Quantitative Trait Variation Research Articles

Transgene effects vary among maize populations with implications for improving quantitative traits

AbstractThe goal of transgenesis in plant breeding is to make step‐change improvements in traits of interest. However, improving quantitative traits, such as yield in maize (Zea mays L.), with transgenes has been difficult. Traditionally, transgene testing is done on a few isogenic lines, and results are extrapolated to entire breeding populations. Testing on limited germplasm does not provide a robust estimate of a transgene's value. Incorporating transgenes directly into breeding populations could increase genetic variance and the rate of genetic gain. Here, we used a transgene that reduces ethylene as a case study and investigated event, transgene, family, and environment effects and their interactions. We also determined whether introduction of the transgene into a breeding population would result in transgenic lines being preferentially selected over nontransgenic lines for yield. We found significant variation in transgene effects across clustered environments and families for multiple traits including yield. In environmental Cluster 2, the transgenic lines yielded 0.4 Mg ha−1 more than nontransgenic lines in family KC22; yet, in family QY43, transgenic lines yielded 0.3 Mg ha−1 less. Similarly, within Cluster 4, the QY43 family had preferential selection of transgenic over nontransgenic lines, whereas in families YE41 and AY91, nontransgenic lines were selected more frequently. These results show the critical importance of evaluating transgenes across broad germplasm diversity to assess their general value to a program. Integrating transgenes, or using gene editing, directly in a breeding program can expand genetic variation for quantitative traits and potentially accelerate genetic gain.

Evaluation of variability of morphometric traits of plants and age spectrum of cenopopulations of Matthiola daghestanica (Brassicaceae) of the Piedmont and Mid‐mountain Dagestan, Russia

Aim: Study of intra‐ and interpopulation variability of quantitative traits of Matthiola daghestanica (Conti) N. Busch and assessment of the age spectrum of natural cenopopulations of Piedmont and Mid‐mountain Dagestan. The material consisted of 90 plants (shoots with inflorescences) taken from coenopopulations of various locations of the studied species (450, 610 and 960 m above sea level). An analysis of the variability of 12 morphological traits of M. daghestanica was carried out. To assess the age spectrum, 5x5 m test plots were laid out at three points (75 m²), where the age (ontogenetic) states of M. daghestanica guided by methods from the works of T.A. Rabotnov (1950) and A.A. Uranov (1957).The variability of the morphological traits of the Dagestan endemic M. daghestanica has been studied and its age spectrum in the natural cenopopulations of Piedmont and Mid‐mountain Dagestan has been assessed. The most variable were the weight traits. Analysis of the significance of the differences between the selected groups using the t‐test confirmed that “Chakh‐Chakh” is highly isolated from other coenopopulations, and to the greatest extent from “Chirkata”. The linear trait “length vegetative features” introduces the greatest significant differences between all coenopopulations. The percentage of age states from the total number of individuals varies among populations. The age spectrum of M. daghestanica in the “Chirkata” cenopopulation is represented by a predominance of the juvenile (25 %) and virginal (25 %) groups and in the “Ashilta” cenopopulation by the adult group (23.9 %). Among the age states of the generative period in all cenopopulations, young generative individuals prevail (16.7–19.4 %). The largest number of middle‐aged generative individuals is in the “Chakh‐Chakh” cenopopulation (16.3 %).Analysis of the variability of morphological characteristics of M. daghestanica plants showed that linear and numerical traits for the three cenopopulations are less variable. Significant variability was revealed in weight characteristics: “mass caulis and leaves” (518.3–818.7 mg); “total mass shoot” (990.7–1342.8 mg). The squared Mahalanobis distances of the characters studied revealed the isolation of the “Chakh‐Chakh” cenopopulation from the other two (“Achilta”, “Chirkata”). The age spectrum of M. daghestanica coenopopulations is similar in the Piedmont and Mid‐mountain Dagestan, despite the different number of age states. Cenopopulations of M. daghestanica are normal, capable of self‐renewal, characterized by recovery indices of 1.2–2.8 %.

Engineering quantitative stomatal trait variation and local adaptation potential by cis-regulatory editing.

Cis-regulatory element editing can generate quantitative trait variation that mitigates extreme phenotypes and harmful pleiotropy associated with coding sequence mutations. Here, we applied a multiplexed CRISPR/Cas9 approach, informed by bioinformatic datasets, to generate genotypic variation in the promoter of OsSTOMAGEN, a positive regulator of rice stomatal density. Engineered genotypic variation corresponded to broad and continuous variation in stomatal density, ranging from 70% to 120% of wild-type stomatal density. This panel of stomatal variants was leveraged in physiological assays to establish discrete relationships between stomatal morphological variation and stomatal conductance, carbon assimilation and intrinsic water use efficiency in steady-state and fluctuating light conditions. Additionally, promoter alleles were subjected to vegetative drought regimes to assay the effects of the edited alleles on developmental response to drought. Notably, the capacity for drought-responsive stomatal density reprogramming in stomagen and two cis-regulatory edited alleles was reduced. Collectively our data demonstrate that cis-regulatory element editing can generate near-isogenic trait variation that can be leveraged for establishing relationships between anatomy and physiology, providing a basis for optimizing traits across diverse environments.

Genetic variability, diversity and principal component analysis in B and R lines of rabi sorghum [Sorghum bicolor (L.) Moench

Hybrid technology is exploited in kharif (rainy) sorghum while the same is not the scenario in Rabi sorghum which is still dominated by landraces and varieties which have poor yield potentiality. Considering the necessity of development of heterotic hybrids, an attempt was made to screen hybrid parents (B and R lines) to assess variability and genetic diversity, for productivity traits. The study was conducted with 32 B and R lines at Regional Agricultural Research Station, Vijayapur during 2021-22. PCV was observed to surpass GCV across all traits. The traits grain yield per plant, fodder yield per plant, grain number per plant, and harvest index exhibited notably high PCV and GCV. Plant height, panicle length, panicle harvest index, and harvest index recorded high heritability and genetic advance, suggesting their control by additive gene action and potential for improvement via selection. Cluster analysis classified the 32 genotypes into four groups. PCA condensed 14 traits into five principal components, capturing 81.50% of total variation. The genotypes remained scattered in all four quadrants in PCA- Biplot, showing large genetic variability in quantitative traits studied. Keywords: Genetic variability, heritability, diversity, clusters, PCA and rabi sorghum

Transgressive Variability of Quantitative Characters in Second Generation (Wheat Hybrids)

The article presents the results of a study of the degree and frequency of transgression in reciprocal hybrids of soft wheat of the second generation (F2). The studies were conducted in the 2020-2021 vegetation year on an experimental plot of the experimental base of the Research Institute of Crop Husbandry of Azerbaijan under irrigated conditions. During the research year, some yield indicators (length of the ear, number of spikelets, number of grains and weight of grains in the ear) of 9 local varieties (Mirbashir-128, Azeri, Gobustan, Fatima, Gyrmyzy gul-1, Murov-2, Askeran, Matin and Onur) of soft wheat and 32 combinations of second-generation hybrids were studied. The degree and frequency of transgression were determined. During the growing season, phenological observations were carried out in accordance with the methodology of scientific research in the field of breeding of grain-crop plants. In the second-generation hybrids (F2), transgressive variability in quantitative traits was calculated using the method of G. S. Voskresensky and V. I. Shpot. The results of the study showed that positive transgression was observed in the second-generation hybrid combinations (F2), which were characterized by high dominance and heterosis in the first generation (F1). In the combinations obtained with the participation of the Gobustan variety, high transgression and frequency were mainly noted in quantitative traits, regardless of whether it was taken as the maternal or paternal form, and negative transgression was mainly recorded when using the Fatima variety as the maternal one. In the reciprocal hybrids Onur × Azeri and Onur × Gyrmyzy gul-1, when the Onur variety was taken as the maternal form, and in the reciprocal hybrids Mirbashir-128 × Gyrmyzy gul-1, when the Mirbashir-128 variety was taken as the maternal form, a positive level of transgression was recorded for all studied traits.

Genome-wide discovery and integrative genomic characterization of insulin resistance loci using serum triglycerides to HDL-cholesterol ratio as a proxy

Insulin resistance causes multiple epidemic metabolic diseases, including type 2 diabetes, cardiovascular disease, and fatty liver, but is not routinely measured in epidemiological studies. To discover novel insulin resistance genes in the general population, we conducted genome-wide association studies in 382,129 individuals for triglyceride to HDL-cholesterol ratio (TG/HDL), a surrogate marker of insulin resistance calculable from commonly measured serum lipid profiles. We identified 251 independent loci, of which 62 were more strongly associated with TG/HDL compared to TG or HDL alone, suggesting them as insulin resistance loci. Candidate causal genes at these loci were prioritized by fine mapping with directions-of-effect and tissue specificity annotated through analysis of protein coding and expression quantitative trait variation. Directions-of-effect were corroborated in an independent cohort of individuals with directly measured insulin resistance. We highlight two phospholipase encoding genes, PLA2G12A and PLA2G6, which liberate arachidonic acid and improve insulin sensitivity, and VGLL3, a transcriptional co-factor that increases insulin resistance partially through enhanced adiposity. Finally, we implicate the anti-apoptotic gene TNFAIP8 as a sex-dimorphic insulin resistance factor, which acts by increasing visceral adiposity, specifically in females. In summary, our study identifies several candidate modulators of insulin resistance that have the potential to serve as biomarkers and pharmacological targets.

An estimate of fitness reduction from mutation accumulation in a mammal allows assessment of the consequences of relaxed selection.

Each generation, spontaneous mutations introduce heritable changes that tend to reduce fitness in populations of highly adapted living organisms. This erosion of fitness is countered by natural selection, which keeps deleterious mutations at low frequencies and ultimately removes most of them from the population. The classical way of studying the impact of spontaneous mutations is via mutation accumulation (MA) experiments, where lines of small effective population size are bred for many generations in conditions where natural selection is largely removed. Such experiments in microbes, invertebrates, and plants have generally demonstrated that fitness decays as a result of MA. However, the phenotypic consequences of MA in vertebrates are largely unknown, because no replicated MA experiment has previously been carried out. This gap in our knowledge is relevant for human populations, where societal changes have reduced the strength of natural selection, potentially allowing deleterious mutations to accumulate. Here, we study the impact of spontaneous MA on the mean and genetic variation for quantitative and fitness-related traits in the house mouse using the MA experimental design, with a cryopreserved control to account for environmental influences. We show that variation for morphological and life history traits accumulates at a sufficiently high rate to maintain genetic variation and selection response. Weight and tail length measures decrease significantly between 0.04% and 0.3% per generation with narrow confidence intervals. Fitness proxy measures (litter size and surviving offspring) decrease on average by about 0.2% per generation, but with confidence intervals overlapping zero. When extrapolated to humans, our results imply that the rate of fitness loss should not be of concern in the foreseeable future.

Phenotypic diversity in qualitative and quantitative traits for selection of high yield potential field pea genotypes

Field pea (Pisum sativum L.) needs improvement to increase productivity due to its high price and demand. However, the incidence of powdery mildew (PM) disease limits its production. This study aimed to analyze the diversity of qualitative and quantitative traits against powdery mildew resistance by utilizing cluster and principal component analysis to explore PM resistance high-yield potential field peas. Shannon–Weaver's diversity index (Hʹ) displayed high intra-genotype diversity for quantitative and qualitative aspects. Heterogeneity was identified for resistance against powdery mildew infections. Eighty-five genotypes were divided into five groups using Mohalanobis generalized distance (D2) statistics. The highest inter-cluster D2 value was observed between clusters 2 and 3 (11.89) while the lowest value was found between clusters 3 and 4 (2.06). Most of the genotypes had noticeable differences, so these could be employed in a crossing scheme. Twelve genotypes were extremely resistant, 29 genotypes were resistant, 25 genotypes were moderately resistant, 18 genotypes were fairly susceptible, and 1 genotype was susceptible to powdery mildew disease. Among 29 resistant genotypes, BFP77, BFP74, BFP63, BFP62, BFP43, and BFP80 were high yielders and, could be used directly and/or transferred through hybridization to high-yielding disease-susceptible genotypes. Among the 25 moderately resistant genotypes, BFP78, BFP45, BFP79, and BFP48 were found to be high yielders. In principal component analysis (PCA), the first four PCs with Eigen values > 1 accounted for 88.4% variability for quantitative traits. Clustering sorted genotypes into five groups, where groups 1 to 5 assembled 37, 28, 1, 8, and 11 genotypes, respectively. Genotypes of cluster 4 were identified as high yielders with its attributes. Pearson correlation significantly and positively correlated across all traits except for PM. This variation suggested that there is a mechanism to select promising genotypes for field pea breeding. Considering all features, BFP78, BFP77, BFP74, BFP63, BFP62, BFP45, BFP79, and BFP80 could be preferred as high yielders and PM resistance owing to longer pod lengths, seeds per pod and pods per plant.

Exploration of the Dayak Onion (Eleutherine palmifolia (L.) Merr) in the Borderlands of North Kalimantan, Indonesia

The Dayak onion (Eleutherine palmifolia (L.) Merr) is a plant endemic to Kalimantan, Indonesia, known for its medicinal properties. This study explores the distribution and morphological diversity of Dayak onions in the border areas of North Kalimantan, encompassing Tana Tidung, Bulungan, Malinau Regencies, and Tarakan City. Fifteen unique accessions were collected, and their morphological traits were characterized both qualitatively and quantitatively. The distribution analysis revealed an even spread of Dayak onions across the studied regions. The diversity analysis, using the Shannon-Wiener index, indicated variations in certain quantitative traits like plant height and root length, while qualitative traits like leaf and bulb characteristics remained largely uniform. Principal Component Analysis (PCA) identified key morphological characters contributing to the observed diversity, and cluster analysis revealed kinship relationships among the accessions, with some groups showing high similarity coefficients. This research provides valuable insights into the distribution, diversity, and genetic relationships of Dayak onions in North Kalimantan, contributing to potential agricultural and conservation applications.

Structure Characteristics, Variation of Main Quantitative Traits, and Probability Grading of Chinese Olive (Canarium album) Seeds

In order to comprehensively describe and evaluate Chinese olive seeds, this study examined 33 varieties (strains) of Chinese olive seeds to address the limitations of previous research on quantitative trait variation and grading among Chinese olive seed varieties (strains). The research specifically focused on evaluating the morphological characteristics, seed locule structure, embryo composition, and phenotypic quantitative traits of Chinese olive seeds. The results indicated that Chinese olive seeds consisted of a core, seed coat, and embryo. Typically, the core contained two to four locules, with each locule containing zero to one embryos. Eight distinct structural variations were identified, with the number of locules per seed ranging from two to four and the number of embryos ranging from one to four. The most common structural types were ‘3-locule 1-embryo’ and ‘3-locule 2-embryo’, each occurring in 100% of the varieties (strains) studied. These two structural types also had a high average proportion within each variety (line), accounting for 50.17% and 42.06%, respectively. The average dimensions of a seed were 31.20 mm in length and 10.89 mm in width, with a shape index of 2.89 and weighing 1.55 g. These quantitative traits displayed significant variation, with the coefficient of variation being highest for single seed weight (19.35%) and lowest for seed length (9.39%). Normality tests revealed that seed width, seed length, and single seed weight followed a normal distribution. These traits were categorized into five levels based on specific points, with probabilities of occurrence approximately 10%, 20%, 40%, 20%, and 10%, respectively. The findings of this study are crucial for understanding and utilizing Chinese olive seed traits and provide valuable insights for the establishment of seed trait standards and data normalization.

A complete chromosome substitution mapping panel reveals genome-wide epistasis in Arabidopsis

Chromosome substitution lines (CSLs) are tentatively supreme resources to investigate non-allelic genetic interactions. However, the difficulty of generating such lines in most species largely yielded imperfect CSL panels, prohibiting a systematic dissection of epistasis. Here, we present the development and use of a unique and complete panel of CSLs in Arabidopsis thaliana, allowing the full factorial analysis of epistatic interactions. A first comparison of reciprocal single chromosome substitutions revealed a dependency of QTL detection on different genetic backgrounds. The subsequent analysis of the complete panel of CSLs enabled the mapping of the genetic interactors and identified multiple two- and three-way interactions for different traits. Some of the detected epistatic effects were as large as any observed main effect, illustrating the impact of epistasis on quantitative trait variation. We, therefore, have demonstrated the high power of detection and mapping of genome-wide epistasis, confirming the assumed supremacy of comprehensive CSL sets.

VARIABILITY OF QUANTITATIVE PLANT CHARACTERS OF EGGPLANT COLLECTION SAMPLES

Purpose. To determine the peculiarities of the variability of the quantitative characteristics of the plant in collection samples of eggplant of different origin during different years of cultivation Methods. During 2021-2023, an eggplant collection consisting of 21 varieties and 10 F1 hybrids of various geographical origins was studied at the experimental base of the Institute of Vegetable and Melon Growing of the National Academy of Sciences. Samples were evaluated by plant height, plant width, number of shoots per plant. Field, biometric, computational and analytical research methods were used. Results. It was found that the height and width of the plant had a tendency to decrease in 2023. The average height of the collection for this year by varieties was 97.4 cm, by hybrids – 98.7 cm. The width of the plant this year was 41.3 cm on average by varieties, by hybrids – 43.4 cm. The lowest plant height was noted variety Hangqi No.1 (81.0 cm on average over the years), the highest plant height is the variety Bambina. (120.7 cm). Among the hybrids, Piatachok F1 was the shortest, Gordita F1 was the tallest (121.7 cm). The smallest plant width among the varieties was the Xingyuun variety (35.3 cm on average over the years), among the hybrids – the Farama F1 hybrid (38.7 cm). The largest plant width is in the Thai Long Green variety (51.3 cm) and in the Gordita F1 and Briska F1 hybrids (49.3 cm). The smallest number of shoots was formed in plants of the Xingyuun variety (2.7 pcs. on average over the years) and the Galchonok F1 hybrid (3.3 pcs.). The variety Luisiana Long Green (6.9 pcs.) and the Purple Dragon F1 hybrid (8.1 pcs.) had the most shoots on the plant. Almost all studied varieties and hybrids were distinguished by weak and medium variability in three characteristics. Only the Zelenenky variety showed itself to be very variable in the number of shoots (CV = 21.16). Among the varieties, the variety Tai Long Green was distinguished by the least variability in height and width of plants, and Louisiana Long Green in the number of shoots on the plant. Among the hybrids, the lowest variability of plant height and width was observed in the Izumrudny F1 hybrid, and the number of shoots per plant in Bibo F1. Thai Long Green and Daejeon Purple varieties showed the least response to the change in growing conditions by plant height, Hangqi No. 1-2 variety by plant width, and Luisiana Long Green by the number of shoots per plant. The most stable among the hybrids were Izumrudny F1 in terms of plant height and width and Bibo F1 in terms of the number of shoots. Conclusions. Thus, breeding studies allowed to determine the levels of variability of quantitative traits of the eggplant plant and to identify valuable collection samples for use in breeding programs.

Clinal variation in quantitative traits but not in evolutionary potential along elevational and latitudinal gradients in the widespread Anthyllis vulneraria.

Strong elevational and latitudinal gradients allow the study of genetic differentiation in response to similar environmental changes. However, it is uncertain whether the environmental changes along the two types of gradients result in similar genetically based changes in quantitative traits. Peripheral arctic and alpine populations are thought to have less evolutionary potential than more central populations do. We studied quantitative traits of the widespread Anthyllis vulneraria in a common garden. Plants originated from 20 populations along a 2000-m elevational gradient from the lowlands to the elevational limit of the species in the Alps, and from 20 populations along a 2400-km latitudinal gradient from the center of the distribution of the species in Central Europe to its northern distributional margin. Most traits showed similar clinal variations with elevation and latitude of origin, and the magnitude of all measured traits in relation to mean annual temperature was similar. Higher QST values than FST values in several traits indicated diversifying selection, but for others QST was smaller than FST. Genetic diversity of quantitative traits and neutral molecular markers was not correlated. Plasticity in response to favorable conditions declined with elevation and less strongly with latitude of origin, but the evolvability of traits did not. The clinal variation suggests adaptive differentiation of quantitative traits along the two gradients. The evolutionary potential of peripheral populations is not necessarily reduced, but lower plasticity may threaten their survival under rapidly changing climatic conditions.

YQTL Pipeline: A structured computational workflow for large scale quantitative trait loci discovery and downstream visualization.

Quantitative trait loci (QTL) denote regions of DNA whose variation is associated with variations in quantitative traits. QTL discovery is a powerful approach to understand how changes in molecular and clinical phenotypes may be related to DNA sequence changes. However, QTL discovery analysis encompasses multiple analytical steps and the processing of multiple input files, which can be laborious, error prone, and hard to reproduce if performed manually. To facilitate and automate large-scale QTL analysis, we developed the yQTL Pipeline, where the 'y' indicates the dependent quantitative variable being modeled. Prior to the association test, the pipeline supports the calculation or the direct input of pre-defined genome-wide principal components and genetic relationship matrix when applicable. User-specified covariates can also be provided. Depending on whether familial relatedness exists among the subjects, genome-wide association tests will be performed using either a linear mixed-effect model or a linear model. The options to run an ANOVA model or testing the interaction with a covariate are also available. Using the workflow management tool Nextflow, the pipeline parallelizes the analysis steps to optimize run-time and ensure results reproducibility. In addition, a user-friendly R Shiny App is developed to facilitate result visualization. It can generate Manhattan and Miami plots of phenotype traits, genotype-phenotype boxplots, and trait-QTL connection networks. We applied the yQTL Pipeline to analyze metabolomics profiles of blood serum from the New England Centenarians Study (NECS) participants. A total of 9.1M SNPs and 1,052 metabolites across 194 participants were analyzed. Using a p-value cutoff 5e-8, we found 14,983 mQTLs associated with 312 metabolites. The built-in parallelization of our pipeline reduced the run time from ~90 min to ~26 min. Visualization using the R Shiny App revealed multiple mQTLs shared across multiple metabolites. The yQTL Pipeline is available with documentation on GitHub at https://github.com/montilab/yQTLpipeline.

A new test for trait mean and variance detects unreported loci for blood-pressure variation

Variability in quantitative traits has clinical, ecological, and evolutionary significance. Most genetic variants identified for complex quantitative traits have only a detectable effect on the mean of trait. We have developed the mean-variance test (MVtest) to simultaneously model the mean and log-variance of a quantitative trait as functions of genotypes and covariates by using estimating equations. The advantages of MVtest include the facts that it can detect effect modification, that multiple testing can follow conventional thresholds, that it is robust to non-normal outcomes, and that association statistics can be meta-analyzed. In simulations, we show control of type I error of MVtest over several alternatives. We identified 51 and 37 previously unreported associations for effects on blood-pressure variance and mean, respectively, in the UK Biobank. Transcriptome-wide association studies revealed 633 significant unique gene associations with blood-pressure mean variance. MVtest is broadly applicable to studies of complex quantitative traits and provides an important opportunity to detect novel loci.

Comprehensive Characterization of Global Barley (Hordeum vulgare L.) Collection Using Agronomic Traits, β-Glucan Level, Phenolic Content, and Antioxidant Activities.

This study characterized the diversity of 367 barley collections from 27 different countries, including 5 control cultivars, using several phenotypic traits. Morphological traits, including spike type, grain morphology, cold damage, and lodging rate, exhibited wide variations. Eighteen accessions matured early, while four accessions had longer culm and spike lengths than the controls. The ranges of total phenolic content (TPC), β-glucan content, ABTS•+ scavenging activity, DPPH• scavenging activity, and reducing power (RP) were 1.79-6.79 mg GAE/g, 0.14-8.41 g/100 g, 3.07-13.54 mg AAE/100 g, 1.56-6.24 mg AAE/g, and 1.31-7.86 mg AAE/g, respectively. Betaone, one of the controls, had the highest β-glucan content. Two accessions had β-glucan levels close to Betaone. Furthermore, 20 accessions exhibited increased TPC compared to the controls, while 5 accessions displayed elevated ABTS•+ scavenging activity. Among these, one accession also exhibited higher DPPH• scavenging activity and RP simultaneously. Based on the statistical analysis of variance, all the quantitative traits were significantly affected by the difference in origin (p < 0.05). On the other hand, grain morphology significantly affected biochemical traits. Multivariate analysis classified barley accessions into eight groups, demonstrating variations in quantitative traits. There were noteworthy correlations between biochemical and agronomical traits. Overall, this study characterized several barley varieties of different origins, anticipating future genomic research. The barley accessions with superior performances could be valuable alternatives in breeding.

ANALYSIS OF INHERITANCE AND HERITABILITY OF ECONOMICALLY VALUABLE TRAITS IN HYBRID BARLEY POPULATIONS

The article presents the results of studying the nature of inheritance, heritability and variability of quantitative traits in 36 hybrid populations in conditions of saline soils of rice systems of the Kazakhstan Aral Sea region. Since variability and inheritance depend on the genotype and environmental conditions, the most valuable is the information obtained in a specific agroclimatic zone for which new varieties are created. It was established that the prevalence of additive gene interactions in the control of the studied traits in the conditions of the Aral Sea region indicates the possibility of effective selection already in the F2 generation, and in more favorable years, due to the high determination of these traits by dominant genes, it is necessary to differentiate hybrid populations, starting from the first generation and further selection to be carried out in several cycles until homozygosity of loci carrying dominant genes is achieved. The most accessible features for selection in early generations are: plant height, ear length, number of grains in an ear, the variability of which is caused by the action of additive genes, for which it is necessary to carry out targeted selection work to increase the productivity of barley in this region. Hybrid populations with high values of the heritability coefficient for certain features and for their complex have been identified: Bi-16 x Saule (by five features); Syr Aruy x Donetskiy 8, Syr Aruy x Odesskiy 100, Bi-17 x Saule (by four), in which it is necessary to select highly productive forms adapted to stressful environmental conditions

Drift on holey landscapes as a dominant evolutionary process.

An organism's phenotype has been shaped by evolution but the specific processes have to be indirectly inferred for most species. For example, correlations among traits imply the historical action of correlated selection and, more generally, the expression and distribution of traits is expected to be reflective of the adaptive landscapes that have shaped a population. However, our expectations about how quantitative traits-like most behaviors, physiological processes, and life-history traits-should be distributed under different evolutionary processes are not clear. Here, we show that genetic variation in quantitative traits is not distributed as would be expected under dominant evolutionary models. Instead, we found that genetic variation in quantitative traits across six phyla and 60 species (including both Plantae and Animalia) is consistent with evolution across high-dimensional "holey landscapes." This suggests that the leading conceptualizations and modeling of the evolution of trait integration fail to capture how phenotypes are shaped and that traits are integrated in a manner contrary to predictions of dominant evolutionary theory. Our results demonstrate that our understanding of how evolution has shaped phenotypes remains incomplete and these results provide a starting point for reassessing the relevance of existing evolutionary models.

Genetic Variability and Divergence Studies in Quantitative Traits of Wild Pomegranate (Punica granatum L)

The mean performance and variability in quantitative traits of Punica granatum seed sources collected from five different districts comprising of ten seed sources. Two seed sources were considered from each district viz; Narag and Neripul from Sirmour district, Waknaghat and Sadhupul from Solan district, Sundernagar and Rewalsar from Mandi district, Mohal and Banjar from Kullu district, Basantpur and Sunni from Shimla district of Himachal Pradesh, India, were evaluated during the year 2018-19. The quantitative traits viz., morphological and seedling characteristics of seed sources varied significantly among the different districts and within the districts. The phenotypic coefficient of variation (PCV) for all the characters was slightly higher than genotypic coefficient of variation (GCV), which signified the presence of environmental influence to some degree in the phenotypic expression of characters. Collar diameter had the highest PCV (76.83) and GCV (26.67). Genetic advance was recorded as maximum for tree diameter per plant (5.57), whereas genetic advance as percent of mean was highest for tree height (4.86). Highest heritability (H2 , 99.77) was coupled with higher genetic advance (5.57) estimated for tree diameter per plant, which indicated that the character is controlled by additive genes and therefore further improvement could brought by selection. Tree diameter was significantly and positively associated with most of the characters except number of branches per plant, at both genotypic and phenotypic levels; therefore, these are important prerequisites to formulate a successful improvement program. Cluster analysis was performed and the seed sources were grouped into three clusters. The results showed significant variance among different morphological characters, traits namely tree height (m), tree diameter (cm), crown spread E-W (m), crown spread N-S (m), fruit weight (g), leaf length(cm), internodal length(cm), collar diameter (mm), number of branches per plant and leaf petiole (cm)

Alternative Splicing Variation: Accessing and Exploiting in Crop Improvement Programs.

Alternative splicing (AS) is a gene regulatory mechanism modulating gene expression in multiple ways. AS is prevalent in all eukaryotes including plants. AS generates two or more mRNAs from the precursor mRNA (pre-mRNA) to regulate transcriptome complexity and proteome diversity. Advances in next-generation sequencing, omics technology, bioinformatics tools, and computational methods provide new opportunities to quantify and visualize AS-based quantitative trait variation associated with plant growth, development, reproduction, and stress tolerance. Domestication, polyploidization, and environmental perturbation may evolve novel splicing variants associated with agronomically beneficial traits. To date, pre-mRNAs from many genes are spliced into multiple transcripts that cause phenotypic variation for complex traits, both in model plant Arabidopsis and field crops. Cataloguing and exploiting such variation may provide new paths to enhance climate resilience, resource-use efficiency, productivity, and nutritional quality of staple food crops. This review provides insights into AS variation alongside a gene expression analysis to select for novel phenotypic diversity for use in breeding programs. AS contributes to heterosis, enhances plant symbiosis (mycorrhiza and rhizobium), and provides a mechanistic link between the core clock genes and diverse environmental clues.