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 - 3.06

ESTIMATION OF GENETIC VARIATION AMONG WILD CARDOON POPULATIONS USING AFLP ANALYSIS

E. Portis*, G. mauromicale**, E. SABA***, L. quagliotti*, A. Acquadro*, c. comino*, S. Lanteri*

*) Di.Va.P.R.A. settore Genetica Agraria, Università di Torino

**) Dipartimento di Scienze Agronomiche, Agrochimiche e delle Produzioni Animali - sezione Scienze Agronomiche, Università di Catania

***) Dipartimento di Scienze agronomiche e Genetica vegetale agraria, Università di Sassari

Cynara cardunculus var. sylvestris, Genetic variability, AFLP, Sicily, Sardinia

Wild cardoon [Cynara cardunculus L. var. sylvestris (Lamk) Fiori] is a rustic and robust perennial plant with a characteristic rosette of large spiny leaves and branched flowering stems. It is native to the Mediterranean basin where it colonizes dry and uncultivated areas. Cytogenetic as well as isozyme studies show that wild cardoon is the ancestor of the cultivated forms C. cardunculus var. scolymus L. (artichoke) and C. cardunculus. var. altilis DC (cardoon), since they are fully cross-compatible and their F₁ hybrids are fully fertile.

Previous studies showed that wild cardoon can be exploited for the production of lignocellulosic biomass for energy or paper pulp as well as for seed oil extraction. Furthermore, wild and cultivated forms within Cynara genus are exploited for the extraction of biopharmaceuticals. Inulin, a natural fiber which was found to improve the balance of friendly bacteria in the intestine, can be extracted from roots, while leaves are very rich in antioxidant compounds. The latter: i.e. luteolin and cynarine, originating from the metabolism of phenylpropanoids, are able to protect bio-molecules (i.e. proteins, lipids and DNA) from oxidative damages caused by free radicals and play an hepato-protective as well as choleretic action, they might also contribute to the prevention of arteriosclerosis and other vascular disorders.

Up to know no information are available on genetic variation in natural population of wild cardoon and even less on chemical characteristics of leaf or root extracts with respect to different genotypes as well as soil and climatic conditions of growing areas. Furthermore, no research has been carried out on the genetic improvement of wild cardoon in order to maximize oil yields and biomass production.

We report on the genetic variation in eight natural populations of wild cardoon, of which five identified in Sicily and three in Sardinia, as measured by amplified fragment length polymorphism (AFLP) markers.

Our results show that: (i) most of the genetic variation is present within populations, which is in keeping with the outcrossing breeding system of the species; (ii) there is a remarkable tendency for plants of each population to cluster together, thus, despite the high ratio of within-to-between population genetic variance, the full AFLP banding pattern of each genotype is a relatively reliable fingerprint diagnostic of its parent population; (iii) because of the confounding effect of habitat fragmentation, the geographical-genetic distance relationship is weak; (iv) the observed genetic distribution among populations provides insights for the identification of suitable strategies in order to sample genotypes representative of the natural genetic variation.

On the whole our results show that the high level of genetic diversity observed stress the need for the application of selection programmes in order to identify genotypes suitable for the extraction of biopharmaceuticals as well as the production of oil and biomass. The selected genotypes might then be tested in different environment in order to evaluate the effect of soil and climate on chemical composition of oil and leaf extracts, seed setting and biomass production.