High genetic diversity promotes a common-garden trial of Quercus robur as a potential seed source

The process of adaptation in forest trees might be facilitated if seeds resulting from crossings among different provenances are used for plantation establishment. This can be accomplished if seeds from existing common-garden trials become available. This paper aims to characterize genetic diversity of a provenance/family common-garden trial of Quercus robur which is considered a possible source of highly diverse seed lots. Provenance/family common-garden trial of Quercus robur located in Oleszyce, Poland, consisting of 8 to 19 families of six Polish provenances was chosen for the study. With the aid of 16 nuclear microsatellite markers, 1812 trees growing in the trial were genotyped. Standard population genetic parameters were calculated, and genetic variation and inbreeding were compared among provenances. Expected heterozygosity and particularly allelic richness appeared to be high, reaching on average 0.847 and 23.5, respectively. We found no signatures of inbreeding (FIS=0.006) and low, although statistically significant, level of genetic differentiation among provenances (FST=0.016). On the other hand, we found high allelic differentiation (AST=0.137) between provenances, though uneven contribution of each provenance to the total allelic richness was noted. Effective population sizes estimated for each provenance based on linkage disequilibrium were highly correlated with the number of families within provenances. We conclude that the studied common-garden trial possesses high genetic diversity and possible mating among different provenances may promote further heterosis effects. Thus the trial may be used in the future as an experimental source of highly diverse seed lots much needed in the context of climate change

Taxus data

Microsatellite genotypes of trees and seedlings, and field measurements of Taxus baccata trees in 10 populations in Poland

Genetic diversity of Dactylorhiza incarnata (Orchidaceae) in northern Poland

The genetic structure of Dactylorhiza incarnata var. incarnata populations is shaped not only by historical events such as recolonization after ice sheet retreat or limited seed and pollen dispersal, but also the bottleneck effect. During the last decade, D. incarnata var. incarnata has also experienced a strong decline in population numbers and sizes, due to habitat loss and fragmentation. In the present research genetic diversity was examined in eight populations located in northern Poland, using six nuclear microsatellites loci. At the species level our results showed a moderate mean level of genetic diversity (A = 4.67; Ae = 2.73; Rs = 4.48; Ho = 0.438; FIS = 0.224), which varied among the studied populations (A: 2.17–3.67; Ae: 1.55–2.69; Rs: 1.31–1.61; Ho: 0.292–0.631; FIS: −0.283–0.340). A considerable overabundance of homozygotes was detected in four populations (FIS within the range of 0.067–0.340), and in the remaining populations an excess of heterozygotes was observed. The average apparent out-crossing rate was also calculated (ta = 0.980), and primarily indicated a tendency to out-cross within the species. Moderate genetic differentiation was found among the studied populations (FST = 0.149; RST = 0.174; p < 0.05). The differentiation of the populations corresponded to relatively low gene flow value (Nm = 0.426) among populations, which amounted to only one migrant every second generation

Data from: Relative strength of fine-scale spatial genetic structure in paternally vs biparentally inherited DNA in a dioecious plant depends on both sex proportions and pollen-to-seed dispersal ratio

In plants, the spatial genetic structure (SGS) is shaped mainly by gene dispersal and effective population density. Among additional factors, the mode of DNA inheritance and dioecy influence SGS. However, their joint impact on SGS remains unclear, especially in the case of paternally inherited DNA. Using theoretical approximations and computer simulations, here we showed that the relative intensity of SGS measured in paternally and biparentally inherited DNA in a dioecious plant population depends on both the proportion of males and the pollen-to-seed dispersal ratio. As long as males do not prevail in a population, SGS is more intense in paternally than biparentally inherited DNA. When males prevail, the intensity of SGS in paternally vs biparentally inherited DNA depends on the compound effect of sex proportions and the pollen-to-seed dispersal ratio. To empirically validate our predictions, we used the case of Taxus baccata, a dioecious European tree. First, we showed that mitochondrial DNA (mtDNA) in T. baccata is predominantly (98%) paternally inherited. Subsequently, using nuclear DNA (nuDNA) and mitochondrial microsatellite data, we compared the fine-scale SGS intensity at both marker types in two natural populations. The population with equal sex proportions showed stronger SGS in mtDNA than in nuDNA. On the other hand, we found lower SGS intensity in mtDNA than in nuDNA in the population with 67% males. Thus, the empirical results provided good support for the theoretical predictions, suggesting that knowledge about SGS in paternally vs biparentally inherited DNA may provide insight into effective sex proportions within dioecious populations

Rural avenues as dispersal corridors for the vulnerable saproxylic beetle Elater ferrugineus in a fragmented agricultural landscape

Understanding factors that limit gene flow through the landscape is crucial for conservation of organisms living in fragmented habitats. We analysed patterns of gene flow in Elater ferrugineus, an endangered click beetle living in old-growth, hollow trees in a network of rural avenues surrounded by inhospitable arable land. Using amplified fragment length polymorphism (AFLP) data, we aimed to evaluate if the landscape features important for the beetle's development are also important for its dispersal. By dividing the sampling area into 30 x 30 m cells, with each cell categorised into one of four classes according to its putative permeability for dispersing beetles, and by correlating matrices of genetic and landscape resistance distances, we evaluated which of the landscape models had the best fit with the observed kinship structure. Significant correlations between genetic and Euclidean distances were detected, which indicated that restricted dispersal is the main constraint driving differentiation between populations of E. ferrugineus. Out of 81 landscape models in total, 54 models yielded significantly weaker correlation between matrices of pairwise kinship and effective distances than the null model. Regression analysis pointed to avenues as having the highest and positive impact on the concordance between matrices of kinship and landscape distances, while open arable land had the opposite effect. Our study thus shows that tree avenues can function as efficient dispersal corridors for E. ferrugineus, highlighting the importance of saving such avenues to increase the connectivity among suitable habitat patches, thereby reducing the risk of local extinctions of E. ferrugineus as well as other saproxylic organisms