Mapping QTL Associated with Carotene Accumulation in Orange Carrot Roots
Pimchanok Satapoomin
1, Joshua Parsons
1, Massimo Iorizzo
1
and Philipp W. Simon
1,2
Department of Horticulture, Plant Breeding and Plant Genetics Program, University of
Wisconsin-Madison, Madison, WI, USA
2USDA-ARS Vegetable Crops Unit, Dept. of
Horticulture, University of Wisconsin- Madison, Madison, WI, USA
Carrots are an excellent source of provitamin A carotenoids in human diet and these pigments
convey the familiar orange root color. Since carotenoids are an important agronomic trait
for breeders, an understanding of genetics and biochemistry of carotenoid is desirable.
Recently, we evaluated genetic differences in carotenoid accumulation between domesticated
orange USDA inbred line (B493) and white wild Queen Anne’s Lace (QAL) carrot. The
Y and
Y2 genes have been characterized in this population. To gain
more insight into the genetic basis underlying this trait, a QTL analysis was then performed
in the F
4 generation. Carrot roots were phenotyped for carotenoid content using
visual assessment and High Performance Liquid Chromatography (HPLC). DNA samples were
collected and genotyped with 3,452 SNP and 52 SSR markers. A single QTL denoted as
Y3 was detected on chromosome 5 with LOD score 7. In addition, a
genome-wide association study indicated a significant association between this trait and
SNPs on chromosome 5. We are currently narrowing down the genetic interval by genotyping
additional markers around a candidate region of chromosome 5 in order to locate where the
gene may lie. Our results provide a first step to identify candidate genes that may play an
important role in increasing carotenoids by selection for elevated carotenoid content. In
addition, markers identified from this study will be useful to carrot breeding programs for
screening materials with high carotenoids to develop new improved varieties.
Last updated
Friday, 02-Aug-2013 11:46:09 CDT
