Variation In Adaptive Traits Research Articles

Adaptive convergence and divergence underpin the diversity of Asteraceae in a semi-arid lowland region

Asteraceae is the most diverse family primarily found in semi-arid areas and species from the same botanical family have comparable phenotypes, occupy semi-arid habitats, and have adaptive convergences to environmental stress. Such characteristics aid in understanding adaptive radiations of recent groups on a regional scale and their successful establishment in habitats with challenging climatic and edaphic conditions. We investigated the adaptive convergence of the family as well as the fragile balance between fine-scale variation in adaptive traits and general convergence towards stress-tolerance and adaptation to aridity, using thorough field surveys and trait-based ecological approaches. Data was collected between 2020 and 2022 using the quadrat approach encompassed across 60 sites and five habitat types. Multivariate statistical methodologies were applied to analyze plant traits and soil variables. The tribes Cichorieae, Cardueae, and Heliantheae emerged as dominant contributors to the flora, illustrating their adaptability to varied ecological conditions. Microphyll emerged as the dominant leaf type, and therophytes prevailed as the most abundant life form. Urban habitats exhibited heightened sensitivity to Asteraceae species, as reflected in diversity indices. Canonical Correspondence Analysis demonstrated the significant influence of soil moisture, pH, phosphorus, and soil saturation on species distribution, with indicator species analysis highlighting habitat-specific plant-environment relationships. The study further classified species into adaptive strategies using CSR (competitive strategy-stress tolerant strategy-ruderal strategy) categorization. While some species exhibited pronounced R or S strategies, a majority demonstrated mixed strategies, such as R/CR, R/CSR, CS/CSR, emphasizing the versatility of adaptation strategies within the Asteraceae family. The findings underscore the intricate interplay between environmental variables and Asteraceae phylogenetic and functional diversity, highlighting the significance of soil properties in influencing plant distribution in semi-arid ecosystems. This research contributes valuable insights into the ecological dynamics of Asteraceae, shedding light on their responses to diverse environmental conditions and providing a nuanced understanding of the factors influencing their spatial distribution.

Mapping of quantitative trait loci for agronomic and morpho‐physiological traits under drought environments in spring barley (Hordeum vulgare L.)

AbstractBarley production is severely affected by drought caused by the unpredictable Mediterranean weather patterns, which include uneven rainfall and extreme temperatures. This leads to a decrease in crop yield. However, to tackle this issue, landraces and wild species are crucial sources of variation for stress adaptive traits. By incorporating these traits into improved varieties, we may see an increase in yield and stability under drought conditions. Seventy‐six quantitative traits loci (QTLs) identified traits were mapped using recombinant inbred lines (RIL) population Arta × Harmal‐2//Esp/1808‐4L, evaluated at six dry and semi‐dry areas over 3 years. The study investigated traits such as grain yield, biological yield, harvest index, kernel weight, seed per head, days to heading, kernel filling duration, growth vigour, growth habit, lodging and plant height. Numerous QTLs were discovered that are associated with various phenotypic traits related to grain yield, kernel yield, duration of filling period and days to heading. For areas with less than 250 mm/annum of rainfall, QTLs were identified on chromosome 2H for biological yield, days to heading, and kernel weight, on 1H for harvest index, and on 2H, 4H, and 5H for kernel weight. For semi‐dry areas with rainfall less than 450 mm, QTLs were found on chromosome 6H for grain yield, 2H and 5H for kernel weight, 1H and 6H for seed per head, and 2H for days to heading. Notably, these QTLs significantly explain more than 10% of phenotypic variation. The 2H chromosome was found to have the most important QTL and pleiotropic effect for yield and its components, such as kernel weight, days to heading, and biological yield. The cross Arta/Harmal was adapted, and mechanisms were developed to cope with drought stress, reflected by the significant and positive correlation of biological yield and harvest index with grain yield. Chromosomes 1H, 2H, 4H and 5H harbour more than 60% of mapped QTLs for dry areas. It is worth noting that the QTLs mentioned earlier, along with the kernel weight QTLs (QKW 1.5, QKW2.7b, QKW4.1, QKW6.7, QKW6.9), have consistently exhibited positive effects on crop yield in semi‐dry and dry areas, making them potential candidates for breeding drought‐tolerant crops. Genomic co‐localisation of the QTL for Arta/Harmal population suggested that selection for drought through linked markers can be an option for drought tolerance selection for barley in dry areas.

Greater ecophysiological stress tolerance in the core environment than in extreme environments of wild chickpea (Cicer reticulatum)

Global climate change and land use change underlie a need to develop new crop breeding strategies, and crop wild relatives (CWR) have become an important potential source of new genetic material to improve breeding efforts. Many recent approaches assume adaptive trait variation increases towards the relative environmental extremes of a species range, potentially missing valuable trait variation in more moderate or typical climates. Here, we leveraged distinct genotypes of wild chickpea (Cicer reticulatum) that differ in their relative climates from moderate to more extreme and perform targeted assessments of drought and heat tolerance. We found significance variation in ecophysiological function and stress tolerance between genotypes but contrary to expectations and current paradigms, it was individuals from more moderate climates that exhibited greater capacity for stress tolerance than individuals from warmer and drier climates. These results indicate that wild germplasm collection efforts to identify adaptive variation should include the full range of environmental conditions and habitats instead of only environmental extremes, and that doing so may significantly enhance the success of breeding programs broadly.

Adaptive potential of maritime pine under contrasting environments

BackgroundPredicting the adaptability of forest tree populations under future climates requires a better knowledge of both the adaptive significance and evolvability of measurable key traits. Phenotypic plasticity, standing genetic variation and degree of phenotypic integration shape the actual and future population genetic structure, but empirical estimations in forest tree species are still extremely scarce. We analysed 11 maritime pine populations covering the distribution range of the species (119 families and 8 trees/family, ca. 1300 trees) in a common garden experiment planted at two sites with contrasting productivity. We used plant height as a surrogate of fitness and measured five traits (mean and plasticity of carbon isotope discrimination, specific leaf area, needle biomass, Phenology growth index) related to four different strategies (acquisitive economics, photosynthetic organ size, growth allocation and avoidance of water stress).ResultsEstimated values of additive genetic variation would allow adaptation of the populations to future environmental conditions. Overall phenotypic integration and selection gradients were higher at the high productivity site, while phenotypic integration within populations was higher at the low productivity site. Response to selection was related mainly to photosynthetic organ size and drought-avoidance mechanisms rather than to water use efficiency. Phenotypic plasticity of water use efficiency could be maladaptive, resulting from selection for height growth.ConclusionsContrary to the expectations in a drought tolerant species, our study suggests that variation in traits related to photosynthetic organ size and acquisitive investment of resources drive phenotypic selection across and within maritime pine populations. Both genetic variation and evolvability of key adaptive traits were considerably high, including plasticity of water use efficiency. These characteristics would enable a relatively fast micro-evolution of populations in response to the ongoing climate changes. Moreover, differentiation among populations in the studied traits would increase under the expected more productive future Atlantic conditions.

Gut microbiota contribute to variations in honey bee foraging intensity.

Gut microbiomes are increasingly recognized for mediating diverse biological aspects of their hosts, including complex behavioral phenotypes. Although many studies have reported that experimental disruptions to the gut microbial community result in atypical host behavior, studies that address how gut microbes contribute to adaptive behavioral trait variation are rare. Eusocial insects represent a powerful model to test this, because of their simple gut microbiota and complex division of labor characterized by colony-level variation in behavioral phenotypes. Although previous studies report correlational differences in gut microbial community associated with division of labor, here, we provide evidence that gut microbes play a causal role in defining differences in foraging behavior between European honey bees (Apis mellifera). We found that gut microbial community structure differed between hive-based nurse bees and bees that leave the hive to forage for floral resources. These differences were associated with variation in the abundance of individual microbes, including Bifidobacterium asteroides, Bombilactobacillus mellis, and Lactobacillus melliventris. Manipulations of colony demography and individual foraging experience suggested that differences in gut microbial community composition were associated with task experience. Moreover, single-microbe inoculations with B. asteroides, B. mellis, and L. melliventris caused effects on foraging intensity. These results demonstrate that gut microbes contribute to division of labor in a social insect, and support a role of gut microbes in modulating host behavioral trait variation.

Genotypic variation of adaptive and yield component traits of introduced grain oats (Avena sativa L.) grown in Bangladesh

Oat (Avena sativa L.) is considered a nutritious cereal. Its demand has surged across the globe steadily for half a decade, including in Bangladesh. Because there is no local variety, the current supply in Bangladesh solely relies on imports. This study aimed to introduce grain oats from the United States of America (U.S.A.) to Bangladesh and determine the extent of their adaptability and yield in this new environment. One hundred oat accessions were introduced in collaboration between North South University, Bangladesh and the University of Florida, U.S.A. They were evaluated in field conditions from November 2019 to April 2020 in the Dinajpur district, Bangladesh in two replicated measurements of 13 morphological traits with RCBD design. The broad-sense heritability ranged from 11.7% to 90.0% for the measured traits. The yield-related trait, spikelet numbers, was positively correlated with height (0.30), dry weight (0.46), and harvest index (0.42) but negatively correlated with heading (-0.05), flowering date (-0.05), and tiller numbers (-0.16). Growth habit was negatively correlated with height (-0.07) and dry weight (-0.25). Principal components 1 and 2 explained 43.01% of the variability and were strongly influenced by heading and flowering date. Cluster analysis assigned the genotypes into six main clusters, and the analysis showed that spikelet numbers, growth habit, height, harvest index, and heading date were key yield-contributing and adaptive traits. Identifying traits highly correlated with oat yield could be useful for developing new varieties adapted to Bangladesh environments. This study is a pioneer; it paved the way to breed new high-yielding grain oat varieties for Bangladesh

Adaptive Trait Variation in Seedlings of Rare Endemic Mexican Spruce Provenances under Nursery Conditions

The distributions of the three Mexican spruces are fragmented, possibly leading to phenological, morphological and genetic differentiation, which is partly caused by local adaptation. In this study, we estimated for the first time the intra- and inter-specific phenotypic variation in 5641 seedlings from provenances of the three Mexican spruces. We examined (i) provenance-related differences in the seedling survival rate, diameter (D), height (H) and seed weight (SW) as quantitative traits, (ii) the association between the survival rate, D, H and SW and climatic and soil variables in the Picea provenances and (iii) (narrow-sense) heritability (within-provenance) based on D and H under the same nursery conditions, assuming that the response can be considered as a proxy for quantitative genetic differentiation between provenances. All Mexican spruce species differed significantly in H, and all eight provenances studied were significantly different in D and H, except for two neighboring provenances of P. mexicana. Very strong, significant correlations (up to R2 = 0.96) were found between H, the survival rate and SW with respect to environmental factors of provenance/seed origin. Additionally, the heritability index explained a high percentage of the provenance-related variance. The use of germplasm for restoration in different sites and with different populations requires collecting seeds from numerous trees from as many provenances as possible, but should be carried out with caution owing to the apparently strong local adaptation in provenances of the Mexican spruces.

Contrasting adaptive trait variation in response to drought in two Mediterranean shrubs

Adaptive evolution and phenotypic plasticity are key mechanisms of climate change responses. However, we still lack a detailed understanding of the strategies different species use to cope with climatic changes such as increased droughts, particularly for species with special edaphic requirements and limited dispersal such as gypsum endemics. In this study, we assessed phenotypic and genotypic selection, phenotypic plasticity and genetic variation in traits potentially related to drought response in two dominant gypsum Mediterranean species, Helianthemum squamatum and Centaurea hyssopifolia. We established a common garden in which 524 plants from 79 maternal families from both species were grown under two contrasting watering treatments. Our results revealed that selection was stronger under drought than well-watered conditions for both species, but we found contrasting adaptive strategies and genetic variation. In H. squamatum, a drought-escape strategy with advanced reproductive phenology and faster growth rates was positively associated with fitness under dry conditions, and most adaptive traits exhibited quantitative genetic variation. In contrast, in C. hyssopifolia, selection under dry conditions favored a drought-tolerance strategy with thicker leaves and longer phenologies, but all traits lacked quantitative genetic variation, indicating that their evolutionary potential may be limited. Most traits exhibited significant plasticity in response to drought and genetic variation for trait plasticity in both species, indicating that trait plasticity can evolve independently of the evolution of trait means in these gypsophiles. Our results show that these gypsum endemic species vary in strategies and adaptive potential in response to drought, which contributes to our understanding of potential adaptive responses to climate change in such edaphic specialists.

Environmental and genetic effects on phenotypic differences between Elaeocarpus photiniifolia (Elaeocarpaceae) ecotypes in dry and mesic habitats on a Japanese oceanic island

AbstractEcological speciation is a consequence of phenotypic and genetic differentiation, which is driven by divergent selection and reproductive isolation between different environments. In Elaeocarpus photiniifolia, a plant species endemic to the Bonin Islands, genetic differentiation between a shrub ecotype in dry habitats and a tree ecotype in mesic habitats occurs in the Chichijima Island Group, while gene flow between the ecotypes and migration between the habitats are feasible. To clarify environmental and genetic effects on traits different between the ecotypes, we examined the soil moisture content, nuclear microsatellite genotypes, plant height, and flowering phenology in dry and mesic habitats in two areas on Chichijima Island. The soil moisture content decreased from June to July in both areas and tended to be lower in dry habitats than in mesic habitats in July. Genetic structure indicated not only genetic differentiation between the ecotypes but also admixture between them and migration between the habitats. Both environmental and genetic effects were detected in plant height and flowering phenology: lower height and earlier flowering of the shrub ecotype in the dry habitats, indicating phenotypic plasticity in response to drought, and genetic variation between ecotypes in both traits. These findings indicate that phenotypic plasticity in response to different environments results in different flowering phenology, which facilitates reproductive isolation and genetic differentiation, leading to genetic variation in adaptive traits associated with the environments.

Evolutionary targets of gene expression divergence in a complex of closely related pine species

AbstractThe environment is a powerful selective pressure for sessile organisms, such as plants, and adaptation to the environment is particularly important for long‐lived species, like trees. Despite the importance of adaptive trait variation to the survival and success of trees, the molecular basis of adaptation is still poorly understood. Gene expression patterns in three closely related, but phenotypically and ecologically divergent, pine species were analyzed to detect differentiation that may be associated with their adaptation to distinct environments. Total RNA of Pinus mugo, Pinus uncinata, and Pinus sylvestris samples grown under common garden conditions was used for de novo transcriptome assembly, providing a new reference dataset that includes species from the taxonomically challenging P. mugo complex. Gene expression profiles were found to be very similar with only 121 genes significantly diverged in any of the pairwise species comparisons. Functional annotation of these genes revealed major categories of distinctly expressed transcripts, including wood trait properties, oxidative stress response, and response to abiotic factors such as salinity, drought, and temperature. We discuss putative associations between gene expression profiles and adaptation to different environments, for example, the upregulation of genes involved in lignin biosynthesis in the species, which have adapted to mountainous regions characterized by strong winds and thick snow cover. Our study provides valid candidates for verification of the importance of the gene expression role, in addition to evidence for selection within genomic regions, in the process of ecological divergence and adaptation to higher altitudes in pine taxa.

Multi-trait association study identifies loci associated with tolerance of low phosphorus in Oryza sativa and its wild relatives

We studied variation in adaptive traits and genetic association to understand the low P responses, including the symbiotic association of arbuscular mycorrhizal (AM) fungal colonization in Oryza species (O. sativa, O. nivara, and O. rufipogon). In the present experiment, we performed the phenotypic variability of the morphometric and geometric traits for P deficiency tolerance and conducted the association studies in GLM and MLM methods. A positive association between the geometric trait of the top-view area and root traits suggested the possibility of exploring a non-destructive approach in screening genotypes under low P. The AMOVA revealed a higher proportion of variation among the individuals as they belonged to different species of Oryza and the NM value was 2.0, indicating possible gene flow between populations. A sub-cluster with superior-performing accessions had a higher proportion of landraces (42.85%), and O. rufipogon (33.3%) was differentiated by four Pup1-specific markers. Association mapping identified seven notable markers (RM259, RM297, RM30, RM6966, RM242, RM184, and PAP1) and six potential genotypes (IC459373, Chakhao Aumbi, AC100219, AC100062, Sekri, and Kumbhi Phou), which will be helpful in the marker-assisted breeding to improve rice for P-deprived condition. In addition, total root surface area becomes a single major trait that helps in P uptake under deficit P up to 33% than mycorrhizal colonization. Further, the phenotypic analysis of the morphometric and geometric trait variations and their interactions provides excellent potential for selecting donors for improving P-use efficiency. The identified potential candidate genes and markers offered new insights into our understanding of the molecular and physiological mechanisms driving PUE and improving grain yield under low-P conditions.

Genetically based adaptive trait shifts at an expanding mangrove range margin

Neotropical black mangrove (Avicennia germinans) is expanding poleward into temperate salt marsh along Atlantic Florida, USA, with field evidence of trait shifts consistent with greater cold tolerance within range margin populations. However, whether these shifts have a genetic basis remains unanswered. To address this gap, we measured multiple phenotypic traits of twenty A. germinans maternal cohorts from areas in both the Atlantic Florida range core and margin in a 2-year greenhouse common garden with annual temperatures analogous to range margin conditions. Compared to those from the range core, range margin cohorts survived in greater numbers, established (i.e., produced first true leaves) more quickly, and were less stressed under winter temperatures. Range margin cohorts were not taller, but invested more into lateral growth and biomass accumulation that presumably reflects adaptation to their colder and open-canopy environment. Range margin cohorts also exhibited leaf traits consistent with greater resource acquisition that may compensate for a shorter growing season and reduced light quality at higher latitude. Our results suggest that genetically based phenotypic differences better enable these range margin mangroves to thrive within their stressful environment and may facilitate further poleward expansion. An improved understanding of adaptive trait variation within ecologically important mangrove foundation species should also help inform coastal restoration initiatives.

Crossbreeding reveals the scale and genetic architecture of local adaptation in a predominantly selfing Hordeum spontaneum

ABSTRACT Environmental variation can be large across a wide range of spatial scales resulting in complex patterns of local adaptation across species ranges. We analyzed the scale, genetic mechanism and direct climatic causes of local adaptation in a widely distributed grass Hordeum spontaneum. We performed artificial crosses of maternal plants representing the same Negev desert population with plants originating elsewhere. Pollen donors were plants from other Negev desert populations, non-desert Israeli populations sampled along an aridity gradient, and accessions covering the entire species range. Our study included planting of inter-population hybrids under favorable and simulated desert experimental conditions, followed by analysis of their performance, variation in adaptive traits and relationship with climatic parameters at sampling locations. The combined results of parental phenotypic variation and performance of hybrids were consistent with local selection, reflecting the importance of both regional and local climates. The adaptive genetic differentiation of barley desert populations had a complex architecture. None of the three effects (additive, dominance and epistasis) were fully responsible for this differentiation. Although genetic effects not related to extrinsic selection appear to contribute to genetic differentiation in barley, epistatic effects arising from local selection clearly predominated. The short-term effect of gene flow by pollen was generally negative, indicating that a majority of the new allele combinations created by recombination were maladaptive. However, the long-term effect of occasional pollen flow from other desert populations appears to be positive, as some new recombined genotypes were superior in fitness to the maternal plants even in the F2 generation.

Morphology of tulips (Tulipa, Liliaceae) in its primary centre of diversity

Environmental variation can be large across a wide range of spatial scales resulting in complex patterns of local adaptation across species ranges. We analyzed the scale, genetic mechanism and direct climatic causes of local adaptation in a widely distributed grass Hordeum spontaneum. We performed artificial crosses of maternal plants representing the same Negev desert population with plants originating elsewhere. Pollen donors were plants from other Negev desert populations, non-desert Israeli populations sampled along an aridity gradient, and accessions covering the entire species range. Our study included planting of inter-population hybrids under favorable and simulated desert experimental conditions, followed by analysis of their performance, variation in adaptive traits and relationship with climatic parameters at sampling locations. The combined results of parental phenotypic variation and performance of hybrids were consistent with local selection, reflecting the importance of both regional and local climates. The adaptive genetic differentiation of barley desert populations had a complex architecture. None of the three effects (additive, dominance and epistasis) were fully responsible for this differentiation. Although genetic effects not related to extrinsic selection appear to contribute to genetic differentiation in barley, epistatic effects arising from local selection clearly predominated. The short-term effect of gene flow by pollen was generally negative, indicating that a majority of the new allele combinations created by recombination were maladaptive. However, the long-term effect of occasional pollen flow from other desert populations appears to be positive, as some new recombined genotypes were superior in fitness to the maternal plants even in the F2 generation.

Divergence in Body Mass, Wing Loading, and Population Structure Reveals Species-Specific and Potentially Adaptive Trait Variation Across Elevations in Montane Bumble Bees

AbstractBiogeographic clines in morphology along environmental gradients can illuminate forces influencing trait evolution within and between species. Latitude has long been studied as a driver of morphological clines, with a focus on body size and temperature. However, counteracting environmental pressures may impose constraints on body size. In montane landscapes, declines in air density with elevation can negatively impact flight performance in volant species, which may contribute to selection for reduced body mass despite declining temperatures. We examine morphology in two bumble bee (Hymenoptera: Apidae: Bombus Latreille) species, Bombus vancouverensis Cresson and Bombus vosnesenskii Radoszkowski, across mountainous regions of California, Oregon, and Washington, United States. We incorporate population genomic data to investigate the relationship between genomic ancestry and morphological divergence. We find that B. vancouverensis, which tends to be more specialized for high elevations, exhibits stronger spatial-environmental variation, being smaller in the southern and higher elevation parts of its range and having reduced wing loading (mass relative to wing area) at high elevations. Bombus vosnesenskii, which is more of an elevational generalist, has substantial trait variation, but spatial-environmental correlations are weak. Population structure is stronger in the smaller B. vancouverensis, and we find a significant association between elevation and wing loading after accounting for genetic structure, suggesting the possibility of local adaptation for this flight performance trait. Our findings suggest that some conflicting results for body size trends may stem from distinct environmental pressures that impact different aspects of bumble bee ecology, and that different species show different morphological clines in the same region.

Development of Wheat (Triticum aestivum L.) Populations for Drought Tolerance and Improved Biomass Allocation Through Ethyl Methanesulphonate Mutagenesis

The narrow genetic variation for drought adaptive traits and biomass allocation in wheat (Triticum aestivum L.) presents a major bottleneck for breeding. Induced mutagenesis creates genetic variation and complements conventional breeding for drought tolerance improvement. The aims of this study were to induce mutations in wheat genotype LM43 using three ethyl methanesulphonate (EMS) treatments, and to develop mutant populations for improving drought tolerance, biomass allocation and agronomic performance. Experiments were conducted under controlled and field conditions at the University of KwaZulu-Natal. Data on percentage germination (%G), days to 90% maturity (DTM), plant height (PH), shoot biomass (SB), root biomass (RB), root-shoot ratio (RSR), spike length (SL), spikelet count (SPS), thousand seed weight (TSW), and grain yield (GY) were collected from M1 to M4 generations. Significant (p < 0.001) differences among individuals and generations were observed for all the assessed traits and the generation × population interaction effects were significant (p < 0.01) for SB, TSW, and GY due to EMS treatments. The differences among the generations showed that the mutagenic effects were cumulative and exhibited clear segregations in subsequent generations. The new selections with unique biomass allocation, drought response and agronomic performance will be useful for wheat improvement programs.

The Impact of Different Environmental Conditions during Vegetative Propagation on Growth, Survival, and Biochemical Characteristics in Populus Hybrids in Clonal Field Trial

To have a cleaner environment, good well-being, and improve the health of citizens it is necessary to expand green urban and suburban areas using productive and adapted material of tree species. The quality of urban greenery, resistance to negative climate change factors and pollution, as well as efficiency of short-rotation forestry in suburban areas, depends primarily on the selection of hybrids and clones, suitable for the local environmental conditions. We postulate that ecogenetic response, phenotypic plasticity, and genotypic variation of hybrid poplars (Populus L.) grown in plantations are affected not only by the peculiarities of hybrids and clones, but also by environmental conditions of their vegetative propagation. The aim of the present study was to estimate growth and biochemical responses, the phenotypic plasticity, genotypic variation of adaptive traits, and genetically regulated adaptability of Populus hybrids in field trials which may be predisposed by the simulated contrasting temperature conditions at their vegetative propagation phase. The research was performed with the 20 cultivars and experimental clones of one intraspecific cross and four different interspecific hybrids of poplars propagated under six contrasting temperature regimes in phytotron. The results suggest that certain environmental conditions during vegetative propagation not only have a short-term effect on tree viability and growth, but also can help to adapt to climate change conditions and grow successfully in the long-term. It was found that tree growth and biochemical traits (the chlorophyll A and B, pigments content and the chlorophyll A/B ratio) of hybrid poplar clones grown in field trials, as well as their traits’ genetic parameters, were affected by the rooting-growing conditions during vegetative propagation phase. Hybrids P. balsamifera × P. trichocarpa, and P. trichocarpa × P. trichocarpa have shown the most substantial changes of biochemical traits across vegetative propagation treatments in field trial. Rooting-growing conditions during vegetative propagation had also an impact on coefficients of genotypic variation and heritability in hybrid poplar clones when grown in field trials.

Genetic variation for adaptive traits is associated with polymorphic inversions in Littorina saxatilis.

Chromosomal inversions have long been recognized for their role in local adaptation. By suppressing recombination in heterozygous individuals, they can maintain coadapted gene complexes and protect them from homogenizing effects of gene flow. However, to fully understand their importance for local adaptation we need to know their influence on phenotypes under divergent selection. For this, the marine snail Littorina saxatilis provides an ideal study system. Divergent ecotypes adapted to wave action and crab predation occur in close proximity on intertidal shores with gene flow between them. Here, we used F2 individuals obtained from crosses between the ecotypes to test for associations between genomic regions and traits distinguishing the Crab‐/Wave‐adapted ecotypes including size, shape, shell thickness, and behavior. We show that most of these traits are influenced by two previously detected inversion regions that are divergent between ecotypes. We thus gain a better understanding of one important underlying mechanism responsible for the rapid and repeated formation of ecotypes: divergent selection acting on inversions. We also found that some inversions contributed to more than one trait suggesting that they may contain several loci involved in adaptation, consistent with the hypothesis that suppression of recombination within inversions facilitates differentiation in the presence of gene flow.

Climate-driven adaptive responses to drought of dominant tree species from Patagonia

The increase in the frequency and severity of extreme weather events affects populations of tree species. As a result, many forests around the world have suffered massive mortality due to extreme droughts. Therefore, it is important to understand the potential adjustments of dominant woody species of temperate forests to climate change. The objective was to show in seedlings inhabiting the most contrasting habitats, forest types, and precipitation regimes the relevance of species-specific and intra-specific adaptive trait variation. Ecophysiological differences between seedlings collected from distinct humid and dry provenances of Nothofagus pumilio and N. dombeyi in northern Patagonia were assessed using common garden and water stress manipulative experiments. Levels of genetic diversity and divergence were evaluated with microsatellite analysis. Seedlings from humid provenances of both species showed increased growth, and leaf traits differed significantly between N. dombeyi provenances. Studied species behaved differently under water stress, isohydric for N. dombeyi and anisohydric for N. pumilio, while no intraspecific differences were measured in the regulation of water status. Humid provenance of N. dombeyi had higher genetic diversity than the dry one, whereas those of N. pumilio were similarly diverse. Yet, low but significantly different from zero genetic divergence was measured between provenances of the latter. Our results show species-specific responses to water stress and that adaptive variation at distinct provenances has a genetic basis that is maintained despite potential gene flow. The strategy of using seedlings from "regional admixture provenancing" is suggested for long-term management of vulnerable taxa to desiccation as the mesic N. dombeyi.

Focused Identification of Germplasm Strategy (FIGS): polishing a rough diamond.

Focused Identification of Germplasm Strategy (FIGS) has been advocated as an efficient approach to predict and harness variation in adaptive traits in genebanks or wild populations of plants. However, a weakness of the current FIGS approach is that it only utilizes a priori knowledge of one evolutionary factor: natural selection. Further optimization is needed to capture elusive traits, and this review shows that nonadaptive evolutionary processes (gene flow and genetic drift) should be incorporated to increase precision. Focusing on plant resistance to insect herbivores, we also note that historic selection pressures can be difficult to disentangle, and provide suggestions for successful mining based on eco-evolutionary theory. We conclude that with such refinement FIGS has high potential for enhancing breeding efforts and hence sustainable plant production.