Assessment of the breeding system in the Algerian narrow coastal endemism Anacyclus linearilobus (Anthemideae, Asteraceae)

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities.