Dipteryx alata Vogel (Fabaceae) a neotropical tree with high level of selfing: implication for conservation and breeding programs

Abstract

Abstract. Dipteryx alata (Fabaceae) is a threatened tropical tree of the Brazilian Savanna. Due to deforestation of its biome, many individuals and populations are now spatially isolated in forest fragments, pastures, and along roads. Plans for in situ and ex situ conservation of the species are urgently needed. To support conservation, the mating system and pollen dispersal patterns must be better understood as they determine the levels of genetic diversity, inbreeding, and effective size of seed generations. Microsatellites were used to investigate the mating system, pollen dispersal, genetic diversity and spatial genetic structure (SGS), in isolated trees in pastures and along roads from two populations with different densities in the Brazilian Savanna. Our aim is to determine the potential of these trees to contribute to seed collection for genetic conservation. We found that the species presents a mixed mating system, strong individual variation in outcrossing rate (0.01-1.0), and non-random mating. Low population density resulted in lower levels of outcrossing (t m = 0.45) and mating among relatives (t m -t s = 0.12), but longer pollen dispersal distances (δ = 6,572 m) than in the higher density populations (t m = 0.90, t m -t s = 0.26, δ = 1,395 m). Mating among relatives was explained by SGS detected in the populations, associated with near-neighbor pollinator foraging behavior. Correlated mating indicates that a low effective number of pollen donors (1.5-10.3) fertilized the trees. Thus, open-pollinated seedling families present mixtures of different levels of relatedness and inbreeding. Our results are discussed in light of strategies for in and ex situ conservation.

GENETIC DIVERSITY AND MATING SYSTEM OF Rhizophora mangle L. (RHIZOPHORACEAE) IN NORTHERN BRAZIL REVEALED BY MICROSATELLITE ANALYSIS

“…However, the mating system patterns of a tree species can be controlled by the environment and genetic processes. Thus, some adult trees, populations or even reproductive events may present higher or lower percentages of self-fertilization (Tambarussi et al, 2016;Tambarussi et al, 2017). This result can be observed in the R. mangle population of this study, which demonstrated progeny array self-fertilization values ranging from 0.488 (for F16) to 0.993 (F30) ( Table 4).…”

“…Thus, the open-pollinated progenies were composed mainly of half-sibs families. These percentages may have strong implications for the collection of seeds for the conservation, restoration of degraded areas and for the preimprovement of the tree species (Tambarussi et al, 2017).…”

Assessing genetic diversity and population structure in a Dipteryx alata germplasm collection utilizing microsatellite markers

“…For the cultivation of a native species, a broad knowledge of its biological and silvicultural characteristics is necessary. To this end, several studies have been conducted on D. alata, most of which aimed to obtain information on food and nutrition (Sousa et al 2018), agronomic and silvicultural aspects (Santos et al 2014, ex situ and in situ conservation (Melo et al 2011, Tambarussi et al 2017, Guimarães et al 2019, and genetic variability (Soares et al 2008a, Soares et al 2008b, Soares et al 2015.…”

Demographic history and spatial genetic structure in a remnant population of the subtropical tree Anadenanthera colubrina var. cebil (Griseb.) Altschul (Fabaceae)

“…cebil displays a mixed mating system. Selfing is common in legumes, and studies on the proportion of selfed vs. outcrossed offspring in other Neotropical legume trees have revealed mixed mating systems, for instance in Senna multijuga (Ribeiro and Lovato 2004), Copaifera langsdorfii (Tarazi et al 2013), and Dipteryx alata (Tambarussi et al 2017). More detailed investigation on the genetic constitution of offspring would be needed for a detailed characterization of the mating system of A. colubrina var.…”