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In the breeding process of agricultural crops, including sorghum, the use of multivariate statistics methods makes it possible to determine the correlation between morphometric traits, yield elements and biochemical parameters of grain in the model population, as well as to identify the load of hypothetical factors. The purpose of the current study was to identify the correlations between morphometric traits, yield elements and biochemical parameters of grain, which characterize the load of hypothetical factors in the model grain sorghum population. For practical breeding process, there have been analyzed 13 economically valuable traits in 27 grain sorghum varieties, developed by the FSBSI Russian Research and Project-technological Institute of sorghum and maize “Rossorgo”. There has been established a different variation degree of the traits of grain sorghum; a strong variation degree was established for such traits as ‘flag leaf area’, ‘the largest leaf area’, ‘panicle stem’, ‘productive tilling capacity’, ‘weight and number of grains per panicle’ (27.3–35.2%); a weak variation degree was established for such traits as ‘protein percentage’ and ‘starch content’ in grain (2.8–8.6%). The group with an average degree of variation includes the traits ‘plant height’ after 30 days of growing and at ripening period, ‘panicle length’, ‘1000-grain weight’, and ‘grain yield’ (10.1–15.6%). When analyzing the matrix of correlation coefficients, there were calculated the hypothetical factors with a contribution of more than 5% to the accumulated variance. There has been built a correlation pleiad, which made it possible to demonstrate mean (r = 0.51–0.68) and strong (r = 0.76–0.94) correlations. There have been considered six hypothetical factors reflecting the total contribution to the accumulated variance, Z-1 – 40.86%, Z-2 – 13.76%, Z-3 – 11.85%, Z-4 – 8.74%, Z- 5 – 6.69%, Z-6 – 5.99%. The first hypothetical factor is determined by such traits as ‘the largest leaf area’ and ‘flag leaf area’ (0.78–0.80), ‘weight and number of grains per panicle’ (0.84–0.91), ‘grain productivity’ (0.77) and ‘productive tillering capacity’ (- 0.78). The results obtained are used in breeding programs to develop grain sorghum varieties and hybrids adapted to the arid conditions of the Lower Volga region.

Intraspecific diversity is a substantial part of biodiversity, yet little is known about its maintenance. Understanding mechanisms of intraspecific diversity shifts provides realistic detail about how phytoplankton communities evolve to new environmental conditions, a process especially important in times of climate change. Here, we aimed to identify factors that maintain genotype diversity and link the observed diversity change to measured phytoplankton morpho-functional traits Vmax and cell size of the species and genotypes. In an experimental setup, the two phytoplankton species Emiliania huxleyi and Chaetoceros affinis, each consisting of nine genotypes, were cultivated separately and together under different fluctuation and nutrient regimes. Their genotype composition was assessed after 49 and 91 days, and Shannon’s diversity index was calculated on the genotype level. We found that a higher intraspecific diversity can be maintained in the presence of a competitor, provided it has a substantial proportion to total biovolume. Both fluctuation and nutrient regime showed species-specific effects and especially structured genotype sorting of C. affinis. While we could relate species sorting with the measured traits, genotype diversity shifts could only be partly explained. The observed context dependency of genotype maintenance suggests that the evolutionary potential could be better understood, if studied in more natural settings including fluctuations and competition.

Intraspecific trait variation (ITV) is common feature of natural communities and has gained increasing attention due to its significant ecological effects on community dynamics and ecosystem functioning. However, the estimation of ITV per se has yet to receive much attention, despite the need for accurate ITV estimation for trait-based ecological inferences. It remains unclear if, and to what extent, current estimations of ITV are biased. The most common method used to quantify ITV is the coefficient of variation (CV), which is dimensionless and can therefore be compared across traits, species, and studies. Here, we asked which CV estimator and data normalization method are optimal for quantifying ITV, and further identified the minimum sample size required for ±5% accuracy assuming a completely random sample scheme. To these ends, we compared the performance of four existing CV estimators, together with new simple composite estimators, across different data normalizations, and sample sizes using both a simulated and empirical trait datasets from local to regional scales. Our results consistently showed that the most commonly used ITV estimator (CV 1= σsample /μsample ), often underestimated ITV-in some cases by nearly 50%-and that underestimation varies largely among traits and species. The extent of this bias depends on the sample size, skewness and kurtosis of the trait value distribution. The bias in ITV can be substantially reduced by using log-transforming trait data and alternative CV estimators that take into consideration the above dependencies. We find that the CV4 estimator, also known as Bao's CV estimator, combined with log data normalization, exhibits the lowest bias and can reach ±5% accuracy with sample sizes greater than 20 for almost all examined traits and species. These results demonstrated that many previous ITV measurements may be substantially underestimated and, further, that these underestimations are not equal among species and traits even using the same sample size. These problems can be largely solved by log-transforming trait data first and then using the Bao's CV to quantify ITV. Together, our findings facilitate a more accurate understanding of ITV in community structures and dynamics, and may also benefit studies in other research areas that depend on accurate estimation of CV.

Some species intrinsically have a high invasiveness capacity, shown by high phenotypic plasticity and rapid growth, enabling a wide distribution across their native habitats and successful invasion in the introduced range. For such species, information from native habitats is critically important. An example is Glechoma hederacea, native to Eurasia but introduced and widespread in the USA. Our main objective was to investigate variation in traits of native G. hederacea populations across contrasting habitats: open, forest edge and understory. Vegetation was sampled and the ecophysiological and morphological traits were measured with accompanying environmental parameters. Results showed that in native habitats environmental conditions cover wide gradients of light and soil moisture. Plants had the highest cover in nutrient-rich, shaded habitats, representing the optimal habitat, indicating shade tolerance of G. hederacea. Plants from forest understory exhibited strong similarities in investigated traits to plants from the forest edge, even though this was a drier, sunnier habitat. Plants from open, sunny habitats experienced stress as indicated by the quantum efficiency of PSII and significantly higher sexual reproduction. Results show that G. hederacea is moderately tolerant simultaneously to shade and drought, a characteristic that has been reported for numerous invasive species, while at the same time it shares some characteristics with weedy plants.

Supported by Portuguese Foundation for Science and Technology (FCT) through the Investigador FCT programme contract (M. Dolbeth, IF/00919/2015) and Decree-law 57/2016 contract (S. Leston), subsidised by the European Social Fund and Portuguese Ministry of Science, Technology and Higher Education (MCTES) through the Human Potential Operational Programme (POPH), and partially supported by the Strategic Funding (UID/Multi/04423/2019) awarded to CIIMAR. We also acknowledge the support of the MARS Network Travel Award for Young Scientists (D. Crespo) and the fellowship from project SmartBioR – Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate (D. Crespo, CENTRO-01-0145- FEDER-000018 co-funded by CENTRO2020/PORTUGAL2020/ FEDER); and the Coastal Biodiversity and Ecosystem Service Sustainability (CBESS) research programme (NE/J015644/1), funded by the U.K. Natural Environment Research Council (M. Solan, NE/ J015075/1). Changes in community structure concurrent with environmental forcing often form a precursor to changes in species diversity, and can have substantive consequences for ecosystem functioning. Here, we assess the effects of altered levels of evenness that are representative of different levels of eutrophication and changes in salinity associated with altered precipitation patterns, on the mediation of nutrient release by sediment-dwelling invertebrate communities. We find that an adjustment towards a more even distribution of species corresponds with an increase in sediment particle reworking that, in general, translates to increased levels of nutrient release. This response, however, is dependent on the functional role of each species in the community and is influenced by concomitant changes in salinity, especially when salinity extends beyond the range typically experienced by the community. Overall, our findings highlight the dynamic nature of species contributions to functioning and reinforce the importance of understanding when, and how, the mechanistic basis of species-environment interactions are modified as the influence of abiotic and biotic factors flex under periods of directional forcing. info:eu-repo/semantics/publishedVersion

Research Highlights: We investigated the variability of vessel diameter distributions within the liana growth form among liana individuals originating from a single site in Laussat, French Guiana. Background and Objectives: Lianas (woody vines) are key components of tropical forests. Lianas are believed to be strong competitors for water, thanks to their presumed efficient vascular systems. However, unlike tropical trees, lianas are overlooked in field data collection. As a result, lianas are often referred to as a homogeneous growth form while little is known about the hydraulic architecture variation among liana individuals. Materials and Methods: We measured several wood hydraulic and structural traits (e.g., basic specific gravity, vessel area, and vessel diameter distribution) of 22 liana individuals in a single sandy site in Laussat, French Guiana. We compared the liana variability of these wood traits and the correlations among them with an existing liana pantropical dataset and two published datasets of trees originating from different, but species-rich, tropical sites. Results: Liana vessel diameter distribution and density were heterogeneous among individuals: there were two orders of magnitude difference between the smallest (4 &micro, m) and the largest (494 &micro, m) vessel diameters, a 50-fold difference existed between extreme vessel densities ranging from 1.8 to 89.3 vessels mm&minus, 2, the mean vessel diameter varied between 26 &micro, m and 271 &micro, m, and the individual theoretical stem hydraulic conductivity estimates ranged between 28 and 1041 kg m&minus, 1 s&minus, 1 MPa&minus, 1. Basic specific gravity varied between 0.26 and 0.61. Consequently, liana wood trait variability, even within a small sample, was comparable in magnitude with tree surveys from other tropical sites and the pantropical liana dataset. Conclusions: This study illustrates that even controlling for site and soil type, liana traits are heterogeneous and cannot be considered as a homogeneous growth form. Our results show that the liana hydraulic architecture heterogeneity across and within sites warrants further investigation in order to categorize lianas into functional groups in the same way as trees