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 Medite rranean area was studied and its relation with life-span and systematic pos ition is discussed. To assess the breeding system we measured seed set in r esponse to different pollination treatments. We performed greenhouse tests for agamospermy, spontaneous self-pollination, induced self-pollination, ge itonogamy, 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 specie s are facultative xenogamous and partially serf-compatible. P/O ratios were rather consistent with the observed xenogamy, although there is no relatio n 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 toward s increased autogamy in annuals, especially in subgenus Staphisagria, was d etected. In these taxa xenogamy and insect pollination are evolutionary pri mitive, and autogamy is derived. Similar reproductive patterns in closely r elated taxa suggest that only slight differentiation occurred after primary strain diversification of this group.