Parental Effects in a Partially Self‐Incompatible HerbCampanula rapunculoidesL. (Campanulaceae): Influence of Variation in the Strength of Self‐Incompatibility on Seed Set and Progeny Performance

Abstract

We employ a full reciprocal diallel design between 10 parental plants that differed in their strength of self-incompatibility (SI; strong, intermediate, and weak) to examine parental effects on seed set and 10 components of fitness of progeny performance in Campanula rapunculoides. We perform ANOVAs to separate the influence of the strength of SI and the identity of the maternal and paternal parent on family performance. We calculate the phenotypic and genetic correlations between traits to determine potentially evolutionary constraints. Finally, we employ maximum likelihood methods to estimate the components of quantitative genetic variance, as defined by Cockerham and Weir in their BioModel c. Our most significant finding is that weak SI plants have high outcrossed seed set as maternal parents. We argue that direct or pleiotropic effects of modifiers of SI probably cause this. Second, we find that extranuclear interactions, as defined by the BioModel, have strong effects on seed set and several vegetative and flowering traits. These findings indicate that some maternal plants selectively provision seeds sired by specific paternal donors and that some of this variation appears to be associated with modifiers of the strength of SI. We find other sources of significant quantitative genetic variation for all of the traits we examine and discuss the possible role these play in the evolution of the reproductive system. Taken together, our findings show that variation in the strength of SI may influence levels of quantitative genetic variation that, in turn, can influence the reproductive success of individuals in C. rapunculoides

Effects of inbreeding on male function and self‐fertility in the partially self‐incompatible herb Campanula rapunculoides (Campanulaceae)

“…For example, we have shown that the strength of SI has a heritable genetic basis (Good-Avila and Stephenson, 2002), that strong and weak SI families differ in inbreeding depression for vegetative traits (Vogler et al, 1999b) and show differential performance as pollen and seed parents (Good-Avila and Stephenson, 2003), and here, we have shown that strong and weak families have differential reproductive output through both male and female function. For example, we have shown that the strength of SI has a heritable genetic basis (Good-Avila and Stephenson, 2002), that strong and weak SI families differ in inbreeding depression for vegetative traits (Vogler et al, 1999b) and show differential performance as pollen and seed parents (Good-Avila and Stephenson, 2003), and here, we have shown that strong and weak families have differential reproductive output through both male and female function.…”

“…In C. rapunculoides, we have now accumulated considerable evidence that variation in the strength of SI among individuals may be of evolutionary importance. For example, we have shown that the strength of SI has a heritable genetic basis (Good-Avila and Stephenson, 2002), that strong and weak SI families differ in inbreeding depression for vegetative traits (Vogler et al, 1999b) and show differential performance as pollen and seed parents (Good-Avila and Stephenson, 2003), and here, we have shown that strong and weak families have differential reproductive output through both male and female function. The strong influence of variation in self-fertility on reproductive success has certainly strengthened our ability to detect associations between genetic load and modifiers of SI.…”

Subindividual variation and genetic versus environmental effects on seed traits in a EuropeanAquilegia

“…We also found a significant maternal effect on the time to seedling emergence (about 25% of the V P ), though not as high as for seed mass. Similarly strong maternal effects are commonly reported for other species in seed size (Antonovics and Schmitt 1986;Mazer 1987b;Schwaegerle and Levin 1990;Biere 1991a;Platenkamp and Shaw 1993;Montalvo and Shaw 1994;Schmid and Dolt 1994;Waser et al 1995;Wolfe 1995;Helenurm and Schaal 1996;Byers et al 1997;Lipow and Wyatt 1999), seed numbers (Mazer 1987b;Waser et al 1995;Good-Avila and Stephenson 2003), and time to germination (Biere 1991a;Platenkamp and Shaw 1993;Schmid and Dolt 1994;Helenurm and Schaal 1996), including the columbine Aquilegia caerulea (Montalvo and Shaw 1994). The importance of maternal effects in these traits is hardly surprising, because seeds develop surrounded and provisioned by maternal tissue and, in addition, the genetic contribution of mothers to seeds is higher compared to that of fathers.…”

Inbreeding depression in male gametic performance

“…In studies that used more than one discrete inbred group, some study traits (37 in total) only differed in f (e.g. Good‐Avila & Stephenson, ; see Table ), therefore potentially creating some pseudo‐replication. However, models fitted to data sets that comprised mean B across each set of study traits that differed only in f yielded similar results (not shown).…”