Molecular fingerprinting and evaluation of genetic distances among selected clones of globe artichoke (Cynara cardunculus L. var. scolymus L.)

Abstract

SummaryGlobe artichoke is a diploid (2n=2x=34), predominantly cross-pollinated, native plant of the Mediterranean basin, and Italy contains the richest gene pool of cultivated varieties. Commercial production is mainly based on perennial cultivation of vegetatively propagated clones, which are highly heterozygous and segregate widely when progeny-tested. Here we report on the application of inter-simple sequence repeats (ISSR) and amplified fragment length polymorphism (AFLP) markers for fingerprinting and evaluating genetic distances among 24 selected clones belonging to varietal type ‘Spinoso sardo’. Twenty-two of the 26 ISSR primers tested gave good amplification, but only seven were efficient in generating polymorphic bands. Thirty-one of the 48 AFLP primer combinations applied gave clear and reproducible amplification patterns, and the number of polymorphic bands ranged from 4 to 19. Furthermore, AFLP led to the identification of two chimeras among the mother plants from which clones originated. AFLP data were analysed by means of: Shannon Index (H’j), Resolving power (Rp), Marker Index (MI) and Polymorphic Information Content (PIC). H’j values showed the highest correlation with genotype identification. AFLP pattern scores were used to produce a dendrogram based on the Jaccard’s Similarity Index (JSI) and UPGMA clustering. Each of the 24 artichoke clones could be fingerprinted, and the JSI values ranged from 0.954 to 0.702. Furthermore, 22 clones yielded distinctive bands. We conclude that AFLP is reliable and highly informative for DNA fingerprinting in globe artichoke, even when genotypes display similar gene combinations.