2021 B493 × Z007 F₃

In order to better characterize the effect that Or alleles have on conditioning the accumulation of carotenoids in roots, we analyzed an F₃ family fixed homozygous recessive for y and y₂, derived from a cross between an orange carrot and a white wild carrot, segregating for the two known Or alleles, which we name Orc and Orw. QTL mapping across three different environments revealed that the accumulation of several carotenoids was associated with the Orc allele, with consistent patterns across environments. A second QTL on chromosome 7, harboring a carotene hydroxylase gene homologous to Lut5 in Arabidopsis, was also associated with the accumulation of several carotenoids. Two alleles for this gene, which we name CHc and CHw, were discovered to be segregating in this population.

2,571 markers across 460 samples clustered into 9 linkage groups and the resulting linkage map has a minimum of 75 markers on chromosome 7 to a maximum of 476 on chromosome 3. The average spacing of markers ranged from a maximum of one marker every 0.9 cM on chromosomes 7 and 9 to a minimum of one marker every 0.4 cM on chromosome 6. The physical spacing of markers ranged from 75 kb on chromosome 4 to 482 kb on chromosome 7. In total, the linkage map was 1384 cM in length.