Mating System Research Articles

Management of bacterial neonatal diarrhea in calves

Diseases such as neonatal diarrhea are common in poorly managed herds and can cause major losses in any cattle breeding system in the world, especially in intensive systems, accounting for 2% of herd losses. As soon as the calf is born, it is exposed to numerous factors, such as agents, the host and the environment, which together can favor the onset of this disease because, due to the reproductive characteristics of the female bovine, there is no transfer of transplacental immunity to the newborn.

Impacts of astaxanthin-enriched Paracoccus carotinifaciens on growth, immune responses, and reproduction performance of broodstock Nile tilapia during winter season.

The growth, immune response, and reproductive performance of broodstock of Nile tilapia (Oreochromis niloticus) under winter stress conditions were investigated the effects of supplementary diets with astaxanthin-enriched Paracoccus carotinifaciens. Throughout an eight-week period in the winter season, male and female tilapia were fed with diets containing different levels of P. carotinifaciens dietary supplementation: 0 g/kg (T1; control), 5 g/kg (T2), 10 g/kg (T3), and 20 g/kg (T4). Subsequently, a four-week mating system was implemented during the winter stress period. The results revealed that there were no significant differences observed in growth, hematological indices, and blood chemical profiles among all treatment groups for both male and female tilapia. However, a significant increase in cholesterol content was noted in both male and female tilapia fed with the T4 diet (p<0.05). The total carotenoid content in the muscle was evaluated, and significantly higher values were found in both male and female tilapia that fed T4 supplementation (p<0.05). Moreover, immunological parameters such as myeloperoxidase and antioxidant parameters in the liver including superoxide dismutase activity and catalase enzyme activity showed significant increases in tilapia fed with the T4 diet. The impact of P. carotinifaciens supplementation on broodstock tilapia indicated a significant increase in spermatozoa concentration in males and increased egg production in females after consumption of the T4 diet (p<0.05). Thus, this study highlighted that the presence of astaxanthin-enriched P. carotinifaciens in the diet of broodstock Nile tilapia can lead to the accumulation of carotenoids in their muscle tissue, improvement in antioxidant status, enhancement of immune function, and potential enhancement of reproductive capabilities, even under overwintering conditions.

Comparative Study of Carcass Characteristics and Meat Quality of Local Mediterranean Donkey Breeds.

This study aimed to evaluate carcass and meat quality traits in Masri (n = 14) and North African (n = 14) male donkeys, raised in a semi-intensive breeding system, grazing on mountainous areas, with supplementation of 1 kg of barley per day per animal, slaughtered at 5 (±0.48) years old. Compared to Masri, the North African population exhibited higher (p < 0.05) final body weights (181.7 ± 2.1 and 212.5 ± 7.6 kg) and cold carcass weights (101.7 ± 1.3 and 116.2 ± 4.5 kg), but lower (p < 0.05) cold dressing percentages (56.0 ± 0.4 and 54.6 ± 0.4%). Meat quality analyses showed higher (p < 0.05) cooking loss values in Masri meat (43.9 ± 0.8 vs. 39.9 ± 1.2%). Among the meat color parameters, the hue value was higher (p < 0.05) in North African samples (0.42 ± 0.01 vs. 0.39 ± 0.1). Meat from North African donkeys had higher (p < 0.05) dry matter, fat, and protein contents. Meat amino acid analysis revealed abundant levels of lysine, leucine, and methionine, in both populations. Donkey meat from both populations presented a high polyunsaturated fatty acids content, resulting in polyunsaturated fatty acids/saturated fatty acids and omega 6/omega 3 ratios for all breeds close to the recommended values for human health. Atherogenic and thrombogenic indices were also suggested to have positive effects on consumers' artery health. The characteristics of donkey meat present intriguing nutritional aspects compared to ruminant meat, and its production should be encouraged in the rural development of inner-Mediterranean areas.

It's about Her: Male Within-Season Movements Are Related to Mate Searching in a Songbird.

AbstractIn species with resource-defense mating systems (such as most temperate-breeding songbirds), male dispersal is often considered to be limited in both frequency and spatial extent. When dispersal occurs within a breeding season, the favored explanation is ecological resource tracking. In contrast, movements of male birds associated with temporary emigration, such as polyterritoriality (i.e., defense of an additional location after attracting a female in the initial territory), are usually attributed to mate searching. We suggest that male dispersal and polyterritoriality are functionally related and that mate searching may be a unifying hypothesis for predicting the within-season movements of male songbirds. Here, we test three key predictions derived from this hypothesis in Wood Warblers (Phylloscopus sibilatrix). We collected data on the spatial behavior of 107 males between 2017 and 2019 and related male movements to a new territory (in both a dispersal and a polyterritorial context) to mating potential in the current territory. Most males dispersed from their territories within days or weeks after failing to attract a female, despite occupying territories in apparently suitable habitat. Probability of polyterritoriality by paired males increased after the peak fertile period of their mate. Males never dispersed following nest predation if the female remained to renest. Thus, our data are consistent with the hypothesis that both movement types are functionally related to mate searching.

How Does Selfing Affect the Pace and Process of Speciation?

Surprisingly little attention has been given to the impact of selfing on speciation, even though selfing reduces gene flow between populations and affects other key population genetics parameters. Here we review recent theoretical work and compile empirical data from crossing experiments and genomic and phylogenetic studies to assess the effect of mating systems on the speciation process. In accordance with theoretical predictions, we find that accumulation of hybrid incompatibilities seems to be accelerated in selfers, but there is so far limited empirical support for a predicted bias toward underdominant loci. Phylogenetic evidence is scarce and contradictory, including studies suggesting that selfing either promotes or hampers speciation rate. Further studies are therefore required, which in addition to measures of reproductive barrier strength and selfing rate should routinely include estimates of demographic history and genetic divergence as a proxy for divergence time.

Cip1, a CDK regulator, determines heterothallic mating or homothallic selfing in a protist

Mating type (sex) plays a crucial role in regulating sexual reproduction in most extant eukaryotes. One of the functions of mating types is ensuring self-incompatibility to some extent, thereby promoting genetic diversity. However, heterothallic mating is not always the best mating strategy. For example, in low-density populations or specific environments, such as parasitic ones, species may need to increase the ratio of potential mating partners. Consequently, many species allow homothallic selfing (i.e., self-fertility or intraclonal mating). Throughout the extensive evolutionary history of species, changes in environmental conditions have influenced mating strategies back and forth. However, the mechanisms through which mating-type recognition regulates sexual reproduction and the dynamics of mating strategy throughout evolution remain poorly understood. In this study, we show that the Cip1 protein is responsible for coupling sexual reproduction initiation to mating-type recognition in the protozoal eukaryote Tetrahymena thermophila. Deletion of the Cip1 protein leads to the loss of the selfing-avoidance function of mating-type recognition, resulting in selfing without mating-type recognition. Further experiments revealed that Cip1 is a regulatory subunit of the Cdk19-Cyc9 complex, which controls the initiation of sexual reproduction. These results reveal a mechanism that regulates the choice between mating and selfing. This mechanism also contributes to the debate about the ancestral state of sexual reproduction.

Reproductive biology in Gomphichis valida Rchb. f. (Orchidaceae: Orchidoideae, Cranichidinae): Generalist pollination in a high‐Andean terrestrial orchid with long‐lived flowers

AbstractFloral features, the pollination process, the breeding system, and fruiting success are documented in the Andean terrestrial orchid Gomphichis valida. Studies were performed at the Department of Ancash, Peru, at ca. 4250 m a.s.l., from June to November 2022. The breeding system was studied through controlled pollinations in plants excluded from pollinators (bagged). Natural pollination was studied in the field and through photos and videos. The flowers are nectariferous and non‐protandrous and present the longest lifespan reported so far for a neotropical terrestrial orchid (53–80 days). This species is pollinator dependent (unable to set fruit and seed without the agency of pollinators) and self‐compatible. The observed pollinators belong to three functional groups that appeared successively (in order of appearance): hummingbirds (Chalcostigma stanleyi), bumblebees (Bombus coccineus and Bombus rubicundus), and solitary Halictidae bees (Augochlorella sp.). All recorded pollinators probe the flowers for nectar. The pollinaria adhere to the bee mouthparts and onto the lateral side of the hummingbird bill. Bumblebees were the most frequent and efficient functional group (up to 62.07% of the observed pollination events), followed by Halictidae (31.03%) and hummingbirds (6.90%). Natural fruiting success is high (66.66%–94.49%). Such high natural fruiting success is unexpected at high altitudes, but it is likely explained by a combination of factors, including the long floral lifespan, nectar secretion, and self‐compatibility. This is the first report of hummingbirds as pollinators of Cranichidinae orchids, and G. valida is, to the best of our knowledge, a neotropical orchidoid orchid with the most generalist pollination biology recorded so far.

Distribution of the invasive ambrosia beetle Anisandrus maiche (Coleoptera, Scolytinae) in Switzerland and first record in Europe of its ambrosia fungus Ambrosiella cleistominuta

Ambrosia beetles are highly successful as invaders because they are often transported internationally with wood packaging and other wood products and because their inbreeding mating systems facilitates establishment of invading populations. In 2022, two independent insect surveys in canton Ticino (southern Switzerland) revealed the widespread occurrence of the invasive ambrosia beetle Anisandrus maiche (Kurentzov, 1941) from southern to central-upper Ticino. This species is native to east Asia and has previously been found as a non-native invasive species in the United States, Canada, western Russia, Ukraine and, in 2021, in northern Italy. Here, we present the results of several trapping studies using different trap types (bottle traps, funnel traps and Polytrap intercept traps) and attractants and a map of the distribution of the species. In total, 715 specimens of A. maiche, all female, were trapped, and the identity of selected individuals was confirmed by morphological and molecular identification based on three mitochondrial and nuclear markers (COI, 28S and CAD). Trap samples from early April to early September 2022 in intervals of two to four weeks showed that flights of A. maiche occurred mainly from June to mid-August. Isolation of fungal associates of A. maiche from beetles trapped alive revealed the presence of four fungal species, including the ambrosia fungus Ambrosiella cleistominuta, the known mutualist of A. maiche. The identity of A. cleistominuta was confirmed by comparing DNA sequences of its nuclear, internal transcribed spacer (ITS) gene with reference sequences in NCBI and BOLDSYSTEMS. This represents the first record of A. cleistominuta in Europe. Of the other fungal associates isolated from A. maiche in Ticino, Fusarium lateritium is of note as there is a possibility that A. maiche could act as a vector of this plant pathogen. We highlight several research needs that should be addressed to gain insight into the potential impact of these non-native species and to overcome problems with heteroplasmy in COI sequences in studies of invasion and population genetics of ambrosia beetles.

Dominance between self-incompatibility alleles determines the mating system of Capsella allopolyploids

Abstract The shift from outcrossing to self-fertilization is one of the main evolutionary transitions in plants and has broad effects on evolutionary trajectories. In Brassicaceae, the ability to inhibit self-fertilization is controlled by 2 genes, SCR and SRK, tightly linked within the S-locus. A series of small non-coding RNAs also encoded within the S-locus regulates the transcriptional activity of SCR alleles, resulting in a linear dominance hierarchy between them. In Brassicaceae, natural allopolyploid species are often self-compatible (SC) even when one of the progenitor species is self-incompatible, but the reason why polyploid lineages tend to lose self-incompatibility (SI) and the timing of the loss of SI (immediately after ancestral hybridization between the progenitor species, or at a later stage after the formation of allopolyploid lineages) have generally remained elusive. We used a series of synthetic diploid and tetraploid hybrids obtained between self-fertilizing Capsella orientalis and outcrossing Capsella grandiflora to test whether the breakdown of SI could be observed immediately after hybridization, and whether the occurrence of SC phenotypes could be explained by the dominance interactions between S-haplotypes inherited from the parental lineages. We used RNA-sequencing data from young inflorescences to measure allele-specific expression of the SCR gene and infer dominance interactions in the synthetic hybrids. We then evaluated the seed set from autonomous self-pollination in the synthetic hybrids. Our results demonstrate that self-compatibility of the hybrids depends on the relative dominance between S-alleles inherited from the parental species, confirming that SI can be lost instantaneously upon formation of the ancestral allopolyploid lineage. They also confirm that the epigenetic regulation that controls dominance interactions between S-alleles can function between subgenomes in allopolyploids. Together, our results illustrate how a detailed knowledge of the mechanisms controlling SI can illuminate our understanding of the patterns of co-variation between the mating system and changes in ploidy.

BIOLOGÍA REPRODUCTIVA DEL CHINCHERO ENANO O CHINCHERO EXCAVADOR XIPHORHYNCHUS FUSCUS

Despite recent advances, the knowledge scarcity on Furnariidae forest species reproduction continues to bias ideas and limit the understanding of avian life history. We studied the reproductive biology of the Lesser Woodcreeper (Xiphorhynchus fuscus; Dendrocolaptinae), which nests in tree cavities, to contribute observations toward ideas about evolution and ecology. In the Atlantic Forest of Argentina (2007–2022), we inspected 26 nests (total: 333 visits), color-banded nine adults, conducted 180 h of focal observations at 11 nests, and analyzed patterns of nest survival and parental care using linear models in R. Lesser Woodcreepers laid two or three white eggs (mean±SE = 2.8±0.1; N = 16) on a bed of bark flakes. One adult (possibly female) carried out construction, incubation, feeding, and nest hygiene, but we frequently observed a second adult (possibly male) singing from 'preferred' perches, sometimes approaching the nest tree in response to alarm calls from the nest. Attending adults brought bark to their nests throughout incubation (19 days) and occasionally during nestling (21 days; range: 20–23). In the absence of adults, eggs and young nestlings were left covered with bark. Nest attention (daytime percentage an adult was inside the cavity) was 63±3% during incubation, fell to 38±9% in the first 4 days after hatching, and approximately 0% after nestlings were 10 days old and had open pin feathers. Nestlings were fed almost exclusively arthropods, and the feeding rate increased as brooding declined. Nest survival was 0.984 (95% CI: 0.970–0.992) daily or 0.50 (0.26–0.70) for the nesting period. For four of six broods, when nestlings fledged, a second adult (possibly a male) participated minimally. Our observations cover the mating system and division of parental care in Furnariidae, the advantages of covering eggs and nestlings, and the possibility that males increase parental care during the vulnerable fledgling stage.

In obsessive-compulsive disorder, autogenous and reactive obsessions are differentiated by disgust and mating strategies

Obsessive-compulsive disorder (OCD) has been conceptualized as the product of dysfunctional harm prevention systems accompanied by heightened negative emotions like disgust. However, models have not fully accounted for functional heterogeneity in OCD, such as the distinction between OCD subtypes (autogenous vs. reactive) and their differing profiles of relationships with other psychological constructs. The current investigation tested hypotheses about different expected associations between OCD subtypes, disgust, and mating strategies. In Study 1 (patients with self-reported diagnoses of OCD; n = 70), reactive obsessions were associated with higher pathogen disgust but had no associations with mating strategy. Autogenous obsessions had no associations with disgust domains but were associated with higher short-term (and lower long-term) mating orientation. In Study 2 (undergraduate sample; n = 458), reactive obsessions, again, were associated with heightened pathogen disgust but again had no association to mating strategy. Autogenous obsessions were associated with lower pathogen, moral, and sexual disgust, and again, higher short-term (and lower long-term) mating orientation. In both studies, we tested sexual disgust as a mediator of the relationship between autogenous obsessions and short-term mating. Significant mediation was found in Study 2, but not Study 1. Results demonstrate that reactive and autogenous forms of OCD are differentiated by disgust and mating strategy and have implications for evolutionary models of OCD.

First detailed report of cooperative breeding in red-billed blue magpie (Urocissa erythrorhyncha) in central China

Abstract The cooperative breeding system of birds is an ideal model for studying and exploring social evolution in animals. However, a basic question, i.e., how many cooperative-breeding bird species exist in the world, remains controversial due to the lack of accumulated knowledge of the natural history of many birds, which prevents a generalized understanding of the evolution of cooperative breeding in birds and challenges the accuracy of results in many comparative studies. In this paper, we provide the first evidence of cooperative breeding in red-billed blue magpies (Urocissa erythrorhyncha). Moreover, we document and discuss potential relationships between cooperative breeding and nest predation, brood parasitism and breeding performance in U. erythrorhyncha. These findings about cooperative breeding in red-billed blue magpie will lay a foundation for further research on this species’ sociality and provide useful insights into the evolution of cooperative breeding and other social systems in birds.

New estimates indicate that males are not larger than females in most mammal species

Sexual size dimorphism has motivated a large body of research on mammalian mating strategies and sexual selection. Despite some contrary evidence, the narrative that larger males are the norm in mammals—upheld since Darwin’s Descent of Man—still dominates today, supported by meta-analyses that use coarse measures of dimorphism and taxonomically-biased sampling. With newly-available datasets and primary sources reporting sex-segregated means and variances in adult body mass, we estimate statistically-determined rates of sexual size dimorphism in mammals, sampling taxa by their species richness at the family level. Our analyses of wild, non-provisioned populations representing >400 species indicate that although males tend to be larger than females when dimorphism occurs, males are not larger in most mammal species, suggesting a need to revisit other assumptions in sexual selection research.

Outcrossing mating system in natural populations of the endangered aquatic fern Ceratopteris thalictroides in China as revealed by microsatellite markers: implications for conservation

In this study, the mating system of the endangered aquatic fern Ceratopteris thalictroides in China was investigated using microsatellite markers. The estimates of the multilocus outcrossing rate (tm) and single-locus outcrossing rate (ts) were high at the species level (tm = 0.701 and ts = 0.595, respectively), indicating that C. thalictroides is a predominantly outcrossing species. Negative F (inbreeding coefficient of the maternal parents) values (-0.137) at the species level indicated an excess of heterozygotes and low inbreeding in the populations analyzed. Our investigation revealed that some of the natural and ex situ conservation populations of C. thalictroides have a prolific capacity for vegetative growth. The results showed that the homosporous pteridophyte C. thalictroides in China predominantly favors gametophytic crossing with a certain level of inbreeding along with vegetative growth. Ten populations have been established for ex situ conservation in Wuhan, China, with a survival rate of more than 90%, and mature spores were collected from them. Several factors, including high dispersal of spores and gametophytes by flowing water, high gene flow, and the wide distribution of the species in China, with the occurrence of some large populations, may have resulted in a high outcrossing rate in Chinese C. thalictroides. The high outcrossing rate of C. thalictroides showed that ex situ plantings are most suitable for enhancing possible mixing of the different populations, thus minimizing inbreeding.

The extent of introgression between incipient Clarkia species is determined by temporal environmental variation and mating system

Introgression is pervasive across the tree of life but varies across taxa, geography, and genomic regions. However, the factors modulating this variation and how they may be affected by global change are not well understood. Here, we used 200 genomes and a 15-y site-specific environmental dataset to investigate the effects of environmental variation and mating system divergence on the magnitude of introgression between a recently diverged outcrosser-selfer pair of annual plants in the genus Clarkia. These sister taxa diverged very recently and subsequently came into secondary sympatry where they form replicated contact zones. Consistent with observations of other outcrosser-selfer pairs, we found that introgression was asymmetric between taxa, with substantially more introgression from the selfer to the outcrosser. This asymmetry was caused by a bias in the direction of initial F1 hybrid formation and subsequent backcrossing. We also found extensive variation in the outcrosser's admixture proportion among contact zones, which was predicted nearly entirely by interannual variance in spring precipitation. Greater fluctuations in spring precipitation resulted in higher admixture proportions, likely mediated by the effects of spring precipitation on the expression of traits that determine premating reproductive isolation. Climate-driven hybridization dynamics may be particularly affected by global change, potentially reshaping species boundaries and adaptation to novel environments.

Revisiting niche divergence hypothesis in sexually dimorphic birds: Is diet overlap correlated with sexual size dimorphism?

The evolution of sexual size dimorphism (SSD) is a long-standing topic in evolutionary biology, but there is little agreement on the extent to which SSD is driven by the different selective forces. While sexual selection and fecundity selection have traditionally been proposed as the two leading hypotheses, SSD may also result from natural selection through mechanisms such as sexual niche divergence, which might have reduced resource competition between sexes. Here, we revisited the niche divergence hypothesis by testing the relationship between the sexual overlap in diet and SSD of 56 bird species using phylogenetic comparative analyses. We then assessed how SSD variation relates to the three main hypotheses: sexual selection, fecundity selection, and sexual niche divergence using phylogenetic generalized least squares (PGLS). Then, we compared sexual selection, fecundity selection and niche divergence selection as SSD drivers through phylogenetic confirmatory path analyses to disentangle the possible causal evolutionary relationships between SSD and the three hypotheses. Phylogenetic generalized least squares showed that SSD was negatively correlated with diet overlap, that is, the greater the difference in body size between males and females, the less diet overlap. As predicted by sexual selection theory, the difference in body size between sexes was higher in polygynous species. Confirmatory phylogenetic path analyses suggested that the most likely evolutionary path might include the mating system as a main driver in SSD and niche divergence as a result of SSD. We found no evidence of a role of fecundity selection in the evolution of female-biased SSD. Our study provides evidence that sexual selection has likely been the main cause of SSD and that dietary divergence is likely an indirect effect of SSD.

Genetic group and heterosis in the behavioural evolution of steers during finishing in confinement

Crossbreeding is one way of achieving complementarity between breeds in relation to economically important characteristics; in addition, it allows the effect of heterosis to be exploited. The aim of this study was to measure the behavioural evolution of different genetic groups and mating systems in continuous alternating crosses of Charolais and Nellore cattle. Seventy-nine purebred Charolais (C) and Nellore (N) steers were evaluated during finishing in confinement, together with their second (3/4C 1/4 N and 3/4 N 1/4C), third (5/8C 3/8 N and 5/8 N 3/8C) and fourth generation (11/16C 5/16 N and 11/16 N 5/16C) crosses. The confinement period was 97 days, including 13 days for adaptation to the environment and feeding regime. Behavioural assessments were carried out when weighing, evaluating the composite scale score, time taken to exit the scales, measurement of flight distance, location of the facial hair whorl, and plasma cortisol level at slaughter. The Charolais animals showed a better composite scale score, longer exit time and shorter flight distance than the Nellore animals. For generation 3 (5/8 animals), the inclusion of Charolais genes afforded a higher composite scale score in each of the assessments, longer flight time in the assessments at 14 and 77 days, shorter flight distance in each of the assessments, with the facial hair whorl positioned further below the eye line, determining animals of a calmer behaviour. Purebred Nellore and predominantly Nellore animals from the third generation of crosses were higher in cortisol at slaughter than the purebred Charolais or predominantly Charolais animals, showing significant heterosis only in the second generation. Bos taurus animals are calmer and have a more suitable temperament than Bos indicus, however, the behaviour of zebu cattle can improve as the period of confinement increases, with the type of handling affecting behaviour and reactivity throughout the assessments.

A field study on Citrus aurantium L. var. dulcis peel essential oil and Yucca schidigera saponins efficacy on broiler chickens health and growth performance during coccidiosis infection in rural free-range breeding system

Avian coccidiosis caused by Eimeria spp. is a relevant disease for poultry usually prevented by synthetic coccidiostats. Citrus aurantium L. var. dulcis peel essential oil (CEO), and Yucca schidigera’s saponins (Ys) were tested as valid natural alternatives to coccidiostats drugs. Their anticoccidial effects, gut health and growth performance of broiler chickens were investigated with discovery-driven research by a field trial during the broiler chicken production cycle in a rural free-range farm with a history of coccidiosis infection. One hundred forty 1-d-old female broiler chickens were assigned to 4 experimental treatment groups (35 broiler chicks each), fed ad libitum with a coccidiostats-free diet, during 9 wk of the trial (63 d). The treatment groups included: control (C); CEO (1 ml/L); Ys pure extract (0.05 ml/L); and CEO + Ys (CEO 1 ml/L + Ys 0.05 ml/L), administered by drinking water. Fecal coccidia oocyst count (OPG), and growth performance were evaluated weekly. On wk 9 all broiler chickens were slaughtered, and serum biochemical indices and intestinal lesions were histologically evaluated and scored. Results showed that from the 6th to 9th wk, the treated groups had lower OPG than the C group (P < 0.05), with the lower value observed in the CEO and Ys groups. More severe coccidiosis intestinal lesions attributable to E. maxima were detected in the C group. All chickens showed a variable degree of intestinal lymphoplasmacytic and heterophilic inflammation without differences in the histological and intestinal lesion scores. At the end of the trial, the body weight (BW) was greater in the treated groups compared to the C group (P < 0.05). However, no differences in FI, WDI, FCR, mortality, and organ weights were evidenced. Albeit within the physiological range, serum AST, cholesterol, total proteins, albumin, and P were higher in the Ys group (P < 0.05), compared to the C group, which was also observed in the CEO + Ys group for the cholesterol, total protein and albumin content. The CEO and Ys biologically active metabolites, even if taken in moderate concentrations, can help to reduce the OPG and gut damage during the coccidia infection, improving the broiler chicken's growth performance.

Development of S Haplotype-Specific Markers to Identify Genotypes of Self-Incompatibility in Radish (Raphanus sativus L.).

Radish (Raphanus sativus L.), a root vegetable belonging to the Brassicaceae family, is considered one of the representative crops displaying sporophytic self-incompatibility (SSI). The utilization of a self-incompatibility system in F1 breeding can improve the efficiency of cross-combinations, leading to a reduction in breeding time and aiding in the development of novel F1 varieties. The successful implementation of this system necessitates the rapid and accurate identification of S haplotypes in parental lines. In this study, we identified a total of nine S haplotypes among 22 elite radish lines through Sanger sequencing. Subsequently, we obtained sequences for showing a 95% similarity to nine S haplotypes, along with sequences identified by other researchers using BLAST. Following this, multiple sequence alignment (MSA) was conducted to identify SRK and SLG sequence similarities, as well as polymorphisms within the class I and II groups. Subsequently, S haplotype-specific marker sets were developed, targeting polymorphic regions of SRK and SLG alleles. These markers successfully amplified each of the nine S haplotypes. These markers will play a crucial role in the rapid and precise identification of parental S haplotypes in the radish F1 breeding process, proving instrumental in the radish F1 purity test.

Optimal open nucleus breeding system for long-term genetic gain in the Pacific white shrimp using genomic selection

The open nucleus breeding system (ONBS) has been widely employed in livestock breeding and has demonstrated a desirable genetic gain compared to the traditional closed nucleus breeding system (CNBS). However, no related study and application for ONBS exist on aquatic animal breeding. The present investigation simulates the family-based ONBS with different proportions of introduced multiplier individuals used as parents of the nucleus population (NP) and CNBS schemes for the harvest body weight of the Pacific white shrimp (Litopenaeus vannamei). The multiplier population (MP) comprised progenies from eight families with high estimated breeding value (EBV) or genomic EBV (GEBV) of NP of the previous generation. ONBS was assigned three proportions (10%, 30%, and 50%) of the introduced MP individuals. The short-term selection (G0 to G10) and long-term selection (G0 to G20) were performed for CNBS and ONBS schemes using pedigree-based best linear unbiased prediction (PBLUP) with the A relationship matrix from the pedigree or single-step genomic BLUP (ssGBLUP) with the H relationship matrix integrating SNP markers and pedigree. The genetic gain of body weight and inbreeding coefficient of NP for eight breeding schemes with CNBS_PBLUP (CP), CNBS_ssGLUP (CS), ONBS_PBLUP (OP10, OP30, OP50), and ONBS_ssGBLUP (OS10, OS30, OS50) with three proportions of the introduced MP individuals were calculated. Compared to CP, genetic gains for the three OP schemes increased by 7.68 to 11.27% after short-term selection, and by 2.51 to 5.79% after long-term selection. In comparison to CS, genetic gains for the three OS schemes increased by 8.21 to 8.96% after short-term selection, and from 4.46 to 5.87% after long-term selection. The ONBS schemes achieved higher genetic gains than the corresponding CNBS schemes whether using genomic or pedigree information. The advantage of ONBS over CNBS is reduced after long-term selection. Genetic gains for the three OS schemes increased by 9.77 to 14.06% after long-term selection compared with the corresponding OP schemes. Furthermore, no significant difference (P > 0.05) in genetic gain was revealed among the ONBS schemes after either pedigree-based or genomic selection. Inbreeding coefficients for the three OP schemes increased from 59.45 to 70.98% compared with CP, whereas inbreeding coefficients for the three OS schemes increased from 24.72 to 32.22% compared with CS. Besides, after long-term selection, inbreeding coefficients for the three OS schemes decreased from 13.13 to 14.79% compared with the corresponding OP schemes. In a nutshell, ONBS using introduced MP individuals has great promise in the selective breeding program of L. vannamei. Genomic information has more potential to improve selection response and control inbreeding level than pedigree information when applying ONBS.