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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

APPLICATION OF AFLP AND ISSR MARKERS TO ARTICHOKE (CYNARA CARDUNCULUS L. VAR. SCOLYMUS) GENOME ANALYSIS

LANTERI S.*, ACQUADRO A.**, DI LEO I.**, SABA E.*, PORTIS E.**

* Dipartimento di Scienze Agronomiche e Genetica Vegetale, Università degli Studi di Sassari, Via E. De Nicola , 07100 Sassari

lanteri@uniss.it

** DI.VA.P.R.A. settore Genetica Agraria, Università degli Studi di Torino, Via L. da Vinci 44, 10095 Grugliasco (TO)

portis@agraria.unito.it

Artichoke (Cynara cardunculus L. var. scolymus) is native to the Mediterranean basin and Italy is the richest source of primary cultivated “gene pool”, since harbours many distinct varietal types, best adapted to local environments and local tastes. The local varietal types include (I) the ‘Spinosi’ group, with long sharp spines on bracts and leaves; (II) the ‘Violetti’ group, with medium-sized, violet-coloured heads; (III) the ‘Romaneschi’ group, with spherical or sub-spherical heads and (IV) the ‘Catanesi’ group, with relatively small, elongated heads.

In Italy artichoke is cultivated on an area of about 50.000 ha (ISTAT, 1998) and, together with potato and tomato, is one of the most important horticultural crops. Since its marketable gross amount corresponds to about one thousand billions (ISMEA, 1999), it is of extreme importance not only a consolidation but also a further development of the invested areas for the valorization of agriculture in Southern Italian regions.

Artichoke can be propagated vegetatively as well as through seeds. However, at present, commercial production is mainly based on perennial cultivation of vegetatively propagated clones. In a previous study, by means of RAPD markers, we detected very wide variability within the cultivated material of ‘Spinoso sardo’, the most widely grown and economically important varietal type in Sardinia. This was attributed to the multiclonal composition of the populations, to mutations occurring over time (chromosomal aberrations, aneuploidy, polyploidy etc), which presumably have been selected and vegetatively propagated together with non-variant plants, as well as to the almost absent selection applied by farmers.

Vegetative propagation is responsible of many disadvantages like: (I) physiological and genetic heterogeneity of the propagative material, (II) diffusion of pathogens, mainly viruses, (III) low rate of multiplication, (IV) high cost for plantation.

Artichoke breeding history is rather limited and breeding programs have traditionally aimed at improving earliness, yield and quality based on intra-clonal selection; only a few experiments have been carried out in order to apply hybridization among varietal types followed by selection.

In order to widen the knowledge on artichoke genome and make it possible the modernization of the breeding strategies, we have developed the AFLP (Amplification Fragment Length Polymorphism) and ISSR (Interspersed Simple Sequence Repeats) technique applied to the species. For both AFLP pre-amplification and amplification steps, many combinations of selective nucleotides with different base composition have been tested and the most suitable ones identified. A wide number of ISSR primers, with variable 2-4 base ‘anchor’ at their 5’ or 3’ ends, has been applied and the ones, allowing to obtain clear and reproducible electrophoretic patterns, selected.

At present these techniques are applied for assessing the genetic uniformity of vegetavively propagated clones, in order to identify suitable material for breeding activities based on seed propagation.