A Self-Compatible Plant of Stephanomeria exigua subsp. Coronaria (Asteraceae) and Its Relevance to the Origin of Its Self-Pollinating Derivative S. malheurensis

The Genetics of Self-Compatibility and Associated Floral Characters inTolpis(Asteraceae) in the Canary Islands

“…The complexity of the SSI system in Asteraceae has been documented though not fully elucidated. A major factor conferring complexity is the possible dominance relationships among S-alleles with SSI (Brauner and Gottlieb 1987;Levin 1996;Hiscock and Tabah 2003;Busch and Schoen 2008;Brennan et al 2011). Dominance among alleles may differ in pollen and stigma, resulting in different compatibility results for reciprocal crosses (Hiscock and Tabah 2003).…”

“…The loss of SI has been documented between sister or progenitor-derivative species (Ornduff 1966;Gottlieb 1973;Beck et al 2006;Busch and Urban 2011;Slotte et al 2012), between sister subspecies (Pettengill and Moeller 2011), among populations of a species (Busch 2005;Koelling et al 2011), and among individuals within populations (Brauner and Gottlieb 1987;Tsukamoto et al 1999;Mable et al 2005). The breakdown of SI may be associated with one or more floral features collectively known as the selfing syndrome (Ornduff 1969), so that closely related SI-PSC and SC species differ by several of these floral characters (Ornduff 1966;Foxe et al 2009;Slotte et al 2012).…”

The demography and population genomics of evolutionary transitions to self-fertilization in plants

“…coronaria was associated with a shift from outcrossing to selfing. This transition resulted from the breakdown of self-incompatibility and the development of hybrid sterility, owing to chromosomal structural differences between the progenitor and derivative [11,12]. Today, it is widely recognized that the loss of self-incompatibility is commonly associated with shifts from outcrossing to selfing, and in many cases this also appears to promote speciation [13].…”

Contemporary and future studies in plant speciation, morphological/floral evolution and polyploidy: honouring the scientific contributions of Leslie D. Gottlieb to plant evolutionary biology

“…Among many other things, it may serve as an isolating mechanism [14][15][16], and indeed in many plant lineages the origin of self-compatibility with the loss of function of the self-incompatibility locus is associated with speciation [16][17][18][19]. In fact, Leslie Gottlieb provided an elegant example of the association of speciation and the transition to selfing in his classic studies in the genus Stephanomeria [20,21]. It had long been recognized that selfing species are less variable genetically at the population level [22], and as discussed by Barrett et al [23] in this issue, Gottlieb was one of the first to use enzyme electrophoresis to document lower genetic diversity in outcrossing compared with selfing plants [20,[24][25][26].…”

“…In his studies of Stephanomeria, Gottlieb was concerned with how initial divergence could have occurred and how the rarer derivative species could coexist with its progenitor at the same locality. While he identified several factors reducing interspecific gene flow and thus presumably explaining the rarity of natural interspecific hybrids in Stephanomeria, he never succeeded in elucidating the factors (indeed, if they existed) contributing to ecological/habitat divergence between the two species growing intermixed at a single locality [20,21,42,43]. The same issues that intrigued Gottlieb decades ago remain of interest and the focus of contemporary studies.…”