Mixed Mating System Are Regulated by Fecundity in Shorea curtisii (Dipterocarpaceae) as Revealed by Comparison under Different Pollen Limited Conditions

Abstract

The maintenance of mixed mating was studied in Shorea curtisii, a dominant and widely distributed dipterocarp species in Southeast Asia. Paternity and hierarchical Bayesian analyses were used to estimate the parameters of pollen dispersal kernel, male fecundity and self-pollen affinity. We hypothesized that partial self incompatibility and/or inbreeding depression reduce the number of selfed seeds if the mother trees receive sufficient pollen, whereas reproductive assurance increases the numbers of selfed seeds under low amounts of pollen. Comparison of estimated parameters of self-pollen affinity between high density undisturbed and low density selectively logged forests indicated that self-pollen was selectively excluded from mating in the former, probably due to partial self incompatibility or inbreeding depression until seed maturation. By estimating the self-pollen affinity of each mother tree in both forests, mother trees with higher amount of self-pollen indicated significance of self-pollen affinity with negative estimated value. The exclusion of self-fertilization and/or inbreeding depression during seed maturation occurred in the mother trees with large female fecundity, whereas reproductive assurance increased self-fertilization in the mother trees with lower female fecundity.

Albinism and inbreeding depression in seedlings of the tropical tree,Shorea laxa

“…We found that lower initial height had a significantly negative effect on seedling survival, which may be because height is advantageous to competing for light on the forest floor (Takeuchi et al 2005). Fitness reduction of inbred individuals at early life stages was commonly found in previous studies of tropical tree species, such as a high abortion rate (Hufford and Hamrick 2003), seed maturation failure (Ghazoul et al 1998;Nagamitsu et al 2000;Tani et al 2015), smaller seed mass (Naito et al 2005), low germination rate (Naito et al 2005;Ismail et al 2014), and lower plant height (Rymer et al 2015).…”

Identification of determinants of pollen donor fecundity using the hierarchical neighborhood model

“…The classic neighborhood model assumes that , and are the same for all sampled families. Here, as in earlier studies (Chybicki & Burczyk, 2013; Chybicki et al, 2019; Tani et al, 2015), we assumed that these probabilities might show inter‐family variation. To do so, a vector for the j‐th family was assumed to follow a Dirichlet distribution with three hyper‐parameters .…”

Exploring the role of genetic diversity and relatedness in tree seedling growth and mortality: A multispecies study in a Bornean rainforest

“…In addition, we cannot exclude potential effects of variation in null alleles across species, which could mask inbreeding effects. Other studies have proposed self‐fertilization and apomixis to be potentially important to dilute the effects of seedling predators (Ghazoul & Satake, ; Tani et al, ). It would be interesting to explore these different stages of reproduction in more detail in future studies.…”