Abstract:

Based on whole-genome resequencing data，a high resolution genetic map was developed by using a set of backcross inbred lines（BILs）crossed by a wild species‘Songzi’with a cultivar‘Amsterdam’，and used to map QTLs for main carotenoids in carrot root. Finally，the genetic map was consisted of 1 976 Bins which contained 29 435 SNPs. The total genetic distance of map was 834.28 cM with an average interval of 0.42 cM between Bin markers. There were 2，2，3，2，2 and 2 main-effect QTLs （M-QTLs）associated with α-carotene，β-carotene，ζ-carotene，lutein，zeaxanthin and total carotenoid contents，respectively，with 11.47%–19.18% phenotypic variance. There were 1，1，2，1 and 1 epistatic QTLs contributed to α-carotene，β-carotene，ζ-carotene，zeaxanthin and total carotenoid contents，respectively，with 2.50%–3.66% phenotypic variance. A total of 36 predicted genes with function annotations were detected in M-QTLs. Among these，gene Dck018297 was ζ-carotene desaturase and associated with β-carotene biosynthesis and total carotenoid contents；gene Dck008006 homologouse to ERF2.2 was associated with α-carotene and zeaxanthin biosynthesis；gene Dck029898 homologouse to bHLH135 was associated with ζ-carotene biosynthesis. These three candidate genes might play central roles in the carotenoid biosynthesis in carrot root.

Key words: carrot, carotenoid, genetic map, fine mapping, QTL