Propagule Size Research Articles

Translating macroecological models to predict microbial establishment probability in an agricultural inoculant introduction

The use of potentially beneficial microorganisms in agriculture (microbial inoculants) has rapidly accelerated in recent years. For microbial inoculants to be effective as agricultural tools, these organisms must be able to survive and persist in novel environments while not destabilizing the resident community or spilling over into adjacent natural ecosystems. Despite the importance of propagule pressure to species introductions, few tools exist in microbial ecology to predict the outcomes of agricultural microbial introductions. Here, we adapt a macroecological propagule pressure model to a microbial scale and present an experimental approach for testing the role of propagule pressure in microbial inoculant introductions. We experimentally determined the risk-release relationship for an IAA-expressing Pseudomonas simiae inoculant in a model monocot system. We then used this relationship to simulate establishment outcomes under a range of application frequencies (propagule number) and inoculant concentrations (propagule size). Our simulations show that repeated inoculant applications may increase establishment, even when increased inoculant concentration does not alter establishment probabilities. Applying ecological modeling approaches like those presented here to microbial inoculants may aid their sustainable use and provide a monitoring tool for microbial inoculants.

Landscape Heterogeneity and Environmental Dynamics Improve Predictions of Establishment Success of Colonising Small Founding Populations.

In long-distance dispersal events, colonising species typically begin with a small number of founding individuals. A growing body of research suggests that establishment success of small founding populations can be determined by the context of the colonisation event and the new environment. Here, we illuminate the importance of these sources of context dependence. Using a spatially explicit, temporally dynamic, mechanistic, individual-based simulator of a model amphibian species, the cane toad (Rhinella marina), we simulated colonisation scenarios to investigate how (1) the number of founding individuals, (2) the number of dispersal events, (3) landscape's spatial composition and configuration of habitats ('spatially heterogeneous landscapes') and (4) the timing of arrival with regards to dynamic environmental conditions ('dynamic environmental conditions') influence the establishment success of small founding populations. We analysed the dynamic effects of these predictors on establishment success using running-window logistic regression models. We showed establishment success increases with the number of founding individuals, whereas the number of dispersal events had a weak effect. At ≥ 20 founding individuals, propagule size swamps the effects of other factors, to whereby establishment success is near-certain (≥ 90%). But below this level, confidence in establishment success dramatically decreases as number of founding individuals decreases. At low numbers of founding individuals, the prominent predictors are landscape spatial heterogeneity and dynamic environmental conditions. For instance, compared to the annual mean, founding populations with ≤ 5 individuals have up to 18% higher establishment success when they arrive in 'packed' landscapes with relatively limited and clustered essential habitats and right before the breeding season. Accounting for landscape spatial heterogeneity and dynamic environmental conditions is integral in understanding and predicting population establishment and species colonisation. This additional complexity is necessary for advancing biogeographical theory and its application, such as in guiding species reintroduction efforts and invasive alien species management.

A re-evaluation of the tidal sorting hypothesis of mangrove zonation: propagule specific gravity matters

There is much controversy surrounding factors that affect the distribution of mangrove plants across the intertidal gradient. It was previously hypothesized that mangrove zonation was attributed to tidal sorting (TSH) of its propagules according to size (weight) or differential ability of propagules to establish in deep water. However, observational and experimental evidence have provided little support for the actual mechanism(s) of mangrove zonation. In general, species distribution pattern is the consequence of propagule dispersal. The specific gravity of water-borne mangrove propagules may affect their buoyancy, with inherent links to dispersal, thereby potentially influencing tree zonation. Propagule specific gravity can influence the distribution of mangroves in the context of global change, particularly in response to changes in seawater salinity. In this study, we measured the specific gravity and weight of 35 mangrove species propagules. There was no correlation between the weight of the propagule and its specific gravity. The specific gravity of propagules of true mangrove species was significantly greater than that of semi-mangrove. The results of the correlation between propagule specific gravity and the relative surface elevation of field distribution support the hypothesis that propagules are subject to tidal sorting and are not related to weight but to specific gravity. This newfound understanding of mangrove dispersal and distribution is critical in the context of mangrove protection and restoration, especially in projecting the effects of anthropogenic activities and global change on mangrove communities.

A simulation study evaluating how population survival and genetic diversity in a newly established population can be affected by propagule size, extinction rates, and initial heterozygosity.

The introduction and establishment of invasive species in regions outside their native range, is one of the major threats for the conservation of ecosystems, affecting native organisms and the habitat where they live in, causing substantial biological and monetary losses worldwide. Due to the impact of invasive species, it is important to understand what makes some species more invasive than others. Here, by simulating populations using a forward-in-time approach combining ecological and single polymorphic nucleotides (SNPs) we evaluated the relation between propagule size (number of individuals = 2, 10, 100, and 1,000), extinction rate (with values 2%, 5%, 10%, and 20%), and initial heterozygosity (0.1, 0.3, and 0.5) on the population survival and maintenance of the heterozygosity of a simulated invasive crab species over 30 generations assuming a single introduction. Our results revealed that simulated invasive populations with initial propagule sizes of 2-1,000 individuals experiencing a high extinction rate (10-20% per generation) were able to maintain over 50% of their initial heterozygosity during the first generations and that under scenarios with lower extinction rates invasive populations with initial propagule sizes of 10-1,000 individuals can survive up to 30 generations and maintain 60-100% of their initial heterozygosity. Our results can help other researchers better understand, how species with small propagule sizes and low heterozygosities can become successful invaders.

Structured and unstructured intraspecific propagule trait variation across environmental gradients in a widespread mangrove.

Increasing studies have shown the importance of intraspecific trait variation (ITV) on ecological processes. However, the patterns and sources of ITV are still unclear, especially in the propagules of coastal vegetation. Here, we measured six hypocotyl traits for 66 genealogies of Kandelia obovata from 26 sites and analyzed how ITV in these traits was distributed across geography and genealogy through variance partitioning. We further constructed mixed models and structural equation models to disentangle the effects of climatic, oceanic, and maternal factors on ITV. Results showed that size-related traits decreased along increasing latitudinal gradients, which was mainly driven by positive regulation of temperature on these traits. By contrast, ITV of shape trait was unstructured along latitudinal gradients and did not show any dependence among environmental variables. These findings indicate that propagule size mainly varied between populations, whereas propagule shape mainly varied between individuals. Our study may provide useful insights into the ITV in propagule from different functional dimensions and on a broad scale, which may facilitate mangrove protection in light of ITV.

Comparison of salinity tolerance between Avicenna marina and Rhizophora mucronata Karachi coast, Pakistan

Mangrove propagule size variation is an important factor in their survival. The main aim of this study was to determine the productivity and identify the comparison between Avicenna marina and Rhizophora mucronata. However, it is less studied about the comparison of mangrove species and their salt tolerance in terms of seedling establishment of propagules. We investigated the propagules size variation of Avicennia marina and Rhizophora mucronata from the Indus delta and were grown in the polythene bags of 5x10″ filled with silty soil from field nursery. We used salinity and nutrients treatments to propagules to identify the growth rate of mangrove species. The surveying technique was also used to collect the information of mangrove forest from local communities. We detected that Rhizophora mucronata had a higher productivity rate due to the given concentration of 50% sea water. While the Avicennia marina showed a lower decline ratios growth at 25% salinity level with further increases in salinity. Using diffusion porometers and infrared gas analyzers (IRGAs), we revealed that stomatal conductance was higher in Rhizophora mucronata, followed by Avicennia marina. Moreover, our outcomes showed a higher Sodium and chloride ions with the increase in salinity and also demonstrated a higher accumulation in Avicennia marina. Overall, its was found that Avicennia marina is the most salt resistant species and it’s a dominated species in littoral forest. Our outcomes can help us to better understand the green infrastructure design of mangroves, suggesting that selecting multiple techniques ensure many post-tsunami restoration initiatives are encountering problems.

Plant Growth and Post-harvest Life of Cut Gladiolus as Influenced by Zinc Level and Corm Grade

Gladiolus is one of the most beautiful, attractive, widely cultivated and economically important flowering plants worldwide including India. The research work was carried out to investigate the effect of corm grade and soil application of zinc sulphate on growth and post-harvest parameters of gladiolus cv. Malaviya Kundan at the Horticulture Research Farm and Post-Harvest Laboratory of Department of Horticulture, Banaras Hindu University, Varanasi. In an experiment seven different grades of mother corm (1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 cm) and zinc sulphate at three levels (15 and 30 kg/ha) along with control were used. Zinc was applied in soil at the time of field preparation. Experiment was replicated four times in Randomized Block Design. Application of ZnSO4 at 15 kg/ha was found beneficial for various growth parameters, whereas, 30 kg/ha was found beneficial for most of the post-harvest parameters. Maximum plant height and duration of flowering was achieved with ZnSO4 at 15 kg/ha, whereas, application of ZnSO4 at 30 kg/ha resulted in maximum length of the spike, total number of florets opened and total uptake of water in vase. Among the various grades, the largest corm grade, i.e. 4.0 cm was found to be the best for growth parameters. Whereas, corm grade 3.0 cm was found to be the best in respect of various post-harvest parameters. Lowest corm grade i.e. 1.0 cm failed to exhibit flower due to small size of propagule.

Evidence that long‐distance dispersal of aquatic invertebrates by ducks increases with propagule size

AbstractMigratory ducks are key dispersal agents for aquatic organisms, yet differences in their potential for short‐ and long‐distance dispersal are still poorly understood, particularly differences among aquatic invertebrate taxa.Using seven species of aquatic invertebrates and a duck species known to feed on them in the wild (the northern shoveler) as a model system, we evaluated whether their potential for endozoochorous dispersal varies among five of the species and scales with propagule size for the seven species. We also tested the expectation of a lower dispersal potential for invertebrate propagules, as compared to plant seeds; and evaluated whether intra‐specific variation (in particular, sexual dimorphism) influences the potential of waterbirds as dispersal vectors.An experiment with five invertebrate species demonstrated that most resting eggs (68%–95%) were retrieved by 4 hr after ingestion, with maximum gut‐passage times ranging from 16 hr forDaphnia magnato 36 hr forArtemia salinaandThamnocephalus platyurus. Using models that combine migratory duck movements with gut‐passage times, we show that aquatic invertebrates may disperse frequently over distances of 15–16 km (median dispersal distance) and regularly over distances up to 110–166 km (Q99distance).Increasing propagule size resulted in increasing gut‐passage times, decreasing survival of gut passage and decreasing hatching success. While propagule size had no effects on “regular” dispersal distances (mean, median,Q95andQ99), the frequency of long‐distance dispersal increased with it.Increasing propagule size therefore had two contrasting effects on invertebrate dispersal potential, decreasing the frequency of dispersal (fewer seeds dispersed) but increasing the potential for long‐distance dispersal.Conclusions: We provide evidence that endozoochory of invertebrate propagules by waterbirds results in frequent dispersal among wetlands (tens of km) and regular dispersal at regional scale (over a hundred km).

To disperse or compete? Coevolution of traits leads to a limited number of reproductive strategies

Reproductive strategies are defined by a combination of behavioural, morphological, and life‐history traits. Reproductive investment and offspring propagule size are two key traits defining reproductive strategies. While a substantial amount of work has been devoted to understanding the independent fitness effects of each of these traits, it remains unclear how coevolution between them ultimately affects the evolution of reproductive strategies, and how this might influence the relationship between dispersal and environmental factors. In this study we explore how the evolution of reproductive strategies defined by these two coevolving traits is influenced by resource availability and spatial structuring of the environment using a simulation model. We find three possible equilibrium strategies across all scenarios: a competitor strategy with high reproductive investment (producing large propagules which disperse short distances), and two coloniser strategies differing in reproductive investment (both producing small propagules which disperse long distances). The possible equilibrium strategies for each scenario depended on starting conditions, spatial structure and resource availability. Evolutionary transitions between these equilibrium strategies were more likely in heterogeneous than homogeneous landscapes and at higher resource levels. Transition from coloniser strategy to competitor strategy was usually a two‐step process, with changes in propagule size following initial evolution in investment. This highlights how the interaction between the two trait axes affects the evolution of reproductive strategies, particularly where fitness valleys preclude the simultaneous evolution of traits. Our results highlight the need to incorporate trait coevolution into evolutionary models to help develop a more integrative understanding of the structure of natural populations and how the interaction between traits constrains or hinders evolutionary processes.

Invasion potential of hornets (Hymenoptera: Vespidae: Vespa spp.).

Hornets are large, predatory wasps that have the potential to alter biotic communities and harm honey bee colonies once established in non-native locations. Mated, diapausing females (gynes) can easily be transported to new habitats, where their behavioral flexibility allows them to found colonies using local food and nest materials. Of the 22 species in the genus Vespa, five species are now naturalized far from their endemic populations and another four have been detected either in nature or during inspections at borders of other countries. By far the most likely pathway of long-distance dispersal is the transport of gynes in transoceanic shipments of goods. Thereafter, natural dispersal of gynes in spring and accidental local transport by humans cause shorter-range expansions and contribute to the invasion process. Propagule pressure of hornets is unquantified, although it is likely low but unrelenting. The success of introduced populations is limited by low propagule size and the consequences of genetic founder effects, including the extinction vortex linked to single-locus, complementary sex determination of most hymenopterans. Invasion success is enhanced by climatic similarity between source locality and introduction site, as well as genetic diversity conferred by polyandry in some species. These and other factors that may have influenced the successful establishment of invasive populations of V. velutina, V. tropica, V. bicolor, V. orientalis, and V. crabro are discussed. The highly publicized detections of V. mandarinia in North America and research into its status provide a real-time example of an unfolding hornet invasion.

Spacing and propagule size on yield and quality of Curcuma aromatica Salisb.

Spacing and propagule size on yield and quality of Curcuma aromatica Salisb.

Resistance from a resident heterospecific affects establishment success of a globally invasive freshwater fish

Abstract The role of biotic resistance is a subject of debate in our understanding of invasions. We used a well‐known system in the Northern Range of Trinidad, where ephemeral conditions in small pool habitats lead to repeated colonisation by two native species (guppies, Poecilia reticulata, and killifish, Anablepsoides hartii), to ask questions about the role of biotic resistance and intraguild predation in natural, small‐water habitats. Using horticultural containers under forest cover, alongside constructed bankside mesocosms, we established populations of each species to test hypotheses concerning the conditions under which the guppy, a globally successful invasive species with the potential to establish populations from a single female, could be excluded by a resident intraguild predator, the killifish. Recruitment success of the guppy depended on founder numbers (propagule size) and introduction order (whether first or last to arrive in the habitat). Single founder guppies always failed to recruit in pools with resident killifish, which we posit is directly attributable to biotic resistance from the resident. However, increased propagule pressure (introduction attempts and propagule number) greatly increased the probability of successful invasion. Our results have two main implications. The first is that guppies are capable of being successful colonisers even in the presence of a resident intraguild predator. The second is to highlight the role that biotic resistance can play in preventing establishment in small‐water habitats, especially under circumstances of low propagule pressure. While previous studies have shown that guppies are strong colonisers outside of their native range, our findings suggest that this may not always be the case when there are other small‐bodied fish present. Accordingly, we argue that in small‐water habitats, biotic resistance and intraguild predation relationships should be important considerations when the ability to establish is being assessed for a taxon.

Moss establishment success is determined by the interaction between propagule size and species identity

Colonization of new habitat patches is a key aspect of metacommunity dynamics, particularly for sessile organisms. Mosses can establish in new patches through fragmentation, with different vegetative structures acting as propagules. Despite the importance of these propagules for successful colonization the specific aspects that favour moss colonization by vegetative propagules remain poorly understood, including the effect of propagule size. We examine the intra- and interspecific variation of establishment and colonization success in culture of propagules of different sizes in six widespread soil moss species of contrasting growth form (Dicranum scoparium, Homalothecium aureum, Hypnum cupressiforme, Ptychostomum capillare, Syntrichia ruralis and Tortella squarrosa). We obtained three different size classes of propagules from artificially fragmented vegetative material, and assessed their establishment under controlled light and temperature conditions. We characterize the size, shape, apparent viability, morphological type and size changes due to hydration states of the propagules, all of them traits with potentially significant influence in their dispersal pattern and establishment. Then we assess the effect of these traits on moss establishment, using indicators of surface establishment (number of established shoots and colonized surface) and biomass production (viable biomass) as proxies of colonization success. The establishment indicators related to colonization surface and biomass production differ among species and propagule sizes. The magnitude of the interspecific differences of all indicators of establishment success was larger at the smaller propagule size class. T. squarrosa was the most successful species, and D. scoparium showed the lowest performance. We also found interspecific differences in the hydration dynamics of the propagules. The process of establishment by vegetative fragments operates differently among moss species. Besides, differences between hydration states in propagules of some species could be part of syndromes for both dispersal and establishment. This study unveils several functional traits relevant for moss colonization, such as wet versus dry area and length of fragments, which may improve our understanding of their spatial dynamics.

The molecular basis of socially induced egg-size plasticity in honey bees.

Reproduction involves the investment of resources into offspring. Although variation in reproductive effort often affects the number of offspring, adjustments of propagule size are also found in numerous species, including the Western honey bee, Apis mellifera. However, the proximate causes of these adjustments are insufficiently understood, especially in oviparous species with complex social organization in which adaptive evolution is shaped by kin selection. Here, we show in a series of experiments that queens predictably and reversibly increase egg size in small colonies and decrease egg size in large colonies, while their ovary size changes in the opposite direction. Additional results suggest that these effects cannot be solely explained by egg-laying rate and are due to the queens' perception of colony size. Egg-size plasticity is associated with quantitative changes of 290 ovarian proteins, most of which relate to energy metabolism, protein transport, and cytoskeleton. Based on functional and network analyses, we further study the small GTPase Rho1 as a candidate regulator of egg size. Spatio-temporal expression analysis via RNAscope and qPCR supports an important role of Rho1 in egg-size determination, and subsequent RNAi-mediated gene knockdown confirmed that Rho1 has a major effect on egg size in honey bees. These results elucidate how the social environment of the honey bee colony may be translated into a specific cellular process to adjust maternal investment into eggs. It remains to be studied how widespread this mechanism is and whether it has consequences for population dynamics and epigenetic influences on offspring phenotype in honey bees and other species.

Jack, master or both? The invasive ladybird Harmonia axyridis performs better than a native coccinellid despite divergent trait plasticity

The plasticity of performance traits can promote the success of biological invasions and therefore, precisely estimating trait reaction norms can help to predict the establishment and persistence of introduced species in novel habitats. Most studies focus only on a reduced set of traits and rarely include trait variability that may be vital to predicting establishment success. Here, using a split-brood full-sib design, we acclimated the globally invasive ladybird Harmonia axyridis and a native co-occurring and competing species Cheilomenes lunata to cold, medium and warm temperature regimes, and measured critical thermal limits, life-history traits, and starvation resistance. We used the conceptual framework of “Jack, Master or both” to test predictions regarding performance differences of these two species. The native C. lunata had a higher thermal plasticity of starvation resistance and a higher upper thermal tolerance than H. axyridis. By contrast, H. axyridis had a higher performance than C. lunata for preoviposition period, fecundity and adult emergence from pupae. We combined trait responses, transport duration and propagule pressure to predict the size of the populations established in a novel site following cold, medium and warm scenarios. Although C. lunata initially had a higher performance than the invasive species during transport, more individuals of H. axyridis survived in all simulated environments due to the combined life-history responses, and in particular, higher fecundity. Despite an increased starvation mortality in the warm scenario, given a sufficient propagule size, H. axyridis successfully established. This study underscores how the combination and plasticity of multiple performance traits can strongly influence establishment potential of species introduced into novel environments.

Clonal Variation in <i>Casuarina junghuhniana</i> and its Hybrids for Vegetative Propagation as Influenced by Propagule Size

This study aimed to evaluate the effect of different cutting sizes on performance of different clones for rooting ability and other morphological parameters for vegetation propagation of Casuarina clones under controlled climatic conditions. Six clones of Casuarina viz. IFGTB CH1, IFGTB CH 2, IFGTB CH 4 IFGTB CH 5, IFGTB CH 6 and IFGTB CJ 7 were selected for the present study. Three cutting sizes i.e. diameter of <0.3cm, 0.3-0.6cm and 0.6- 0.9cm were tested to see the effect on propagation. Clone IFGTB CH 4 registered its superiority for sprouting (69.61%), survival (37.75%) and days taken for sprouting (3.00 days). Clone IFGTB CH 5 performed better for shoot and root parameters. Cutting diameter of <0.3cm resulted in highest survival (40.01%), plant height (46.63 cm), number of days taken for sprouting initiation (4.66 days) and branches number (1.41). High genotypic coefficient of variation, phenotypic coefficient of variation, heritability and genetic gain were recorded for most of the traits. Highest phenotypic correlation was observed between root dry weight and root fresh (0.9219). Highest direct effect on root dry weight was recorded by root fresh weight (0.2828) and indirect effect was registered by root length through collar diameter (0.2486).

Identifying trait‐based tolerance to sediment dynamics during seedling establishment across eight mangrove species

AbstractMechanical disturbance from waves and sediment dynamics is a key bottleneck to mangrove seedling establishment. Yet, how species vary in tolerance to sediment dynamics has not been quantified. We identified how tolerance to sediment dynamics differs for three mangrove propagule traits: propagule size, successional stage, and type of embryo development. We selected eight mangrove species growing in south China that vary from small seeds to large elongated propagules, pioneer to climax species, and non‐viviparous to viviparous. In a mesocosm set‐up, we applied bed level treatments to establishing seedlings: erosion, control, or accretion, by removing 2 cm, 0 cm, or adding 1 cm of sediment per week over 3 weeks. We measured seedling survival, shoot, and root lengths, and the critical erosion depth that leads toppling or dislodgement. We identified five relationships between seedling morphology and accretion and erosion thresholds: (1) tall (viviparous) propagules likely had highest accretion thresholds; (2) small pioneer propagules grew relatively fast to increase accretion thresholds; (3) there was a strong correlation between the erosion threshold and root length; and (4) climax species grew longest roots overall, (5) while pioneer species grew longer roots fast in response to sediment erosion. We identify distinct strategies for successful establishment in sediment dynamics that contribute to understanding mangrove zonation and underpin the importance of restoring diverse forests containing not just robust climax species, but also adaptable pioneers. Furthermore, this study reveals maximum shoot and root length as key determinants for seedling stability across species, providing a simple proxy for modeling establishment events.

Body size determines multitrophic soil microbiota community assembly associated with soil and plant attributes in a tropical seasonal rainforest.

To understand soil biodiversity we need to know how soil communities are assembled. However, the relationship between soil community assembly and environmental factors, and the linkages between soil microbiota taxonomic groups and their body sizes, remain unexplored in tropical seasonal rainforests. Systematic and stratified random sampling was used to collect 243 soil and organism samples across a 20-ha plot in a tropical seasonal rainforest in southwestern China. High-throughput sequencing, variation analysis and principal coordinates of neighbourhood matrices were performed. Soil community composition, spatial distribution and assembly processes based on propagule size (including archaea, bacteria, fungi and nematodes) were investigated. The results showed that: (i) the community assembly of small soil microorganisms (bacteria, fungi) was mostly influenced by stochastic processes while that of larger soil organisms (nematodes) was more deterministic; (ii) the independent effects of habitat (including soil and topographic variables) and its interaction with plant attributes for community structure significantly decreased with increasing body size; and (iii) plant leaf phosphorus directly influenced the spatial distribution of soil-available phosphorus, which indicates their indirect impact on the assembly of the soil communities. Our data suggest that the assembly of multitrophic soil communities can be explained to some extent by changes in above-ground plant attributes. This highlights the importance of above- and below-ground linkages in influencing multitrophic soil microbiota community assembly.

Nuanced qualitative trait approaches reveal environmental filtering and phylogenetic constraints on lichen communities

AbstractWe propose that a qualitative trait approach based on more detailed nuanced traits may reveal previously overlooked patterns, especially when combined with phylogenetic perspectives. By sampling epiphytic lichens and using a functional approach based on nuanced qualitative traits, such as a much greater resolution over photobiont identity, type of cortex, and chemical compounds, we evaluated the effects of environmental filtering and phylogenetic constraints on community assembly along a natural succession of Atlantic rainforest. We found changes in taxonomic, functional, and phylogenetic composition, structure, and diversity. Functional traits such as photobiont genera, type of cortex, reproductive structures, propagule size, and protection strategies showed strong responses to succession. Mature forests with a closed canopy impose strong environment filtering that is reflected in lichen species turnover, limiting diversity, but also holding different functional and phylogenetic composition. The use of a nuanced qualitative trait approach may overcome some of the limitations of using this type of traits and shows the importance of often‐overlooked key lichen functional traits, including the presence of carbon‐concentrating mechanisms in photobionts and cortex properties. Furthermore, this is the first study showing how patterns of phylogenetic assembly along forest succession structure lichen communities.

High-throughput measurement of plant fitness traits with an object detection method using Faster R-CNN.

Summary Revealing the contributions of genes to plant phenotype is frequently challenging because loss‐of‐function effects may be subtle or masked by varying degrees of genetic redundancy. Such effects can potentially be detected by measuring plant fitness, which reflects the cumulative effects of genetic changes over the lifetime of a plant. However, fitness is challenging to measure accurately, particularly in species with high fecundity and relatively small propagule sizes such as Arabidopsis thaliana.An image segmentation‐based method using the software ImageJ and an object detection‐based method using the Faster Region‐based Convolutional Neural Network (R‐CNN) algorithm were used for measuring two Arabidopsis fitness traits: seed and fruit counts.The segmentation‐based method was error‐prone (correlation between true and predicted seed counts, r 2 = 0.849) because seeds touching each other were undercounted. By contrast, the object detection‐based algorithm yielded near perfect seed counts (r 2 = 0.9996) and highly accurate fruit counts (r 2 = 0.980). Comparing seed counts for wild‐type and 12 mutant lines revealed fitness effects for three genes; fruit counts revealed the same effects for two genes.Our study provides analysis pipelines and models to facilitate the investigation of Arabidopsis fitness traits and demonstrates the importance of examining fitness traits when studying gene functions.