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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Characterization, Taxonomy, and Acquisition of Genetic Resources for Carrot, Potato, and Their Related Wild Species

Location: Vegetable Crops Research

Title: Phylogenetic prediction of Alternaria leaf blight resistance in wild and cultivated species of carrots (Daucus, Apiaceae)

Author
item Arbizu, Carlos
item Tas, Pamela
item Simon, Philipp
item Spooner, David

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Alternaria leaf blight (ALB) is among the most devastating diseases of carrots worldwide. The ability to predict traits for disease resistance from knowledge of taxonomic relationships would help plant breeders to choose resistant germplasm to use in breeding programs. In a study of 106 accessions of wild and cultivated carrots, we determined plant height is the best character to predict ALB resistance. The most disease resistant species to ALB was the non-carrot species technically known as Ammi visnaga and the wild carrot technically known as Daucus crinitus. We found that species that belong to a group of wild carrots that contain cultivated carrots are slightly more resistant to ALB than members of other species examined. These results will guide breeders into the wild and cultivated carrots to use in their carrot improvement studies.

Technical Abstract: Plant scientists make inferences and predictions from phylogenetic trees to solve scientific problems. Crop losses due to disease damage is an important problem that many plant breeders would like to solve, so the ability to predict traits like disease resistance from phylogenetic trees derived from diverse germplasm would be a significant approach to facilitate cultivar improvement. Alternaria leaf blight (ALB) is among the most devastating disease of carrots worldwide. Thus, new approaches to identify resistant germplasm to this disease are needed. In a study of 106 accessions of wild and cultivated Daucus and related genera, we determined plant height is the best explanatory variable to predict ALB resistance using a phylogenetic linear regression model. Using the estimated area under the disease progress curve, the most resistant species to ALB were the non-carrot relative Ammi visnaga and the wild carrot relative D. crinitus. A permutation tail probability test was conducted considering phylogenetic signal to evaluate the strength of association between the Daucus phylogeny and ALB resistance. We found that species that belong to clade A, which includes carrots and other Daucus possessing 2n = 18 chromosomes, are slightly more significantly resistant to ALB than members of other clades of the Daucus phylogeny.

Last Modified: 08/16/2017
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