Breeding systems and floral biology in the genus briza

Abstract

Floral morphology is shown to be closely correlated with the type of breeding system in the genus Briza L. (Gramineae). The outbreeding species have large anthers and stigmas that are well exerted at anthesis whereas in the inbreeding species anthers and stigmas are small and the flowers are frequently cleistogamous. Self-incompatibility in B. media is controlled by two genes, both with multiple alleles. Identity at both loci is necessary for pollen inhibition. Pollen control is gametophytic, incompatible pollen tubes are inhibited on the stigmatic surface. Unilateral incompatibility occurs in crosses between self-incompatible and self-compatible species. Self-compatible pollen is inhibited on self-incompatible stigmas but the reciprocal shows no inhibition. © 1974 The Genetical Society of Great Britain.