Mating system of a population of Myracrodruon urundeuva F.F. & M.F. Allemão using the fAFLP molecular marker

The mating system and genetic diversity were studied in a natural population of Myracrodruon urundeuva originating from 30 open-pollinated trees at the Paulo de Faria Ecological Station, SP, Brazil. The progenies were planted on the Teaching and Research Farm of the Ilha Solteira Engineering School, UNESP. Using the fAFLP molecular marker, eleven loci were selected to study the mating system. The mating system was analyzed using the multilocus mixed-mating model. The estimates of genetic divergence between pollen and ovule allele frequencies were significant for eight loci, suggesting nonrandom outcrossing. The estimates of the multilocus outcrossing rate revealed that M. urundeuva possesses a mating system with a predominance of outcrossing events (theta = 0.940 ± 0.086). The estimates of coancestry among plants within progenies (theta = 0.185) was higher than that expected for half-sib progenies (0.125) and the indirect estimate of the correlation of outcrossed paternity within progeny arrays (r p) was 0.403, suggesting that progenies have a high proportion of full-sibs. Result analysis suggests the need for the application of biometric models that take into account deviations from random outcrossing in the estimations of genetic parameters for quantitative traits and the need for retaining large sample sizes in order to preserve genetic variability.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

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

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. Microsatellite were used to investigated the mating system, pollen dispersal, genetic diversity, spatial genetic structure (SGS), and inbreeding 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 (tm = 0.45) and mating among relatives (tm - ts = 0.12), but longer pollen dispersal distances (δ = 6,572 m) than in the higher density populations (tm = 0.90, tm - ts = 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

Data from: Long-distance pollen and seed dispersal and inbreeding depression in Hymenaea stigonocarpa (Fabaceae: Caesalpinioideae) in the Brazilian savannah

Hymenaea stigonocarpa is a Neotropical tree that is economically important due to its high-quality wood; however, because it has been exploited extensively, it is currently considered threatened. Microsatellite loci were used to investigate the pollen and seed dispersal, mating patterns, spatial genetic structure (SGS), genetic diversity, and inbreeding depression in H. stigonocarpa adults, juveniles and open-pollinated seeds, which were sampled from isolated trees in a pasture and trees within a forest fragment in the Brazilian savannah. We found that the species presented a mixed mating system, with population and individual variations in the outcrossing rate (0.53–1.0). The studied populations were not genetically isolated due to pollen and seed flow between the studied populations and between the populations and individuals located outside of the study area. Pollen and seed dispersal occurred over long distances (> 8 km); however, the dispersal patterns were isolated by distance, with a high frequency of mating occurring between near-neighbour trees and seeds dispersed near the parent trees. The correlated mating for individual seed trees was higher within than among fruits, indicating that fruits present a high proportion of full-sibs. Genetic diversity and SGS were similar among the populations, but offspring showed evidence of inbreeding, mainly originating from mating among related trees, which suggests inbreeding depression between the seed and adult stages. Selfing resulted in a higher inbreeding depression than mating among relatives, as assessed through survival and height. As the populations are not genetically isolated, both are important targets for in situ conservation to maintain their genetic diversity; for ex situ conservation, seeds can be collected from at least 78 trees in both populations separated by at least 250 m

Selecting for rust (Puccinia psidii) resistance in Eucalyptus grandis in São Paulo State, Brazil

In Brazil, Eucalyptus grandis is a key species for wood production. However, some genotypes are susceptible to rust (Puccinia psidii), mainly in São Paulo State, where climatic conditions are favorable for its development. Rust represents a high economic risk to forest companies because of the high potential of damage to commercial eucalypt plantations. The aims of the present study were (i) to select progenies of E. grandis for stability and adaptability regarding resistance to rust at different locations; (ii) compare the selections under these different climatic conditions; and (iii) compare rust severity in the field with the theoretical model. We observed that climatic conditions were extremely influential factors for rust development, but even under favorable conditions for disease development, we found rust-resistant progenies. In sites unfavorable for rust development, we detected highly susceptible progenies. We found significant correlation among the genetic material, environmental conditions and disease symptoms, however, we observed a simple genotype-environmental interaction and significant genetic variability among the progenies. The average heritability was high among the progenies in all sites, indicating substantial genetic control for rust resistance. We also observed a good relationship between rust severity in the field and the theoretical model that considered annual average temperature and leaf wetness. © 2013 Elsevier B.V