Search Results (752)

Doubled haploid (DH) technology accelerates maize breeding by generating completely homozygous lines within two generations, but its efficiency depends on reliable haploid identification markers. The Purple plant 1 (Pl-1) root pigmentation marker has emerged as a promising alternative to R1-Navajo (R1-nj), which suffers from frequent suppression in tropical germplasm. This study evaluated Pl-1 expression and seedling vigor in 298 diverse Thai maize genotypes across four market classes under controlled growth chamber conditions (24 ± 1 °C, 85–90% humidity, and standardized lighting), followed by testcross analysis with 89 representative genotypes crossed with BHI306 to distinguish between allelic absence and epistatic suppression mechanisms. Complete absence of Pl-1 expression was observed in 99.3% of Thai genotypes, contrasting with consistent expression in the temperate-derived control (BHI306). Testcross F₁ progeny from 89 Thai × BHI306 crosses exhibited intermediate expression levels (1.57–2.05) across all market classes, confirming allelic absence rather than suppressor-mediated inhibition. Substantial genetic diversity was detected in seedling vigor traits independent of Pl-1 status, with root length varying 43-fold and fresh weight 20-fold, showing highly significant genotypic effects. The uniform lack of Pl-1 expression across Thai germplasm eliminates background interference, highlighting its utility as a complementary marker when introgressed from inducer lines. These findings establish the genetic foundation for implementing optimized DH breeding strategies in tropical maize through marker-assisted backcrossing approaches. Full article

The ancestry of domestic species from their closest wild relatives is one of the most debated and intriguing topics in evolutionary genetics. This review synthesizes current scientific understanding of the phylogenetic relationships between wild mouflon populations and domestic sheep (Ovis aries). It delves into the complex ancestry, tracing the primary role of the Asiatic mouflon (Ovis gmelini) as the progenitor, while also addressing the debated contributions of other wild Ovis species. The report explores the insights gained from diverse genetic markers, including mitochondrial DNA haplogroups and comprehensive whole-genome sequencing, highlighting their strengths, limitations, and the resolution of phylogenetic discrepancies. The multi-faceted taming process is examined, discussing proposed evolutionary mechanisms such as the domestication syndrome and thyroid hormone hypotheses, alongside human-mediated selection for key phenotypic traits like horn morphology, coat type, and tail characteristics. Furthermore, the pervasive role of hybridization and introgression between wild and domestic populations is analyzed, detailing its impact on genetic distinctiveness, adaptive potential, and the critical implications for conservation strategies. Finally, the review addresses ongoing scientific debates, particularly concerning the taxonomic classification of European mouflon, and identifies crucial avenues for future research to further unravel the intricate evolutionary tapestry of Ovis species. To ensure taxonomic consistency and promote conservation, nomenclature should be updated across all public repositories. Following the widely accepted classification that recognizes its lineage from the Asian mouflon, the Corsican and Sardinian mouflon should be designated as Ovis gmelini musimon. Full article

Cotton fiber quality improvement remains a fundamental challenge in breeding programs due to the complex genetic architecture underlying fiber development. The narrow genetic base of upland cotton (Gossypium hirsutum L.) and the quantitative nature of fiber quality traits necessitate innovative approaches for identifying and incorporating superior alleles from related species. We developed a BC₆F₂ population by introgressing chromosome segments from the sea island cotton variety Xinhai 36 (G. barbadense) into the upland cotton variety Xinluzhong 60 (G. hirsutum). Based on fiber strength phenotyping, we constructed two DNA bulks representing extreme phenotypes (20 superior and 12 inferior individuals) for bulked segregant analysis sequencing (BSA-Seq). High-throughput sequencing generated 225.13 Gb of raw data with average depths of 20× for parents and 30× for bulks. SNP calling and annotation were performed using GATK and ANNOVAR against the upland cotton reference genome (TM-1). BSA-Seq analysis identified 13 QTLs primarily clustered within a 1.6 Mb region (20.6–22.2 Mb) on chromosome A10. Within this region, we detected nonsynonymous mutation genes involving a total of six genes. GO and KEGG enrichment analyses revealed significant enrichment for carbohydrate metabolic processes, protein modification, and secondary metabolite biosynthesis pathways. Integration with transcriptome data prioritized GH_A10G1043, encoding a β-amylase family protein, as the key candidate gene. Functional validation through overexpression and RNAi knockdown in Arabidopsis thaliana demonstrated that GH_A10G1043 significantly regulates starch content and β-amylase activity, though without visible morphological alterations. This study successfully identified potential genomic regions and candidate genes associated with cotton fiber strength using chromosome segment substitution lines combined with BSA-Seq. The key candidate gene GH_A10G1043 provides a valuable target for marker-assisted selection in cotton breeding programs. Our findings establish a foundation for understanding the molecular mechanisms of fiber quality formation and offer genetic resources for developing superior cotton varieties with enhanced fiber strength. Full article

Psathyrostachys huashanica (2n = 2x = 14, NsNs) and Leymus mollis (2n = 4x = 28, NsNsXmXm) are important wild relatives of common wheat. The Ns chromosomes from two species have been successfully introgressed into wheat through distant hybridization. To compare the genetic effects and evolutionary relationship of Ns chromosomes from different genera in a wheat background, wheat-P. huashanica derivative WH15 and wheat-L. mollis derivative WM14-2 were selected. Sequential FISH-GISH showed that both WH15 and WM14-2 contained 40 wheat chromosomes (with 2D deletion) and two Ns chromosomes with different FISH karyotypes. Molecular markers and SNP array analysis revealed that the two lines both introduced 2Ns chromosomes. However, the P. huashanica 2Ns and L. mollis 2Ns had distinct sequence compositions, and the different SNPs between the two species 2Ns chromosomes were primarily clustered on the short arm. WH15 and WM14-2 exhibited significant differences in spike-related morphologies but shared leaf rust resistance and susceptibility to powdery mildew and Fusarium head blight. Cytogenetic analysis confirmed stable meiotic inheritance of the introduced 2Ns chromosomes. We further developed universal diagnostic markers for 2Ns chromosomes based on SLAF-seq. Therefore, substantial divergence likely exists between the Ns genomes of P. huashanica and L. mollis, and P. huashanica is probably not the direct Ns genome donor for Leymus. Our research-developed derivatives provide unique resources for comparative studies of the structural and functional evolution of homoeologous Ns chromosomes across genera, while offering valuable alleles for wheat improvement. Full article

Hybridization is common among minnows and shiners in the family Leuciscidae, and mitonuclear discordance can reveal evidence of historical hybridization and introgression events that have shaped extant species and populations. We have identified a notable case of serial mitogenome replacement in populations of two shiner species, Luxilus zonatus and L. chrysocephalus, which are syntopic in drainages throughout the northern and eastern Ozark Interior Highlands of North America. These mitogenome replacement events involved L. zonatus acquiring the mitogenome of L. chrysocephalus, and populations of L. chrysocephalus acquiring the mitogenome of an allopatric congeneric species, L. cornutus. The latter species has a more northern distribution that was likely shifted southward by glacial advances during the Pleistocene. The geographic extent of mitogenome replacements in both species spans multiple separate drainages encompassing most of the major river systems that comprise the northern and eastern Ozark Highlands. We attribute these patterns to shifting species distributions, which were impacted by multiple glacial advances and coincident geomorphological changes to Ozark Highland drainages throughout the Pleistocene. The serial nature of mitogenome replacements in L. zonatus and L. chrysocephalus may exclude a role for natural selection in these introgression events, but the dynamic shifts in species distributions and gene flow connections throughout the Pleistocene may have favored an invasion-with-hybridization model that predicts massive asymmetric introgression between invading and resident species. These results have applied significance for eDNA metabarcoding methods of biodiversity assessment in Ozark streams, as they are dependent on mitogenome detections. Full article

Global trade facilitates multiple introductions of alien species, yet the role of genetic admixture between divergent lineages in driving invasion success remains debated. Here, we address this question by analyzing dynamic genetic changes across invasion stages in the dioecious weed Amaranthus palmeri, introduced to China from North and South America. Combining chloroplast phylogeography with nuclear genetic analyses, we systematically investigated genetic changes in populations at casual, naturalized, invasive, and dispersal stages. Initial casual populations originated from distinct North and South American lineages, but all established populations (naturalized, invasive, dispersal) retained only North American haplotypes. South American genetic introgression decreased progressively during invasion (from 34% in naturalized to 3% in dispersal populations), accompanied by declining inbreeding coefficients. Established populations exhibited high inter-population crosses within the North American lineage (54–60%), maintaining genetic diversity and overcoming bottlenecks. Our findings demonstrate that invasion success in A. palmeri may be driven by gene flow within the North American lineage, rather than admixture between divergent lineages. These findings enhance our understanding of the genetic mechanisms underpinning plant invasions, highlighting lineage-specific management as a critical strategy for controlling invasive populations. Full article

The development of a new salt–alkaline-tolerant hybrid japonica rice is crucial for enhancing japonica rice supply and ensuring national food security. Utilizing molecular marker-assisted selection (MAS) technology combining Kompetitive Allele-Specific PCR (KASP) markers and a gene breeding chip, the salt-tolerant gene SKC1 was introgressed into a rice genotype Fan 14. This led to the development of Shenyanhui 1, a new high-quality, strongly heterotic, and salt-tolerant japonica restorer line. Subsequently, the high-quality, salt-tolerant japonica three-line hybrid rice variety Shenyanyou 1 was developed by crossing the BT-type japonica cytoplasmic male sterile (CMS) line Shen 21A with the restorer line Shenyanhui 1. Shenyanyou 1 carries the major salt tolerance gene SKC1, exhibiting excellent salt tolerance with seedling stage salt tolerance reaching level 5. Under precise salt tolerance evaluation throughout its growth cycle, Shenyanyou 1 achieved a yield of 3640.5 kg/hm², representing an extremely significant increase of 20.7% over the control variety Yandao 21. Shenyanyou 1 exhibits superior grain quality, meeting the Grade 3 high-quality rice standards issued by the Ministry of Agriculture. Shenyanyou 1 has good comprehensive resistance, aggregating rice blast resistance genes such as Pi2, Pita, Pizt and LHCB5, bacterial blight resistance genes Xa26/Xa3, stripe blast resistance gene STV11, semi-dwarf gene Sdt97, nitrogen-efficient utilization gene NRT1.1B, the light repair activity enhancement gene qUVR-10, the cold resistance gene qLTG3-1, and the iron tolerance gene OsFRO1. It has good resistance to biotic and abiotic stresses. This paper details the breeding process, key agronomic traits, salt tolerance, yield performance, and grain quality characteristics of Shenyanyou 1. Full article

Seed vigor critically determines sowing performance, while grain quality fundamentally influences commercial value. Elucidating the genetic mechanisms governing these traits is critical for enhancing both seed vigor and grain quality in rice cultivation. Here, we demonstrate that the endosperm-specific gene OsEnS-42 is highly expressed in germinating seeds and developing seeds at the early filling stage. OsEnS-42 is localized in the nucleus and cytoplasm. The seed vigor of OsEnS-42 knockout plants decreased, manifested as decreases in germination rate, seedling length, and root length. In addition, OsEnS-42 knockout plants showed increased chalkiness and amylose content. The transcriptome and physiological indicators showed that OsEnS-42 regulates seed vigor through soluble sugars and redox metabolism, and regulates grain quality via soluble sugars and seed development-related enzymes. Haplotype analysis of OsEnS-42 across global rice germplasm revealed four distinct haplotypes (Hap 1–4) with subspecies-specific distributions. Crucially, accessions with Hap 4 exhibit a lower percentage of grain with chalkiness than accessions with Hap 1 (predominantly indica), enabling marker-assisted introgression to reduce chalkiness without subspecies barriers. Meanwhile, accessions with Hap 2 show lower amylose content, providing targets for specialty rice breeding. Our findings elucidate the pathways through which OsEnS-42 regulates seed vigor and grain quality, and provide new molecular breeding targets for improving seed vigor and grain quality in rice. Full article

The closely related Naupactini species Naupactus leucoloma, Naupactus peregrinus, and Naupactus minor—collectively known as “white-fringed weevils”—form a monophyletic group within the N. leucoloma species group. Mostly parthenogenetic, a few sexually reproducing populations of both N. leucoloma and N. peregrinus occur in their native ranges (Argentinian Mesopotamian region), where they overlap. In 2013, after several decades during which only females had been recorded, a few males potentially belonging to these species were discovered. To clarify their taxonomic identity and understand the group’s evolutionary dynamics, we analyzed their mitochondrial and nuclear genetic markers to assess their genetic variation distribution and infer their phylogenetic relationships. Molecular phylogenetic analyses revealed that these males constitute an independently evolving lineage, whereas morphological comparisons produced inconclusive results. Statistical tests confirmed introgression between these unidentified males and N. leucoloma. These findings uncover unexpected levels of genetic divergence within this group of Neotropical weevils. Full article

As the primary harvested organ, fruit size and weight hold significant economic importance during tomato production. Therefore, elucidating the genetic mechanisms underlying fruit size and weight is of considerable agronomic value. In this study, the Solanum pimpinellifolium introgression lines were constructed with “LA2093” as the donor and “Jina” as the recipient, and a genetic linkage map was constructed. Preliminary QTL mapping was conducted using four fruit-related traits: single fruit weight, fruit diameter, fruit length, and fruit shape index. A total of 10 QTLs were identified, including one for single fruit weight (qFw-3), five for fruit diameter (qFtd-3-1, qFtd-3-2, qFtd-4, qFtd-7, and qFtd-12), two for fruit length (qFl-3 and qFl-11), and two for fruit shape index (qFsi-2 and qFsi-3). To explore the key regulatory genes of the single fruit weight QTL qFw-3 locus, it was further finely mapped between SSR3-14 and C03M65101. The SSR3-14 and C03M65101 interval contained 57 genes on chromosome 3 (64.68–65.10 Mb) in the reference genome. Among these, eight genes, including Solyc03g114830, Solyc03g114870, Solyc03g114880, Solyc03g114890, Solyc03g114900, Solyc03g114910, Solyc03g115200, and Solyc03g115380, were identified as candidate genes involved in regulating fruit weight. These studies provide a basis for future functional validation of key regulatory genes and offer valuable genetic resources for the improvement of fruit size and weight during tomato breeding. Full article

The fungal pathogen Puccinia striiformis f. sp. tritici, which causes yellow rust disease, poses a significant economic threat to wheat production not only in Uzbekistan but also globally, leading to substantial reductions in grain yield. This study aimed to develop yellow rust-resistance wheat lines by introgressing Yr10 and Yr15 genes into high-yielding cultivar Grom using the marker-assisted backcrossing (MABC) method. Grom was crossed with donor genotypes Yr10/6*Avocet S and Yr15/6*Avocet S, resulting in the development of F₁ generations. In the following years, the F₁ hybrids were advanced to the BC₂F₁ and BC₂F₂ generations using the MABC approach. Foreground and background selection using microsatellite markers (Xpsp3000 and Barc008) were employed to identify homozygous Yr10- and Yr15-containing genotypes. The resulting BC₂F₂ lines, designated as Grom-Yr10 and Grom-Yr15, retained key agronomic traits of the recurrent parent cv. Grom, such as spike length (13.0–11.9 cm) and spike weight (3.23–2.92 g). Under artificial infection conditions, the selected lines showed complete resistance to yellow rust (infection type 0). The most promising BC₂F₂ plants were subsequently advanced to homozygous BC₂F₃ lines harboring the introgressed resistance genes through marker-assisted selection. This study demonstrates the effectiveness of integrating molecular marker-assisted selection with conventional breeding methods to enhance disease resistance while preserving high-yielding traits. The newly developed lines offer valuable material for future wheat improvement and contribute to sustainable agriculture and food security. Full article

Aflatoxin contamination, primarily caused by Aspergillus flavus, poses a significant threat to peanut (Arachis hypogaea L.) production, food safety, and global trade. Despite extensive efforts, breeding for durable resistance remains difficult due to the polygenic and environmentally sensitive nature of resistance. Although germplasm such as J11 have shown partial resistance, none of the identified lines demonstrated stable or comprehensive protection across diverse environments. Resistance involves physical barriers, biochemical defenses, and suppression of toxin biosynthesis. However, these traits typically exhibit modest effects and are strongly influenced by genotype–environment interactions. A paradigm shift is underway with increasing focus on host susceptibility (S) genes, native peanut genes exploited by A. flavus to facilitate colonization or toxin production. Recent studies have identified promising S gene candidates such as AhS5H1/2, which suppress salicylic acid-mediated defense, and ABR1, a negative regulator of ABA signaling. Disrupting such genes through gene editing holds potential for broad-spectrum resistance. To advance resistance breeding, an integrated pipeline is essential. This includes phenotyping diverse germplasm under stress conditions, mapping resistance loci using QTL and GWAS, and applying multi-omics platforms to identify candidate genes. Functional validation using CRISPR/Cas9, Cas12a, base editors, and prime editing allows precise gene targeting. Validated genes can be introgressed into elite lines through breeding by marker-assisted and genomic selection, accelerating the breeding of aflatoxin-resistant peanut varieties. This review highlights recent advances in peanut aflatoxin resistance research, emphasizing susceptibility gene targeting and genome editing. Integrating conventional breeding with multi-omics and precision biotechnology offers a promising path toward developing aflatoxin-free peanut cultivars. Full article

Elucidating the coexistence mechanisms of rapidly diverging species has long been a challenge in evolutionary biology. Genome-wide polymorphic loci are expected to provide insights into the speciation processes of these closely related species. This study focused on seven Chinese sclerophyllous oaks, represented by Quercus spinosa, Quercus aquifolioides, Quercus rehderiana, Quercus guyavifolia, Quercus monimotricha, Quercus semecarpifolia, and Quercus senescens, employing 27,592 single-nucleotide polymorphisms to examine their phylogenetic relationships at the genomic level. Combined with genetic structure analysis, phylogenetic trees revealed that the genetic clustering of individuals was influenced by both geographic distance and ancestral genetic components. Furthermore, this study confirmed the existence of reticulate evolutionary relationships among the species. Frequent gene flow and introgression within the seven species were primarily responsible for the ambiguous interspecies boundaries, with hybridization serving as a major driver of reticulate evolution. Additionally, the seven species exhibited distinct differences in niche occupancy. By reconstructing the climatic adaptability of ancestral taxonomic units, we found that the climatic tolerance of each species displayed differential responses to 19 climatic factors. Consequently, ecological niche differentiation and variations in habitat adaptation contributed to the preservation of species boundaries. This study provides a comprehensive understanding of the speciation processes in rapidly diverging genera and underscores the significance of both genetic and ecological factors in the formation and maintenance of species boundaries. Full article

Climate change is jeopardizing global food security, with at least 713 million people facing hunger. To face this challenge, legumes as common beans could offer a nature-based solution, sourcing nutrients and dietary fiber, especially for rural communities in Latin America and Africa. However, since common beans are generally heat and drought susceptible, it is imperative to speed up their molecular introgressive adaptive breeding so that they can be cultivated in regions affected by extreme weather. Therefore, this study aimed to couple an advanced panel of common bean (Phaseolus vulgaris L.) × tolerant Tepary bean (P. acutifolius A. Gray) interspecific lines with Bayesian regression algorithms to forecast adaptation to the humid and dry sub-regions at the Caribbean coast of Colombia, where the common bean typically exhibits maladaptation to extreme heat waves. A total of 87 advanced lines with hybrid ancestries were successfully bred, surpassing the interspecific incompatibilities. This hybrid panel was genotyped by sequencing (GBS), leading to the discovery of 15,645 single-nucleotide polymorphism (SNP) markers. Three yield components (yield per plant, and number of seeds and pods) and two biomass variables (vegetative and seed biomass) were recorded for each genotype and inputted in several Bayesian regression models to identify the top genotypes with the best genetic breeding values across three localities on the Colombian coast. We comparatively analyzed several regression approaches, and the model with the best performance for all traits and localities was BayesC. Also, we compared the utilization of all markers and only those determined as associated by a priori genome-wide association studies (GWAS) models. Better prediction ability with the complete SNP set was indicative of missing heritability as part of GWAS reconstructions. Furthermore, optimal SNP sets per trait and locality were determined as per the top 500 most explicative markers according to their β regression effects. These 500 SNPs, on average, overlapped in 5.24% across localities, which reinforced the locality-dependent nature of polygenic adaptation. Finally, we retrieved the genomic estimated breeding values (GEBVs) and selected the top 10 genotypes for each trait and locality as part of a recommendation scheme targeting narrow adaption in the Caribbean. After validation in field conditions and for screening stability, candidate genotypes and SNPs may be used in further introgressive breeding cycles for adaptation. Full article

The morphological diversity of Moroccan honey bees (Apis mellifera) was investigated using geometric morphometrics to assess wing venation patterns among three populations representing three climatic zones: desert, semiarid, and Mediterranean. A total of 193 honey bee samples were analyzed and compared to historical reference samples from the Morphometric Bee Data Bank in Oberursel, representing the three subspecies: A. m. intermissa, A. m. sahariensis, and A. m. major. Principal component analysis and linear discriminant analysis revealed significant, yet overlapping morphological differences among the climatic groups. Spatial modeling showed a significant southwest–northeast clinal gradient in wing morphology. Almost all samples were assigned to the African evolutionary lineage, except one, suggesting a dominant African genetic background. Interestingly, all three populations showed greater morphological affinity to A. m. intermissa than to A. m. sahariensis, which could indicate introgression or limitations in the current reference dataset. These discrepancies highlight the necessity of revising subspecies boundaries using updated morphometric and genomic approaches. These findings improve our understanding of honey bee biodiversity in Morocco and provide valuable information for conservation and breeding programs. Full article