Plastic Genotypes Research Articles

Phenotypic Plasticity Index as a Strategy for Selecting Water-Stress-Adapted Coffee Genotypes

The adaptive potential of plants is commonly used as an indicator of genotypes with higher breeding program potential. However, the complexity and interaction of plant metabolic parameters pose a challenge to selection strategies. In this context, this study aimed to explore phenotypic plasticity within the germplasm of Hybrid Timor coffee. Additionally, we assessed the utility of the multivariate phenotypic plasticity index (MVPi) as a promising tool to predict genotype performance across diverse climatic conditions. To achieve this, we evaluated the performance of seven accessions from the Hybrid Timor germplasm in comparison to the Rubi and IPR 100 cultivars, known for their susceptibility and resistance to drought, respectively. The experiment took place in a greenhouse under two conditions: one with normal soil moisture levels near maximum capacity, and the other with a water deficit scenario involving a period of no irrigation followed by rehydration. Data on physiological and biochemical factors were collected at three stages: before applying the water deficit, during its imposition, and after rehydration. Growth data were obtained by the difference between the beginning and end of the experimental period Furthermore, field evaluations of the productivity of the same genotypes were carried out over two consecutive seasons. Based on physiological and biochemical assessments, the MVPi was computed, employing Euclidean distance between principal component multivariate analysis scores. Subsequently, this index was correlated with growth and productivity data through linear regressions. Our findings reveal that the plastic genotypes that are capable of significantly altering physiological and biochemical parameters in response to environmental stimuli exhibited reduced biomass loss in both aerial and root parts. As a result, this positively influenced their productivity. Enhanced plasticity was particularly prominent in accessions from the MG Germplasm Collection: MG 311—Hybrid Timor UFV 428-02, MG 270—Hybrid Timor UFV 377-21, and MG 279—Hybrid Timor UFV 376-31, alongside the Rubi MG 1192 cultivar. The MVPi emerged as a valuable instrument to assess genotype adaptability and predict their performance under varying climatic scenarios.

Assessment of the adaptability of spring film oats in terms of yield and grain quality in the conditions of the Kirov region

Studies were carried out in order to assess the varieties and lines of spring covered oats by the ability to form stable high quality grain yields in the conditions of the Kirov region; to identify promising highly adaptive, plastic genotypes that most fully realize their yield potential in changing environmental conditions. The results of the study of 11 varieties and promising lines of spring covered oats in the nursery of competitive variety testing in the Kirov region in the period from 2020 to 2022 are presented. The Krechet varieties were used as standards generally accepted in the Volga-Vyatka region (during the research period), which are included in the State Register. The most optimal conditions for the growth and development of oats were in 2022 and 2020 when the duration of the period from seedlings to heading averaged 52 and 46 days, and the average yield in varieties was 6.21 and 6.18 t/ha, respectively. Promising lines 91h18 (6.14 t/hа) and 41h18 (5.78 t/hа), which is 0.95 and 0.59 t/ha higher than the Krechet standard. Were characterized by the highest yield while line 91h18 had a high level of plasticity (bi =1.13) and stability (Si2=0.00) based on «yield» parameter. A fairly high plasticity (bi= 1.12) and stability (Si2= 0.01) in terms of yield and grain quality indicators (for protein - bi= 1.12, Si2= 0.20, fat - bi= 1.11, Si2 = 0.00) is characterized by an intensive ‘Medved’ type variety. High indices of plasticity (bi = 1.42) and stability (Si2 = 0.00) on the basis of the parameter «grain protein content» were noted at line 162h15. The highest grain fat content was characterized for lines 178h13 (5.3 %), 4h14 (5.4 %), and 41h18 (5.6 %). Almost all the studied varieties have a high stability (Si2=0,00…0,21) of the sign. When increasing the plasticity and stability of varieties in terms of yield, a decrease in these grain quality indicators was observed, as well as a close negative relationship of the grain protein content with yield (r = -0.83). A high degree of positive dependence of the duration of the germination-heading period with HTC (r = 0.97) and yield (r = 0.79) has been established.

Genotypic stability in root system architecture and aboveground biomass revealed diverse adaptability of peanut (Arachis hypogaea L.) to moderate water deficit

AbstractMany crop species, including cultivated peanut (Arachis hypogaea L.), modify their above‐ and below‐ground growth to cope with water deficit stress. This acclimation to water deficit often triggers a biomass partitioning shift—allocating more biomass to the roots, to increase the accessibility of roots to water resources. However, additional carbon partitioning to roots may not always translate into increased water use and maintenance of aboveground biomass (ABM) and yield. Therefore, selecting an efficient root system architecture (RSA) should aim to sustain a high ABM production under a water deficit scenario. To better understand the associations of above and belowground biomass partitioning under moderate water deficit, this study evaluated the genotypic stability of 40 peanut genotypes in ABM and RSA in greenhouse experiments and further assessed genotypic differences in 4 site‐year field experiments. Our results suggested that higher ABM‐producing genotypes generally had high plasticity when subjected to water deficit whereas the low ABM‐producing genotypes had relatively high stability. Hierarchical clustering analysis further revealed that genotypes with a high root‐to‐shoot ratio potentially had increased genotypic stability in ABM underwater deficit. Interestingly, genotypes that maintained the highest ABM underwater deficit did not have the highest total root biomass and length. Instead, these genotypes had the highest root length in the top layer of soil (0–0.3 m) and relatively fewer roots in the deeper layer of soil (0.3–1 m). Greenhouse‐screened stable genotypes exhibited minimal yield reduction when subjected to mid‐season water deficit in some of the field validation experiments, but it also happened to some plastic genotypes, indicating that further validation of controlled environment screenings for genotypic water‐deficit tolerance in the field is necessary.

Ecological plasticity and adaptive potential of annual form of white sweet clover (Melilotus albus Medik)

The ecological plasticity, stability, and adaptive potential of varieties and promising genetic lines of the annual form of white sweet clover were assessed. The studies were carried out in 2016-2020 in Volga Scientific Research Institute of Selection and Seed-Growing named after P.N. Konstantinov, Samara Federal Research Scientific Center, Russian Academy of Sciences. According to the parameters of ecological plasticity and stability, the studied varieties and genetic lines were differentiated into groups according to their response to the changes in environmental conditions. Most of studied varieties belonged to highly plastic genotypes; varieties Srednevolzhsky, Kinelsky, Zavolzhsky, and genetic line Hugh 0 were characterized by the highest stability under the conditions of the Samara Trans-Volga Region. Varieties Srednevolzhsky, Kinelsky, Zavolzhsky, and genetic lines Hugh 0, Hugh 40 and Indus 1 were highly resistant to unfavorable environmental factors. All the studied genetic lines and varieties are characterized by high selective value and thus may be used as a starting material for developing of new varieties of the annual form of white sweet clover.

Niche breadth and elevational range size: a comparative study on Middle-European Brassicaceae species.

High-elevation species are predicted to have larger elevational ranges compared with species of lower elevations. The reasoning is that temperature variability is greater at higher elevation, selecting for wider niche breadth and more plastic genotypes. We used macroevolutionary comparisons involving 90 Brassicaceae species of the central Alps to test for associations among median elevation of occurrence, elevational range size and thermal variability over space and time on the one hand, and their associations with performance breadth or trait plasticity on the other hand. Performance breadth and trait plasticity were estimated by raising replicate plants per species under three temperature treatments (mild, recurrent frost, recurrent heat). Against prediction, we found that mid-elevation species had the largest elevational ranges, and their ranges were associated with increased spatial thermal variability. Nevertheless, variability in the thermal regime was positively associated neither with niche breadth nor with plasticity. Evidence for adaptive constraints was limited to a trade-off between acclimation-based increases in frost and heat resistance, and phylogenetic niche conservatism for median elevation of occurrence and temporal thermal variability. Results suggest that large elevational range size is associated with divergent adaptation within species, but not with more niche breadth or trait plasticity. This article is part of the theme issue 'Species' ranges in the face of changing environments (part I)'.

Has yield plasticity already been exploited by soybean breeding programmes in Argentina?

This study focuses on the impact of genetic improvement of seed yield plasticity in soybean (Glycine max L.) in high-yielding environments (between 4000 kg ha-1 and 7000 kg ha-1) of Central Argentina. The association between seed yield and its plasticity was analysed with (i) a historical collection of 148 genotypes released to the market between 1980 and 2013 and (ii) 165 currently available commercial genotypes. The impact on seed yield of soybean breeding programmes in Argentina reveals higher genetic progress of the lowest (1.7% year-1) rather than the highest yielding genotypes (0.9% year-1). At the same time, seed yield plasticity has been exploited indirectly. Increased seed yield plasticity over time contributed to a reduction in genotypic seed yield variability (P<0.0001). Seed yield plasticity was related to seed yield in high-yielding environments (>5500 kg ha-1). Plastic genotypes showed a positive correlation with the length of the seed-filling period (r=0.5), suggesting that a longer seed-filling period could be required to maximize seed yield plasticity under high-yielding environments. To increase productivity, clarifying the value of plasticity will aid genotype selection for target environments, as well as the development of high-yielding cultivars specifically adapted to high-yielding conditions.

Assessment of Agrocenosis Adaptability of Winter Wheat in the Conditions of the Foothill Zone of the Central Caucasus

This paper presents the results of multi-year research on the adaptability of winter wheat varieties to the conditions of the foothill zone of the Central Caucasus. Characteristics such as ductility and stability were used to assess varieties for conformity to the cultivation conditions. Plant homeostaticity served as the indicator of ontogenetic adaptability. Phenological observations and reports were carried out according to the state variety testing methodology. The species composition of weed vegetation was established using the Agroecological Atlas of Russia. Conventional insect accounting methods were used to consider phytophages and plants damaged by them. It was established that the dominant pests of winter grains in the early periods of vegetation include phytophage bugs and cereal leaf beetle Oulema melanopus L. The maximum number of phytophage bugs was noted during the earing-flowering period. The proportion of pathogens of spike Fusarium head blight, tan spot and Septoria spot prevailed in the pathogenic complex. In total, 36.7% of varieties, including Kuma, Deya, Esaul, Starshina, Delta, Nota and Antonina, were medium-resistant to Fusarium head blight damage. According to the results of a comprehensive assessment of winter wheat selection by the parameters of adaptability, productivity and resistance to diseases, highly plastic genotypes responsive to environmental factors were distinguished: Kuma, Deya, Veda, Tanya, and List 25 (bi = 2.2; 2,3; 2,1). The selection of varieties was based on the adaptive properties of winter wheat. Fusarium head blight decreased by 20.8% in the mixed variety Batko+Deya, and the yield of mixed variety crops increased by 9%. Methods for compiling mixed varieties and designing the mosaics of varieties in the area of grain agrocenosis are recommended.&#x0D; Keywords: winter wheat, sustainability of agrocenosis, productivity, ecological plasticity, mixed varieties

Different selection practices affect the environmental sensitivity of beef cattle.

The objective of the present study was to evaluate the effects of different selection practices on the environmental sensitivity of reproductive and growth traits in males and females of three Nellore selection lines [control (NeC), selection (NeS), and traditional (NeT) lines]. Moreover, genetic trends for the intercept and slope were estimated for each line, and the possible reranking of sires was examined. A total of 8,757 records of selection weight (SW), 3,331 records of scrotal circumference (SC), and 2,311 records of days to first calving (DFC) from Nellore cattle born between 1981 and 2017 were analyzed. (Co)variance components and genetic parameters of all traits were estimated using a reaction norm model with Gibbs sampler. In all cattle lines, the mean heritability of the studied traits ranged from 0.39 to 0.75 for SW in both males and females, from 0.46 to 0.68 for SC, and from 0.06 to 0.57 for DFC along with the environmental descriptor. In all cattle lines, the genetic correlation coefficients between the intercept and slope ranged from 0.03 to 0.81 for SW, from -0.14 to 0.39 for SC, and from -0.87 to -0.42 for DFC. Genetic trends for the slope and proportion of plastic genotypes indicated that the NeS line was more responsive to environmental changes, whereas the NeC and NeT lines tended to respond more modestly. Reranking of sires was observed for all traits, specifically in the NeC and NeT lines, because of the weak correlation between the opposite extreme environments. In the NeS line, reranking of sires was observed for DFC alone. Our results indicate that the effects of genotype-environment interaction are important and should be considered in genetic evaluations of Nellore cattle. Moreover, different selection practices affected the environmental sensitivity of the Nellore selection lines tested in this study.

Plasticity via feedback reduces the cost of developmental instability.

Costs of plasticity are thought to have important physiological and evolutionary consequences. A commonly predicted cost to plasticity is that plastic genotypes are likely to suffer from developmental instability. Adaptive plasticity requires that the developing organism can in some way sense what environment it is in or how well it is performing in that environment. These two information pathways—an “environmental signal” or a “performance signal” that indicates how well a developing phenotype matches the optimum in the current environment—can differ in their consequences for the organism and its evolution. Here, we consider how developmental instability might emerge as a side‐effect of these two distinct mechanisms. Because a performance cue allows a regulatory feedback loop connecting a trait to a feedback signal, we hypothesized that plastic genotypes using a performance signal would be more developmentally robust compared to those using a purely environmental signal. Using a numerical model of a network of gene interactions, we show that plasticity comes at a cost of developmental instability when the plastic response is mediated via an environmental signal, but not when it is mediated via a performance signal. We also show that a performance signal mechanism can evolve even in a constant environment, leading to genotypes preadapted for plasticity to novel environments even in populations without a history of environmental heterogeneity.

Simulating the effects of local adaptation and life history on the ability of plants to track climate shifts.

Many studies have examined the impact of dispersal on local adaptation, but much less attention has been paid to how local adaptation influences range shifts. The aim of this study was to test how local adaptation might affect climate-driven range shifts in plants, and if this might differ between plants with different life histories. Simulated range shift dynamics were compared for hypothetical annual, perennial and tree species, each comprised of either one plastic genotype or six locally adapted genotypes. The landscape consists of shifting climate bands made up of 20 × 20 m patches containing multiple individuals. Effects of seed dispersal, breadth of the plastic species’ tolerance, steepness of the climate gradient and rate of the climate shift are also examined. Local adaptation increased the equilibrium range size and aided range shifts by boosting fitness near range edges. However, when the rate of climate change was doubled on a steep gradient, locally adapted trees exhibited a higher percent loss of range during the climate shift. The plastic annual species with short dispersal was unable to recover its range size even after the climate stabilized, while the locally adapted annuals tracked climate change well. The results suggest that in most situations local adaptation and longer dispersal distances will be advantageous, though not necessarily sufficient, for tracking suitable climates. However, local adaptation might put species with long generation times at greater risk when climate shifts are very rapid. If confirmed by empirical tests, these results suggest that identifying variation between species in how fitness varies along climate gradients and in these key demographic rates might aid in prioritizing management actions.

Phenological and fitness responses to climate warming depend upon genotype and competitive neighbourhood in Arabidopsis thaliana

Abstract Increasing temperatures during climate change are known to alter the phenology across diverse plant taxa, but the evolutionary outcomes of these shifts are poorly understood. Moreover, plant temperature‐sensing pathways are known to interact with competition‐sensing pathways, yet there remains little experimental evidence for how genotypes varying in temperature responsiveness react to warming in realistic competitive settings. We compared flowering time and fitness responses to warming and competition for two near‐isogenic lines (NILs) of Arabidopsis thaliana transgressively segregating temperature‐sensitive and temperature‐insensitive alleles for major‐effect flowering time genes. We grew focal plants of each genotype in intraspecific and interspecific competition in four treatments contrasting daily temperature profiles in summer and fall under contemporary and warmed conditions. We measured phenology and fitness of focal plants to quantify plastic responses to season, temperature and competition and the dependence of these responses on flowering time genotype. The temperature‐insensitive NIL was constitutively early flowering and less fit, except in a future‐summer climate in which its fitness was higher than the later flowering, temperature‐sensitive NIL in low competition. The late‐flowering NIL showed accelerated flowering in response to intragenotypic competition and to increased temperature in the summer but delayed flowering in the fall. However, its fitness fell with rising temperatures in both seasons, and in the fall its marginal fitness gain from decreasing competition was diminished in the future. Functional alleles at temperature‐responsive genes were necessary for plastic responses to season, warming and competition. However, the plastic genotype was not the most fit in every experimental condition, becoming less fit than the temperature‐canalized genotype in the warm summer treatment. Climate change is often predicted to have deleterious effects on plant populations, and our results show how increased temperatures can act through genotype‐dependent phenology to decrease fitness. Furthermore, plasticity is not necessarily adaptive in rapidly changing environments since a nonplastic genotype proved fitter than a plastic genotype in a warming climate treatment. A plain language summary is available for this article.

Plasticity in native perennial grass populations: Implications for restoration

AbstractIncreasing the evolutionary potential of restored populations has become a viable objective of restoration activities. Choosing plant materials genetically adapted to the restoration environment is critical for success, and phenotypic plasticity may also contribute to establishment and persistence in disturbed environments. To select seed sources for restoration informed by plasticity, we must answer the question: Do some source environments produce more plastic genotypes than others? Using a dataset of maternal families from 130 western US source populations of the perennial bunchgrass Poa secunda, we used variance components to determine the contribution of source population to phenotypic plasticity in two common gardens over two growing seasons. Compared with the genetic contribution to phenotypes, plasticity explained a large fraction of phenotypic variation and was particularly strong for phenology (timing of reproductive events) traits. Plasticity values among phenology traits were also highly correlated. For the morphological traits (panicle length, leaf size) and survival, the genetic contribution to the phenotype was greater than the plastic contribution, but plasticity values among these traits were not highly correlated. Seeds collected from warm and dry locations produced plants with more plasticity in phenology, panicle number, and biomass; cool and wet locations were associated with more plasticity in leaf size, panicle length, plant habit (prostrate or erect), and survival. Plasticity may complement genetic variation for adaptation in restoration materials in some traits.

What is the basis of variation in stress tolerance in plants?

The life cycle of plant, from seed germination, seedling growth, flowering to fruiting, depends on the suitable environment conditions. Plants have a remarkable capacity to occupy ecological niches that are shaped by their edaphic, climatic and biotic environments with extremes that have cyclic patterns, occur very infrequently or heterogeneously, or are chronic. Natural genetic variation for adaptation and acclimation mechanisms provide this inherent ecological niche capacity. To survive in an extreme environment, the growth pattern and flowering time of plants are changed by the organ evolution, even the life cycle, to adapt the special habitats. The evolved organs and living characteristics of these species also make the special habitats become their living environment for the reproduction and propagation. For adaptive phenotypic plasticity to evolve, individuals must be capable of responding to predictable environmental signals, and plastic genotypes must have a fitness advantage over genotypes that are incapable of altering their phenotypes. Plasticity in phenotypic traits can be heritable and subject to natural selection. One important feature distinguishing plants from other complex multicellular organisms is that plants are sessile and thus have to endure environmental challenges such as soil salinity, drought and cold temperatures. Water is an important component of living organisms, in addition to maintaining cell turgor, and metabolism of organism required. When plants suffer from drought stress, the reduction of photosynthesis is beneficial to reduce the damage of ROS to the cells. Photosynthetic metabolism in the chloroplasts of C3 plants applies highly cooperative regulation to minimize the fluctuation of metabolite concentration profiles in the face of transient perturbations. Highly cooperative regulation assures the robustness of the biological system and that there is closer cooperation under perturbation conditions than under normal conditions. Minimizing fluctuations in the profiles of metabolite concentrations is the key to maintaining a system’s function. Although salt, water and cold stresses are clearly different from each other in their physical nature and each elicits specific plant responses, they also activate some common reactions in plants. The most widely studied common response is the induction of some plant genes by environmental stresses. Plant research dedicated to the understanding of mechanisms allowing plant to adjust to environmental constraints is amongst the most significant research domains both in quantity and quality. Plants provide unique opportunities to study the mechanistic basis and evolutionary processes of adaptation to diverse environmental conditions. Though various abiotic stresses negatively impact plant growth and productivity of crops, plants have adapted to respond to these stresses at the molecular, cellular, physiological, and biochemical level, enabling them to survive. Understanding stress signaling and responses will increase our ability to improve stress resistance in crops to achieve agricultural sustainability and food security for a growing world population.

Is plasticity across seasons adaptive in the annual cleistogamous plant Lamium amplexicaule?

Many angiosperms exhibit cleistogamy, the production of both cleistogamous flowers (CL), which remain closed and obligately self-pollinated, and chasmogamous flowers (CH), which are potentially open-pollinated. The CH proportion can be plastic. Plasticity is adaptive if environmental changes can be reliably assessed and responded to with an appropriate phenotype and if plastic genotypes have higher fitness in variable environments than non-plastic ones. We studied the plastic response of four natural populations from northern and southern France of an annual cleistogamous plant, Lamium amplexicaule, to predictable seasonal variation. Plants were grown in a semi-controlled environment in spring and in autumn. We assessed the variation in flower number, phenology and cleistogamy-related traits, which were all plastic with respect to season. The CH proportion was higher in spring than in autumn in all four populations. We showed significant stabilizing selection for cleistogamy traits, with higher optimal CH proportions and more pronounced stabilizing selection in spring than in autumn. Observed CH proportions were close to the predicted optimal CH proportions in each season except in autumn for southern populations, which do not experience the autumnal growing season in nature. These results are consistent with adaptive plasticity across seasons of cleistogamy in L. amplexicaule.We propose that adaptive plasticity of cleistogamy could be driven by pollination environment variation, with CL flowers providing reproductive assurance when pollinators are scarce and CH flowers reducing the inbreeding depression in offspring when pollinators are abundant.

Environmental heterogeneity leads to higher plasticity in dry‐edge populations of a semi‐arid Chilean shrub: insights into climate change responses

Summary Interannual variability in climatic conditions should be taken into account in climate change studies in semi‐arid ecosystems. It may determine differentiation in phenotypic plasticity among populations, with populations experiencing higher environmental heterogeneity showing higher levels of plasticity. The ability of populations to evolve key functional traits and plasticity may determine the survival of plant populations under the drier and more variable climate expected for semi‐arid ecosystems. Working with populations of the semi‐arid Chilean shrub Senna candolleana along its entire distribution range, we assessed inter‐ and intra‐population variation in functional traits as well as in their plasticity in response to water availability. We measured morphological and physiological traits related to drought resistance in both field conditions and in a greenhouse experiment, where drought response was evaluated under two water availability treatments. All populations responded plastically, but higher precipitation heterogeneity in dry‐edge populations seemed to have selected for more plastic genotypes compared to populations growing at mesic sites and with more homogeneous environmental conditions. Synthesis. Our results suggest adaptive plasticity since higher levels of phenotypic plasticity were positively associated with plant performance. However, we did not find evidence for genetic variation for plasticity within populations. To the extent that phenotypic plasticity may play a key role in future persistence, populations at mesic sites may be more vulnerable to climate change due to their lower plasticity and their current limitations to evolve novel norms of reaction. Conversely, although Senna candolleana populations at the dry edge are exposed to higher levels of stress, they may be less susceptible to climate change in view of their greater plasticity. We highlight the need to consider population differentiation in both mean traits and their plasticity to model realistic scenarios of species distribution under climate change.

Plant pathogen evolution and climate change.

Abstract The earth's system is currently experiencing dramatic climate change, with predicted rates of global-mean temperature increase unprecedented in the past 1000 years. Also temperature patterns at the local scale and precipitation regimes are rapidly changing. Extreme climatic events are becoming more intense and frequent, especially on the regional scale. Such sudden environmental changes reduce the time for adaptation and increase the vulnerability of natural ecosystems. Plant pathogens have three major adaptive responses to climate change: to exploit the existing phenotypic plasticity, to migrate to areas with more suitable climate and/or to evolve new attributes. Plastic genotypes may quickly adapt to a broad range of environmental conditions, but if phenotypic plasticity is insufficient, migration and/or evolution (which are facilitated by large population size, mixed mating system and parasexuality) are the only options. Global trade in live plants, which is nowadays the main pathway of introduction of alien plant pathogens to new areas, further complicates the picture. Once introduced into a new environment, pathogens may adapt their lifestyle to new local hosts (host jump), or evolve by introgressing useful genes for adaptation through hybridization with resident species or horizontal gene transfer. The implications of climate change for plant pathogens are difficult to predict, but since pathogens have an array of adaptive mechanisms much wider than their hosts and shorter generation times, their opportunities to adapt/evolve will probably increase. New strategies for predicting and monitoring plant pathogen evolution need to be developed to prevent the spread of new plant pathogens on naive or vulnerable hosts likely weakened by climate change pressure.

Genetic basis and selection for life-history trait plasticity on alternative host plants for the cereal aphid Sitobion avenae.

Sitobion avenae (F.) can survive on various plants in the Poaceae, which may select for highly plastic genotypes. But phenotypic plasticity was often thought to be non-genetic, and of little evolutionary significance historically, and many problems related to adaptive plasticity, its genetic basis and natural selection for plasticity have not been well documented. To address these questions, clones of S. avenae were collected from three plants, and their phenotypic plasticity under alternative environments was evaluated. Our results demonstrated that nearly all tested life-history traits showed significant plastic changes for certain S. avenae clones with the total developmental time of nymphs and fecundity tending to have relatively higher plasticity for most clones. Overall, the level of plasticity for S. avenae clones’ life-history traits was unexpectedly low. The factor ‘clone’ alone explained 27.7–62.3% of the total variance for trait plasticities. The heritability of plasticity was shown to be significant in nearly all the cases. Many significant genetic correlations were found between trait plasticities with a majority of them being positive. Therefore, it is evident that life-history trait plasticity involved was genetically based. There was a high degree of variation in selection coefficients for life-history trait plasticity of different S. avenae clones. Phenotypic plasticity for barley clones, but not for oat or wheat clones, was frequently found to be under significant selection. The directional selection of alternative environments appeared to act to decrease the plasticity of S. avenae clones in most cases. G-matrix comparisons showed significant differences between S. avenae clones, as well as quite a few negative covariances (i.e., trade-offs) between trait plasticities. Genetic basis and evolutionary significance of life-history trait plasticity were discussed.

Identification of potential genotypes of coriander (Coriandrum sativumL.) suitable for rainfed vertisols

The present study was conducted during 3 consecutive years (2009–2010 to 2011–12) at Horticultural Research Station, Lam, Andhra Pradesh (India) to evaluate ten promising and diverse genotypes of coriander (Coriandrum sativum L.) procured from different states of India. Maximum yield was achieved in genotype LCC-237 (959.0 kg ha−1) followed by LCC-236 (897 kg ha−1) which were on par with each other but significantly superior over check variety Sudha (723 kg ha−1). Considering the stability parameters for yield, genotypes RKD-13 and LCC-236 with almost unit regression (−0.90 and 1.12, respectively) may be considered as stable genotypes. The genotype LCC-236 with significant deviation in regression coefficient may be considered as plastic genotype that outperformed other genotypes including best check (Sudha) in all the seasons tested. The mean performance of genotype RKD-13 was significantly lower than check Sudha, hence considered as a poor yielder. Early flowering and maturity, coupled with superiority in these traits, when correlated with yield was found to be the reason for better performance of genotype LCC-236 under diverse environmental conditions. This genotype also possessed high essential oil content than other genotypes evaluated.

Phenotypic plasticity with instantaneous but delayed switches

Phenotypic plasticity is a widespread phenomenon, allowing organisms to better adapt to changing environments. Most empirical and theoretical studies are restricted to irreversible plasticity where the expression of a specific phenotype is mostly determined during development. However, reversible plasticity is not uncommon; here, organisms are able to switch back and forth between phenotypes. We present two optimization models for the fitness of (i) non-plastic, (ii) irreversibly plastic, and (iii) reversibly plastic genotypes in a fluctuating environment. In one model, the fitness values of an organism during different life phases act together multiplicatively (so as to consider traits that are related to survival). The other model additionally considers additive effects (corresponding to traits related to fecundity). Both models yield qualitatively similar results. If the only costs of reversible plasticity are due to temporal maladaptation while switching between phenotypes, reversibility is virtually always advantageous over irreversibility, especially for slow environmental fluctuations. If reversibility implies an overall decreased fitness, then irreversibility is advantageous if the environment fluctuates quickly or if stress events last relatively short. Our results are supported by observations from different types of organisms and have implications for many basic and applied research questions, e.g., on invasive alien species.

The evolution of quantitative traits in complex environments

Species inhabit complex environments and respond to selection imposed by numerous abiotic and biotic conditions that vary in both space and time. Environmental heterogeneity strongly influences trait evolution and patterns of adaptive population differentiation. For example, heterogeneity can favor local adaptation, or can promote the evolution of plastic genotypes that alter their phenotypes based on the conditions they encounter. Different abiotic and biotic agents of selection can act synergistically to either accelerate or constrain trait evolution. The environmental context has profound effects on quantitative genetic parameters. For instance, heritabilities measured in controlled conditions often exceed those measured in the field; thus, laboratory experiments could overestimate the potential for a population to respond to selection. Nevertheless, most studies of the genetic basis of ecologically relevant traits are conducted in simplified laboratory environments, which do not reflect the complexity of nature. Here, we advocate for manipulative field experiments in the native ranges of plant species that differ in mating system, life-history strategy and growth form. Field studies are vital to evaluate the roles of disparate agents of selection, to elucidate the targets of selection and to develop a nuanced perspective on the evolution of quantitative traits. Quantitative genetics field studies will also shed light on the potential for natural populations to adapt to novel climates in highly fragmented landscapes. Drawing from our experience with the ecological model system Boechera (Brassicaceae), we discuss advancements possible through dedicated field studies, highlight future research directions and examine the challenges associated with field studies.