Self‐incompatibility and floral parameters inHypochaerissect.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.

Self-incompatibility, floral parameters, and pollen characterization in the narrow endemic and threatened species <i>Artemisia granatensis</i> (Asteraceae)

“…Additionally, stamen, ovary, and style sizes were comparable. Previous reports in some Asteraceae showed that flowersize differences could be related to the loss of self-incompatibility in small populations (Ortiz & al., 2006), and this trend has also been found for another selfincompatible species in fragmented habitats (Taisma & Varela, 2005). Our results indicate that AG1 and AG2 plants have no morphological differences and, therefore, these traits could not be related to differential self-incompatibility expression.…”

“…Some studies have related self-incompatibility systems to floral and inflorescence size (Gibbs & al., 1975;Ortiz & al., 2006). For example, in the genus Hypochaeris L. partial self-compatible heads are larger than self-incompatible heads (Ortiz & al., 2006).…”

“…For example, in the genus Hypochaeris L. partial self-compatible heads are larger than self-incompatible heads (Ortiz & al., 2006). Thus, the evaluation of a self-incompatibility system must include the flower and inflorescence morphology in order to gain a full understanding of the reproductive potential.…”

“…Since A. granatensis, belonging to Asteraceae, a family with selfincompatible established in around 40 genera (Charlesworth, 1985), and with some reports on partial self-incompatibility (Ortiz & al., 2006), could have a self-incompatibility system which has not previously been tested.…”

Strong inbreeding depression and individually variable mating system in the narrow endemic <i>Erodium cazorlanum</i> (Geraniaceae)

“…Recent comparative analyses suggested that endemic species tend to evolve self-compatibility (SC) systems (Alonso & al., 2010) but PSC was not considered as a possible stage. Interestingly, PSC has been found in several endemic species (e.g., Byers, 1995;Bush, 2005;Glemin & al., 2005, Ortiz & al., 2006Nielsen & al., 2007;Weber & Goodwillie, 2009;Crawford & al., 2010;Narbona & al., 2011) suggesting that endemics could be good species candidates for studying ongoing evolutionary changes in mating system. Endemic species frequently experience high pollen limitation in the characteristically diverse communities where they occur (Vamosi & al., 2006;Alonso & al., 2010).…”