Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 17, 2011
Publication Date: November 29, 2011
Citation: Baransi, R., Maksylewicz-Kaul, A., Nothnagel, T., Cavagnaro, P., Simon, P.W., Grzebelus, D. 2011. Genetic diversity of carrot (Daucus carota L.) cultivars revealed by analysis of SSR loci. Genetic Resources and Crop Evolution. 59(2):163-170.
Interpretive Summary: Carrot is a crop cultivated around the world, and carrots grown in some regions are very different from typical carrots in the U.S. today. Not much is recorded in written history to document how, when, or why carrots spread as a crop. This study used molecular markers called SSRs to fingerprint a collection of diverse cultivated carrots from a round the world. Results indicated that the broad variation we observe in carrot plants, such as color of the root, is confirmed by SSRs. Results indicate that carrots in Asia were developed somewhat separately from carrots in Europe, although quite a bit of overlap was observed for these 2 groups. This study is of interest to vegetable breeders, growers, and to botanists studying crop origins.
In this work we evaluate a collection of 88 carrot cultivars and landraces for polymorphisms at SSR loci and use the obtained markers to assess the genetic diversity, and we show molecular evidence for divergence between Asiatic and Western carrot genetic pools. The use of primer pairs flanking repetitive motifs allowed successful amplification and separation of products for 30 SSR loci. For each accession, a distinct band pattern was obtained indicating there were no duplicates in the collection. In total, 227 alleles were identified and the number of alleles ranged from 3 to 15 depending on the locus with the mean of 7.6 The results of the Bayesian clustering indicate that the set of accessions used in this study is structured with at least two distinct genetic groups containing 17 and 61 accessions, and for further assessment of genetic diversity the remaining 10 unclassified accessions originating from various world regions were not taken into account. The results of both PCoA and Bayesian clustering are highly congruent and revealed that most of carrot cultivars can be separated into two genetic pools, although there was no clear delimitation between them. The first pool comprised predominantly the landraces originating from continental Asia i.e., Turkey, Pakistan, India, China, and Russia, all of yellow, red, and purple root color, and additionally, two cultivars from Japan, the only two Japanese with red and yellow roots In contrast, cluster 2 comprised mainly European accessions, and additionally seven Japanese, four American, and one from Australia. In this group, only a single breeding material created in German research institute was originally of Asiatic origin. Most of the accessions (92%) developed orange roots typical for western carrot type. Thus, this cluster can be considered as the Western gene pool.