Divergent ecological selection maintains species boundaries despite gene flow in a rare endemic tree, Quercus acerifolia (maple-leaf oak).

Strong gene flow from outcrossing relatives tends to blur species boundaries, while divergent ecological selection can counteract gene flow. To better understand how these two forces affect the maintenance of species boundaries, we focused on a species complex including a rare species, maple-leaf oak (Quercus acerifolia), which is found in only four disjunct ridges in Arkansas. Its limited range and geographic proximity to co-occurring close relatives create the possibility for genetic swamping. In this study, we gathered genome-wide single nucleotide polymorphisms (SNPs) using restriction-site-associated DNA sequencing (RADseq) from 190 samples of Q. acerifolia and three of its close relatives, Q. shumardii, Q. buckleyi, and Q. rubra. We found that Q. shumardii and Q. acerifolia are reciprocally monophyletic with low support, suggesting incomplete lineage sorting, introgression between Q. shumardii and Q. acerifolia, or both. Analyses that model allele distributions demonstrate that admixture contributes strongly to this pattern. Populations of Q. acerifolia experience gene flow from Q. shumardii and Q. rubra, but we found evidence that divergent selection is likely maintaining species boundaries: 1) ex situ collections of Q. acerifolia have a higher proportion of hybrids compared to the mature trees of the wild populations, suggesting ecological selection against hybrids at the seed/seedling stage; 2) ecological traits co-vary with genomic composition; and 3) Q. acerifolia shows genetic differentiation at loci hypothesized to influence tolerance of radiation, drought, and high temperature. Our findings strongly suggest that in maple-leaf oak, selection results in higher divergence at regions of the genome despite gene flow from close relatives.

Genetic resources of narrow-leaved lupine (Lupinus angustifolius L.) and their role in its domestication and breeding.

Narrow-leaved lupine (Lupinus angustifolius L.) is a cultivated multipurpose species with a very short history of domestication. It is used as a green manure, and for feed and food. This crop shows good prospects for use in pharmacology and as a source of f ish feeds in aquaculture. However, its genetic potential for the development of productive and adaptable cultivars is far from being realized. For crop species, the genetic base of the cultivated gene pool has repeatedly been shown as being much narrower than that of the wild gene pool. Therefore, eff icient utilization of a species' genetic resources is important for the crop's further improvement. Analyzing the information on the germplasm collections preserved in national gene banks can help perceive the worldwide diversity of L. angustifolius genetic resources and understand how they are studied and used. In this context, the data on the narrow-leaved lupine collection held by VIR are presented: its size and composition, the breeding status of accessions, methods of studying and disclosing intraspecif ic differentiation, the classif ications used, and the comparison of this information with available data on other collections. It appeared that VIR's collection of narrow-leaved lupine, ranking as the world's second largest, differed signif icantly from others by the prevalence of advanced cultivars and breeding material in it, while wild accessions prevailed in most collections. The importance of the wild gene pool for the narrow-leaved lupine breeding in Australia, the world leader in lupine production, is highlighted. The need to get an insight into the species' ecogeographic diversity in order to develop cultivars adaptable to certain cultivation conditions is shown. The data on the testing of VIR's collection for main crop characters valuable for breeders are presented. Special attention is paid to the study of accessions with limited branching as a promising gene pool for cultivation in relatively northern regions of Russia. They demonstrate lower but more stable productivity, and suitability for cultivation in planting patterns, which has a number of agronomic advantages. Analyzing the work with narrow-leaved lupine genetic resources in different national gene banks over the world helps shape the prospects of further activities with VIR's collection as the only source of promising material for domestic breeding.

Botanic Gardens Complement Agricultural Gene Bank in Collecting and Conserving Plant Genetic Diversity.

Originating in Europe in the 16th century, botanic gardens are found in nearly every country in the world. Botanic gardens have had various roles during this time, including as physic gardens, as adaptation centers for commercial crops, as pleasure gardens, and more recently as conservation institutions. The role of botanic gardens in the conservation of Crop Wild Relatives is becoming increasingly important. At least 6000 taxa related to 68 crop genera are maintained by the world's botanic gardens with several gardens having specialist collections. The extent of infra-specific genetic diversity of these Plant Genetic Resources for Food and Agriculture (PGRFA) being conserved is currently unknown, although based on existing evidence it is likely to be low. However, these PGRFA collections, through display and education, play a significant role in linking the public to important issues, including food security and the need to conserve crop diversity. Today there are some 2700 botanic gardens in existence, and they are visited by over 500 million people every year. The majority of these gardens are found in temperate regions. At least 30% of all known plant species are found in botanic garden collections, including 41% of threatened species. These ex situ collections are conserved in a variety of ways, including as seed bank collections. Around 350 botanic gardens together maintain seed collections of 57,000 taxa. These seed bank collections have a variety of uses, including for research and reintroduction.