Paternity analysis reveals significant isolation and near neighbor pollen dispersal in small Cariniana legalis Mart. Kuntze populations in the Brazilian Atlantic Forest

Throughout the world, large trees are increasingly rare. Cariniana legalis is the tallest tree species of the Brazilian Atlantic Forest, reaching up to 60 m in height. Due to extensive deforestation of the Atlantic Forest, remnant C. legalis populations are small and spatially isolated, requiring the development of strategies for their conservation. For in situ and ex situ genetic conservation to be effective, it is important to understand the levels and patterns of spatial genetic structure (SGS), and gene flow. We investigated SGS and pollen flow in three small, physically isolated C. legalis stands using microsatellite loci. We measured, mapped, and sampled all C. legalis trees in the three stands: 65 trees from Ibicatu population, 22 trees from MGI, and 4 trees from MGII. We also collected and genotyped 600 seeds from Ibicatu, 250 seeds from MGI, and 200 seeds from MGII. Significant SGS was detected in Ibicatu up to 150 m, but substantial levels of external pollen flow were also detected in Ibicatu (8%), although not in MGI (0.4%) or MGII (0%). Selfing was highest in MGII (18%), the smallest group of trees, compared to MGI (6.4%) and Ibicatu (6%). In MGI and MGII, there was a strong pattern of mating among near-neighbors. Seed collection strategies for breeding, in situ and ex situ conservation and ecological restoration, must ensure collection from seed trees located at distances greater than 350 m and from several forest fragments

Inbreeding depression from selfing and mating between relatives in the Neotropical tree Cariniana legalis Mart. Kuntze

Selfing or mating between related individuals in self-compatible hermaphroditic tree species may lead to inbreeding depression (ID) due to homozygosis in recessive, identical by descent alleles. In general, studies of ID in tree species have been based on comparisons of selfed individuals (produced by controlled pollination) with outcrossed individuals for quantitative traits in progeny tests. However, this approach requires a long time to quantify the extent of ID. Thus, we used an approach based on genetic markers to estimate coancestry coefficients between assigned parents from paternity analysis in two populations of the Neotropical tree Cariniana legalis. Using this method, we were able to determine which seedlings in a nursery trial originated from; i) outcrossing between un-related trees, ii) mating between related trees and iii) selfing. We detected a low selfing rate (< 10%), but a substantial quantity of seedlings from mating between related parents (minimum of 35.7%). In general, the outcrossed seedlings from unrelated parents exhibited significantly greater genetic diversity than those resulting from selfing and mating among relatives. The extent of ID varied among traits and populations. Outcrossed seedlings originating from unrelated trees generally showed greater survival than seedlings originating from selfing and related parents. Inbreeding depression was greater in the selfed seedlings than in those from mating among related parents. The results are discussed in terms of implications for genetic conservation, breeding and environmental restoration using the species

Paternity analysis reveals significant isolation and near neighbor pollen dispersal in small Cariniana legalis Mart. Kuntze populations in the Brazilian Atlantic Forest

Throughout the world, large trees are increasingly rare. Cariniana legalis is the tallest tree species of the Brazilian Atlantic Forest, reaching up to 60 m in height. Due to extensive deforestation of the Atlantic Forest, remnant C. legalis populations are small and spatially isolated, requiring the development of strategies for their conservation. For in situ and ex situ genetic conservation to be effective, it is important to understand the levels and patterns of spatial genetic structure (SGS), and gene flow. We investigated SGS and pollen flow in three small, physically isolated C. legalis stands using microsatellite loci. We measured, mapped, and sampled all C. legalis trees in the three stands: 65 trees from Ibicatu population, 22 trees from MGI, and 4 trees from MGII. We also collected and genotyped 600 seeds from Ibicatu, 250 seeds from MGI, and 200 seeds from MGII. Significant SGS was detected in Ibicatu up to 150 m, but substantial levels of external pollen flow were also detected in Ibicatu (8%), although not in MGI (0.4%) or MGII (0%). Selfing was highest in MGII (18%), the smallest group of trees, compared to MGI (6.4%) and Ibicatu (6%). In MGI and MGII, there was a strong pattern of mating among near-neighbors. Seed collection strategies for breeding, in situ and ex situ conservation and ecological restoration, must ensure collection from seed trees located at distances greater than 350 m and from several forest fragments

Inbreeding depression from selfing and mating between relatives in the Neotropical tree Cariniana legalis Mart. Kuntze

Selfing or mating between related individuals in self-compatible hermaphroditic tree species may lead to inbreeding depression (ID) due to homozygosis in recessive, identical by descent alleles. In general, studies of ID in tree species have been based on comparisons of selfed individuals (produced by controlled pollination) with outcrossed individuals for quantitative traits in progeny tests. However, this approach requires a long time to quantify the extent of ID. Thus, we used an approach based on genetic markers to estimate coancestry coefficients between assigned parents from paternity analysis in two populations of the Neotropical tree Cariniana legalis. Using this method, we were able to determine which seedlings in a nursery trial originated from; i) outcrossing between un-related trees, ii) mating between related trees and iii) selfing. We detected a low selfing rate (&lt; 10%), but a substantial quantity of seedlings from mating between related parents (minimum of 35.7%). In general, the outcrossed seedlings from unrelated parents exhibited significantly greater genetic diversity than those resulting from selfing and mating among relatives. The extent of ID varied among traits and populations. Outcrossed seedlings originating from unrelated trees generally showed greater survival than seedlings originating from selfing and related parents. Inbreeding depression was greater in the selfed seedlings than in those from mating among related parents. The results are discussed in terms of implications for genetic conservation, breeding and environmental restoration using the species

Several small: how inbreeding affects conservation of Cariniana legalis Mart. Kuntze (Lecythidaceae) the Brazilian Atlantic Forest’s largest tree

We investigated the impact of population size on genetic diversity, inbreeding and mating system in small remnant stands of the Neotropical tree, Cariniana legalis, using microsatellite loci. All adult trees within three different size stands (4, 22 and 65 trees) were sampled, along with open-pollinated seeds. A number of impacts related to population size were evident. Allelic richness was significantly lower among progeny in the smallest fragment, as was outcrossing rate. Individual tree outcrossing rates were predominantly high, but several trees presented significant mating among relatives. The correlation of paternity within fruits was significantly higher than among fruits in all populations, indicating that the probability of full-sibs being produced is highest within fruits. Our results show that low population size can increase the rate of selfing in C. legalis and that open-pollinated seed from the largest populations may also include inbreeding from mating among relatives

Several small: how inbreeding affects conservation of Cariniana legalis Mart. Kuntze (Lecythidaceae) the Brazilian Atlantic Forest’s largest tree

We investigated the impact of population size on genetic diversity, inbreeding and mating system in small remnant stands of the Neotropical tree, Cariniana legalis, using microsatellite loci. All adult trees within three different size stands (4, 22 and 65 trees) were sampled, along with open-pollinated seeds. A number of impacts related to population size were evident. Allelic richness was significantly lower among progeny in the smallest fragment, as was outcrossing rate. Individual tree outcrossing rates were predominantly high, but several trees presented significant mating among relatives. The correlation of paternity within fruits was significantly higher than among fruits in all populations, indicating that the probability of full-sibs being produced is highest within fruits. Our results show that low population size can increase the rate of selfing in C. legalis and that open-pollinated seed from the largest populations may also include inbreeding from mating among relatives