Quantitative Traits In Plants Research Articles

Biomorphological traits and leaf dry matter content are important to plant persistence in a highly unstable volcanic ground

The colonisation of newly formed territories by plants during primary succession is a crucial stage in the formation of ecosystems. Adaptations of species to withstand harsh environment allow them to survive and form pioneer communities. We analysed ten categorical and quantitative plant traits to examine their role in plant resistance to substrate instability in primary volcanic habitats. The research questions were: 1) which plant traits enable plants to persist under the most unstable ground conditions?; 2) what are the ecological strategies of species that grow under the condition of stress, such as low mineral nutrition, coupled with intense disturbance, such as unstable ground? The research was conducted on the Tolbachinsky Dol plateau in Kamchatka, Russia, on loose volcanic sediments of the 1975 eruption. At altitudes ranging from 700 m a.s.l. to 1000 m a.s.l., 40 sample plots were established along the gradients of altitude and degrees of ground instability. The species composition of vascular plants and the percentage cover of species, as well as other habitat characteristics, were assessed. Linear models were used to investigate the relationship between traits and ground instability. The principal component analysis was used to identify groups of characteristic traits. Leaf dry matter content (LDMC) had the largest explained variance. The LDMC community weighted means decreased with increasing disturbance (ground instability). A whole set of categorical traits, i.e. plant functional types, characterised the adaptation of plants to unstable ground. These characteristics include life-form (according to Serebryakov classification), density of shoots arrangement, morphology of underground organs, and, to a lesser extent, dispersal mode. The study analysed 45 species, and it was found that only four of them were adapted to perform under conditions of high substrate instability. The study showed that the mutual interaction of a suite of biomorphological traits and leaf density characteristics formed a syndrome of pioneer species adapted to unstable ground. The ecological strategies of the majority of species in the studied communities were characterised by the predominance of the stress-tolerant strategy, explained by the extremely poor mineral nutrition in the primary habitats. Under conditions of both low nutrient availability and high disturbance intensity, species with a mixed stress-tolerant-ruderal strategy are favoured. In the gradient of increasing disturbance, the role of the ruderal axis increased while stress tolerance decreased. However, the role of ecological strategy may be weakened by the presence of other important adaptive traits.

UNRAVELING THE GENETIC ARCHITECTURE OF COMPLEX TRAITS IN PLANTS

Complex traits are those whose inheritance does not follow simple and predictable patterns. They are not governed by a single locus, instead, they are determined by several loci and are influenced by the environment. Most of the traits with agronomic interest and economic importance such as resistance to biotic and abiotic stress, and yield, among others, are quantitative traits and their study is based on dissecting the underlying genetic architecture, the number of loci responsible for the variance of a quantitative trait, the relevant contribution made by each locus and their interaction with the environment. This review provides the most relevant conceptual bases for the study of the genetic architecture of complex quantitative traits in plants. The methodologies that allow identifying the loci and candidate genes that govern this type of traits are described, such as QTL mapping by linkage and association mapping. In addition, the incorporation of these loci in phenotype prediction strategies such as marker-assisted selection and genomic selection, exhibits the benefits and limitations of these approaches. Finally, the challenges and perspectives facing the study of the genetic architecture of complex traits in plants are discussed.

Evaluation of Aus rice genotypes grown under rainfed and irrigated conditions

Bangladesh must keep increasing the production of rice (Oryza sativa L.), which is consumed by more than half of the world's population in order to ensure a steady supply of food for everyone. A field experiment was conducted to select short durated with high yield potential Aus rice genotypes under rainfed condition in a split plot design with three replications. Two water regimes (irrigated and rainfed) were imposed into main plot and 39 Aus rice genotypes were assigned into sub plots. In order to categorize the genotypes into various groups, multivariate studies including cluster analysis, principal component analysis (PCA), and discriminantfunction analysis (DFA) were carried out using fifteen quantitative plant traits. Results based on agronomic traits, the genotypes were grouped into six clusters. Early maturing genotypes are represented in cluster II, and genotypes with outstanding yield performance under irrigation are grouped in cluster III. Additionally, clusters III and IV indicate genotypes that mature quickly and a high yield potentiality under rainfed conditions, respectively. Biological yield played a very vital role under both irrigated and rainfed conditions. PCA revealed that PC 1, 2, 3, 4, and 5 described 84.90% variation under irrigated and 84.83% variation in rainfed condition, altogether. Stepwise DFA showed function 1 and 2 accounted for a cumulative of 95.40% of total variance in irrigated and of 92.3% variance in rainfed condition. BR24, Rupsail, Kachilon, Kachiloon2, Darial, Katak-Tara2, BRRI dhan43, Bowalia, BRRI dhan55 and BR14 showed the best performance under rainfed condition. The genotypes like Laksmilota, Loroi, Dhala Saita-3 and Kala manik can be used for further study as early maturing genotypes. Ann. Bangladesh Agric. (2022) 26 (1) : 91-111

Newly Developed MAGIC Population Allows Identification of Strong Associations and Candidate Genes for Anthocyanin Pigmentation in Eggplant.

Multi-parent advanced generation inter-cross (MAGIC) populations facilitate the genetic dissection of complex quantitative traits in plants and are valuable breeding materials. We report the development of the first eggplant MAGIC population (S3 Magic EGGplant InCanum, S3MEGGIC; 8-way), constituted by the 420 S3 individuals developed from the intercrossing of seven cultivated eggplant (Solanum melongena) and one wild relative (S. incanum) parents. The S3MEGGIC recombinant population was genotyped with the eggplant 5k probes SPET platform and phenotyped for anthocyanin presence in vegetative plant tissues (PA) and fruit epidermis (FA), and for the light-insensitive anthocyanic pigmentation under the calyx (PUC). The 7,724 filtered high-confidence single-nucleotide polymorphisms (SNPs) confirmed a low residual heterozygosity (6.87%), a lack of genetic structure in the S3MEGGIC population, and no differentiation among subpopulations carrying a cultivated or wild cytoplasm. Inference of haplotype blocks of the nuclear genome revealed an unbalanced representation of the founder genomes, suggesting a cryptic selection in favour or against specific parental genomes. Genome-wide association study (GWAS) analysis for PA, FA, and PUC detected strong associations with two myeloblastosis (MYB) genes similar to MYB113 involved in the anthocyanin biosynthesis pathway, and with a COP1 gene which encodes for a photo-regulatory protein and may be responsible for the PUC trait. Evidence was found of a duplication of an ancestral MYB113 gene with a translocation from chromosome 10 to chromosome 1 compared with the tomato genome. Parental genotypes for the three genes were in agreement with the identification of the candidate genes performed in the S3MEGGIC population. Our new eggplant MAGIC population is the largest recombinant population in eggplant and is a powerful tool for eggplant genetics and breeding studies.

Cost‐effective, high‐throughput phenotyping system for 3D reconstruction of fruit form

AbstractReliable phenotyping methods that are simple to operate and inexpensive to deploy are critical for studying quantitative traits in plants. Traditional fruit shape phenotyping relies on human raters or 2D analyses to assess form, e.g., size and shape. Systems for 3D imaging using multi‐view stereo have been implemented, but frequently rely on commercial software and/or specialized hardware, which can lead to limitations in accessibility and scalability. We present a complete system constructed of consumer‐grade components for capturing, calibrating, and reconstructing the 3D form of small‐to‐moderate sized fruits and tubers. Data acquisition and image capture sessions are 9 seconds to capture 60 images. The initial prototype cost was $1600 USD. We measured accuracy by comparing reconstructed models of 3D printed ground truth objects to the original digital files of those same ground truth objects. The R2 between length of the primary, secondary, and tertiary axes, volume, and surface area of the ground‐truth object and the reconstructed models was >0.97 and root‐mean square error (RMSE) was < 3 mm for objects without locally concave regions. Measurements from 1 mm and 2 mm resolution reconstructions were consistent (R2 > 0.99). Qualitative assessments were performed on 48 fruit and tubers, including 18 strawberries, 12 potatoes, five grapes, seven peppers, and four Bosc and two red Anjou pears. Our proposed phenotyping system is fast, relatively low cost, and has demonstrated accuracy for certain shape classes, and could be used for the 3D analysis of fruit form.

Study of morpho-biological characteristics of rice samples grown under conditions of insufficient and optimal water supply

The article shows the results of a morpho-biological study of rice cultivars grown in the fields of the Rostov Region under drought conditions and normal water supply. The aim of the research is a comparative structural analysis of rice samples under conditions of soil and air drought and under normal flooding with water. The formation of quantitative traits in plants under normal watering conditions and with a moisture deficit occurred in different ways. Under drought conditions, compared with the norm, the yield decreased (67.9% of the norm), the number of plants to be harvested per 1 m2, the mass of the panicle, the mass of 1000 grains; increased bushiness, the number of spikelets on the panicle and its density, the growing season “flooding with water – flowering”. The number of empty spikelets on a panicle and the percentage of empty grain increased especially strongly. The values of the remaining studied characteristics were at the same level in both variants of the experiment. The maximum yield in dry conditions was formed by the varieties Boyarin (4.43 t/ha), Contact (4.53 t/ha), Zolotye vshody (4.60 t/ha) and Sukhodol (4.60 t/ha). Drought-resistant forms that can be used to create dry-land rice varieties have been identified.

An Efficient Score Test Integrated with Empirical Bayes for Genome-Wide Association Studies.

Many methods used in multi-locus genome-wide association studies (GWAS) have been developed to improve statistical power. However, most existing multi-locus methods are not quicker than single-locus methods. To address this concern, we proposed a fast score test integrated with Empirical Bayes (ScoreEB) for multi-locus GWAS. Firstly, a score test was conducted for each single nucleotide polymorphism (SNP) under a linear mixed model (LMM) framework, taking into account the genetic relatedness and population structure. Then, all of the potentially associated SNPs were selected with a less stringent criterion. Finally, Empirical Bayes in a multi-locus model was performed for all of the selected SNPs to identify the true quantitative trait nucleotide (QTN). Our new method ScoreEB adopts the similar strategy of multi-locus random-SNP-effect mixed linear model (mrMLM) and fast multi-locus random-SNP-effect EMMA (FASTmrEMMA), and the only difference is that we use the score test to select all the potentially associated markers. Monte Carlo simulation studies demonstrate that ScoreEB significantly improved the computational efficiency compared with the popular methods mrMLM, FASTmrEMMA, iterative modified-sure independence screening EM-Bayesian lasso (ISIS EM-BLASSO), hybrid of restricted and penalized maximum likelihood (HRePML) and genome-wide efficient mixed model association (GEMMA). In addition, ScoreEB remained accurate in QTN effect estimation and effectively controlled false positive rate. Subsequently, ScoreEB was applied to re-analyze quantitative traits in plants and animals. The results show that ScoreEB not only can detect previously reported genes, but also can mine new genes.

Association mapping for yield traits in Paeonia rockii based on SSR markers within transcription factors of comparative transcriptome

BackgroundAllelic variation underlying the quantitative traits in plants is caused by the extremely complex regulation process. Tree peony originated in China is a peculiar ornamental, medicinal and oil woody plant. Paeonia rockii, one of tree peony species, is a precious emerging woody oil crop. However, in this valuable plant, the study of functional loci associated with yield traits has rarely been identified. Therefore, to explore the genetic architecture of 24 yield quantitative traits, the association mapping was first reported in 420 unrelated cultivated P. rockii individuals based on the next-generation sequencing (NGS) and single-molecule long-read sequencing (SMLRS).ResultsThe developed 58 pairs of polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers from 959 candidate transcription factors (TFs) associated with yield were used for genotyping the 420 P. rockii accessions. We observed a high level of genetic diversity (polymorphic information content, PIC = 0.514) and low linkage disequilibrium (LD) between EST-SSRs. Moreover, four subpopulations in the association population were revealed by STRUCTURE analyses. Further, single-marker association analysis identified 141 significant associations, involving 17 quantitative traits and 41 EST-SSRs. These loci were mainly from AP2, TCP, MYB, HSF, bHLH, GATA, and B3 gene families and showed a small proportion of the phenotypic variance (3.79 to 37.45%).ConclusionsOur results summarize a valuable collection of functional loci associated with yield traits in P. rockii, and provide a precious resource that reveals allelic variation underlying quantitative traits in Paeonia and other woody oil crops.

The geographic and climatic distribution of plant height diversity for 19,000 angiosperms in China

The geographic distribution of plant form and function has been studied for over a century for purposes ranging from vegetation classification to global vegetation modeling. Despite this attention we have surprisingly few studies that have actually mapped the distribution and diversity of quantitative plant traits on continental scales and quantified the drivers of these spatial patterns. This limitation has been largely due to the inherent patchiness in trait and spatial databases. Here we analyze the distribution and diversity of plant maximum height in relation to climatic gradients for ~ 19,000 Angiosperm species across China. First, we quantify the relationship between the mean maximum height with climatic variables to test the prediction that precipitation and temperature both should restrict the maximum heights possible in a region. Second, we used null model analysis to address the fundamental question of whether gradients in plant species richness coincide with an increased trait range as expected under limiting similarity theory or whether more species are simply packed into the same range of trait values. The results show that the mean maximum height in a plant assemblage is highest in regions with higher temperatures and annual precipitation indicating that increases in precipitation are enough to offset the concomitant increase in temperature, which was expected to limit plant height. The range and packing of height space were found to increase with species richness and in less climatically variable environments. Null modeling results also show that the deviation of the observed results from expected has a distinct spatial signature for herbaceous and woody plants. Our results highlight plant height diversity, including the range and packing of plant height space, are sensitive to environment, and the mechanisms driving the range and packing of height space in the two growth forms may be different.

Genetic patterns of breeding upon creation of the first Ukrainian waxy barley cultivar Shedevr

Aim. The study’s purpose was to establish genetic patterns of waxy barley breeding on the basis of determination of genetic and breeding characteristics of accessions with different fractional composition of starch during 10/11-year cycles of the breeding process upon creation of waxy barley cultivars. Methods. Analysis of variance, calculus of variations, correlation analysis, genetic and breeding methods were used to investigate peculiarities of genotypes in topcross, diallel and pair-crossing designs. Results. The important scientific problem concerning establishment of genetic patterns of waxy spring barley breeding was solved. We determined morpho-biological features, variability, correlations and genetic peculiarities of inheritance, heritability, genetic variation and combining ability for quantitative traits of plants as well as for amylopectin content in starch of F1 hybrids derived from forms with different fractional composition of starch. As a result of establishing the patterns, the effectiveness of creation of valuable lines and waxy barley cultivar Shedevr with amylopectin starch was demonstrated. Conclusions. The morpho-biological, breeding and genetic peculiarities of plant traits with different fractional composition of starch were determined. On this basis, the genetic patterns of waxy barley breeding were established, and the first Ukrainian waxy barley cultivar Shedevr (with amylopectin starch) was created.
 Keywords: Hordeum vulgare L., accession, cultivar, amylopectin starch, genetic peculiarities.

Undergraduates Phenotyping Arabidopsis Knockouts in a Course-Based Undergraduate Research Experience: Exploring Plant Fitness and Vigor Using Quantitative Phenotyping Methods.

We present a curriculum description, an initial student outcome investigation, and sample scientific results for a representative Course-Based Undergraduate Research Experience (CURE) that is part of the “Undergraduates Phenotyping Arabidopsis Knockouts” (unPAK) network. CUREs in the unPAK network characterize quantitative phenotypes of the model plant Arabidopsis from across environments to uncover connections between genotype and phenotype. Students in unPAK CUREs grow plants in a replicated block design and make quantitative measurements throughout the semester. This CURE enables students to answer plant science questions that draw from fields such as environmental science, genetics, ecology, and evolution. Findings indicate that this experience provides students with opportunities to make relevant scientific discoveries. Eighty percent of student datasets produced from the CURE met criteria for inclusion in the project database, indicative of student learning in data collection and analysis of quantitative plant traits. Student datasets uncovered novel effects of mutation on plant form. In addition, students’ science self-efficacy increased as a result of course participation, and faculty feedback on course implementation was positive. We present unPAK as a new network that supports CUREs and research experiences focused on collecting biological data made publicly available to the scientific community. The unPAK CUREs can be tailored to address instructor interests or pedagogical needs while involving students in research investigating quantitative plant phenotypes.

Potential of pepper plant accessions for ornamental purposes using diallel analysis.

The genus Capsicum is cultivated in various parts of the world, with C. annuum showing high diversity and potential for ornamental purposes and genetic improvement. The aim of this work was to evaluate the combining ability and heterosis of seedling and plant traits in accessions of ornamental pepper and their hybrids. Seven accessions of C. annuum were handcrossed and twelve quantitative plant traits were evaluated. The data were subjected to analysis of variance, the Scott-Knott test and diallel analysis using Griffing's method I (fixed model). Heterosis and its components were also determined. Non-additive effects were found for seedling height, cotyledonous leaf length and width; stem diameter and chlorophyll b content. All other traits showed predominance of additive effects. Heterosis effects were found for some hybrids and UFPB134 x UFPB137, UFPB134 x UFPB390, UFPB134 x UFPB004 and UFPB099 x UFPB004 showed seedlings that are more vigorous.

Effective Genomic Selection in a Narrow-Genepool Crop with Low-Density Markers: Asian Rapeseed as an Example.

Genomic selection (GS) has revolutionized breeding for quantitative traits in plants, offering potential to optimize resource allocation in breeding programs and increase genetic gain per unit of time. Modern high-density single nucleotide polymorphism (SNP) arrays comprising up to several hundred thousand markers provide a user-friendly technology to characterize the genetic constitution of whole populations and for implementing GS in breeding programs. However, GS does not build upon detailed genotype profiling facilitated by maximum marker density. With extensive genome-wide linkage disequilibrium (LD) being a common characteristic of breeding pools, fewer representative markers from available high-density genotyping platforms could be sufficient to capture the association between a genomic region and a phenotypic trait. To examine the effects of reduced marker density on genomic prediction accuracy, we collected data on three traits across 2 yr in a panel of 203 homozygous Chinese semiwinter rapeseed ( L.) inbred lines, broadly encompassing allelic variability in the Asian genepool. We investigated two approaches to selecting subsets of markers: a trait-dependent strategy based on genome-wide association study (GWAS) significance thresholds and a trait-independent method to detect representative tag SNPs. Prediction accuracies were evaluated using cross-validation with ridge-regression best linear unbiased predictions (rrBLUP). With semiwinter rapeseed as a model species, we demonstrate that low-density marker sets comprising a few hundred to a few thousand markers enable high prediction accuracies in breeding populations with strong LD comparable to those achieved with high-density arrays. Our results are valuable for facilitating routine application of cost-efficient GS in breeding programs.

Quantification of complex modular architecture in plants.

Morphometrics, the assignment of quantities to biological shapes, is a powerful tool to address taxonomic, evolutionary, functional and developmental questions. We propose a novel method for shape quantification of complex modular architecture in thalloid plants, whose extremely reduced morphologies, combined with the lack of a formal framework for thallus description, have long rendered taxonomic and evolutionary studies extremely challenging. Using graph theory, thalli are described as hierarchical series of nodes and edges, allowing for accurate, homologous and repeatable measurements of widths, lengths and angles. The computer program MorphoSnake was developed to extract the skeleton and contours of a thallus and automatically acquire, at each level of organization, width, length, angle and sinuosity measurements. Through the quantification of leaf architecture in Hymenophyllum ferns (Polypodiopsida) and a fully worked example of integrative taxonomy in the taxonomically challenging thalloid liverwort genus Riccardia, we show that MorphoSnake is applicable to all ramified plants. This new possibility of acquiring large numbers of quantitative traits in plants with complex modular architectures opens new perspectives of applications, from the development of rapid species identification tools to evolutionary analyses of adaptive plasticity.

Natural variation of hormone levels in Arabidopsis roots and correlations with complex root architecture.

Studies on natural variation are an important tool to unravel the genetic basis of quantitative traits in plants. Despite the significant roles of phytohormones in plant development, including root architecture, hardly any studies have been done to investigate natural variation in endogenous hormone levels in plants. Therefore, in the present study a range of hormones were quantified in root extracts of thirteen Arabidopsis thaliana accessions using a ultra performance liquid chromatography triple quadrupole mass spectrometer. Root system architecture of the set of accessions was quantified, using a new parameter (mature root unit) for complex root systems, and correlated with the phytohormone data. Significant variations in phytohormone levels among the accessions were detected, but were remarkably small, namely less than three‐fold difference between extremes. For cytokinins, relatively larger variations were found for ribosides and glucosides, as compared to the free bases. For root phenotyping, length‐related traits—lateral root length and total root length—showed larger variations than lateral root number‐related ones. For root architecture, antagonistic interactions between hormones, for example, indole‐3‐acetic acid to trans‐zeatin were detected in correlation analysis. These findings provide conclusive evidence for the presence of natural variation in phytohormone levels in Arabidopsis roots, suggesting that quantitative genetic analyses are feasible.

High-Throughput Phenotyping in Plant Stress Response: Methods and Potential Applications to Polyamine Field.

High-throughput phenotyping has opened whole new perspectives for crop improvement and better understanding of quantitative traits in plants. Generation of loss-of-function and gain-of-function plant mutants requires processing and imaging a large number of plants in order to determine unknown gene functions and phenotypic changes generated by genetic modifications or selection of new traits. The use of phenomics for the evaluation of transgenic lines contributed significantly to the identification of plants more tolerant to biotic/abiotic stresses and furthermore, helped in the identification of unknown gene functions. In this chapter we describe the High-throughput phenotyping (HTP) platform working in our facility, drawing the general protocol and showing some examples of data obtainable from the platform. Tomato transgenic plants over-expressing the arginine decarboxylase 2 gene, which is involved in the polyamine biosynthetic pathway, were analyzed through our HTP facility for their tolerance to abiotic stress and significant differences in water content and ability to recover after drought stress where highlighted. This demonstrates the applicability of this methodology to the plant polyamine field.

Towards a trait‐based ecology of wetland vegetation

Summary Functional traits mechanistically capture plant responses to environmental gradients as well as plant effects on ecosystem functioning. Yet most trait‐based theory stems from terrestrial systems and extension to other habitats can provide new insights. Wetlands differ from terrestrial systems in conditions (e.g. soil water saturation, anoxia, pH extremes), plant adaptations (e.g. aerenchyma, clonality, ubiquity of bryophytes) and important processes (e.g. denitrification, peat accumulation, methane emission). Wetland plant adaptations and trait (co‐)variation can be situated along major plant trait trade‐off axes (e.g. the resource economics spectrum), but soil saturation represents a complex stress gradient beyond a simple extension of commonly studied water availability gradients. Traits that affect ecosystem functioning overlap with patterns in terrestrial systems. But wetland‐specific traits that mediate plant effects on soil redox conditions, microbial communities and on water flow, as well as trait spectra of mosses, vary among wetland types. Synthesis. With increasing availability of quantitative plant traits a trait‐based ecology of wetlands is emerging, with the potential to advance process‐based understanding and prediction. We provide an interactive cause‐and‐effect framework that may guide research efforts to disentangle the multiple interacting processes involved in scaling from environmental conditions to ecosystem functioning via plant communities.

Correlation between traits of spring barley varieties

In 2014-2015, the Laboratory of Barley Breeding and Genetics of the Plant Production Institute nd. a VYa Yuryev of National Academy of Agrarian Sciences of Ukraine determined correlations between indices of quantitative traits of spring barley varieties by paired correlation coefficients. The aim and tasks of the study. The research aim was to determine correlations between quantitative traits of spring barley varieties. Materials and methods. The following spring barley varieties were studied: Modern, Hranal, Zvershennia, Vitrazh, Etiket, Dzherelo, Vzirets, Badioryy, Maliovnychyy, Pasadena, Tolar. Paired correlation coefficients (r) between quantitative traits of plants were determined by BA Dospekhov’s method. Results and discussion. In the test varieties, there were significantly strong (r> 0,70) and moderate (r <0,70) correlations both in 2014 and in 2015 between the following traits: productivity (grain weight) of plant and productive tillering (moderate in 2014 with r = 0.62; strong in 2015 with r = 0.72); productivity of plant and straw weight (strong in 2014 with r = 0.89 and in 2015 with r = 0.81); 1000-grain weight and plant height (strong in 2014 with r = 0.75, moderate in 2015 with r = 0.65); the grain number per spike and the spikelet number per spike (strong in 2014 with r = 0.96 and in 2015 with r = 0.91); the spikelet number per spike and plant height (moderate in 2014 with the r = 0.55 and in 2015 with the r = 0.55); productive tillering and straw weight (moderate in 2014 with r = 0.61 and strong in 2015 with r = 0.76.); productive tillering and total tillering (higher than moderate in 2014 with r = 0.70 and strong in 2015 with r = 0.82); 1000-grain weight and grain weight per spike (moderate in 2014 with r = 0.63 and in 2015 with r = 0.54). It is possible to select plants for a trait, using the parameter of another trait. Conclusions. Over two years (2014-2015), we found significantly strong and moderate correlations between the quantitative traits of “plant productivity” and its structural components for the test spring barley varieties (Modern, Hranal, Zvershennia, Vitrazh, Etket, Dzherelo, Vzirets, Badioryy, Maliovnychyy, Pasadena, Tolar), which makes selections based on relationships between these traits expedient.

Genome-Wide Association Mapping and Genomic Prediction Elucidate the Genetic Architecture of Morphological Traits in Arabidopsis.

Quantitative traits in plants are controlled by a large number of genes and their interaction with the environment. To disentangle the genetic architecture of such traits, natural variation within species can be explored by studying genotype-phenotype relationships. Genome-wide association studies that link phenotypes to thousands of single nucleotide polymorphism markers are nowadays common practice for such analyses. In many cases, however, the identified individual loci cannot fully explain the heritability estimates, suggesting missing heritability. We analyzed 349 Arabidopsis accessions and found extensive variation and high heritabilities for different morphological traits. The number of significant genome-wide associations was, however, very low. The application of genomic prediction models that take into account the effects of all individual loci may greatly enhance the elucidation of the genetic architecture of quantitative traits in plants. Here, genomic prediction models revealed different genetic architectures for the morphological traits. Integrating genomic prediction and association mapping enabled the assignment of many plausible candidate genes explaining the observed variation. These genes were analyzed for functional and sequence diversity, and good indications that natural allelic variation in many of these genes contributes to phenotypic variation were obtained. For ACS11, an ethylene biosynthesis gene, haplotype differences explaining variation in the ratio of petiole and leaf length could be identified.

Variability of biometric indices of plants of breeding forms of sweet pepper under condition of sexual and combined apomictically-sexual reproduction

The actual problem in sweet pepper breeding is working out alternative methods for speeded genetic stabilization of valuable genotypes unlike those using sexual hybridization. The aim and tasks of the study. The aim of investigation is to evaluate efficiency of genetic stabilization of sweet pepper population when using sexual and combined apomictically-sexual hybridization. The task of investigation is to study manifestation of quantitative traits of plants that belong to populations of apomictic lines and original forms. Material and methods. In the work were used 4 original forms and 7 apomictic lines derivates thereof. In the period of biological ripeness of fruits there were compared such quantitative traits: “plant height”, “leaf length”, “leaf width”, “quantity of fruits on a plant”, “productivity of a plant”. The scope pf traits variation was determined with the help of coefficient of variation (CV). Investigation were conducted according to conventional methods for carrying out sweet pepper breeding under field conditions. Results and discussion. Two-year biometric measurements of plants of apomictic lines revealed the scope of 3 qualitative traits variation: “plant height”, “leaf length”, “leaf width” within the range of CV up to 33 %. In comparison with the original forms there was noted a lover value of CV simultaneously by two-three traits in 4 apomictic lines. The greatest instability of manifestation was in the trait “quantity of fruits on a plant” in original forms and apomictic lines. In apomictic lines the scope of variation of CV by the trait “plant height” was 18-38,1 %, “leaf length” – 15,1-31,9 %, “leaf width” – 22,0-31,3 %, “quantity of fruits on a plant” – 22,1-55,7 %. The line Velikan (d271, AA) had the greatest productivity – 676,8 g. Conclusions. Comparative analysis of two methods of sweet pepper breeding samples reproduction the stable tendency to greater stability of quantitative traits manifestation when using combined apomictically-sexual reproduction.