Efficient Breeding Research Articles

Delineation of Selection Criterion Using Correlation and Path Analysis in Forage Pearl Millet (Pennisetum glaucum (L.) R. Br.) in North Gujarat Condition

Knowledge of genetic and phenotypic association among economic traits helps plant breeders in outlying efficient breeding strategies for development of high yielding forage pearl millet variety. An experiment was conducted at the research farm of Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, Gujarat to evaluate plant characteristics associated with green forage yield and its attributes in forage pearl millet [Pennisetum glaucum (L.) R. Br.] genotypes in north Gujarat condition through correlation and path analyses during 2023. Twelve independent and 1 dependent variables were evaluated for the character association analysis of the 30 forage pearl millet genotypes. The evaluation was performed in a Randomized Complete Block Design with three replications. Data collection was done from 5 randomly selected plants and this data was used for analysis using R Studio. The green forage yield per plant had positive and significant correlation with plant height, number of tiller per plant, stem thickness, leaf length, leaf width, and dry fodder yield per plant at both genotypic and phenotypic level. Path analysis revealed the importance of leaf width and dry fodder yield per plant by showing high and positive direct effects towards green forage yield per plant. These characters also exhibited significant and positive association with green forage yield per plant at the genotypic and phenotypic. Hence, these traits could be considered as the vital component characters for development of high yielding genotypes in forage pearl millet.

Genetic Variability, Heritability, Genetic Advance, Path Coefficient Analysis, and Inter-Character Relationships in Colocynth (Citrullus colocynthis [L.] Schrad.) from Southeastern Villages of the Benin Republic

Genetic improvement of crops for important traits requires reliable estimates of genetic variability. heritability and genetic advance of intending parent materials to identify traits useful in planning an efficient breeding program through selection. Hence, the effectiveness of genetic improvement of a crop depends on the variability in the morpho-agronomic traits of individual genotypes. Understanding the variation that exists will allow the breeder to determine strategies to be adopted in his breeding program. The objectives of the present study were to estimate the magnitude of genetic variability and advance, heritability and inter-character relationships by simple correlations and path coefficient analysis in 40 local colocynth genotypes from Southeastern Benin. The experiment was carried out in a randomized complete block design with three replications in three locations for three years. 34 morpho-agronomic traits were observed in each genotype. Analysis of variance revealed that effects of genotype, genotype by year or location and genotype by year by location interactions were significant (p ≤ 0.01 or 0.05) for all the characters. Phenotypic coefficients of variation (PCV) values were relatively greater than genotypic coefficients of variation (GCV) for all traits. High magnitude of phenotypic and genotypic coefficients of variation as well as high heritability along with high genetic advance were recorded particularly for qualitative traits. All yield components, except time to emergence, time to tailspins, leaf limb width, fruit number per plant, fruit width, seed length, seed tegument percentage and stem pubescence texture, had significant and positive correlations with yield attributes represented by thousand-seed weight (TSW) and seed number per plant (SNP). Path coefficient analysis indicated that all the characters (except leaf pubescence texture, stem pubescence texture, fruit design produced by secondary skin color and male flower size) had positive direct effects on TSW and partly SNP. Results suggested that most of the 34 quantitative and qualitative traits studied could be effectively used as selection criteria in the breeding program of Citrullus colocynthis varieties with high yield.

Processo digestivo em ruminantes e tecnologias de monitoramento utilizadas em rebanhos leiteiros

Cattle are ruminant herbivores with great productive capacity due to a highly efficient digestive system adapted to degrade and take advantage of complex compounds, such as plant structural carbohydrates. The fermentative capacity present in their digestive tract comes from the colonization of microorganisms such as bacteria, fungi and protozoa that transform ingested food into substrates for energy production, while the regulation of consumption comes from environmental and physiological factors, involving the central nervous system and hormone production. The decision to consume or refuse food will be based on sensory perception and metabolic demand. Management errors and diseases are evidenced when there is a decrease in food production and consumption. These can be preemptively corrected with the use of animal monitoring technologies to predict drops in production. As an example of these technologies, animal monitoring collars evaluate rumination, activity, idleness and panting for 24 hours, establishing individual curves and notifying when the animal demonstrates alterations and, based on this diagnosis, it is possible to identify alterations due to environmental or physiological factors. Other technologies such as intelligent consumer feeders allow individual assessment and help identify the quality of the diet offered. Thus, the use of animal monitoring systems, combined with knowledge of their physiology, provides a more efficient breeding system with better animal welfare.

Harnessing Multi-Omics Strategies and Bioinformatics Innovations for Advancing Soybean Improvement: A Comprehensive Review.

Soybean improvement has entered a new era with the advent of multi-omics strategies and bioinformatics innovations, enabling more precise and efficient breeding practices. This comprehensive review examines the application of multi-omics approaches in soybean-encompassing genomics, transcriptomics, proteomics, metabolomics, epigenomics, and phenomics. We first explore pre-breeding and genomic selection as tools that have laid the groundwork for advanced trait improvement. Subsequently, we dig into the specific contributions of each -omics field, highlighting how bioinformatics tools and resources have facilitated the generation and integration of multifaceted data. The review emphasizes the power of integrating multi-omics datasets to elucidate complex traits and drive the development of superior soybean cultivars. Emerging trends, including novel computational techniques and high-throughput technologies, are discussed in the context of their potential to revolutionize soybean breeding. Finally, we address the challenges associated with multi-omics integration and propose future directions to overcome these hurdles, aiming to accelerate the pace of soybean improvement. This review serves as a crucial resource for researchers and breeders seeking to leverage multi-omics strategies for enhanced soybean productivity and resilience.

Advancements in Cold-Region Rice Breeding: The 4S Phenotypic-Design Breeding System and Its Applications in Heilongjiang.

Heilongjiang, located in the cold region, is China's largest rice-producing and commercializing province. The variety selection of rice in cold regions (RCR) is indispensable in promoting the rice industry's development, and technological innovation in breeding theory plays a significant role in breeding breakthrough. Based primarily on long-term research, contemplation, and breeding practices, the 4S (selected topic, selected breeding, selected progenies, and selected promotion) phenotypic-design breeding technical system for RCR, which has revolutionized the theoretical basis and deepened the conceptual model, has been developed through systematic analyses and generalization. The system covers several key aspects such as scientific question formulation, breeding objective optimization, parental taxa hybridization, progeny population selection, and innovation dissemination, aiming to improve the foresight, precision, and efficiency of breeding. Furthermore, the system has demonstrated successful cases of rice variety breeding over the past 20 years, such as for Suijing 3, Suijing 4, Suijing 18, and a series of other rice varieties, providing theoretical and technical supports for cold-region rice breeding.

Hybridization and growth characteristics of interspecific crosses between Crassostrea hongkongensis and Crassostrea iredalei

Interspecific hybridization of oysters is a highly efficient breeding strategy that can produce commercially viable phenotypes. Crassostrea hongkongensis, the primary cultivar in southern China, faces increasing summer mortality risks and slow growth rates, which elevate commercial risks for farmers. C. iredalei, a commercially cultivated species in Southeast Asia, has been expanding its ecological niche northward in recent years, providing opportunities for interspecific hybridization with C. hongkongensis. This study conducted a 2 × 2 factorial cross between C. hongkongensis and C. iredalei (II: C. iredalei ♀ × C. iredalei ♂, HH: C. hongkongensis ♀ × C. hongkongensis ♂; IH: C. iredalei ♀ × C. hongkongensis ♂, HI: C. hongkongensis ♀ × C. iredalei ♂) and set up 6 salinity treatments (14, 17, 20, 23, 26 and 29 ppt) to explore the optimal salinity for embryo hatching. The results showed that the hybridization was successful, despite bidirectional fertilization and pronounced asymmetry in fertilization success. The optimal hatching salinity for C. iredalei and C. hongkongensis was 23 ppt and 17–20 ppt, respectively, while the optimal salinity for reciprocal hybrids was 20 ppt. Notably, the hatching rate of IH was lower than that of the control group at the optimal salinity. During the pelagic larval stage, hybrid larvae exhibited significant hybrid inferiority, with slower growth rates and higher mortality rates compared to intraspecific hybridization. It is worth noting that IH failed to overcome genetic incompatibility, resulting in complete mortality during the pelagic larval stage and failure to enter the growth stage. At the 360th day of the growth period, HI hybrids grown in Sanbaimen Sea exhibited significant hybrid vigor in shell height (15.65 %), and in Daya Bay Marine Biology Research Station, Chinese Academy of Sciences (MBRS), they showed significant single-parent hybrid advantages in shell height (28.44 %) and cumulative survival rate (58.11 %) compared to C. hongkongensis. In terms of gonadal development, HI hybrids were able to produce functional and viable gametes, although with some delay compared to their parents. The hybrid offspring inherited the phenotypic traits of their parents, with a grayish-yellow flesh color intermediate between the two oyster species. HI is a valuable genetic resource for oyster breeding, and its growth potential should be further explored to meet commercialization demands.

Metabolomic and Transcriptomic Analyses Reveal the Potential Mechanisms of Dynamic Ovarian Development in Goats during Sexual Maturation.

The ovary is a crucial reproductive organ in mammals, and its development directly influences an individual's sexual maturity and reproductive capacity. To comprehensively describe ovarian sexual maturation in goats, we integrated phenotypic, hormonal, metabolomic, and transcriptomic data from four specific time points: after birth (D1), at 2 months old (M2), at 4 months old (M4), and at 6 month old (M6). The study showed that during the early stage (D1-M2), ovarian growth was the most rapid, with weight and morphology increasing by 284% and 65%, respectively, and hormone levels rose significantly, with estradiol increasing by 57%. Metabolomic analysis identified 1231 metabolites, primarily lipids, lipid molecules, and organic acids, which can support hormone balance and follicle development by providing energy and participating in signaling transduction. Transcriptomic analysis identified 543 stage-specific differentially expressed genes, mainly enriched in steroid biosynthesis, amino acid metabolism, and the PI3K/AKT pathway, which are key factors influencing ovarian cell proliferation, apoptosis, hormone secretion, and metabolism. The integrated analysis revealed the key processes in the ovarian steroid hormone biosynthesis pathway and gene/metabolite networks associated with ovarian phenotypes and hormone levels, ultimately highlighting scavenger receptor class B type 1 (SCARB1), Cytochrome P450 Family 1 Subfamily A Member 1 (CYP11A1), 3beta-hydroxysteroid dehydrogenase (3BHSD), progesterone, estradiol, and L-phenylalanine as key regulators of ovarian morphological and functional changes at different developmental stages. This study is the first to reveal the metabolic changes and molecular regulatory mechanisms during ovarian sexual maturation in goats, providing valuable insights for understanding reproductive system development and optimizing reproductive performance and breeding efficiency.

Host genetics and gut microbiota synergistically regulate feed utilization in egg-type chickens

BackgroundFeed efficiency is a crucial economic trait in poultry industry. Both host genetics and gut microbiota influence feed efficiency. However, the associations between gut microbiota and host genetics, as well as their combined contributions to feed efficiency in laying hens during the late laying period, remain largely unclear.MethodsIn total, 686 laying hens were used for whole-genome resequencing and liver transcriptome sequencing. 16S rRNA gene sequencing was conducted on gut chyme (duodenum, jejunum, ileum, and cecum) and fecal samples from 705 individuals. Bioinformatic analysis was performed by integrating the genome, transcriptome, and microbiome to screen for key genetic variations, genes, and gut microbiota associated with feed efficiency.ResultsThe heritability of feed conversion ratio (FCR) and residual feed intake (RFI) was determined to be 0.28 and 0.48, respectively. The ileal and fecal microbiota accounted for 15% and 10% of the FCR variance, while the jejunal, cecal, and fecal microbiota accounted for 20%, 11%, and 10% of the RFI variance. Through SMR analysis based on summary data from liver eQTL mapping and GWAS, we further identified four protein-coding genes, SUCLA2, TNFSF13B, SERTM1, and MARVELD3, that influence feed efficiency in laying hens. The SUCLA2 and TNFSF13B genes were significantly associated with SNP 1:25664581 and SNP rs312433097, respectively. SERTM1 showed significant associations with rs730958360 and 1:33542680 and is a potential causal gene associated with the abundance of Corynebacteriaceae in feces. MARVELD3 was significantly associated with the 1:135348198 and was significantly correlated with the abundance of Enterococcus in ileum. Specifically, a lower abundance of Enterococcus in ileum and a higher abundance of Corynebacteriaceae in feces were associated with better feed efficiency.ConclusionsThis study confirms that both host genetics and gut microbiota can drive variations in feed efficiency. A small portion of the gut microbiota often interacts with host genes, collectively enhancing feed efficiency. Therefore, targeting both the gut microbiota and host genetic variation by supporting more efficient taxa and selective breeding could improve feed efficiency in laying hens during the late laying period.

Unraveling the impact of hyperleptinemia on female reproduction: insights from transgenic pig model

BackgroundInfertility is a growing global health concern affecting millions of couples worldwide. Among several factors, an extreme body weight adversely affects reproductive functions. Leptin is a well-known adipokine that serves as an endocrine signal between adiposity and fertility. However, the exact mechanisms underlying the effects of high leptin level on female reproduction remain unclear.MethodsTransgenic pigs overexpressing leptin (♀) were produced by backcrossing and screened for leptin overexpression. The growth curve, fat deposition, reproductive performance, apoptosis, serum hormones and cholesterol production, RNA sequencing, and single-nucleus RNA sequencing (snRNA-seq) of the leptin-overexpressing pigs and wild-type group were evaluated.ResultsTransgenic pigs overexpressing leptin (♀) were obtained, which exhibited significantly reduced body weight, body size, and back fat thickness. These pigs manifested a late onset of puberty (330 ± 54.3 vs. 155 ± 14.7 days), irregular estrous behavior characterized by increased inter-estrous interval (29.2 ± 0 vs. 21.3 ± 0.7 days), and more number of matings until pregnancy (at least 3 times). This reproductive impairment in leptin pigs was related to hormonal imbalances characterized by increased levels of FSH, LH, prolactin, E2, P4, and TSH, altered steroidogenesis such as increased levels of serum cholesterol esters along with steroidogenic markers (StAR, CYP19A), and ovarian dysfunctions manifested by neutrophilic infiltration and low expression of caspase-3 positive cells in the ovaries. Moreover, bulk RNA sequencing of the ovaries also revealed neutrophilic infiltration followed by upregulation of inflammation-related genes. Furthermore, snRNA-seq reflected that leptin overexpression triggered immune response, suppressed follicle development and luteinization, resulting in metabolic dysfunction and hormone imbalance in the ovary.ConclusionsLow body weight in leptin overexpressing pigs adversely affects the reproductive performance, causing delayed puberty, irregular estrous cycles, and reduced breeding efficiency. This is linked to metabolic imbalances, an increased immune response, and altered ovarian functions. This study provides a theoretical basis for the complex mechanisms underlying leptin, and infertility by employing leptin-overexpressing female pigs.

Individual Identification and Assessment of Genetic Diversity Using Microsatellite Markers in Racing Pigeons Raised in Turkiye

The implementation of a swift and economical molecular genetic approach, ensuring both efficacy and cost-effectiveness and facilitating population certification, is of utmost significance for breeders and the conservation of Turkiye's native pigeon biodiversity. In this study, we aimed to examine the genetic structure of racing pigeons (Columba livia domestica) raised in Turkiye using a genetic marker panel consisting of eight short tandem repeat (STR) loci. For this purpose, DNA was isolated from the shed feathers of 216 pigeons. Genomic DNA was amplified using the multiplex allele-specific PCR and subsequent capillary electrophoresis with ABI PRISM 3130XL Genetic Analyzer. Next, PCR products were analyzed in the GeneMapper Software program (Applied Biosystems). For parent testing, paternity index (PI), combined paternity index (CPI), and cumulative probability of paternity (CPP) were calculated. Furthermore, population genetic diversity was evaluated using heterozygosity (He), polymorphism information content (PIC), and Hardy–Weinberg equilibrium (HWE) testing. Results revealed that the total number of alleles is 81 and the number of alleles per locus varies between 4 and 19. The similarity rate between parent and offspring was calculated as 99.99% and above. Since no pedigree information was given when the samples were analyzed, obtaining this similarity ratio demonstrates the reliability of the panel. He values range from 0.362 to 0.919, and the PIC values range from 0.295 to 0.909. Loci PG-1, PG-2, and PG-3 show significant genetic diversity, with moderate to high PIC values reflecting varied allele frequencies in the population. Consequently, the set of seven STR markers (+ one sex marker) can be applied to identify and confirm parentage on a regular basis, thereby facilitating efficient breeding programs and ensuring genetic diversity conservation. This panel enables efficient pedigree analysis and gender determination, optimizing cost-effectiveness. The methodology presented in this study is ideal for pedigree analysis and breed certification in the Turkish pigeon breeding industry. Consequently, we affirm that the study data carries considerable national importance.

Key role of CYP17A1 in Leydig cell function and testicular development in Qianbei Ma goats

Reproductive traits are vital economic parameters in goat production, and boosting the reproductive capacity of breeding rams is crucial for enhancing the profitability of goat farming. Currently, research on the reproductive performance of Qianbei Ma goats mainly centers on investigating mechanisms associated with prolificacy and estrous ovulation in ewes, with limited emphasis on ram reproductive aspects. This study used scanning electron microscopy and enzyme-linked immunosorbent assay (ELISA) to profile the morphology of testis and the dynamic changes of Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH), and Testosterone (T) in serum at different developmental stages of Qianbei Ma goats. Meanwhile, transcriptome sequencing technology was used to investigate the mRNA expression patterns in testicular tissues at different developmental stages: newborn (0 M), puberty (6 M), sexual maturity (12 M), and physical maturity (18 M). The results showed that the diameter, circumference, and area of the testicular seminiferous tubules gradually increased with age. The levels of T and LH in serum significantly increased from 0 to 6 months after birth (p < 0.05), followed by a stabilization of T levels and a significant decrease in LH levels (p < 0.05). Meanwhile, FSH shows a decreasing trend between 0 and 18 months after birth. A total of 26,437 differentially expressed genes were identified in 6 comparison groups, which involve various biological processes such as immunity, growth, metabolism, development, and reproduction, and are significantly enriched in signaling pathways related to testicular development and spermatogenesis. WGCNA analysis identified 6 regions significantly associated with testicular development and spermatogenesis, and selected 320 genes for constructing a PPI network. Ten candidate genes related to testicular development and spermatogenesis were identified, including TP53, PLK4, RPS9, PFN4, ACTB, CYP17A1, GPX4, CLDN1, AMH and DHH. Of these, the CYP17A1 gene promotes interstitial cell proliferation, and promotes T synthesis. This study provides a theoretical basis and data support for promoting efficient breeding of goats and early breeding of excellent male goats.

Development of Reliable Male-Specific Molecular Markers for Genetic Sex Identification in Sea Cucumber Apostichopus japonicus.

Apostichopus japonicus is an important marine aquaculture species in China, with high nutritional and economic value. In A. japonicus, there is no obvious sexual dimorphism in external appearance, and sex differentiation primarily relies on the observation of mature gonads after dissection, which leads to difficulties in sex identification. The confusion in sex identification greatly reduces breeding efficiency in the sea cucumber industry. Therefore, developing a reliable sex-specific marker is crucial. In this study, we identified 586 male-specific sequences through whole-genome assembly and sequence alignment, but did not identify any female-specific sequences, inferring an XY-type sex determination system in sea cucumbers. We developed a set of male-specific molecular markers to establish an accurate, stable, and widely adaptable genetic sex identification technique for A. japonicus. The male-specific molecular markers were validated with 100% accuracy in sea cucumber populations from six different geographical regions in China. In conclusion, this study provides further evidence for the XY-type sex determination system in A. japonicus and establishes an effective genetic sex identification method for multi-geographic populations, which benefits future study on reproductive biology and has significant implications in sea cucumber aquaculture industry.

Understanding molecular mechanisms of vertebral number of variations on Mongolian sheep using candidate genes analysis.

This study aimed to investigate the genetic link between variations in vertebral number and meat production traits, such as body weight and body measurements (body length, body height, heart girth, and shin width) in Mongolian (Bayantsagaan) sheep. Additionally, we examined the association of single-nucleotide polymorphisms (SNPs) in candidate genes, particularly Vertnin (VRTN), Nuclear receptor subfamily 6, group A, member 1 (NR6A1), and synapse differentiation-inducing 1-like (SYNDIG1L), with vertebral number variations and their potential impact on meat production traits. The study involved 220 Bayantsagaan sheep from Bayantsagaan soum, Tov province, Mongolia, including 104 sheep with extra vertebrae group and 116 individuals with typical vertebral number as the control group. Morphological data, including body weight and body measurements, were collected, and genetic samples were obtained. The impact of vertebral number on morphological traits was estimated using a general linear model. SNPs in the VRTN, NR6A1, and SYNDIG1L genes were sequenced, and their association with vertebral number was analyzed using one-way ANOVA. Bayantsagaan sheep with extra vertebrae were, on average, 4.45 kg heavier and exhibited higher variability in body size traits compared to the control group. Four polymorphic sites were identified at the VRTN gene, with one polymorphic locus (VRTN1716) showing a significant association with vertebrae number and body size. Sheep with C/C genotype at VRTN1716 locus, had more vertebrae and larger body size compared to other genotypes. The findings suggest that variations in vertebral number and VRTN gene polymorphisms are linked to favorable meat production traits in Bayantsagaan sheep. The identified SNP (VRTN1716) associated with vertebral number and body size offers the potential for marker-assisted selection in breeding programs. These results provide valuable insights into the genetic basis of meat production traits in Bayantsagaan sheep and may contribute to the development of more efficient breeding strategies.

HSP70 and APX1 play important roles in cotton male fertility by mediating ROS homeostasis

Male sterility is used in the production of hybrid seeds and can improve the breeding efficiency of cotton hybrids. Reactive oxygen species is closely associated with the tapetum and pollen development, but their relationship in cotton male fertility remains unclear. In this study, we comprehensively compared the cytology and proteome of the anthers from an Upland cotton (Gossypium hirsutum) material, Shida 98 (WT), and its nearly-isogenic male sterile line Shida 98A (MS). Cytology indicated delayed PCD in the tapetum and defects in microspores in MS anthers. And further studies revealed disruption of ROS homeostasis. Proteomic analysis identified proteins with differential abundance mainly being related to redox homeostasis, protein folding, and apoptotic signaling pathways. GhAPX1 interacted with GhHSP70 and played a crucial role in the development of cotton anthers. Exogenous application of HSP70 inhibitor increased H2O2 content and decreased the activity of APX1 and pollen viability. The GhAPX1 mutants generated by CRISPR/Cas9-mediated gene editing exhibited premature degradation of the tapetum, significant decrease in pollen viability, and significant increase in H2O2 content. Altogether, our results imply HSP70 and APX1 being the key players jointly regulating male fertility by mediating ROS homeostasis. These results provide insights into the proteins associated with male fertility.

Maintenance Breeding in Pigeonpea [Cajanus cajan (L.) Millspaugh] — An Assessment and Advanced Strategies

AbstractThe sustainable maintenance breeding of pigeonpea germplasm, genetic stocks, released cultivars, and hybrid parents is a tough job. The prime reason for their genetic contamination is the insect‐aided cross‐pollination. Although various public and private seed agencies are involved in maintenance breeding to produce different grades of pigeonpea seeds, but the limitation of resources and low priority make it difficult to meet the national seed requirements. This manuscript, aside from reviewing the present pigeonpea maintenance breeding methods, their limitations, and accomplishments, also highlights some advanced breeding and genomics approaches to enhance the efficiency of maintenance breeding.

Comparative analysis of breeding patterns and reproductive efficiency of mares in subtropical conditions of Pakistan.

The present study aimed to evaluate and compare the overall and breed-specific seasonal breeding patterns, fertility rates, cyclicity, and follicular dynamics of Arab, Thoroughbred, and Percheron mares under the subtropical conditions of Pakistan. A retrospective analysis of climatic data and breeding records of eleven breeding studs spanning four years (2020-2023) was made to find out the overall seasonality in the breeding pattern of mares. Fifty mares of each breed (n=150 in total) were scanned by ultrasonography for a calendar year to find the cyclicity pattern and follicular dynamics (follicular growth rate, size of ovulatory follicle, and days from estrus till ovulation). The statistical analysis of breeding records demonstrated a clear pattern of seasonal breeding (p<0.05). The highest monthly foalings were noted in March (247±45.37), and overall breeding activities peaked in Spring season (p<0.05). Breed-specific results of Arab, Thoroughbred, and Percheron mares revealed that Arab mares maintained stable breeding activity throughout the year, with the highest activity in spring and peak conception rate in winter (56.25%±32.78; p>0.05). Thoroughbred mares experienced significant seasonal declines from spring to winter with a peak conception rate in winter (63.89%±27.37, p>0.05). Percherons showed the most pronounced seasonal effects, especially with a high fall conception rate (73.04%±19.61) and a sharp decrease in winter breeding metrics (p<0.05). Furthermore, Thoroughbred and Percheron mares displayed the most pronounced seasonal effects on the percentage of cyclic mares 77.3% and 56% in winters (p<0.05). Moreover, the follicular dynamics of the three breeds also exhibited significant differences (p<0.05). The current study concludes that seasonal and breed-specific variability exists among the reproductive parameters of Arab, Thoroughbred, and Percheron mares in subtropics, necessitating breed-specific reproductive management measures to maximize mare breeding efficiency.

Genetic Evaluation of Water Use Efficiency and Nutrient Use Efficiency in Populus deltoides Bartr. ex Marsh. Seedlings in China.

Populus deltoides Bartr. ex Marsh. represents a valuable genetic resource for fast-growing plantations in temperate regions. It holds significant cultivation and breeding potential in northern China. To establish an efficient breeding population of poplar, we studied the genetic variation of P. deltoides from different provenances. Our focus was on genotypes exhibiting high growth rates and efficient water and nutrient use efficiency (WUE and NUE). We evaluated 256 one-year-old seedlings from six provenances, measuring height, ground diameter, total biomass, and leaf carbon and nitrogen isotope abundance (δ13C and δ15N). Our analytical methods included variance analysis, multiple comparisons, mixed linear models, correlation analysis, and principal component analysis. The results showed that the coefficient of variation was highest for δ15N and lowest for δ13C among all traits. Except for δ15N, the effects of intra- and inter-provenance were highly significant (p < 0.01). The rates of variation for all traits ranged from 78.36% to 99.49% for intra-provenance and from 0.51% to 21.64% for inter-provenance. The heritability of all traits in AQ provenance was over 0.65, and all exhibited the highest level except for seedling height. All traits were significantly positively correlated with each other (p < 0.05), while ground diameter, total biomass, and WUE were highly significantly negatively correlated with latitude (p < 0.01). After a comprehensive evaluation, two provenances and eight genotypes were selected. The genetic gains for seedling height, ground diameter, total biomass, WUE, and NUE were 27.46 cm (178-2-106), 3.85 mm (178-2-141), 16.40 g (178-2-141), 0.852‱ (LA05-N15), and 3.145‱ (174-1-2), respectively. Overall, we revealed that the abundant genetic variation in P. deltoides populations mainly comes from intra-provenance differences and evaluated provenances and genotypes. The results of this study will contribute to optimizing and enhancing the breeding process of Chinese poplar and improving the productivity of fast-growing plantations.

Genetic diversity and genome-wide association study of partial resistance to Sclerotinia stem rot in a Canadian soybean germplasm panel.

Developing genetically resistant soybean cultivars is key in controlling the destructive Sclerotinia Stem Rot (SSR) disease. Here, a GWAS study in Canadian soybeans identified potential marker-trait associations and candidate genes, paving the way for more efficient breeding methods for SSR. Sclerotinia stem rot (SSR), caused by the fungal pathogenSclerotinia sclerotiorum, is one of the most important diseases leading to significant soybean yield losses in Canada and worldwide. Developing soybean cultivars that are genetically resistant to the disease is the most inexpensive and reliable method to control the disease. However, breeding for resistance is hampered by the highly complex nature of genetic resistance to SSR in soybean. This study sought to understand the genetic basis underlying SSR resistance particularly in soybean grown in Canada. Consequently, a panel of 193 genotypes was assembled based on maturity group and genetic diversity as representative of Canadian soybean cultivars. Plants were inoculated and screened for SSR resistance in controlled environments, where variation for SSR phenotypic response was observed. The panel was also genotyped via genotyping-by-sequencing and the resulting genotypic data were imputed using BEAGLE v5 leading to a catalogue of 417K SNPs. Through genome-wide association analyses (GWAS) using FarmCPU method with threshold of FDR-adjustedp-values < 0.1, we identified significant SNPs on chromosomes 2 and 9 with allele effects of 16.1 and 14.3, respectively. Further analysis identified three potential candidate genes linked to SSR disease resistance within a 100Kb window surrounding each of the peak SNPs. Our results will be important in developing molecular markers that can speed up the breeding for SSR resistance in Canadian grown soybean.

Unlocking the mystery of heterosis opens the era of intelligent rice breeding.

Heterosis refers to the phenomenon where the first filial offspring (F1) from genetically diverse parents displays advantages in growth rate, yield, and adaptability compared with its parents. The exploitation of heterosis in rice breeding has greatly increased the productivity, making a significant contribution to food security in the last half of the century. Conventional hybrid rice breeding highly relies on the breeder's experience on random crossing and comprehensive field selection. This process is time-consuming and labor-intensive. In recent years, rice hybrid breeding has encountered challenges stemming from limited germplasm resource, low breeding efficiency, and high uncertainty, which constrain the progress in yield increase, coupled with difficulties in balancing grain yield, quality, and resistance. Understanding the genetic basis of rice heterosis could lead to significant advancements in breeding concepts and methods. This will fully unleash the advantages of heterosis. In this review, we focus on the research progress of the genetic dissection of crop heterosis and briefly introduce some key advancements in modern intelligent breeding of rice hybrid.

The art of tartness: the genetics of organic acid content in fresh fruits.

Organic acids are major determinants of fruit flavor and a primary focus of fruit crop breeding. The accumulation of organic acids is determined by their synthesis, degradation, and transport, all of which are manipulated by sophisticated genetic mechanisms. Constant exploration of the genetic basis of organic acid accumulation, especially through linkage analysis, association analysis, and evolutionary analysis, have identified numerous loci in recent decades. In this review, the genetic loci and genes responsible for malate and citrate contents in fruits are discussed from the genetic perspective. Technologies such as gene transformation and genome editing as well as efficient breeding using marker-assisted selection (MAS) and genomic selection (GS) are expected to break the bottleneck of traditional fruit crop breeding and promote fruit quality improvement.