Variation In Traits Research Articles

Characterization of microbiota signatures in Iberian pig strains using machine learning algorithms

BackgroundThere is a growing interest in uncovering the factors that shape microbiome composition due to its association with complex phenotypic traits in livestock. Host genetic variation is increasingly recognized as a major factor influencing the microbiome. The Iberian pig breed, known for its high-quality meat products, includes various strains with recognized genetic and phenotypic variability. However, despite the microbiome’s known impact on pigs’ productive phenotypes such as meat quality traits, comparative analyses of gut microbial composition across Iberian pig strains are lacking. This study aims to explore the gut microbiota of two Iberian pig strains, Entrepelado (n = 74) and Retinto (n = 63), and their reciprocal crosses (n = 100), using machine learning (ML) models to identify key microbial taxa relevant for distinguishing their genetic backgrounds, which holds potential application in the pig industry. Nine ML algorithms, including tree-based, kernel-based, probabilistic, and linear algorithms, were used.ResultsBeta diversity analysis on 16 S rRNA microbiome data revealed compositional divergence among genetic, age and batch groups. ML models exploring maternal, paternal and heterosis effects showed varying levels of classification performance, with the paternal effect scenario being the best, achieving a mean Area Under the ROC curve (AUROC) of 0.74 using the Catboost (CB) algorithm. However, the most genetically distant animals, the purebreds, were more easily discriminated using the ML models. The classification of the two Iberian strains reached the highest mean AUROC of 0.83 using Support Vector Machine (SVM) model. The most relevant genera in this classification performance were Acetitomaculum, Butyricicoccus and Limosilactobacillus. All of which exhibited a relevant differential abundance between purebred animals using a Bayesian linear model.ConclusionsThe study confirms variations in gut microbiota among Iberian pig strains and their crosses, influenced by genetic and non-genetic factors. ML models, particularly CB and RF, as well as SVM in certain scenarios, combined with a feature selection process, effectively classified genetic groups based on microbiome data and identified key microbial taxa. These taxa were linked to short-chain fatty acids production and lipid metabolism, suggesting microbial composition differences may contribute to variations in fat-related traits among Iberian genetic groups.

How do aboveground and belowground functional traits correlate with the demography of tree seedlings regenerated after landslide disturbances?

ABSTRACT Trait-based plant ecology is commonly used to study plant demography in forests, especially after disturbances. However, how functional traits affect the demography of regenerating seedlings after landslides remains largely unknown. This study conducted a 2-year monitoring of Abies sachalinensis (evergreen species) and Acer mono (deciduous species) seedlings dominantly regenerating in artificial landslide areas in northern Japan. We investigated the correlations between intraspecific variations in functional traits and two demographic properties (growth and mortality). We found that growth of evergreen tree seedlings was correlated with functional traits related to leaf and root construction costs and light capture capacity. However, there were no significant correlations between mortality and the functional traits for either species in the post-landslide forests. Our results emphasize the importance of both aboveground and belowground functional traits in understanding vegetation recovery after landslides. This work suggests that the intraspecific trait-demography relationships can vary depending on the demographic properties in post-landslide forests.

Wood Anatomical and Hydraulic Traits of Tamarix Species Across a Large Eurasian Gradient Show a Stronger Climatic Than Phylogenetic Signal

ABSTRACTAimTamarisk (Tamarix) is the predominant but taxonomically complex genus of the Tamaricaceae. The morphologically similar shrub or tree species grow in arid, salt‐influenced habitats of Eurasia and Africa. We sampled woody shoots of seven species at the eastern margin (NW China; T. ramosissima) and the centre (Uzbekistan; T. hispida) of the Indo‐Turanian region as well as at the eastern (Israel; T. aphylla, T. negevensis, T. nilotica) and western margin (southern Spain; T. boveana, T. gallica) of the Mediterranean region, the two diversity centres of the genus. To explore the drivers of intrageneric trait variability, we investigated whether differences in the anatomical‐hydraulic wood traits among the species are related to climate or phylogeny.LocationEurasia.TaxonTamarix L. (Tamaricaceae).MethodsWe determined features of wood anatomy and calculated the hydraulic conductivity (kt) and the water potential at 50% loss of hydraulic conductance (P50). We related these traits to climate variables and to the phylogenetic distances among the species.ResultsTamarix nilotica, T. negevensis and T. ramosissima exhibited large conduit areas, large hydraulic diameters and high kt, whereas the Spanish species T. gallica and T. boveana displayed high wood densities and a small fraction of large conduits. The phylogenetically distant species T. aphylla and T. hispida took intermediate positions. Tamarix ramosissima, which grows in regions with cold winters and hot‐dry summers, exhibited the most negative P50 values, indicative of a low susceptibility to a failure of the water‐conducting system. Trait differences among the species were unrelated to the species' phylogenetic relatedness but correlated with climate variables.Main ConclusionsDespite strong similarity in morphology and habitat preferences, Tamarix species displayed significant differences in their anatomical‐hydraulic traits. These differences were related to climate conditions rather than phylogeny and are indicative of specific local adaptations to environmental conditions.

Genome Scan Analysis for Advancing Knowledge and Conservation Strategies of Primitivo Clones (Vitis vinifera L.)

The success of the Primitivo variety underscores the critical need for the managing of clone genetic conservation, utilization, and improvement. By combining genomic and environmental data, breeders can better predict the performance of varieties, thereby improving breeding efficiency and enabling more targeted development of high-quality grapevine cultivars. In this study, 35 Primitivo clones were analysed, including selected and certified clones that have been propagated over several years in Apulia. Genetic variability among the Primitivo clones was assessed through genotyping by sequencing. Using 38,387 filtered SNPs, pairwise identity-by-state (IBS) analysis demonstrated the uniqueness of the 35 clones (IBS < 0.75), indicating a high degree of variability among the samples. Genetic diversity analysis revealed three primary groups, which were differentiated based on geographic origin. The clones from Gioia del Colle were grouped into two distinct clusters, which aligns with the observed variation in grape-related traits. The fixation index (FST > 0.50) identified numerous loci putatively associated with stress responses and developmental traits, including genes involved in key plant biological processes, stress response regulation, and adaptation to environmental conditions such as glutamate receptors, auxin, and ethylene signalling.

Harnessing Genetic Diversity And Vigor Of Onion From Multi-generatio Study

This study investigates the genetic variation, vigor, and performance of onion generations resulting from crosses. The experiment was conducted at the Spices Research Centre, Shibganj, Bogura, during 2021-22, following diallel mating design with three parental varieties, BARI piaz1, BARI piaz4, and BARI piaz6. The research focuses on evaluating yield and yield-contributing traits, including bulb dimensions, bulbing index, and individual bulb weight. The results demonstrate significant genetic diversity among onion generations, offering opportunities for the breeders to select and develop superior lines. Hybrid vigor and heterosis, particularly evident in F1 generations, suggest that combining genetically diverse parental lines can lead to progeny with superior performance compared to their parents. However, the choice of parental lines significantly influences the stability and performance of hybrid progeny, with certain varieties demonstrating consistent performance across generations (Parent, F1, F2). Trait segregation and variability within F2 hybrid populations underscore the importance of evaluating large populations to identify individuals with desired trait combinations. Overall, the findings highlight the importance of leveraging genetic diversity and hybrid vigor in onion breeding programs to develop cultivars. By employing breeding strategies the high-performing onion varieties capable of thriving in diverse agro-climatic conditions in onion farming. Bangladesh J. Agri. 2024, 49(2): 31-44

Variations in Leaf Functional Traits of Pseudotsuga sinensis Across Forests With Varying Levels of Rocky Desertification.

Pseudotsuga sinensis is a distinctive plant species endemic to China, predominantly found in areas affected by varying degrees of rocky desertification. Despite its wide distribution, the physiological mechanisms underlying its adaptation to harsh environments remain unclear. In this study, we investigated 16 leaf traits, including the morphological, anatomical, and chemical characteristics of the leaves of P. sinensis across forests with mild, moderate, severe, and extremely severe rocky desertification to elucidate the adaptive strategies of P. sinensis in response to arid conditions and nutrient-poor soils. Our findings revealed that P. sinensis leaves from forests with mild and moderate rocky desertification exhibited higher specific leaf area (SLA) and magnesium concentrations but lower leaf dry matter content (LDMC), abaxial epidermis thickness, and adaxial epidermis thickness than in those from forests with severe and extremely severe desertification. Principal component analysis indicated that forests with mild to moderate desertification employ resource acquisition strategies characterized by greater SLA and magnesium concentrations than those in forests with severe and extremely severe desertification. In contrast, forests with severe to extremely severe desertification adopted resource-conserving strategies, as evidenced by higher LDMC, epidermal thickness, and calcium concentrations than those in forests with mild to moderate desertification. The N:P ratio of P. sinensis across all desertification levels was consistently below 14, suggesting nitrogen limitation in P. sinensis in regions with rocky desertification. Thus, these results provide valuable reference for guiding vegetation restoration under degraded habitats.

Genetic Diversity Analysis and Comprehensive Evaluation of “M82” in EMS-Mutagenized Tomato

Background: Ethyl methyl sulfonate (EMS) mutagenesis is widely used because of its advantages of inducing point mutations and no need for genetic transformation. To identify germplasm resources of processed tomatoes with superior comprehensive traits suitable for cultivation in Xinjiang. Methods: In this study, tomato seeds were treated with 2% EMS reagent for 12 h, 21 quality traits and 20 quantitative traits of 33 processed tomatoes derived from EMS-mutagenized“M82”were evaluated. Results: The results indicated that for traits such as hypocotyl color, growth habit, plant type, leaf type, and leaf shape, the range of quantitative trait variation was 8.45–37.25%, with a genetic diversity index ranging from 1.25 to 2.07. Conclusions: Cluster analysis of quantitative traits categorized the 33 EMS-mutagenized “M82” processed tomato resources into five groups: Group I contained 22 robust germplasm samples; Group II consisted of a single potential high-quality germplasm; Group III comprised five germplasm with a small and extreme plant type; Group IV included four high-yield germplasm; and Group V represented one moderate, conventional germplasm. Raw data from 15 quantitative traits across the 33 accessions were standardized using the “extreme method” to extract six comprehensive factors. The top 10 germplasm resources based on the comprehensive score were 76, 137, 97, 102, 19, 104, 21, 108, 17, and 147. It provides some theoretical basis for realizing the high-yield and high-quality cultivation and variety breeding of processed tomatoes in Xinjiang.

Developing pangenomes for large and complex plant genomes and their representation formats.

The development of pangenomes has revolutionized genomic studies by capturing the complete genetic diversity within a species. Pangenome assembly integrates data from multiple individuals to construct a comprehensive genomic landscape, revealing both core and accessory genomic elements. This approach enables the identification of novel genes, structural variations, and gene presence-absence variations, providing insights into species evolution, adaptation, and trait variation. Representing pangenomes requires innovative visualization formats that effectively convey the complex genomic structures and variations. This review delves into contemporary methodologies and recent advancements in constructing pangenomes, particularly in plant genomes. It examines the structure of pangenome representation, including format comparison, conversion, visualization techniques, and their implications for enhancing crop improvement strategies. Earlier comparative studies have illuminated novel gene sequences, copy number variations, and presence-absence variations across diverse crop species. The concept of a pan-genome, which captures multiple genetic variations from a broad spectrum of genotypes, offers a holistic perspective of a species' genetic makeup. However, constructing a pan-genome for plants with larger genomes poses challenges, including managing vast genome sequence data and comprehending the genetic variations within the germplasm. To address these challenges, researchers have explored cost-effective alternatives to encapsulate species diversity in a single assembly known as a pangenome. This involves reducing the volume of genome sequences while focusing on genetic variations. With the growing prominence of the pan-genome concept in plant genomics, several software tools have emerged to facilitate pangenome construction. This review sheds light on developing and utilizing software tools tailored for constructing pan-genomes in plants. It also discusses representation formats suitable for downstream analyses, offering valuable insights into the genetic landscape and evolutionary dynamics of plant species. In summary, this review underscores the significance of pan-genome construction and representation formats in resolving the genetic architecture of plants, particularly those with complex genomes. It provides a comprehensive overview of recent advancements, aiding in exploring and understanding plant genetic diversity.

Genetic variability and association of traits in common bean ( Phaseolus vulgaris L.) genotypes in Sekota, North Eastern Ethiopia

Genetic variability and association of traits in common bean ( <i>Phaseolus vulgaris</i> L.) genotypes in Sekota, North Eastern Ethiopia

Direct and indirect genetic effects on early neurodevelopmental traits.

Neurodevelopmental conditions are highly heritable. Recent studies have shown that genomic heritability estimates can be confounded by genetic effects mediated via the environment (indirect genetic effects). However, the relative importance of direct versus indirect genetic effects on early variability in traits related to neurodevelopmental conditions is unknown. The sample included up to 24,692 parent-offspring trios from the Norwegian MoBa cohort. We use Trio-GCTA to estimate latent direct and indirect genetic effects on mother-reported neurodevelopmental traits at age of 3 years (restricted and repetitive behaviors and interests, inattention, hyperactivity, language, social, and motor development). Further, we investigate to what extent direct and indirect effects are attributable to common genetic variants associated with autism, ADHD, developmental dyslexia, educational attainment, and cognitive ability using polygenic scores (PGS) in regression modeling. We find evidence for contributions of direct and indirect latent common genetic effects to inattention (direct: explaining 4.8% of variance, indirect: 6.7%) hyperactivity (direct: 1.3%, indirect: 9.6%), and restricted and repetitive behaviors (direct: 0.8%, indirect: 7.3%). Direct effects best explained variation in social and communication, language, and motor development (5.1%-5.7%). Direct genetic effects on inattention were captured by PGS for ADHD, educational attainment, and cognitive ability, whereas direct genetic effects on language development were captured by cognitive ability, educational attainment, and autism PGS. Indirect genetic effects on neurodevelopmental traits were primarily captured by educational attainment and/or cognitive ability PGS. Results were consistent with differential contributions to neurodevelopmental traits in early childhood from direct and indirect genetic effects. Indirect effects were particularly important for hyperactivity and restricted and repetitive behaviors and interests and may be linked to genetic variation associated with cognition and educational attainment. Our findings illustrate the importance of within-family methods for disentangling genetic processes that influence early neurodevelopmental traits, even when identifiable associations are small.

Energy acquisition and allocation strategies in scleractinian corals: insights from intraspecific trait variability

Energy acquisition and allocation strategies in scleractinian corals: insights from intraspecific trait variability

Oyster shells as archives of present and past environmental variability and life history traits: A multi‐disciplinary review of sclerochronology methods and applications

AbstractOysters inhabit a variety of coastal and deep‐sea settings over a wide latitudinal range and have a role as ecosystem engineers. They also represent an important food source for humans since hunter‐gatherer times, which motivates interest in using oyster shells as environmental and life history archives. Still, oysters have often been disregarded in sclerochronology studies, although several methods based on both microtextural and geochemical approaches have successfully been investigated. We review how these methods have been used to improve interpretations of shell records, and we identify knowledge gaps in a variety of disciplines. Those include ecology to study larval dispersal and growth rates; archaeology to determine shell midden constructions and site occupations; and palaeoenvironmental and palaeoclimate reconstructions from tidal to annual timescales. We also suggest standardizing sclerochronology procedures to improve palaeoenvironmental reconstructions and biophysical models on oyster larval dispersal.

Phenotypic Variation in Cone Scales and Seeds as Drivers of Seedling Germination Dynamics of Co-Occurring Cedar and Fir Species

The intraspecific trait variations in the reproductive structures and early growth of seedlings may be critical in determining further regeneration. However, modularly built organisms, such as trees, challenge our notion of the phenotype concept, as the arrays of nonidentical homologous organs, such as seed-bearing cone scales and seeds, depending on the individual capacity to produce phenotypically variable arrangements, but they also reflect abiotic selective effects. We investigated the variability in cone scale morphology, seed traits, and germination dynamics in coexisting fir (Abies marocana) and cedar (Cedrus atlantica) trees from northern Morocco. We quantified the degree of trait overlap in two co-occurring populations of both species, as a measure of population/species functional similarity. Cone scale size and seedling growth rate were species-dependent traits, as 70%–80% of the variance was explained by the species, while only 0%–2% was explained by the population. Conversely, seed weight was a tree-dependent trait, as 70% of the variation was observed among trees, while the species only explained 20% of the variation, and the contribution of the population was negligible. Species and populations showed the same characteristics in the correlations between variables, supporting different magnitudes but a constant relationship. Substantial variations in seed weight and early seedling growth occur concurrently among cones of a single tree, independently of the tree species or population. Further studies should consider both phenotype selection and inheritance of traits’ variance on the establishment, survival, and growth of seedlings in A. marocana and C. atlantica in nurseries and reforestation sites to improve adaptive capacity to changing environmental conditions.

Bug off or bug out: mapping flight secrets of Triatoma garciabesi (Hemiptera: Reduviidae) through climate, geography, and greenery

IntroductionTriatoma garciabesi is a vector of Trypanosoma cruzi, the causative agent of Chagas disease, and is found across northwest and central Argentina, southern Bolivia, and western Paraguay. It frequently invades rural houses during the warm seasons and is common in peridomestic and wild environments. Recently, the existence of two lineages has been demonstrated based on variation in cytochrome c oxidase I gene (coI). These lineages occur across the species distribution range and coincide with different ecological regions. Here, we aim to examine how phenotypic variation in flight-related traits is structured, determine the association between these traits and geographic distance, and identify the climatic, geographic, and/or vegetation cover variables that best explain the morphometric variation in flight-related traits.MethodsA total of 198 males of T. garciabesi from 24 populations in Argentina and Paraguay were included in this study, covering almost the entire T. garciabesi distribution range. Size and shape components of the forewing, membranous, and stiff portions of the forewing and head were measured using a landmark-based methodology.ResultsOur study documents that the size component of the membranous and stiff portions showed significant variation across the species range. Although forewing and head shape did not show significant differences in Procrustes distances across all pairs of populations, the membranous and stiff portions did. There is a strong and consistent association between shape and geographic distances at all levels of comparison (species and lineage ranges). The size and shape components and the geographic, climatic, and/or vegetation indexes explained covariation in all flight-related traits.DiscussionT. garciabesi appears to be a species sensitive to vegetation cover and landscape features. This study provides evidence for this by showing clear variation in flight-related traits across the species and lineage distribution range, as well as indications of isolation by distance and variation in flight-related traits according to climate, geography, and vegetation cover.

Trade-off strategies between growth and defense of spring ephemeral plants in early spring

IntroductionSpring ephemeral plants represent a unique ecological category of herbaceous plants, characterized by early blooming and vivid flowers with significant ornamental value. Understanding the adaptive strategies of spring ephemerals is crucial for the introduction and cultivation of early spring plants, as well as for optimizing light energy utilization and nutrient cycling within ecosystems.MethodsWe evaluated 26 functional traits across four spring ephemerals and four spring non-ephemeral plants along an elevation gradient. By establishing a plant functional trait network, we examined the adaptation strategies of early spring plants at different elevations and compared the differences in adaptation strategies between two types of plants.ResultsSpring ephemerals exhibited higher concentrations of carbon and nitrogen, lower concentrations of carbohydrates, higher edge density and modularity in trait networks, and stronger linkages between defense traits. Plants at higher elevations demonstrated higher leaf dry matter content and leaf total flavonoid concentration, and lower nitrogen concentration, influenced by temperature, precipitation, and soil nutrients.DiscussionThese results demonstrated that spring ephemerals have a strong nutrient uptake capacity, and adopt resource competition strategies to rapidly accumulate nutrients and reproduce. The plants at higher elevations adopt more conservative strategies, with trait networks showing increased modularity, edge density, and closer correlations among traits to enhance resource utilization. This study provides new insights into the adaptive strategies of spring ephemerals by demonstrating how plants allocate resources for growth and defense through the regulation of trait variation and correlations among traits.

Divergence of vessel diameter explains interspecific variation in hydraulic safety to salinity in the Sundarbans mangrove ecosystem

Abstract Despite their crucial role in providing ecosystem services and livelihood support in 124 countries, mangroves are facing challenges from warming, altered seasonal precipitation and sea level rise (SLR) in the face of climate change. Variation in intra‐ and interspecific hydraulic traits and related xylem anatomy may allow trees to adapt to changing environmental conditions, yet little is known about adaptive plasticity in mangroves. We examined (i) xylem and hydraulic trait variation across three (low, medium and high) salinity zones in three widespread mangrove species (Exocecaria agallocha, Xylocarpus moluccensis and Heritiera fomes) with distinct shade tolerance characteristics in the Bangladesh Sundarbans, (ii) associations of xylem and hydraulic traits, and (iii) habitat (regulator, resource and forest structure) effects on vessel diameter due to its strong influence on hydraulic conductivity variation. Although potential conductivity (KP) and leaf‐specific conductivity (KL) showed species‐specific variation, a notably greater conductivity was found in the low‐salinity zone (LSZ), which had lower vessel wall reinforcement (t/b)2. Xylem and hydraulic traits exhibited mostly strong phylogenetic signals, whereas pairwise relationships between traits were phylogenetically independent. The study species had distinct hydraulic characteristics, where vessel diameter (D) was strongly related to the variation in KP and KL. Furthermore, the study species exhibited a weak trade‐off between hydraulic efficiency and safety. A greater percentage of smaller vessel diameters in light‐demanding E. agallocha indicates greater hydraulic safety against cavitation under stressful conditions than in shade‐tolerant H. fomes, followed by X. moluccensis. Although species characteristics place broad bounds on xylem traits, the combined effects of salinity, nutrient availability and tree size modulate vessel diameter, which leads to hydraulic conductivity variation. The contrasting safety in terms of vessel diameter in mangroves suggests an important role in adaptation to salinity and species distribution. The results also provide insight into salinity‐induced growth reduction and mortality in mangroves. Read the free Plain Language Summary for this article on the Journal blog.

Selective disappearance based on navigational efficiency in a long-lived seabird.

Whilst efficient movement through space is thought to increase the fitness of long-distance migrants, evidence that selection acts upon such traits remains elusive. Here, using 228 migratory tracks collected from 102 adult breeding common terns (Sterna hirundo) aged 3-22 years, we find evidence that older terns navigate more efficiently than younger terns and that efficient navigation leads to a reduced migration duration and earlier arrival at the breeding and wintering grounds. We additionally find that the age-specificity of navigational efficiency in adult breeding birds cannot be explained by within-individual change with age (i.e. learning), suggesting the selective disappearance of less navigationally efficient individuals. This suggests that, at least in common terns, learning of navigational skills may be largely absent in adulthood, and limited to the pre-breeding phase of life where tracking is more difficult. We propose that selection might explain parts of the age-specificity of navigational performance observed in migratory taxa more generally; discuss the causes and evolutionary implications of variation in navigational traits and the selective agents acting upon them; and highlight the necessity of longitudinal studies when considering changes in behaviour with age.

From low to high elevations, flowers adapt traits and phenology to climate, but phenology‐trait relationships weak

Abstract Flowering phenology is central to plant reproductive success and can relate to morphological traits such as size and quality of flowers, but phenology–trait associations of flowers remain unclear. Phenology–trait associations can vary within and among species, especially across climate gradients, due to allocational trade‐offs in response to selective pressures from abiotic stress and/or biotic factors such as pollinator availability. It is unknown whether floral morphology and phenology experience coordinated selection across climate gradients or vary independently. Understanding the drivers of trait variation and its implications for floral phenology may be especially relevant in mountains where climate and abiotic gradients change sharply with elevation. At higher elevations, increasing cold and aridity may favour higher quality, stress‐tolerant flowers that withstand harsher conditions better than cheaper flowers, but trade‐off with size and showiness to pollinators. Relatively benign conditions at lower elevations may permit more flexible phenotypes and weaker association between trait and phenology by allowing species more leeway for flowering times compared with the short growing season at higher elevations. We examined trait–phenology associations within and among 250 herbaceous species in the Western Himalayas, spanning 2000–4500 m AMSL. Intraspecific variation in traits and phenology decreased from low to high elevation at the community scale, but species showed idiosyncratic responses. Trait–trait correlations indicated stronger selection and constraints on phenotypes and phenology at higher elevations. However, trait–phenology correlations were relatively weak throughout, suggesting independent selection on flower morphology vs. phenology. Overall, climate imposed strong selection on flower traits and regulated floral phenology, but without any strong or consistent associations between traits and phenology. It is likely that flower morphology responded to multiple abiotic and biotic drivers, within and across elevations, whereas phenology mainly responded to temperature and thaw. Our findings suggest that selection from ongoing warming will operate separately on floral morphology and phenology of alpine plant communities, and mechanisms and consequences should be evaluated using experiments. Read the free Plain Language Summary for this article on the Journal blog.

Rainfall seasonality shapes belowground root trait dynamics in an Amazonian tropical rainforest: A test of the stress‐dominance hypothesis

Abstract The stress‐dominance hypothesis (SDH) predicts that trait variation at the community level increases with the availability of limiting resources, driving spatial and temporal patterns in above‐ground plant functional trait expression. Here, we test the assumption that the SDH also applies to fine roots responding to spatial and temporal fluctuations in soil resource availability. We monitored fine root mass and functional root traits associated with resource acquisition, that is specific root length (SRL), specific root tip abundance (SRTA) and branching index (BI), and traits related to stress tolerance, such as root diameter (RD) and tissue density (RTD) in a Central Amazonian tree community. To test for spatial differences in root traits, we separated the uppermost organic (O‐A horizon, 0–5 cm) and mineral soil (B horizon, 5–15 cm) layers, and for temporal fluctuations, we investigated the relationship of precipitation on community‐level root variation over a period of 27 months. In accordance with the SDH, we found that fine roots in the O‐A horizon have on average 15% higher SRL, 23% higher BI, 32% higher SRTA and 15% lower RTD than those in the B horizon. Similarly, precipitation shifted the community over time to higher mean SRL, BI and SRTA (r = 0.92, 0.84 and 0.94, p &lt; 0.0001 respectively), although trait shifts occurred in the trimester after the rainy season onset, revealing a time‐lag between rainfall patterns and community response. We also detected a positive increase in trait range for SRL and SRTA with lagged precipitation (r = 0.90 and 0.79, p &lt; 0.0001). On the other hand, traits related to stress showed a weaker negative relationship with instantaneous precipitation (r = −0.7 and −0.57, p = 0.046 and p = 0.1 for RD and RTD, respectively). Our results supported the SDH predictions that root systems will become more acquisitive in areas with more resources, and that the community will shift to more acquisitive but also broader trait dispersion as hydric stress decreases. We conclude that although higher resource availability may increase competition for acquisition, trait overdispersion seems to promote species coexistence. Our results highlight how dynamic root systems can be in response to environmental cues, cautioning the common practice of making conclusions about root traits adaptations to environmental gradients based on a single sampling observation. Read the free Plain Language Summary for this article on the Journal blog.

Assessment of Genetic Variability, Correlation and Path Analysis in Bread Wheat (Triticum aestivum L.) Genotypes for Yield and its Attributing Traits

This study investigated the genetic variability and agronomic traits influencing wheat yield across multiple genotypes. Conducted during the 2021-2022 rabi season at the Research Farm of BRD PG College, Deoria, the experiment included 31 treatments and a standard check variety, HD-2967, arranged in a randomized block design (RBD) with three replications. Analysis of variance (ANOVA) revealed significant genetic variation among the genotypes for traits such as Days to 50% Flowering (DF), Days to Maturity (DM), Plant Height (PH), and Grain Yield per Plant (GYP). Genotypic correlation analysis showed significant positive associations between DF and DM, and negative correlations between DF, DM, and GYP, highlighting the complex trade-offs among traits. Traits like Test Weight (TW) and Biological Yield (BY) were positively correlated with GYP, indicating their potential as key selection criteria for breeding. Path coefficient analysis identified DF and Test Weight as having strong direct effects on GYP, while traits such as Plant Height and Number of Grains per Spike had negative impacts. These results provide valuable insights into the genetic and phenotypic relationships that can guide the development of superior wheat genotypes with improved yield potential.