Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.04

AFLP markers DISCLOSE diversity in a collection of artichoke germplasm

G. SONNANTE*, M. IPPEDICO*, A. DE PAOLIS**, D. PIGNONE*

*) CNR, Intitute of Plant Genetics, Research Section of Bari

**) CNR, Institute of Plant Production Science, Section of Lecce

AFLP, artichoke, germplasm, wild progenitor, genetic similarity

Artichoke, Cynara cardunculus L. var. scolymus (L.) Fiori is a diploid outcrossing species, originated in the Mediterranean basin, which has been much appreciated since ancient times for both its tasty heads and pharmaceutical properties. Artichoke is traditionally cultivated all over the Mediterranean Basin and is generally vegetatively propagated; the highest density of cultivation is found in Italy, where the largest germplasm diversity is also observed. Wild cardoons are also widespread in Central and Southern Italy.

The primary gene pool of artichoke includes wild (C. cardunculus L. var. sylvestris Lam.) and cultivated (C. cardunculus L. var. altilis DC) cardoons. These latter subspecies are genetically cohesive with the cultivated artichokes. The wild cardoons are considered to be the progenitors of cultivated Cynara.

In order to assess genetic variation and relationships among artichoke varieties and between these and cardoons, AFLP markers were developed and used in genetic analysis. Forty artichoke varieties and/or ecotypes were selected from the world-wide artichoke living collection held at the Institute of Plant Genetics in Bari according to their morpho-productive characteristics and geographical origin; moreover, one genotype of cultivated cardoon and two genotypes of wild cardoon, were included in the analysis pool. AFLP analysis was performed using fluorescence labelled selective primers and samples were run in an automated sequencer. Nine primer combinations were selected for further analysis out of the 24 initially tested. A total of 650 fragments were detected, 88.46% of which were polymorphic. The data were scored as presence or absence of a given fragment and similarity among samples was calculated on the basis of Jaccard's index. The similarity matrix so obtained was used to perform cluster analyses using UPGMA method and principal coordinate analysis (PCO). Both the dendrogram and PCO plot evidenced a clear separation of the cultivated and wild cardoon from the cultivated artichoke. Within the cultivated artichokes, genotypes were clustered mostly on the basis of the morphological characteristics of capitula, which allow to distinguish four main groups in this crop: "Spinosi", "Violetti", "Catanesi" and "Romaneschi".

It is worth noticing that AFLP markers, thanks to their high level of polymorphism in this gene pool, proved particularly useful in distinguishing between closely related genotypes and between morpho-goups. Their usefulness in managing artichoke living collections is discussed in detail.