Hybridization studies in Silene subgen. Petrocoptis (Caryophyllaceae)

Silene subgenus Petrocoptis comprises sexual diploid taxa and it is restricted to calcareous cliffs in the Iberian peninsula. Artificial crosses involving Silene pyrenaica (Bergeret) Mayol et Rosselló (≡ Petrocoptis pyrenaica (Bergeret) Walp.), Silene laxipruinosa Mayol et Rosselló and S. montserratii subsp. crassifolia (Rouy) Mayol et Rosselló (≡ P. crassifolia Rouy) were attempted to assess the extent of barriers developed within the subgenus Petrocoptis. Usually, intraspecific crosses involving allopatric populations were successful, suggesting that geographically isolated populations are not genetically isolated. Cross-compatibility was noted among the polymorphic S. pyrenaica, which developed fertile F1 hybrids. All other interspecific crosses failed due to cross- or seed-incompatibility. Crossing results agree with available evidence supporting the merging of segregates of S. pyrenaica within a single taxon.