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

Abstract

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.