Evaluation of root yield traits and glucosinolate concentration of different Armoracia rusticana accessions in Basilicata region (southern Italy)

Armoracia rusticana (horseradish) is a Brassicaceae species cultivated for its roots. It is appreciated for its intense flavour due to the richness of secondary metabolites, such as glucosinolates (GLS) and their breakdown products. Roots of horseradish well suitable for agro-industrial and pharmaceutical sectors are selected based on yield, biometrical characteristics and qualitative composition. Six horseradish accessions from southern Italy were compared based on root traits, yield and GLS concentration. The genetic variability of the accessions was also investigated using the amplified fragment length polymorphism (AFLP) markers. Phenotypically, the six accessions showed significant differences for the sprout number on the crown as well as for the root diameters and length. Among the accessions, wide diversity in total and marketable root yield per plant was also found. The root GLS analysis revealed significant differences for the individual and total GLS concentration. Particularly, this latter ranged from 1.73 to 37.7 μmol g−1 of dry weight, with sinigrin as predominant GLS in all accessions, contributing from 53% to 87% of the total GLS concentration. By using AFLP markers, the percentage of polymorphisms detected was high. The similarity clusters developed based on root biometric characteristics, yield and total GLS concentration was different from the cluster based on AFLP markers. Wide variability among the horseradish accessions was found on the basis of the morphological and qualitative traits, and molecular markers. The genetic diversity of horseradish germplasm still available in the Basilicata region deserves to be preserved and protected against genetic erosion.