Different Combinations Of Traits Research Articles

Genetic control of pod morphological traits and pod edibility in a common bean RIL population

Key messageQTL mapping, association analysis, and colocation study with previously reported QTL revealed three main regions controlling pod morphological traits and two loci for edible pod characteristics on the common bean chromosomes Pv01 and Pv06.Bean pod phenotype is a complex characteristic defined by the combination of different traits that determine the potential use of a genotype as a snap bean. In this study, the TUM RIL population derived from a cross between ‘TU’ (dry) and ‘Musica’ (snap) was used to investigate the genetic control of pod phenotype. The character was dissected into pod morphological traits (PMTs) and edible pod characteristics (EPC). The results revealed 35 QTL for PMTs located on seven chromosomes, suggesting a strong QTL colocation on chromosomes Pv01 and Pv06. Some QTL were colocated with previously reported QTL, leading to the mapping of 15 consensus regions associated with bean PMTs. Analysis of EPC of cooked beans revealed that two major loci with epistatic effect, located on chromosomes Pv01 and Pv06, are involved in the genetic control of this trait. An association study using a subset of the Spanish Diversity Panel (snap vs. non-snap) detected 23 genomic regions, with three regions being mapped at a position similar to those of two loci identified in the TUM population. The results demonstrated the relevant roles of Pv01 and Pv06 in the modulation of bean pod phenotype. Gene ontology enrichment analysis revealed a significant overrepresentation of genes regulating the phenylpropanoid metabolic process and auxin response in regions associated with PMTs and EPC, respectively. Both biological functions converged in the lignin biosynthetic pathway, suggesting the key role of the pathway in the genetic control of bean pod phenotype.

Interspecific Integration of Chemical Traits in Desert Plant Leaves with Variations in Soil Water and Salinity Habitats

Understanding the relationship between soil environmental conditions and the interspecific integration of plant traits might shed light on how plants adapt to their environment. In order to clarify the adaptation strategies of desert plants in the various habitats, this study calculated interspecific trait integration (ITI) and plant trait networks (PTN) by selecting plants from high water-salinity habitat (HSM) with salt stress and low water-salinity habitat (LSM) with drought stress in the Ebinur Lake region. Eight different phytochemical traits were taken into consideration, including carbon (C), nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), sodium (Na), and magnesium (Mg). Six soil factors were chosen, including soil pH, water content (SVWC), electrical conductivity (EC), soil nitrogen (N), phosphorus (P), and potassium (K). The results obtained are shown below: (1) the relationship between plant leaf chemical traits was closer in HSM than in LSM, and the correlation between C and other leaf chemical traits was significant in HSM and insignificant in LSM; (2) the correlations between soil factors and ITI were not statistically significant; however, in both soil water-salinity habitats, the strength of fit between SVWC and ITI was the greatest, while the strength of fit between EC and ITI was the smallest; and (3) according to the PTN, C and Ca are the two most central traits for the growth of desert leaf chemical plants in Ebinur Lake, which is consistent with the results of the PCA. Coordination of plant leaf traits along water-salinity gradients involves many different combinations of traits, and the use of ITI and PTN can quantify the complex relationships between multiple traits to a greater extent, highlighting the multivariate mechanisms of plant response and adaptation to soil habitats. This information will help expand and optimize our ability to observe and predict desert plant responses to habitat change, providing powerful insights for assessing desert plant survival strategies.

Interacting ecological filters influence success and functional composition in restored plant communities over time.

A trait-based community assembly framework has great potential to direct ecological restoration, but uncertainty over how traits and environmental factors interact to influence community composition over time limits the widespread application of this approach. In this study, we examined how the composition of seed mixes and environment (north- vs. south-facing slope aspect) influence functional composition and native plant cover over time in restored grassland and shrubland communities. Variation in native cover over 4 years was primarily driven by species mix, slope aspect, and a species mix by year interaction rather than an interaction between species mix and slope aspect as predicted. Although native cover was higher on wetter, north-facing slopes for most of the study, south-facing slopes achieved a similar cover (65%-70%) by year 4. While community-weighted mean (CWM) values generally became more resource conservative over time, we found shifts in particular traits across community types and habitats. For example, CWM for specific leaf area increased over time in grassland mixes. Belowground, CWM for root mass fraction increased while CWM for specific root length decreased across all seed mixes. Multivariate functional dispersion remained high in shrub-containing mixes throughout the study, which could enhance invasion resistance and recovery following disturbance. Functional diversity and species richness were initially higher in drier, south-facing slopes compared to north-facing slopes, but these metrics were similar across north- and south-facing slopes by the end of the 4-year study. Our finding that different combinations of traits were favored in south- and north-facing slopes and over time demonstrates that trait-based approaches can be used to identify good restoration candidate species and, ultimately, enhance native plant cover across community types and microhabitat. Changing the composition of planting mixes based on traits could be a useful strategy for restoration practitioners to match species to specific environmental conditions and may be more informative than using seed mixes based on growth form, as species within functional groups can vary tremendously in leaf and root traits.

Molecular Big Data in Sports Sciences: State-of-Art and Future Prospects of OMICS-Based Sports Sciences.

Together with environment and experience (that is to say, diet and training), the biological and genetic make-up of an athlete plays a major role in exercise physiology. Sports genomics has shown, indeed, that some DNA single nucleotide polymorphisms (SNPs) can be associated with athlete performance and level (such as elite/world-class athletic status), having an impact on physical activity behavior, endurance, strength, power, speed, flexibility, energetic expenditure, neuromuscular coordination, metabolic and cardio-respiratory fitness, among others, as well as with psychological traits. Athletic phenotype is complex and depends on the combination of different traits and characteristics: as such, it requires a “complex science,” like that of metadata and multi-OMICS profiles. Several projects and trials (like ELITE, GAMES, Gene SMART, GENESIS, and POWERGENE) are aimed at discovering genomics-based biomarkers with an adequate predictive power. Sports genomics could enable to optimize and maximize physical performance, as well as it could predict the risk of sports-related injuries. Exercise has a profound impact on proteome too. Proteomics can assess both from a qualitative and quantitative point of view the modifications induced by training. Recently, scholars have assessed the epigenetics changes in athletes. Summarizing, the different omics specialties seem to converge in a unique approach, termed sportomics or athlomics and defined as a “holistic and top-down,” “non-hypothesis-driven research on an individual’s metabolite changes during sports and exercise” (the Athlome Project Consortium and the Santorini Declaration) Not only sportomics includes metabonomics/metabolomics, but relying on the athlete’s biological passport or profile, it would enable the systematic study of sports-induced changes and effects at any level (genome, transcriptome, proteome, etc.). However, the wealth of data is so huge and massive and heterogenous that new computational algorithms and protocols are needed, more computational power is required as well as new strategies for properly and effectively combining and integrating data.

Why Are Species’ Traits Weak Predictors of Range Shifts?

We examine the evidence linking species’ traits to contemporary range shifts and find they are poor predictors of range shifts that have occurred over decades to a century. We then discuss reasons for the poor performance of traits for describing interspecific variation in range shifts from two perspectives: ( a) factors associated with species’ traits that degrade range-shift signals stemming from the measures used for species’ traits, traits that are typically not analyzed, and the influence of phylogeny on range-shift potential and ( b) issues in quantifying range shifts and relating them to species’ traits due to imperfect detection of species, differences in the responses of altitudinal and latitudinal ranges, and emphasis on testing linear relationships between traits and range shifts instead of nonlinear responses. Improving trait-based approaches requires a recognition that traits within individuals interact in unexpected ways and that different combinations of traits may be functionally equivalent.

Plant functional traits reflect different dimensions of species invasiveness.

Trait-based invasiveness studies typically categorize exotic species as invasive or noninvasive, implicitly assuming species form two homogenous groups. However, species can become invasive in different ways (e.g., high abundance, fast spread), likely relying on different functional traits to do so. As such, binary classification may obscure traits associated with invasiveness. We tested whether (1) the way in which invasiveness is quantified influences its correlation with functional traits and (2) different demography-based metrics are related to different sets of traits. Using a case study of 251 herbs exotic to Victoria, Australia, we quantified species' invasiveness using 10 metrics: four continuous, demography-based dimensions of invasiveness (spread rate, local abundance, geographic and environmental range sizes) and six binary classifications of invasiveness (based on alternative sources and invasion criteria). We examined the correlation between species' invasiveness and a set of four traits known to relate to plant demography and invasion. Then, we examined whether different demographic dimensions of invasiveness were better explained by different sets of traits. We found that the way invasiveness was quantified was important: different traits were linked with different invasiveness metrics, and some traits showed opposite effects across metrics. Species with fast spread were either tall with small seeds (i.e., good colonizers), or had heavy, animal-dispersed seeds. Plants with a large environmental range had greater plasticity for some traits. Locally abundant plants had low SLA and heavy seeds (i.e., strong competitors). Animal dispersal was also key to reach a large geographic range. No traits were consistently related to the six binary classifications. Our results indicate that exotic plants are invasive in different ways and rely on different combinations of traits to be so. Some traits (e.g., seed mass) had complex relationships with invasion: they apparently promote, hampered, or had no influence on different dimensions of invasiveness. Our findings are consistent with the notion that plant species use strategies that may be near optimal under some, but not all, ecological conditions. Compared to binary classifications of invasiveness, the use of invasiveness dimensions advances clearer hypothesis testing in invasion science.

Trait Diversity of Pulse Species Predicts Agroecosystem Properties Trade-Offs.

Crop diversity management in agriculture is a fundamental principle of agroecology and a powerful way to promote resilient and sustainable production systems. Pulses are especially relevant for diversification issues. Yet, the specific diversity of legumes is poorly represented in most cropping systems. We used the trait-based approach to quantify the functional diversity of 30 pulses varieties, belonging to 10 species, grown under common field conditions. Our aim was to test relationships between traits, yield, and supporting agroecosystem properties. Our experimental results highlighted trade-offs between agroecosystem properties supported by different combinations of traits. Also, results demonstrated the relevance of leaf nitrogen content (LNC), leaf area ratio (LAR), and reproductive phenology to predict most of the trade-offs observed between agroecosystem properties. A comparison with a previous analysis based on literature data collected in diverse agronomic situations suggested that some traits are more plastic than others and therefore contribute differently to frame legumes diversity depending on the conditions of observation. Present results suggested that the implementation of such trait-based approach would rapidly benefit the selection of species/varieties for specific targeted agroecosystem services provisioning under specific (environmental or management) conditions.

Different sets of traits explain abundance and distribution patterns of European plants at different spatial scales

AbstractAimPlant functional traits summarize the main variability in plant form and function across taxa and biomes. We assess whether geographic range size, climatic niche size, and local abundance of plants can be predicted by sets of traits (trait syndromes) or are driven by single traits.LocationEurasia.MethodsSpecies distribution maps were extracted from the Chorological Database Halle to derive information on the geographic range size and climatic niche size for 456 herbaceous, dwarf shrub and shrub species. We estimated local species abundances based on 740,113 vegetation plots from the European Vegetation Archive, where abundances were available as plant species cover per plot. We compiled a complete species‐by‐trait matrix of 20 plant functional traits from trait databases (TRY, BiolFlor and CLO‐PLA). The relationships of species’ geographic range size, climatic niche size and local abundance with single traits and trait syndromes were tested with multiple linear regression models.ResultsGenerally, traits were more strongly related to local abundances than to broad‐scale species distribution patterns in geographic and climatic space (range and niche size), but both were better predicted by trait combinations than by single traits. Local abundance increased with leaf area and specific leaf area (SLA). Geographic range size and climatic niche size both increased with SLA. While range size increased with plant height, niche size decreased with leaf carbon content.ConclusionFunctional traits matter for species’ abundance and distribution at both local and broad geographic scale. Local abundances are associated with different combinations of traits as compared to broad‐scale distributions, pointing to filtering by different environmental and ecological factors acting at distinct spatial scales. However, traits related to the leaf economics spectrum were important for species’ abundance and occurrence at both spatial scales. This finding emphasizes the general importance of resource acquisition strategies for the abundance and distribution of herbaceous, dwarf shrub and shrub species.

PhenoSpace: A Shiny application to visualize trait data in the phenotypic space of the global spectrum of plant form and function.

A recent analysis of variation in six major traits conducted on a large worldwide sample of vascular plant species showed that three‐quarters of trait variation was captured by a two‐dimensional global spectrum of plant form and function (“global spectrum” hereafter). We developed the PhenoSpace application, whose aim is to visualize and export the position of any individual/population/species in the phenotypic space of the global spectrum.PhenoSpace is a Shiny application that helps users to manipulate and visualize data pertaining to the global spectrum of plant form and function. It is freely accessible at the following URL: https://shiny.cefe.cnrs.fr/PhenoSpace/.PhenoSpace has three main functionalities. First, it allows users to visualize the phenotypic space of the global spectrum using different combinations of traits and growth forms. Second, trait data from any new user‐defined dataset can be projected onto the phenotypic space of the global spectrum, provided that at least two of the six traits are available. Finally, figures produced and loadings of the imported data on the PCA axes can be downloaded, allowing users to conduct further analyses.PhenoSpace fulfills the practical goal of positioning plants in the phenotypic space of the global spectrum, making it possible to compare trait variation at any level of organization against the worldwide background. This serves a major aim of comparative plant ecology, which is to put specific sets of individuals, populations or species into a broader context, facilitating comparison and synthesis of results across different continents and environments using relevant indicators of plant design and function.

Genomic and plumage variation in Vermivora hybrids

AbstractHybrids with different combinations of traits can be used to identify genomic regions that underlie phenotypic characters important to species identity and recognition. Here, we explore links between genomic and plumage variation in Blue-winged Warbler x Golden-winged Warbler (Vermivora cyanoptera x V. chrysoptera) hybrids, which have traditionally been categorized into 2 discrete types. “Lawrence’s” hybrids are yellow overall, similar to Blue-winged Warblers, but exhibit the black throat patch and face mask of Golden-winged Warblers. “Brewster’s” hybrids are similar to Golden-winged Warblers, but lack the black throat patch and face mask, and sometimes have yellow on their underparts. Previous studies hypothesized that (1) first generation hybrids are of the Brewster’s type and can be distinguished by the amount of yellow on their underparts, and that (2) the throat patch/mask phenotype is consistent with Mendelian inheritance and controlled by variation in a locus near the Agouti-signaling protein (ASIP) gene. We addressed these hypotheses using whole genome re-sequencing of parental and hybrid individuals. We found that Brewster’s hybrids had genomic hybrid index scores indicating this phenotype can arise by majority ancestry from either parental species, that their plumage varied in levels of carotenoid pigmentation, and individuals captured in multiple years grew consistently less yellow over time. Variation in carotenoid pigmentation showed little relationship with genomic hybrid index score and is thus inconsistent with previous hypotheses that first generation hybrids can be distinguished by the amount of yellow in their plumage. Our results also confirm that variation near ASIP underlies the throat patch phenotype, which we refined to an ~10–15 Kb region upstream of the coding sequence. Overall, our results support the notion that traditional categorization of hybrids as either Lawrence’s or Brewster’s oversimplifies continuous variation in carotenoid pigmentation, and its inferred underlying genetic basis, and is based primarily on one discrete trait, which is the throat patch/mask phenotype.

Selection indices for enhanced selection efficiency in Indian mustard under terminal heat stress conditions

With global increase in temperature, terminal heat stress (THS) has emerged as a major challenge in food crops. Indian mustard (Brassica juncea L. Czern and Coss), C3 plant, grows well at 15-20°C. Heat stress at seedling as well as at flowering stage leads to enhanced vegetative growth and flower abortion leading to loss in seed yield. Late sowing after cotton and rice harvest expose the crop to high temperature stress during reproductive stage of development. A fixed diversity stock of 486 Indian mustard lines were evaluated under delayed planting conditions to expose the crop to THS for two consecutive years. Selection indices were computed using four different combinations of traits via Kang_SAS Path computer program along with expected genetic advance (GA) at 5% selection intensity. Set1, comprised of five traits viz., plant height (PH), number of secondary branches (NSB), number of siliquae on main shoot (NSMS), seed yield (SY) and 1000-seed weight (TSW) were recorded the highest GA (8.612) in comparison to other trait combinations tested in present study. Other important finding was slight difference in GA of set I (8.612; SY included) and set II (8.599; SY excluded) with efficiency of selection index 131% and 130%, respectively. This recommended that in initial breeding generations (F2/F3), a breeder may base his selection on four yield related traits (PH, NSB, NSMS and TSW) only without significant loss in genetic gains. This will save resources and time of breeders to compute seed yield. This is the first report on computation of selection index for efficient simultaneous selection under THS in Indian mustard.

Evaluation of pulse crops\u2019 functional diversity supporting food production

Pulses, defined as legumes which produce dry seed used for human consumption, are plants of great agronomic value, at the food system level as much as the field level but their diversity has been largely underused. This study aimed at analyzing existing data on cultivated pulse species in the literature to provide a broad and structured description of pulses’ interspecific functional diversity. We used a functional trait-based approach to evaluate how pulse diversity could support food production in agroecosystems constrained by low water and nutrient availability and exposed to high weed pressure. We gathered data for 17 functional traits and six agroecosystem properties for 43 pulse species. Our analytical framework highlights the correlations and combinations of functional traits that best predict values of six agroecosystem properties defined as ecosystem services estimates. We show that pulse diversity has been structured both by breeding and by an environmental gradient. The covariance space corresponding to agroecosystem properties was structured by three properties: producers, competitors, stress-tolerant species. The distribution of crop species in this functional space reflected ecological adaptive strategies described in wild species, where the size-related axis of variation is separated from variation of leaf morpho-physiological traits. Six agroecosystem properties were predicted by different combinations of traits. However, we identified ubiquitous plant traits such as leaflet length, days to maturity, seed weight, and leaf nitrogen content, that discriminated agroecosystem properties and allowed us to gather individual species into three clusters, representative of the three strategies highlighted earlier. Implications for pulses provisioning of services in agroecosystems are discussed.

A Molecular Genetics Study of Silver and Downy Birches in Peatland and Paludified Forest Types in the Center of the East European Plain

Taxonomic status of birches (Betula pendula, B. pubescens or their hybrids) is identified by molecular genetics assay of the ploidy level using SSR-markers in moist and peatland forest types. Studies are performed on experimental forest sites of the Institute of Forest Science in the center of the East European plain. B. pendula × B. pubescens hybrids accounted for 11% of the combined dataset. Thus, the birch hybrids are essential components of natural communities. We demonstrate for the first time that B. pendula is predominant, the hybrids are rare, and B. pubescens occurs sporadically on oligotrophic peat bogs. B. pendula grew in the canopy while B. pubescens and the hybrids grew in second story of moist blueberry pine forests. Identification of birch species using keys for the flora species is proven to be confusing due to the occurrence of different combinations of traits. All genetically identified B. pendula trees had twigs growing upwards, without pendulous traits.

Histological and developmental insights into the herbivorous dentition of tapinocephalid therapsids.

Tapinocephalids were one of the earliest therapsid clades to evolve herbivory. In acquiring derived tooth-to-tooth occlusion by means of an exaggerated heel and talon crown morphology, members of this family have long been considered herbivorous, yet little work has been done to describe their dentition. Given the early occurrence of this clade and their acquisition of a dentition with several derived features, tapinocephalids serve as an important clade in understanding adaptations to herbivory as well as macroevolutionary patterns of dental trait acquisition. Here we describe the histology of tapinocephalid jaws and incisors to assess adaptations to herbivory. Our results yield new dental characters for tapinocephalids including a peculiar enamel structure and reduced enamel deposition on the occlusal surface. These traits are convergent with other specialized herbivorous dentitions like those found in ornithischian dinosaurs and ungulates. Furthermore, these results demonstrate that while acquiring some specializations, tapinocephalids also retained plesiomorphic traits like alternate, continuous replacement. We interpret these findings as an example of how different combinations of traits can facilitate a derived and specialized dentition and then discuss their implications in the acquisition of a mammal-like dentition.

Integration of Genotype, Physiological Performance, and Survival in a Lizard (Uta stansburiana) with Alternative Mating Strategies.

Covariation among behavioral and physiological traits is thought to enhance reproductive success and Darwinian fitness. Species that exhibit alternative mating strategies provide excellent opportunities to assess the relative contributions of physiological and behavioral traits to fitness. Male side-blotched lizards (Uta stansburiana) exhibit three heritable throat color morphs that are associated with alternative mating behaviors. The three morphs differ in resource holding potential, mate attraction, mate defense, and physiological performance. We examined interrelationships of body mass, stamina, field metabolic rate, growth rate, and survival to the second capture (a fitness proxy). Relationships among variables were complex, and mass, stamina, and throat color interacted to predict male survival. Our analyses suggest that male side-blotched lizards exhibit trade-offs among physiological traits related to reproductive success and survival and that differential survival for different combinations of traits has caused correlational selection, leading to adaptive integration of phenotypic traits associated with alternative mating strategies.

Variation in Morphology and Kinematics Underlies Variation in Swimming Stability and Turning Performance in Freshwater Turtles

AbstractAmong swimming animals, stable body designs often sacrifice performance in turning, and high turning performance may entail costs in stability. However, some rigid-bodied animals appear capable of both high stability and turning performance during swimming by propelling themselves with independently controlled structures that generate mutually opposing forces. Because such species have traditionally been studied in isolation, little is known about how variation within rigid-bodied designs might influence swimming performance. Turtles are a lineage of rigid-bodied animals, in which most species use contralateral limbs and mutually opposing forces to swim. We tested the stability and turning performance of two species of turtles, the pleurodire Emydura subglobosa and the cryptodire Chrysemys picta. Emydura subglobosa exhibited both greater stability and turning performance than C. picta, potentially through the use of subequally-sized (and larger) propulsive structures, faster limb movements, and decreased limb excursions. These data show how, within a given body design, combinations of different traits can serve as mechanisms to improve aspects of performance with competing functional demands.

Habitat loss causes non-linear genetic erosion in specialist species

Habitat loss can lead to non-linear declines in species abundance once the amount of landscape-wide habitat is reduced to a critical value. Previous studies have suggested that such non-linear responses to landscape-wide habitat loss might also exist in genetic variation, and an in-depth understanding of non-linear habitat loss effects on all levels of biodiversity levels is vital to take appropriate conservation actions.Using individual-based simulations we evaluated the existence of generic non-linear responses in three different response variables and across different combinations of traits related to dispersal and population density. We simulated habitat loss scenarios by incrementally reducing the landscape-wide habitat amount within a previously undisturbed landscape and monitored population abundance, genetic diversity and differentiation of populations within constant sampling areas over time. We found aside from population abundance, genetic variation also responded non-linearly to habitat loss across all scenarios. Importantly, the populations that persisted in remaining habitat fragments experienced genetic erosion before a noticeable effect on local abundance occurred. The observed increase in genetic differentiation and the decrease in genetic diversity of remaining populations are likely caused by the indirect effects of landscape-wide habitat loss on effective patch isolation. Thus, genetic data might have the potential to detect indirect effects of landscape-wide habitat loss before it directly affects the size of a population. Since indirect effects of habitat loss might go unnoticed when extinction risk is estimated from abundance data alone, we argue that an improved understanding of genetic effects is crucial to anticipate and ultimately prevent the negative effects of habitat loss.

Selection indices for improving selection efficiency in Indian mustard

ABSTRACTIn Indian mustard (Brassica juncea L. Czern & Coss), a major oilseed brassica crop, oil yield is the ultimate trait of economic value, which is determined by seed yield (SY) and oil content (OC). SY, the end product of many complex biological processes, is influenced by many traits, such as plant height (PH), branch number, siliqua number, seed weight, seed size and pod length. It is difficult to accurately select for high-yielding genotypes based exclusively on SY, neglecting other yield-determining traits in commercial breeding programs. Therefore, it is desirable for breeders to simultaneously improve several traits of economic importance, most of which are quantitative in nature. The purpose of the present study was to develop selection indices for simultaneous selection of multiple quantitative traits to enhance selection efficiency of the mustard breeding program of Punjab Agricultural University (PAU) located in Abohar, Punjab. A set of 487 diverse mustard genotypes, comprising germplasm accessions of Indian and European origin, advanced breeding lines, landraces, and cultivars, was evaluated using an alpha lattice design for 2 years (2015–16 and 2016–17) at the Regional Research Station of PAU, Abohar, District Fazilka (the major mustard-growing region of the Punjab state). Data on PH, main shoot length (MSL), number of primary branches (NPB), number of secondary branches (NSB), number of siliquae on main shoot (NSMS), siliqua length (SL), number of seeds per pod (NSP), 1000-seed weight (TSW), SY on a plot basis and OC were recorded. To compute selection indices, economic weights, as determined via path coefficient analysis, were assigned to major yield-determining traits. Out of eight recorded agronomic traits, four traits, viz., NSMS, TSW, NSB and NPB, had larger direct effects on SY than other traits, and hence were assigned relative economic weights of 0.60, 0.20, 0.12 and 0.08, respectively. Selection indices were computed using different combinations of traits via Kang_SASPath computer program. When seven traits were used in a selection index (PH, NPB, NSB, NSMS, SY, TSW and MSL; or PH, NPB, NSB, NSMS, SY, TSW and OC), expected genetic advance (GA)at 5% selection intensity was about the same (9.55; selection efficiency or SE = 163% compared with selection based on SY alone).The GA was 9.46 (SE = 161%)for five traits, viz., NPB, NSB, NSMS, SY and TSW; and 9.30 (SE = 159%)for four traits, viz., NPB, NSB, NSMS, and TSW. These GAs were compared with the GA for SY only, which was 5.90 (benchmark; SE = 100%). We concluded that simultaneous selection based on multiple traits was always more efficient than selection based on SY alone. As there was only a small difference between the GA based on four traits (SE = 161%) and GA based on seven traits (SE = 163%), we suggest that mustard breeders use the parsimonious combination of four traits, viz., NPB, NSB, NSMS, and SY, to enhance SY and, consequently, oil yield in mustard.

Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study.

Plants have developed morphological, physiological, biochemical, cellular, and molecular mechanisms to survive in drought-stricken environments with little or no water caused by below-average precipitation. In this mini-review, we highlight the characteristics that allows marama bean [Tylosema esculentum (Burchell) Schreiber], an example of an orphan legume native to arid regions of southwestern Southern Africa, to flourish under an inhospitable climate and dry soil conditions where no other agricultural crop competes in this agro-ecological zone. Orphan legumes are often better suited to withstand such harsh growth environments due to development of survival strategies using a combination of different traits and responses. Recent findings on questions on marama bean speciation, hybridization, population dynamics, and the evolutionary history of the bean and mechanisms by which the bean is able to extract and conserve water and nutrients from its environment as well as aspects of morphological and physiological adaptation will be reviewed. The importance of the soil microbiome and the genetic diversity in this species, and their interplay, as a reservoir for improvement will also be considered. In particular, the application of the newly established marama bean genome sequence will facilitate both the identification of important genes involved in the interaction with the soil microbiome and the identification of the diversity within the wild germplasm for genes involved drought tolerance. Since predicted future changes in climatic conditions, with less water availability for plant growth, will severely affect agricultural productivity, an understanding of the mechanisms of unique adaptations in marama bean to such conditions may also provide insights as to how to improve the performance of the major crops.

Niche modeling reveals lack of broad-scale habitat partitioning in extinct horses of North America

The classic traits of modern horses (Equidae) – large body size, high-crowned teeth (hypsodonty), and a single toe (monodactyly) – are often considered adaptations to grassland environments. However, extinct horses that varied in these three traits overlapped geographically for millions of years during the Miocene and Pliocene. It has been hypothesized that co-occurring horse species partitioned habitats, with large-bodied, hypsodont, and monodactyl equids dominating open grasslands, while equids with different combinations of traits lived in more wooded areas. We tested for the presence of broad-scale habitat partitioning by compiling a large database of North American horse fossil occurrences with data on trait state (body size, hypsodonty index, and toe number) and paleoenvironment (derived from paleovegetation records). Null modeling of niche overlap in each of the North American Land Mammal Ages of the Miocene and Pliocene revealed that taxonomic and trait-based groups show no differences in habitat occupancy. Cluster dendrograms visualizing niche overlap showed that some ecological guilds shared derived traits, but derived traits were not associated exclusively with grassland habitats. Trait values are not predicted by the proportion of grassland habitats in time bins. Further, the three traits show no co-evolution across the equid tree when corrected for phylogenetic relatedness. Together, these results suggest that the evolution of large body size, hypsodonty, and monodactyly in equids was not due to a shared selective regime in response to expanding grassland habitats; instead, these traits may have evolved separately, likely due to a variety of small-scale selective pressures acting across the variety of habitats present in the Miocene and Pliocene.