Breeding system of Bulnesia retama (Gillies ex Hook & Arn.) Gris. (Zygophyllaceae) in the Central Monte Desert (Mendoza, Argentina)

Reproductive and phenological patterns of Bulnesia retama were analysed in the Ñacuñán Biosphere Reserve. Flowering spanned approximately 4 weeks, while mature fruits dispersed in 75 days. Six flower stages were determined, protogyny occurred in early stages, receptive stigmas and nectar production were detected during stages 1–4. Pollinator and flower predator behaviors are described. Mating treatments namely autogamy, geitonogamy, cross-pollination, and an open pollinated control showed statistical differences in seed and fruit production. Seed viability was high in all four treatments. Although B. retama has been considered self-compatible, few seeds were produced by selfing compared with cross-pollination, suggesting inbreeding depression.