28Flavonoids are products from specialized metabolism that contribute to fruit sensorial (colour) and 29 nutritional (antioxidant properties) quality. Here, using a pseudo full-sibling F1 progeny previously 30 studied for fruit sensorial quality of cultivated strawberry (Fragaria x ananassa), we explored over two 31 successive years the genetic architecture of flavonoid-related traits using LC-ESI-MS (13 compounds 32 including anthocyanins, flavonols and flavan-3-ols) and colorimetric assays (anthocyanins, flavonoids, 33 phenolics, FRAP and TEAC antioxidant capacity). Network correlation analysis highlighted the high 34 connectivity of flavonoid compounds within each chemical class and low correlation with colorimetric 35 traits except anthocyanins. Mapping onto the female and male linkage maps of 152 flavonoid metabolic 36 QTLs (mQTLs) and of 26 colorimetric QTLs indicated co-localization on few linkage groups of major 37 flavonoid-and taste-related QTLs previously uncovered. These results pave the way for the discovery of 38 genetic variations underlying flavonoid mQTLs and for marker-assisted selection of strawberry varieties 39 with improved sensorial and nutritional quality.40 41 Keywords. Fragaria x ananassa, fruit, specialized metabolism, flavonoids, anthocyanins, mQTL, colour, 42 antioxidant, nutritional quality 43 44 93 by Marker-Assisted Selection (MAS) of the sensorial and nutritional quality of strawberry fruit.94 95 Material and methods 96 Plant materials and preparation.
97A pseudo full-sibling F1 population of 165 individuals obtained from a cross between the variety 98 'Capitola' (CA75.121-101 x Parker, University of California, Davis, USA) and the advanced line 'CF1116' 99 (['Pajaro' x ('Earlyglow' x 'Chandler')], reference from Ciref, France) was developed. The two parents,
100'Capitola' and 'CF1116', display many contrasting fruit quality traits. (20,26). For each of the two 101 consecutive study years (2010 and 2011), six cold-stored strawberry plants per genotype, which were 102 planted in 2009 and 2010, were grown in soil-free pine bark substrate under plastic tunnel with daily 103 ferti-irrigation and control of biotic stresses. Mapping population included a total of 165 individuals over 104 the two study years.
105Within this progeny, 72 and 131 individuals including parents were respectively phenotyped in 2010 106 and in 2011. Fruits were harvested at red ripe stage, when red coloration of the fruit is homogeneous.
107To ensure conformity of the fruit samples and to avoid undesirable effects on antioxidant and fruit 108 polyphenolic contents, several precautions were taken. Fruits were collected in the morning and those 109 showing abnormal shape and size, or injuries were not harvested. For each genotype, two harvests of 4-110 8 fruits each were performed at the peak of fruit production (8-16 fruits in total). Fruits were 111 immediately frozen in liquid nitrogen and stored at -80°C, in order to avoid degradation of antioxidants 112 and polyphenolics. They were then ground into a fine po...