AFLP genetic characterization in Asparagus officinalis doubled haploid (DH) clones collection

This work focused on the genetic characterization of several double haploid lines, part of a large collection present at Montanaso Lombardo C.R.A. Institute (Italy). This DH clones were used as parentals for obtaining hybrids, of commercial (Asparagus officinalis), wild species and some genotypes from interspecific crosses named OMAO {[(officinalis × maritimus) × acutifolius] × officinalis}. Sampling was completed in Autumn 2007-Spring 2008 by taking materials from six different Asparagus species (A. acutifolius, scaber, verticillus, prostratus, stipularis and officinalis) and A. officinalis is the larger group among them with 182 samples divided in local population, commercial cultivars and DH clones. Genetic diversity was analyzed using AFLP molecular markers strategy; forward primers of the nine primer-pairs used were labelled with ABI PRISM fluorescent dye 6-FAM, and the PCR reactions were run on ABI PRISM. The automated sequence system ABI PRISM combined with fluorescent labelling of expected fragments has been applied as an alternative to radioactivity detection using 32P or 33P-labelling. This technology provides an automatic and rapid sizing of the fragments through the use of specific internal size standard (GS500-Liz) and allows analysis of fragments. The data collected from each sample were automatically analysed by GeneMapper Analysis Software. The genetic diversity was estimated, and multivariate analysis methods were applied for the analysis of genetic relationships among double haploid accessions. Our results demonstrates that cultivated cultivars and DH genotypes form only one cluster instead of wild species and interspecific genotypes (forming another separate specific cluster). The only two tetraploid cultivated cultivar (the Italian ‘Violetto d’Albenga’ and the Spanish ‘Morado’), are in the cultivated cultivars cluster but they show an high genetic similarity with the only tetraploid wild specie in our panel: A. acutifolius