chromosome 8 in 2016 and 2018 and these were significant in the malic acid model (Figure S7, Table S6). QTL modeling in 2016 indicated a significant interaction was observed between QTL on  
Figure 4: Individual anthocyanin diglucosides and total diglucoside LOD scores for 2013.  
chromosome 1 and 8 (Table S6). Additive modeling of QTL on chromosomes 1, 6, and 8 explained more than 50% of the malic acid variation. Collocation of the TA and malic acid QTL was observed on chromosome 6 at 7.86 Mb in 2016 and on chromosome 1 at 5.59 Mb in 2018. Mean trait effect plots by genotypes for malic acid peak positions on chromosome 1 and chromosome 6 indicated _V. riparian_ 'Manitoba 37' was the responsible grandparent for high malic acid in all years (Figure 5). Two _MALATE DEHYDROGENASE_ (Vitvi01g002239 and Vitvi01g002240) and one _MALATE DEHYDROGENASE PRECURSOR_ (Vitvi01g01744) were identified as candidate genes within the 95% confidence interval for the chromosome 1 malic acid QTL. Two _ALUMINIUM-ACTIVATED MALATE TRANSPORTER 2-LIKE_ genes (Vitvi06g00922, Vitvi01g6g00928) were identified as candidate genes for malic acid QTL on chromosome 6. In addition, modeling of malic acid identified a potential QTL chromosome 8 in 2016 and 2018. An _ALUMINIUM ACTIVATED MALATE TRANSPORT 8-LIKE_ (Vitvi08g00636) was also identified in the confidence interval of that QTL. The Vitvi08g00636 and Vitivi08g00142 genes are closest to QTL peak positions. The mean TA ranged from 12.88 to 28.28 g/L across three years (2013, 2016, and 2018) and generations (grandparents, parent, and F\({}_{2}\) population mean) (Table S3). The VRS-F\({}_{2}\) TA had strong positive correlations across three years (0.82 to 0.89) and there was a strong correlation with malic acid (Table S5). Five significant QTL were observed for TA, on chromosome 6 for all three years and on chromosome 1 in 2016 and 2018 (Table 3).