Breeding systems in tribe Delphinieae (Ranunculaceae) in the western Mediterranean area

The breeding system of 30 populations belonging to 20 species of Aconitum, Delphinium and Consolida (Delphiniene, Ranunculaceae) in the western Mediterranean area was studied and its relation with life-span and systematic position is discussed. To assess the breeding system we measured seed set in response to different pollination treatments. We performed greenhouse tests for agamospermy, spontaneous self-pollination, induced self-pollination, geitonogamy, cross-pollination and, in some cases, insect exclusion tests in the field. Morphological characters like stamen number, pollen production, ovule production and pollen: ovule ratio (P/O) were quantified. Most species are facultative xenogamous and partially serf-compatible. P/O ratios were rather consistent with the observed xenogamy, although there is no relation between P/O values and selfing rates. P/O ratio was positively correlated with seed weight, but is heavily influenced by one species. A trend towards increased autogamy in annuals, especially in subgenus Staphisagria, was detected. In these taxa xenogamy and insect pollination are evolutionary primitive, and autogamy is derived. Similar reproductive patterns in closely related taxa suggest that only slight differentiation occurred after primary strain diversification of this group.