Genotyping-by-sequencing reveals the origin of the Tunisian relatives of cultivated carrot

Authors: MEZGHANI, NAJLA - National Bank Of Genes; Ruess, Holly; TARCHOUN, NEJI - Tunisian National Institute Of Agronomy; BEN AMOR, JIHENE - Tunisian National Institute Of Agronomy; Simon, Philipp; Spooner, David

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2018
Publication Date: 5/11/2018
Citation: Mezghani, N., Ruess, H.M., Tarchoun, N., Ben Amor, J., Simon, P.W., Spooner, D.M. 2018. Genotyping-by-sequencing reveals the origin of the Tunisian relatives of cultivated carrot. Genetic Resources and Crop Evolution. 65:1359-1368. https://doi.org/10.1007/s10722-018-0619-4.

Interpretive Summary: Knowledge of the diversity of a germplasm collection is fundamental for genebank managers and plant breeders. The main objective of this work was to characterize the diversity of 33 primitive varieties of carrot from 13 different regions of Tunisia, based on 34 morphological characters related to leaves and roots. A measure of such diversity, called the Shannon-Weaver Diversity index, was used to ananyze these 34 characters in the collection. This diversity measure ranged from a low of 0.19 for the color of the interior of the carrot to a high of 0.99 for a measure of how the leaves are divided. Another statistical mkeasure called the analysis of variance revealed significant differences among these 33 primitive varieties for all quantitative characters, in contrast to qualitative characters. Our study discovered that qualitative characters were the best for the assessment of diversity in this collection. This study outlined four distinct groups. Now that we understand how the collection is divided into these four groups we can better advide genebank curators and carrot breeders into the management and use of this collection.

Technical Abstract: Knowledge of the morphological diversity of a germplasm collection is fundamental for genebank managers and plant breeders. The main objective of this work was to characterize 33 landraces of carrot from 13 different regions of Tunisia, based on 34 agro-morphological characters related to leaves and roots. The Shannon-Weaver Diversity index was used to study the phenotypic diversity. The estimated H’ ranged from 0.19 for core colour compared to cortex colour to 0.99 for leaf division. Analysis of variance revealed significant differences among landraces for all quantitative characters. Stepwise multivariate analyses were carried out to identify the useful characters that can distinguish among landraces. This study showed that qualitative characters were the best for the delimitation of landraces in this collection. Cluster analysis permitted the subdivision of carrot collection into four distinct groups independent of their geographic distribution. This information will be helpful to curators in the management and improvement of carrot germplasm in Tunisia.