Indirect Selection Research Articles

Multiple-trait genomic prediction for swine meat quality traits using gut microbiome features as a correlated trait.

Traits such as meat quality and composition are becoming valuable in modern pork production; however, they are difficult to include in genetic evaluations because of the high phenotyping costs. Combining genomic information with multiple-trait indirect selection with cheaper indicator traits is an alternative for continued cost-effective genetic improvement. Additionally, gut microbiome information is becoming more affordable to measure using targeted rRNA sequencing, and its applications in animal breeding are becoming relevant. In this paper, we investigated the usefulness of microbial information as a correlated trait in selecting meat quality in swine. This study incorporated phenotypic data encompassing marbling, colour, tenderness, loin muscle and backfat depth, along with the characterization of gut (rectal) microbiota through 16S rRNA sequencing at three distinct time points of the animal's growth curve. Genetic progress estimation and cross-validation were employed to evaluate the utility of utilizing host genomic and gut microbiota information for selecting expensive-to-record traits in crossbred individuals. Initial steps involved variance components estimation using multiple-trait models on a training dataset, where the top 25 associated operational taxonomic units (OTU) for each meat quality trait and time point were included. The second step compared the predictive ability of multiple-trait models incorporating different numbers of OTU with single-trait models in a validation set. Results demonstrated the advantage of including genomic information for some traits, while in some instances, gut microbial information proved advantageous, namely, for marbling and pH. The study suggests further investigation into the shared genetic architecture between microbial features and traits, considering microbial data's compositional and high-dimensional nature. This research proposes a straightforward method to enhance swine breeding programs for improving costly-to-record traits like meat quality by incorporating gut microbiome information.

Assessing genetic parameters for first parity reproductive traits for early selection in Saanen × Beetal goats of India.

The present study aimed to evaluate the genetic parameters of first parity reproductive traits. Information on 762 reproductive records on Saanen × Beetal (S × B) goats reared for approximately five decades was collected from ICAR-National Dairy Research Institute, Karnal, Haryana (1973-2020). For genetic analysis, single-trait and multiple-trait animal models were used. Gibbs sampler for animal model (GSAM) approach was used for estimating (co)variance components of reproductive traits. Six different single-trait animal models (with or without maternal and environmental effects) were used and the deviance information criterion (DIC) determined the best model. The least squares mean for age at first service (AFS), age at first kidding (AFK), service period (SP), dry period (DP), gestation length (GL), kidding interval (KI), litter weight (LW), number of kids born (NKB) and number of female kids born (NFKB) in first parity were 526.99 ± 4.86, 662.96 ± 5.03, 219.11 ± 6.25, 109.38 ± 6.00, 150.48 ± 0.27, 356.63 ± 4.80 days, 3.87 ± 0.05 kg, 1.27 ± 0.02 and 0.67 ± 0.03, respectively. Lower heritability estimates for these reproductive traits revealed a sparse scope for genetic improvement. Multivariate analysis using Model 1 was carried out to evaluate the genetic and phenotypic correlation of these nine reproductive traits. The genetic correlation of DP and SP was negatively with LW, NKB and NFKB, which is favourable as reduction in SP and DP can improve these economically important traits through indirect selection. Consistent efforts towards genetic improvement of these goat flock poses a promising future for meat industry owing to high prolificacy and good reproductive potential in this flock.

Genetic parameters, correlation and path analysis for fodder and dual purpose sorghum [Sorghum bicolor (L.) Moench] genotypes

About 60 diverse sorghum genotypes were evaluated to assess the genetic parameters, association among fodder and grain yield component traits and their direct and indirect effects on grain yield. The experiment was conducted in randomized block design at Instructional Farm, Department of Genetics and Plant Breeding, Rajasthan College of Agriculture (MPUAT), Udaipur in collaboration with AICRP on Sorghum. Analysis of variance revealed highly significant differences among the genotypes for all 14 traits studied. In the present investigation range of the magnitudes of all genetic parameters for each trait was classified based on mean and standard deviation (SD) into three categories viz., high (> ), medium (in between ) and low (< ). Traits viz., total soluble solids (%), grain yield per plant (g), leaf breadth (cm) and dry fodder yield per plant (g) were the most approachable for selection as they had higher GCV, PCV, genetic gain and moderate to high heritability in a broad sense. Hence, simple selection could be effective for further improvement of these characters. Based on correlation and path analysis, the traits, dry fodder yield per plant, harvest index, green fodder yield per plant, leaf breadth, protein content and plant height might be considered as indirect selection indices for improvement in grain and fodder yields of sorghum.

Selection based on the Breeding Soundness Evaluation is associated with the improvement of the reproductive quality of young Nellore bulls

Breeding soundness evaluation (BSE) is the best methodology to estimate the fertility potential of future bulls and performing indirect selection for their fertility. However, the outcome of the BSE is influenced by several factors, including genetics, environment, and BSE guidelines. Herein, in this retrospective study, our first aim was to characterize the reasons for failure in 46,566 BSE from 2-year-old beef Bos indicus bulls (Nellore) born from 1997 to 2018. Our second aim was to determine whether or not BSE was associated with reproductive potential improvement of the bulls over the years. Due to changes in the BSE criteria, we used the same dataset, but only bulls born from 2002 to 2018 were included resulting in 35,856 BSE. For the second aim, the effect of the year and farm were included in the model of the multivariate logistic regression. We also determined if the main reasons for BSE failure decreased over time. Bulls were classified as approved (satisfactory potential breeders and qualified for natural breeding service) and not approved (deferred and unsatisfactory potential breeders). The reasons for BSE failure in Nellore bulls were poor semen quality (53.1 %) and physical defects (46.9 %), with the main physical defect being testis abnormalities (19.7 %). The overall percentage of bulls approved each year was 87.1 %, with no improvement over the years of study. However, the percentage of approved bulls at the first BSE increased over the years (P < 0.05). This increase was evident by a reduction in the difference between the overall percentage of the bulls approved vs the percentage of bulls approved at the first BSE. Furthermore, there was an increase in the percentage of bulls classified as satisfactory potential breeders in the BSE and an evident decrease in the percentage of bulls qualified only for natural breeding service (P < 0.05). In addition, an increase of the scrotal circumference (SC) of the herd was found (P < 0.05). These results indicate the overall quality of the bulls improved over the years. To associate and identify the main sperm abnormalities, 3461 not approved bulls were clustered. The most frequent defects were strongly coiled tail spermatozoa, proximal droplets, and acrosomal defects. Overall, there was no change in the frequency of bulls not approved by the sperm morphology nor the frequency of the main sperm abnormalities over the years. Nevertheless, the frequency of the defects remained very low, implying they were controlled. Additionally, abnormalities in the testis decreased over the years and was associated with the increase in the SC of the herd and a decrease of culled bulls due to low SC. In conclusion, this study demonstrates that there is an association between implementation and use of BSE with improvements in the reproductive quality of future generation bulls.

Identifying indirect selection traits to improve winter hardiness in barley

Identifying indirect selection traits to improve winter hardiness in barley

Exploring Gene Action Underlying Post-Harvest Water Loss in Fresh Market Peppers

The objective of this study was to evaluate the genetic effects involved in post-harvest water loss of C. baccatum fruits and to correlate fruit morphological characteristics. Fruits of eight landraces of C. baccatum and their twenty-eight hybrids were evaluated in a randomized, complete block design. Analysis of variance, diallel analysis, phenotypic and genotypic correlation, and path analysis for eight fruit traits were performed. Fruit width, fruit length, dry matter content, and fruit wall thickness were determined by additive gene effects. On the other hand, the non-additive effects played more important role than additive ones, including water loss, cuticle thickness, exocarp thickness, and total soluble solids. The relationship of fruit traits suggested that indirect selection can be carried out from field experiments under different environmental conditions. Overall, genitors 4, 24, 50, and 56 should be selected to form new populations to improve these traits. The Brazilian pepper landraces of C. baccatum species are a source of genetic variability for plant breeders, and the new segregating populations emerging through the crossing of pepper lines with reduced water loss should be developed, opening new ways for conventional breeding.

Genetic parameters of meat quality, external morphology, and growth traits in Pacific white shrimp (Penaeus vannamei) from an Ecuadorian population

In shrimp production, product quality plays a crucial role and determines consumer acceptance. However, there are no studies on its genetic determination. The main purpose of this study was, for first time in Penaeus vannamei, to estimate the additive genetic variation of flesh quality traits in terms of composition and texture, and their genetic correlation with growth and morphological traits. To this end, 388 shrimps from the fourth generation of the PMG-BIOGEMAR© breeding program, belonging to 79 full-sib families, were reared under an extensive industrial culturing system (PRODUMAR, Durán, Ecuador). At the same day, they were harvested and measured for fresh weight. They were kept at −20 °C for later sampling for flesh quality traits, in terms of composition, by Near-Infrared spectroscopy (NIR), and texture by Texture analyzer technologies. Growth and morphological traits were manually measured with a vernier caliper. Low heritabilities were estimated for flesh composition traits (0.01 to 0.07), and low-medium for meat quality traits related to texture (0.01 to 0.37). Medium-high heritabilities were estimated for total length and weight (0.35 and 0.50, respectively), with a very high genetic correlation between both (0.99). Regarding morphological traits, heritabilities ranged from 0.05 to 0.52 for length-related traits, from 0.15 to 0.36 for height-related traits, and from 0.22 to 0.42 for width-related traits. Cephalothorax length showed the highest heritability among all analyzed traits (0.52), with high genetic correlations with growth, flesh composition, and texture traits. The high genetic correlations found between growth and morphometric traits, and both flesh composition and texture traits suggest indirect selection as a successful, undemanding, and cost-effective method to obtain high-quality shrimps under industrial conditions.

Canonical correlations between morphoagronomic and production traits in traditional cowpea varieties based on genotypic values

Obtaining information about the main morphoagronomic and yield components, as well as their interrelationships, is of utmost importance in cowpea breeding programs, aiming at the selection of superior genotypes. The analysis of canonical correlations allows us to predict and describe the relationship between groups of characters, allowing the indirect selection of superior genotypes. The objective of this work was to verify relationships between morphological characters and production components through the analysis of canonical correlations using genotypic values obtained via mixed REML/BLUP models in traditional cowpea varieties. The experiment was conducted in a randomized block design with three replications and 12 treatments. Traditional varieties were characterized and evaluated during the germination, seedling, flowering and harvest stages with data obtained from plants, pods and seeds. Using the genotypic correlation matrix, two sets of characteristics were established, Group I, formed by production components and Group II, formed by morphoagronomic characters. A second correlation analysis was performed to verify associations between morphoagronomic and seed traits (seed length, width and thickness). It was found that dependence between the groups evaluated and intergroup associations can be established, which allows the study of cause-effect and the practice of indirect selection between groups of variables studied. An increase in pod length, hundred-grain mass and seed size is achieved through the selection of early maturing plants, with greater width of the apical leaflet and length of the hypocotyl.

The use of fixed shelling percentage biases genotype selection in hybrid maize multi-environment yield trials

Context or problemPhenotyping is an integral part of plant breeding operations. In many cases the trait measured is not identical to the target trait for reasons of speed and or cost. This is a form of indirect selection, where correlation between the trait measured and the target phenotype influences the rate of genetic gain. Low correlations lead to slow rates of genetic gain. In sub-Saharan African maize breeding programs, maize grain yield in breeding experimental plots is measured as a field weight (FW), which includes the grain and cob. The weight of grain from each plot is estimated as a standard proportion of grain to total ear weight using a shelling percentage of 80 %. This approach assumes that there is no genetic, environment or genetic by environment interaction in shelling percentage which, if present, would contribute to slower rates of genetic gain for grain yield. Objective or research questionThis study investigated the magnitude of genetic and environmental variation in shelling percentage and its impact on selection in six hybrid maize multi-environment yield trials in Ethiopia over two seasons. MethodsThe data of shelled grain weight (SW) and cob weight (CW) from the trials were analyzed using a bivariate linear mixed model. ResultsGenetic variances for both traits varied across the six testing sites ranging from 0.199 to 2.975 for SW and from 0.029 to 0.245 for CW. The genetic correlations between pairs of sites for SW and CW also varied, indicating the existence of genotype by environment interaction for these traits. Additionally, the bivariate regressions between FW and SW indicated there was substantial genetic deviation around the 80 % shelling response, and this relationship was impacted by environmental influences. ConclusionThe use of a constant relationship of 80 % shelling biases grain yield prediction in multi-environment hybrid maize yield trials and thus reduces the rate of genetic gain in maize breeding programs. Implications or significanceTaking into account the variations in the shelling percentage of the genotypes across sites in predicting grain yield from field weight improves the accuracy of genotype selection and the rate of genetic gain in maize breeding programs.

Sugarcane (saccharum officinarum L.) traits associated with ratooning ability

ABSTRACT Indirect selection for yield in sugarcane (Saccharum officinarum L.) production can be achieved by identifying and selecting for plant traits that are correlated to yield. This study aimed to identify and quantify sugarcane traits that are associated with ratooning ability to generate information for varieties’ selection. Data sourced from three variety trials established at three sites, comprising eight varieties, and collected over six successive crops (plant cane and five ratoons) were used for this study. The data were subjected to linear mixed model, Spearman’s correlation, and biplot analyses. Stalk height, stalk population, stalk mass, and stalk sucrose mass were significantly correlated with cane and sucrose yield across all ratoon crops, suggesting that varieties that combine these traits over multiple crops will have higher ratoon cane and sucrose yields. Significant correlation between brix and sucrose content suggested that brix can be used to indirectly select for sucrose content. Measuring brix is easier, cheaper, and faster than measuring sucrose content. Significant site and variety effects on ratoon crop yields indicated the existence of opportunities to identify good ratooning varieties that are specifically and or broadly adapted to different growing conditions.

Unveiling Drought-Resilient Latin American Popcorn Lines through Agronomic and Physiological Evaluation.

Water stress can lead to physiological and morphological damage, affecting the growth and development of popcorn. The objective of this study was to identify the yield potential of 43 popcorn lines derived from a Latin American germplasm collection, based on agronomic and physiological traits, under full irrigation (WW) and water deficit conditions (WS), aiming to select superior germplasm. The evaluated agronomic traits included the ear length and diameter, number of grains per row (NGR) and rows per ear (NRE), grain yield (GY), popping expansion (EC), volume of expanded popcorn per hectare (VP), grain length (GL), width, and thickness. The physiological traits included the chlorophyll, anthocyanin, and flavonoid content in the leaves. The genetic variability and distinct behavior among the lines for all the agronomic traits under WW and WS conditions were observed. When comparing the water conditions, line L292 had the highest mean for the GY, and line L688 had the highest mean for the EC, highlighting them as the most drought-tolerant lines. A water deficit reduced the leaf greenness but increased the anthocyanin content as an adaptive response. The GY trait showed positive correlations with the VP, NGR, and GL under both water conditions, making the latter useful for indirect selection and thus of great interest for plant breeding targeting the simultaneous improvement of these traits.

Consequences of partially recessive deleterious genetic variation for the evolution of inversions suppressing recombination between sex chromosomes1.

The evolution of suppressed recombination between sex chromosomes is widely hypothesized to be driven by sexually antagonistic selection (SA), where tighter linkage between the sex-determining gene(s) and nearby SA loci is favored when it couples male-beneficial alleles to the proto-Y chromosome, and female-beneficial alleles to the proto-X. Although difficult to test empirically, the SA selection hypothesis overshadows several alternatives, including an incomplete but often-repeated "sheltering" hypothesis which suggests that expansion of the sex-linked region (SLR) reduces the homozygous expression of deleterious mutations at selected loci. Here, we use population genetic models to evaluate the consequences of partially recessive deleterious mutational variation for the evolution of otherwise neutral chromosomal inversions expanding the SLR on proto-Y chromosomes. Both autosomal and SLR-expanding inversions face a race against time: lightly-loaded inversions are initially beneficial, but eventually become deleterious as they accumulate new mutations, after which their chances of fixing become negligible. In contrast, initially unloaded inversions eventually become neutral as their deleterious load reaches the same equilibrium as non-inverted haplotypes. Despite the differences in inheritance and indirect selection, SLR-expanding inversions exhibit similar evolutionary dynamics to autosomal inversions over many biologically plausible parameter conditions. Differences emerge when the population average mutation load is quite high; in this case large autosomal inversions that are lucky enough to be mutation-free can rise to intermediate to high frequencies where selection in homozygotes becomes important (Y-linked inversions never appear as homozygous karyotypes); conditions requiring either high mutation rates, highly recessive deleterious mutations, weak selection, or a combination thereof.

Pigmented radish (Raphanus sativus): Genetic variability, heritability and interrelationships of total phenolics, anthocyanins and antioxidant activity

Radish (Raphanus sativus L.) is an important salad vegetable grown and consumed throughout the world for fleshy roots which has numerous categories– varying in root colour, size, shape and flavour. The uses of coloured radishes in the salads and their anthocyanins as colourants are gaining popularity because of the colour characteristics, health benefits as well as antioxidant activities. However, information on the genetic variability, heritability and inter-relationship of total phenolics, anthocyanins and antioxidant activities in pigmented radish is very limited, but pre-requisite to initiate breeding programme; and therefore investigated in the present study. Radish genotypes were significantly diverse for all the antioxidants; differed by 4.98-fold for total phenolics, 36.16-fold for anthocyanins content, 4.96-fold for FRAP activity and 4.03-fold for CUPRAC activity; and the genotypes accounted for &gt;97% of total variations. The meager differences between phenotypic and genotypic coefficient of variation reveals the greater role of genotypes and lesser influence of the environment on the biosynthesis and accumulation of antioxidants. Significantly positive correlations along with higher magnitude for anthocyanins content, total phenolics, FRAP activity and CUPRAC activity (r= 0.823 to 0.964) could be used as indirect selection criteria for improving levels of antioxidant compounds. The estimates of heritability and genetic advance indicate the role of additive and non-additive genes for biosynthesis of antioxidants and root development, respectively; therefore, recurrent selection would be the best breeding approach to improve both the traits simultaneously in coloured radish.

Seedling root system adaptation to water availability during maize domestication and global expansion.

The maize root system has been reshaped by indirect selection during global adaptation to new agricultural environments. In this study, we characterized the root systems of more than 9,000 global maize accessions and its wild relatives, defining the geographical signature and genomic basis of variation in seminal root number. We demonstrate that seminal root number has increased during maize domestication followed by a decrease in response to limited water availability in locally adapted varieties. By combining environmental and phenotypic association analyses with linkage mapping, we identified genes linking environmental variation and seminal root number. Functional characterization of the transcription factor ZmHb77 and in silico root modeling provides evidence that reshaping root system architecture by reducing the number of seminal roots and promoting lateral root density is beneficial for the resilience of maize seedlings to drought.

Comparison of genomic prediction methods for early growth traits of Inner Mongolia cashmere goats based on multi trait models.

Inner Mongolia cashmere goat is an excellent livestock breed formed through long-term natural selection and artificial breeding, and is currently a world-class dual-purpose breed producing cashmere and meat. Multi trait animal model is considered to significantly improve the accuracy of genetic evaluation in livestock and poultry, enabling indirect selection between traits. In this study, the pedigree, genotype, environment, and phenotypic records of early growth traits of Inner Mongolia cashmere goats were used to build multi trait animal model., Then three methods including ABLUP, GBLUP, and ssGBLUP wereused to estimate the genetic parameters and genomic breeding values of early growth traits (birth weight, weaning weight, average daily weight gain before weaning, and yearling weight). The accuracy and reliability of genomic estimated breeding value are further evaluated using the five fold cross validation method. The results showed that the heritability of birth weight estimated by three methods was 0.13-0.15, the heritability of weaning weight was 0.13-0.20, heritability of daily weight gain before weaning was 0.11-0.14, and the heritability of yearling weight was 0.09-0.14, all of which belonged to moderate to low heritability. There is a strong positive genetic correlation between weaning weight and daily weight gain before weaning, daily weight gain before weaning and yearling weight, with correlation coefficients of 0.77-0.79 and 0.56-0.67, respectively. The same pattern was found in phenotype correlation among traits. The accuracy of the estimated breeding values by ABLUP, GBLUP, and ssGBLUP methods for birth weight is 0.5047, 0.6694, and 0.7156, respectively; the weaning weight is 0.6207, 0.6456, and 0.7254, respectively; the daily weight gain before weaning was 0.6110, 0.6855, and 0.7357 respectively; and the yearling weight was 0.6209, 0.7155, and 0.7756, respectively. In summary, the early growth traits of Inner Mongolia cashmere goats belong to moderate to low heritability, and the speed of genetic improvement is relatively slow. The genetic improvement of other growth traits can be achieved through the selection of weaning weight. The ssGBLUP method has the highest accuracy and reliability in estimating genomic breeding value of early growth traits in Inner Mongolia cashmere goats, and is significantly higher than that from ABLUP method, indicating that it is the best method for genomic breeding of early growth weight in Inner Mongolia cashmere goats.

Evolutionary pathways to lower biomass allocation to the seed coat in crops: insights from allometric scaling.

Crops generally have seeds larger than their wild progenitors´ and with reduced dormancy. In wild plants, seed mass and allocation to the seed coat (a proxy for physical dormancy) scale allometrically so that larger seeds tend to allocate less to the coats. Larger seeds and lightweight coats might thus have evolved as correlated traits in crops. We tested whether 34 crops and 22 of their wild progenitors fit the allometry described in the literature, which would indicate co-selection of both traits during crop evolution. Deviations from the allometry would suggest that other evolutionary processes contribute to explain the emergence of larger, lightweight-coated seeds in crops. Crops fitted the scaling slope but deviated from its intercept in a consistent way: Seed coats of crops were lighter than expected by their seed size. The wild progenitors of crops displayed the same trend, indicating that deviations cannot be solely attributed to artificial selection during or after domestication. The evolution of seeds with small coats in crops likely resulted from a combination of various pressures, including the selection of wild progenitors with coats smaller than other wild plants, further decreases during early evolution under cultivation, and indirect selection due to the seed coat-seed size allometry.

Molecular Diversity and Combining Ability in Newly Developed Maize Inbred Lines under Low-Nitrogen Conditions.

Nitrogen is an essential element for maize growth, but excessive application can lead to various environmental and ecological issues, including water pollution, air pollution, greenhouse gas emissions, and biodiversity loss. Hence, developing maize hybrids resilient to low-N conditions is vital for sustainable agriculture, particularly in nitrogen-deficient soils. Combining ability and genetic relationships among parental lines is crucial for breeding superior hybrids under diverse nitrogen levels. This study aimed to assess the genetic diversity of maize inbred lines using simple sequence repeat (SSR) markers and evaluate their combining ability to identify superior hybrids under low-N and recommended conditions. Local and exotic inbred lines were genotyped using SSR markers, revealing substantial genetic variation with high gene diversity (He = 0.60), moderate polymorphism information content (PIC = 0.54), and an average of 3.64 alleles per locus. Twenty-one F1 hybrids were generated through a diallel mating design using these diverse lines. These hybrids and a high yielding commercial check (SC-131) were field-tested under low-N and recommended N conditions. Significant variations (p < 0.01) were observed among nitrogen levels, hybrids, and their interaction for all recorded traits. Additive genetic variances predominated over non-additive genetic variances for grain yield and most traits. Inbred IL3 emerged as an effective combiner for developing early maturing genotypes with lower ear placement. Additionally, inbreds IL1, IL2, and IL3 showed promise as superior combiners for enhancing grain yield and related traits under both low-N and recommended conditions. Notably, hybrids IL1×IL4, IL2×IL5, IL2×IL6, and IL5×IL7 exhibited specific combining abilities for increasing grain yield and associated traits under low-N stress conditions. Furthermore, strong positive associations were identified between grain yield and specific traits like plant height, ear length, number of rows per ear, and number of kernels per row. Due to their straightforward measurability, these relationships underscore the potential of using these traits as proxies for indirect selection in early breeding generations, particularly under low-N stress. This research contributes to breeding nitrogen-efficient maize hybrids and advances our understanding of the genetic foundations for tolerance to nitrogen limitations.

Determination of udder and teat linear morphological traits in Awassi and Bafra (Chios × Karayaka) Ewes

This study was carried in order to evaluate the linear morphological characteristics of the udder and teats in the breeder conditions of Awassi and Bafra (Chios × Karayaka) ewes (Ovis aries) and to determine the udder types, lactation milk yield and the lactation period of the ewes. One hundred two Awassi and 61 Bafra ewes were included in the study. The means of the linear scores of udder depth, udder furrow, udder attachment, teat shape, teat angle and teat placement in Awassi ewes were determined as 6.10 ± 0.27, 6.33 ± 0.27, 4.49 ± 0.27, 6.49 ± 0.33, 3.98 ± 0.29, and 1.47 ± 0.14, respectively. The same parameters were determined as 6.31 ± 0.28, 6.77 ± 0.32, 5.72 ± 0.24, 1.20 ± 0.11, 1.72 ± 0.26, and 1.20 ± 0.11, respectively, in Bafra ewes. Significant differences were found between Awassi and Bafra breeds in terms of udder types (P&lt;0.01). The type 3 udder, suitable for milking, was determined at the highest rate in both breeds, but type 2 udder was not detected in Awassi ewes. Statistically significant differences were found between Awassi and Bafra ewes in terms of linear morphological characteristics of udder and teat, udder attachment, teat shape, teat angle and 60th day milk yield, daily average milk yield and lactation period (P&lt;0.01). Lactation milk yield and lactation period were calculated as 139.85 ± 5.31 kg and 208.53 ± 4.471 days, respectively, in Awassi ewes and 145.91 ± 9.97 kg and 175.23 ± 4.635 days in Bafra ewes, respectively. As a result, in order for linear udder characteristics to be used safely as an indirect selection criterion, there is a need for studies with a higher number of ewes and to calculate the repeatability and heritability.

Root system architecture variation among barley (Hordeum vulgare L.) accessions at seedling stage under soil acidity condition.

Soil acidity in Ethiopian highlands impacts barley production, affecting root system architecture. Study on 300 accessions showed significant trait variability, with potential for breeding enhancement. Soil acidity poses a significant challenge to crop production in the highland regions of Ethiopia, particularly impacting barley, a crucial staple crop. This acidity serves as a key stressor affecting the root system architecture (RSA) of this crop. Hence, the objective of this study was to assess the RSA traits variability under acidic soil conditions using 300 barley accessions in a greenhouse experiment. The analysis of variance indicated substantial variations among the accessions across all traits studied. The phenotypic coefficient of variation ranged from 24.4% for shoot dry weight to 11.1% for root length, while the genotypic coefficient variation varied between 18.83 and 9.2% for shoot dry weight and root length, respectively. The broad-sense heritability ranged from 36.7% for leaf area to 69.9% for root length, highlighting considerable heritability among multiple traits. The genetic advances as a percent of the mean ranged from 13.63 to 29.9%, suggesting potential for enhancement of these traits through breeding efforts. Principal component analysis and cluster analysis grouped the genotypes into two major clusters, each containing varying numbers of genotypes with contrasting traits. This diversegrouppresents an opportunity to access a wide range ofpotential parentcandidates to enhance geneticvariablity in breeding programs. The Pearson correlation analysis revealed significant negative associations between root angle (RA) and other RSA traits. This helps indirect selection of accessions for further improvement in soil acidity. In conclusion, this study offers valuable insights into the RSA characteristics of barley in acidic soil conditions, aiding in the development of breeding strategies to enhance crop productivity in acidic soil environments.

Social interactions generate complex selection patterns in virtual worlds.

Understanding the influence of social interactions on individual fitness is key to improving our predictions of phenotypic evolution. However, we often overlook the different components of selection regimes arising from interactions among organisms, including social, correlational, and indirect selection. This is due to the challenging sampling efforts required in natural populations to measure phenotypes expressed during interactions and individual fitness. Furthermore, behaviours are crucial in mediating social interactions, yet few studies have explicitly quantified these selection components on behavioural traits. In this study, we capitalize on an online multiplayer video game as a source of extensive data recording direct social interactions among prey, where prey collaborate to escape a predator in realistic ecological settings. We estimate natural and social selection and their contribution to total selection on behavioural traits mediating competition, cooperation, and predator-prey interactions. Behaviours of other prey in a group impact an individual's survival, and thus are under social selection. Depending on whether selection pressures on behaviours are synergistic or conflicting, social interactions enhance or mitigate the strength of natural selection, although natural selection remains the main driving force. Indirect selection through correlations among traits also contributed to the total selection. Thus, failing to account for the effects of social interactions and indirect selection would lead to a misestimation of the total selection acting on traits. Dissecting the contribution of each component to the total selection differential allowed us to investigate the causal mechanisms relating behaviour to fitness and quantify the importance of the behaviours of conspecifics as agents of selection. Our study emphasizes that social interactions generate complex selective regimes even in a relatively simple ecological environment.