Does differential seed siring success change over time or with pollination history in wild radish, Raphanus sativus (Brassicaceae)?

Abstract

Previous work with wild radish has shown that pollen donors sire different numbers of seeds and that the condition of the maternal tissue affects seed paternity, suggesting that both pollen donor characteristics and maternal tissue affect mating. However, because these results are from the greenhouse, it is difficult to know whether they would hold true in the field. Here, we performed hundreds of crosses on several maternal plants to simulate changes during the flowering season of field plants. During the experiment, maternal resource availability changed due to the costs of producing fruits, and we determined the pollination history of a plant by performing crosses in specific orders. Examination of seed paternity showed that there were small differences in pollen donor success at the beginning of the experiment when maternal resources were abundant. Differential pollen donor success was greatest slightly later in the flowering period, but declined toward the end of the experiment. Thus, maternal plants may distinguish most among pollen donors when they have both abundant resources and experience with the differences in quality of available pollen donors. In contrast, there were few significant effects of the recent pollination history of plants on pollen donor success. Finally, despite the changes in mating performance over time, there were strong overall differences in pollen donor success, suggesting that seasonal changes in the field will not eliminate the potential for nonrandom mating.

Post-pollination mechanisms in Nicotiana longiflora and N. plumbaginifolia: pollen tube growth rate, offspring paternity and hybridization

“…In plants, post-pollination mechanisms can act as selective agents determining the siring success of pollen donors (Marshall and Ellstrand 1986;Marshall 1988Marshall , 1991Snow and Spira 1991;Montalvo 1992;Walsh and Charlesworth 1992;Rigney et al 1993;Carney et al 1994;Marshall et al 1996;Eckert and Allen 1997;Skogsmyr and Lankinen 1999;Marshall and Diggle 2001;Marshall and Oliveras 2001;Lankinen and Skogsmyr 2002;Shaner and Marshall 2003;Bernasconi et al 2004;Haileselassie et al 2005;Kruszewski and Galloway 2006;Marshall et al 2007). For instance, self-incompatibility reactions are a common post-pollination mechanism present in angiosperms (de Nettancourt 2001;Franklin-Tong and Franklin 2003).…”

Males outcompete hermaphrodites for seed siring success in controlled crosses in the polygamous Fraxinus excelsior (Oleaceae)

“…Moreover, maintenance of androdioecy requires a male fertility advantage of males over hermaphrodites. More generally, although seed paternity is nonrandom when pollen from two or more pollen donors is applied to stigmas (see Marshall and Oliveras [2001] for a review of these studies), this has usually been related to pollen tube growth rate differences rather than phenotypic differences between the pollen donors (see for example; Björkman et al, 1995;Snow and Spira, 1996;Pasonen et al, 1999). In natural populations however, male and hermaphrodite individuals may compete for seed siring (Pannell and Ojeda, 2000), and paternity analysis is needed to determine the effective male reproductive success of male vs. hermaphrodite individuals.…”

Defining features of age‐specific fertility and seed quality in senescing indeterminate annuals

“…However, reproductively indeterminate annuals like Brassica have determinate vegetative bodies and they do not increase their vegetative biomass after reproduction begins. Other factors include pollinator availability (albeit weakly; Marshall and Oliveras, ), pollen load, and paternal genetic effects, all of which can cause fertility fluctuations and regulate the extent of seed abortion in an out‐crossing species like Brassica (e.g., Marshall and Ellstrand, ; Diggle et al., ). Nonetheless, age‐specific fertility in self‐pollinated Arabidopsis and Brassica showed similar trends, suggesting a greater role for internal senescence‐related factors in regulating fertility.…”