title: Self-incompatibility and floral parameters in Hypochaeris sect. Hypochaeris (Asteraceae).
abstract: We studied the relationships between self-incompatibility mechanisms and floral parameters in the genus Hypochaeris L. sect. Hypochaeris (consisting of H. glabra, H. radicata, H. arachnoidea, and H. salzmanniana). We assessed at intra- and interspecific levels (1) the self-incompatibility (SI) mechanism and its distribution among populations, (2) the relationship between SI and floral parameters, and (3) the relationship of SI to reproductive success. Hypochaeris salzmanniana is semi-incompatible, H. glabra is self-compatible, and H. arachnoidea and H. radicata are self-incompatible. Floral parameters differed among populations of H. salzmanniana: plants in self-compatible populations had fewer flowers per head, a smaller head diameter on the flower, and a shorter period of anthesis than self-incompatible populations. We also detected this pattern within a semi-compatible population of H. salzmanniana, and these differences were also found between species with different breeding mechanisms. Fruit to flower ratio in natural populations was generally high (>60%) in all species, regardless of breeding system. It is hypothesized that self-compatibility may have arisen through loss of allelic diversity at the S locus due to bottleneck events and genetic drift.
authors.affiliation: Departamento de Biologia Vegetal y Ecologia, Universidad de Sevilla, Apdo-1095, 41080 Sevilla, Spain;
authors.forename: Maria Ángeles
authors.initials: MÁ
authors.lastname: Ortiz
authors.forename: Salvador
authors.initials: S
authors.lastname: Talavera
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Garcia-Castaño
authors.forename: Karin
authors.initials: K
authors.lastname: Tremetsberger
authors.forename: Tod
authors.initials: T
authors.lastname: Stuessy
authors.forename: Francisco
authors.initials: F
authors.lastname: Balao
authors.forename: Ramón
authors.initials: R
authors.lastname: Casimiro-Soriguer