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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 Unit

Title: Fruit morphological descriptors as a tool for discrimination of Daucus L. germplasm

Authors
item Mezghani, Najla -
item Zaouali, Imen -
item Bel Amri, Wided -
item Rouz, Slim -
item Simon, Philipp
item Hannachi, C -
item Ghrabi, Z -
item Neffati, M -
item Bouzbida, B -
item Spooner, David

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2013
Publication Date: February 1, 2014
Repository URL: http://handle.nal.usda.gov/10113/58558
Citation: Mezghani, N., Zaouali, I., Bel Amri, W., Rouz, S., Simon, P.W., Hannachi, C., Ghrabi, Z., Neffati, M., Bouzbida, B., Spooner, D.M. 2014. Fruit morphological descriptors as a tool for discrimination of Daucus L. germplasm. Genetic Resources and Crop Evolution. 61(2):499-510.

Interpretive Summary: Collections of crop species and crop species wild relatives are regularly made by scientists in order to place these collections in gene banks. These collections are then evaluated by scientists in order to inform breeders about the availability and useful characteristics of these collections so that they can be used for crop improvement. This paper uses characteristics of the 97 collections of seeds of wild and cultivated carrots collected in Tunisia on two separate expeditions in 2008 and 2009 in order to identify these collections to species. In total, 14 seed traits were measured on mature fruits and analyzed by various statistical methods. The study was able to identify five groups of collections that correspond to traditionally recognized carrot species. This study is useful because it shows the ability to seed traits alone to identify carrots in Tunisia, suggests the utility of these techniques for wild and cultivated collections of carrots in other countries, and informs the breeding community about these new collections that are now available for carrot improvement programs.

Technical Abstract: Morphological diversity of a Daucus L. germplasm collection maintained at the National Gene Bank of Tunisia was assessed using fourteen morphological descriptors related to mature fruits. Quantification of variability for each character was investigated using the standardized Shannon-Weaver Diversity index (H’). General structure of genetic diversity was established by factorial analysis of correspondence and cluster analysis. The computing H’ index ranged from 0.31 for stylopodium shape to a maximum of 0.81 for spine shape. A mean diversity index for all traits recorded across all populations averaged 0.58 indicating existence of an important genetic diversity within the collection. Multivariate analysis of factorial correspondence and cluster analysis on morphological descriptors permitted the subdivision of the Daucus collection into five distinct groups including one single accession group, two groups with six accessions, one group of nine accessions and one large group with 81 accessions corresponding each one to a species among Daucus. The grouping of populations did not reflect bioclimatic and geographic patterns, suggesting no adaptation of populations to local environments.

Last Modified: 8/29/2014
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