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Comparisons between floral scent-based and DNA-molecular-based taxonomies are rare, yet such comparisons indicate that scent can provide useful taxonomic information. Here, we correlate the phytochemical differentiation in floral scent to the DNA-molecular-based differentiation in the genus Sorbus. Inflorescence scent patterns of the apomictic and endemic Sorbus latifolia microspecies Sorbus franconica, Sorbus adeana, and Sorbus cordigastensis originated by hybridization as well as their parental taxa Sorbus aria agg. and Sorbus torminalis were investigated with the dynamic headspace method. The scent data (presence/absence of compounds) were used to construct an UPGMA tree, to calculate a similarity matrix, and to correlate them with the published amplified fragment length polymorphism (AFLP) data of the same individuals, populations, and taxa. Flow cytometry was used to estimate the DNA-ploidy level of the taxa. Scent analyses showed a total of 68 substances, among them aromatic compounds, terpenoids, aliphatics, and nitrogen-containing compounds. The scent patterns were taxon-specific, and the number of scent components differed among taxa. The correlations with the published AFLP data on population and individual level are highly significant, indicating that the scent and AFLP data are highly congruent in the plants studied. Scent therefore provides useful taxonomic characters in Sorbus. [ABSTRACT FROM AUTHOR]

The Franconian Alb (Bavaria, Germany) is rich in endemic Sorbus taxa, considered as apomictic microspecies and derived by hybridization between Sorbus aria aggregate and Sorbus torminalis ( Sorbus latifolia aggregate). Molecular studies using the AFLP technique, neighbour joining, Bayesian clustering, principal coordinate analysis (PCo) and voucher studies were used to investigate genetic structure and origin of adult plants and cultivated offspring of three endemic S. latifolia taxa, namely Sorbus cordigastensis, Sorbus franconica and Sorbus adeana and probable parental species from the S. aria agg. and S. torminalis. The S. latifolia taxa, adults and progeny, showed low genetic variability and a more or less clonal structure, confirming an apomictic mode of reproduction. The investigated S. latifolia taxa were remarkably different among each other, confirming their status as microspecies. The AFLP data confirmed the hybrid origin of the S. latifolia taxa, they were 1.3-1.5 times more closely related to S. aria agg. than to S. torminalis. The S. aria agg. showed a complicate genetic structure and fell into four main groups, two intermediate groups besides Sorbus pannonica and Sorbus aria sensu stricto ( S. aria s.str.). Some progeny of S. pannonica was more variable than expected and clustered partly with other groups indicating gene flow within S. aria agg. Different subgroups of the S. aria aggregate may be parental for the S. latifolia taxa, contributing to the remarkable genetic distances between them. [ABSTRACT FROM AUTHOR]