Search Results (465)

Sex control technology has become a key technique in aquatic animal breeding, as many aquatic species exhibit distinct sexual dimorphism in growth, reproduction, immunity, and other economically important traits. Therefore, methods such as regulating sex ratios and establishing unisexual populations can significantly enhance aquaculture productivity and breeding efficiency. Recent years have seen a rapid advancement in the field of research on the mechanisms of sex determination and differentiation in aquatic animals, as well as sex control technologies. This review summarizes the latest advances in research on the mechanisms of sex formation in aquatic animals, including genetic sex determination, environmental sex determination, and genotype-environment interactions. Furthermore, this review outlines the major sex-linked genes and molecular markers used for genetic sex identification, introduces key male and female regulatory factors involved in gonadal differentiation, and explores the application of major sex control methods in aquaculture breeding, including techniques such as interspecific hybridization, environmental regulation, hormone induction, parthenogenesis, and gene editing. Full article

Reproductive barriers severely limit interspecific hybridization success among Hydrangea macrophylla, H. paniculata, and H. arborescens, thereby restricting the combination of ornamental traits and cold hardiness. We evaluated cross-compatibility, pollen tube growth, and embryo development in both direct and reciprocal crosses involving H. macrophylla with H. paniculata and H. arborescens. Both species pairs exhibited pronounced unilateral incompatibilities. When H. macrophylla served as the maternal parent, the percentages of seedling emergence were higher, whereas reciprocal crosses produced >84% ovary swelling but resulted in almost no seedlings. Fluorescence microscopy revealed mild prezygotic barriers in direct crosses but strong inhibition of pollen germination and pollen tube growth in reciprocal crosses. Paraffin section observations showed that postzygotic barriers were the primary cause of hybrid failure, with endosperm-type abortion predominating in direct crosses and embryo-type or complete abortion in reciprocal crosses. Consistent with these abortion patterns, direct crosses maintained higher proportions of normal embryos, whereas reciprocal crosses dropped below 10% at the globular stage and approached 0% at later stages. These findings support the use of timely embryo rescue for direct crosses and targeted mitigation of prezygotic barriers in reciprocal crosses to improve Hydrangea interspecific hybridization efficiency. Full article

The evolution of herbicide resistance can increase, decrease, or have no effect on the growth rate, competitive ability, and fitness of field-selected populations. The growth response of an ACCase-resistant (R) johnsongrass [Sorghum halepense (L.) Pers.] population harboring an Ile1781Leu mutation, and a susceptible (S) population was studied in pot experiments under intraspecific and interspecific competition with corn or sunflower, using a target-neighborhood design. The R population in the intraspecific competition indicated greater fitness-related traits such as height (H), tiller number (TN), aboveground fresh weight (AFW), and rhizome fresh weight (RFW) than the S population. Aggressiveness, competitive ratio, competition intensity index, and relative competition intensity indices confirmed also the superiority of the R population. Similarly, the R population grown in interspecific competition with corn or sunflower produced greater H, TN, and AFW than the S population. In addition, both R and S populations growing in competition with corn produced more H, TN, and AFW than those growing in competition with sunflower. Furthermore, the R population in competition with corn hybrids resulted in a greater reduction in H and AFW in corn plants. These findings strongly support the evidence of fitness advantage in the R population harboring the 1781Leu mutant allele as compared to the S counterpart. Full article

Cotton, as a globally significant economic crop, is intricately regulated in its growth and development by the key genes for SA (Salicylic acid) biosynthesis. In the present study, a systematic analysis of genes related to SA biosynthesis was conducted across four cotton species, leading to the identification of 70 genes. Specifically, the tetraploid species Gossypium hirsutum and G. barbadense were found to harbor 22 and 23 genes, respectively, representing a substantial expansion compared to the 12 and 13 genes identified in the diploid progenitors G. arboreum and G. raimondii. Comprehensive characterization of chromosomal localization, phylogeny, domain architecture, and promoter cis-elements revealed a uniform distribution of key genes involved in SA biosynthesis across A/D sub-genomes of tetraploids with extensive interspecific collinearity; whole-genome and segmental duplication act as the dominant drivers for the expansion of this gene family, while partial gene loss following polyploidization results in non-doubled gene copy numbers in tetraploids relative to diploids, which reflects the evolutionary selection for genomic dosage balance. The key genes for SA biosynthesis demonstrate a high degree of conservation in protein sequences, protein structures, and conserved motifs, which constitute the structural basis for the stable maintenance of their core functions in the SA biosynthesis pathway during plant evolution. This is closely related to their core function in the salicylic acid (SA) synthesis pathway and serves as the structural basis for the stable maintenance of gene functions during evolution. Analysis of cis-elements revealed that the expression of key genes involved in SA biosynthesis is governed by a complex interplay of phytohormones, stress signals, and transcription factors. Yeast one-hybrid (Y1H) assays confirmed the interaction between the GhPAL and GhICS gene and predicted candidate transcription factors, specifically the binding of GhWRKY21 to GhICS2-1 promoter and GhMYB12 to GhPAL1-2 promoter, thus elucidating their stage-specific regulatory mechanisms in cotton fiber development and reflecting their evolution. This study provides a fundamental basis for investigating the role of the SA signaling pathway in cotton development and offers support for cotton molecular breeding. Full article

The utilization of cytoplasmic male sterility (CMS) is essential in hybrid seed production; however, its operational value in eggplant is insufficiently documented under practical conditions. This study compared CMS-based and conventional (non-CMS) hybridization systems with respect to flower production, flower functionality, and hybrid seed production efficiency, quantified as seed and viable seedling output per unit time, in three eggplant cultivars (‘Emi’, ‘Langada’, and ‘Tsakoniki’) in intra- and interspecific crosses. CMS did not affect total flower production or inflorescence architecture, which were primarily genotype-dependent. However, it altered flower opening, resulting in genotype- and position-dependent proportions of semi-opened and closed flowers at anthesis. Despite this effect, sufficient flowers suitable for hybridization remained available across all genotypes. CMS substantially simplified the hybridization process by eliminating emasculation, reducing flower manipulation time by approximately 55%, and increasing crossing rate by nearly twofold. Importantly, CMS did not negatively affect female fertility, as indicated by comparable percentages of successful crosses and high seed germination rates across cytoplasmic backgrounds. Seed production per fruit was moderately but significantly increased in intraspecific crosses, while it remained comparable between CMS and non-CMS systems for the interspecific crosses. As a result, CMS significantly increased hybrid seed output and effective seedling production per unit time in intraspecific crosses, while similar trends were observed in interspecific crosses, with gains ranging from 86% to 184% depending on genotype and pollen parent. Overall, this study demonstrates, from an operational perspective, that CMS enhances the efficiency of eggplant hybrid seed production by reducing labor requirements and increasing output per unit time without compromising reproductive performance. These findings highlight the practical value of CMS as a tool for improving hybrid seed production systems, including applications in both commercial hybrid development and rootstock breeding. Full article

Almond (Prunus dulcis (Mill.) D.A. Webb) is one of the most economically important nut crops worldwide, valued for its nutritional properties and adaptability to diverse agroecological environments. This review summarizes current knowledge on almond domestication, genetic diversity, production trends, and improvement strategies, with a focus on drought tolerance under climate change. Archaeobotanical and molecular evidence indicate central Asia and the eastern Mediterranean as key centers of origin, where recurrent introgression from wild Prunus species contributed to the high genetic variability of cultivated almond. Global production trends reveal increasing challenges due to prolonged drought, climate variability, and rising water and energy costs, particularly affecting major producers such as the United States. Mediterranean regions are transitioning from traditional low-density orchards to intensive systems, where cultivar and rootstock choice are crucial for sustainability. Self-fertile and late-blooming cultivars improve yield stability, while interspecific hybrid rootstocks enhance water use efficiency and tolerance to drought and poor soils. Drought stress impacts almond physiology and yield, although moderate deficit irrigation can maintain productivity and improve kernel quality. Future improvement relies on germplasm conservation, marker-assisted selection, and genomic tools to develop climate-resilient cultivars integrated with sustainable water management strategies. Full article

Understanding the genetic diversity and population structure of Cucurbita species is essential for effective germplasm conservation and the development of improved cultivars. This study aimed to evaluate the genetic diversity, population structure, and genetic relationships among accessions of C. pepo, C. moschata and C. maxima and their interspecific hybrids (Tetsukabuto hybrid C. maxima × C. moschata). A total of 92 accessions were analyzed using 22 polymorphic simple sequence repeat (SSR) markers selected from previous studies due to their high polymorphic information content (PIC). Genetic diversity parameters were estimated, and population structure was inferred using Bayesian clustering, complemented by dendrogram and principal component analysis (PCA). All markers were successfully amplified in C. pepo, C. moschata, C. maxima, and the hybrids, with polymorphic information content (PIC) values ranging from 0.191 (CMTm232) to 0.448 (CMTm48) and average of 0.274. The AMOVA analysis showed that 50% of the total variation was attributed to differences both within and among groups. PCA revealed clear genetic differentiation among the analyzed species, with C. maxima and hybrid accessions clustering closely and exhibiting lower genetic dissimilarity. In contrast, C. pepo displayed greater genetic divergence, supporting its distinct evolutionary trajectory. According STRUCTURE analysis the accessions can be divided into four subpopulations, which are closely related to the species. PCA and dendrogram showed similar results for genetic structure of Cucurbita germplasm; C. maxima and hybrid accessions clustering closely and C. pepo as a distinct group. These findings provide valuable insights for breeding programs, germplasm management, and conservation strategies aimed at preserving genetic diversity and exploiting interspecific variation. Full article

In this study, 101 F₁ hybrid lines were constructed using Medicago sativa L. ‘Xinjiang Daye’ and Medicago falcata L. ‘Hulunbeier’ as parents, and their agronomic and quality traits were systematically evaluated over two consecutive years. The results showed that the hybrid progeny exhibited more pronounced phenotypic variation in the second year. Specifically, the X4H4 combination demonstrated superior biomass accumulation, while the H4X4 combination showed notable advantages in quality indices. In the second year, the correlations among agronomic traits were clearly strengthened, with morphological traits closely associated with biomass; coordinated variation was also observed among quality traits, as crude protein content was negatively correlated with fiber-related indices. Based on principal component and heterosis analysis, the hybrid lines were classified into distinct advantage groups: Group 1 exhibited clear agronomic heterosis, while Groups 2 and 3 displayed distinct advantages in quality traits. Finally, 12 elite individuals were selected based on integrated KASP molecular marker profiling and comprehensive phenotypic evaluation. This study establishes a strategy for marker-assisted phenotypic evaluation in alfalfa breeding, providing a theoretical basis and germplasm resources for the development of high-yield and high-quality cultivars. Full article

To mitigate supply risks associated with Hevea brasiliensis, Taraxacum kok-saghyz is being developed as a promising temperate source of natural rubber. For it to be successfully integrated into conventional cropping systems, optimized agronomic practices are required. The present study investigates the effects of sowing season (spring vs. autumn) and harvest timing (June–October) on rubber yield, determined by root dry weight and rubber content. Field trials were conducted at two contrasting locations in Germany using wild-type T. kok-saghyz and the interspecific hybrid ‘Hyb207’. Root dry weight accumulation was influenced by genotype, sowing season, harvest date and site conditions. Despite this variability, autumn sowing increased modeled root dry weight by approximately 81% and rubber content by 84% on average compared to spring sowing. In addition, autumn-sown plants reached peak root dry weight earlier in the season than their spring-sown counterparts. These results demonstrate that strategic selection of sowing and harvest windows is critical for optimizing yield formation. Site-specific management strategies can enhance biomass production and facilitate the integration of Tks into temperate cropping systems. Full article

(1) Reproductive isolation serves as a critical mechanism that prevents interspecific hybridization among closely related species, thereby preserving species integrity. In termites, hybridization between certain closely related species can overcome prezygotic isolation and produce offspring. However, whether these hybrids can overcome postzygotic barriers remains substantially underexplored. (2) This investigation conducted a comparative analysis of reproductive output (egg production and offspring count), physiological traits (body weight), functional characteristics (locomotor capacity), and hybrid fertility between the hybrid colony that was established by Reticulitermes flaviceps and R. chinensis and the conspecific pairing colonies of R. flaviceps and R. chinensis, respectively. (3) The results showed that hybrid colonies laid significantly more eggs and produced significantly more larvae than conspecific colonies. The hybrid offspring showed no decline in weight and locomotor capacity. Furthermore, the hybrid offspring maintained balanced sex ratios with unimpaired caste differentiation and fertility in both sexes. (4) These results demonstrate that the prezygotic reproductive isolation mechanism is incomplete between two closely related termite species, and there is a risk of forming hybrid populations. This work not only provides a theoretical basis for monitoring the risk of hybrid populations in termite management but also offers new insights into the evolution of reproductive isolation and speciation in social insects. Full article

Blackberry cultivars typically exhibit high fruit antioxidant levels but poor drought tolerance compared with their wild Rubus relatives. Few studies have employed wild Rubus species in hybridization programs aimed at improving drought tolerance and fruit quality in cultivated blackberries. In this study, we comprehensively assessed growth traits, fruit characteristics, and drought tolerance in 108 F₁ progenies derived from a cross between the cultivated blackberry ‘Prime-Ark^® Freedom’ and the wild species Rubus chingii. Correlation analysis of fruit morphological traits indicated significant positive associations among single fruit weight, fruit thickness, and fruit diameter, reflecting coordinated fruit development. Among the nutritional quality traits evaluated, both anthocyanin and total phenolic contents exhibited transgressive segregation. Specifically, 47.78% of the progeny demonstrated higher anthocyanin content, and 45.56% exhibited greater total phenolic content than the higher-performing parent. The corresponding genetic transmission ability (Ta) reached 139.23% and 101.24% for these traits, respectively, indicating pronounced additive genetic effects and high heritability. After a 7-day drought treatment, the hybrid progenies exhibited significant heterosis in catalase (CAT) activity, with 24.07% exceeding the higher-parent value. In contrast, proline content exhibited high broad-sense heritability (H² = 0.990) and considerable genetic variation. Under drought stress, all chlorophyll components were strongly positively correlated. Using principal component analysis (PCA), we established comprehensive evaluation models for fruit quality and drought tolerance. Based on these models, seven accessions—H3, H4, H8, H10, H11, H14, and H25—were identified as superior in both drought tolerance and fruit quality. This study provides an integrated evaluation framework for selecting drought-tolerant and high-quality genotypes from interspecific hybrid progenies in blackberry, offering a theoretical basis for utilizing wild Rubus resources in breeding improved cultivars. Full article

Freshwater macrophytes shape not only the morphological “architecture” of shallow-water ecosystems but also their chemical milieu via low-molecular-weight organic compounds (LMWOCs) that may regulate phytoplankton, periphyton, and the microbiome within the leaf/shoot diffusive boundary layer and the surrounding water column. In this study, GC–MS (gas chromatography–mass spectrometry) was used to identify major LMWOCs of the low-molecular-weight metabolome (LMWM) in 11 widely distributed macrophyte species (Myriophyllum spicatum L., Sparganium emersum Rehm., Sparganium gramineum Georgi, the hybrid Sparganium × foliosum A. A. Bobrov, Volkova, Mochalova et Chemeris, Persicaria amphibia (L.) Delarbre, Potamogeton perfoliatus L., Nuphar lutea (L.) Sibth. & Sm., Potamogeton pectinatus L., Potamogeton natans L., Lobelia dortmanna L., and Ceratophyllum demersum L.). Compounds contributing more than 1% to the total LMWOCs pool were considered major, increasing the ecological realism of interpretations by focusing on metabolites more likely to reach effective concentrations in the plant microenvironment. For interspecific comparisons, the maximum recorded values of relative abundance and concentrations were used to estimate species “potential”. In total, 137 major LMWOCs were detected (four remained unidentified), and their numbers varied markedly among taxa (from 11 in N. lutea to 71 in P. perfoliatus). Similarity analyses (Jaccard, Sørensen–Czekanowski, Morisita–Horn) indicated that similarity based on compound lists and similarity based on dominance structure may diverge, reflecting differences between the “LMWOCs set” and the quantitative architecture of LMWOCs within the LMWM. Fatty acids formed the core of the major fraction in all species: they were among the top three compounds in all 11 macrophytes and ranked first or second in 10 of 11, highlighting the lipid module as a universal “structure–signaling–defense/allelopathy” hub in aquatic plants. Also, an analysis of the ecological-biochemical role of the main major LMWOCs in the studied aquatic macrophytes is presented. Overall, the data offer a comparable, ecologically oriented framework for interpreting chemical regulation of communities in macrophyte-dominated habitats and for selecting target compounds/species for subsequent bioassay and field studies. Full article

Hybridization is considered an important process in plant evolution, especially in the origins of domesticated plant taxa, with many crop species being the result of interspecific hybridization events. There are several unidentified lineages of Spondias in the northeastern region of Brazil known only by vernacular names such as ‘cajaguela’, ‘umbu-cajá’, and ‘umbuguela’. These taxa are often regarded as being of hybrid origin, based on supposedly intermediate morphological features. However, the morphology-based hypotheses of hybrid origin and parentage of these Spondias taxa remain largely untested experimentally. We collected 355 accessions of Spondias, including S. bahiensis, other putative hybrid taxa, and both native (S. mombin, S. tuberosa, and S. venulosa) and introduced (S. purpurea) species believed to be the parental taxa. We then reconstructed phylogenies of plastid and nuclear markers and haplotype networks in order to ascertain the genetic affinities between putative hybrids and other Spondias species. All taxa with intermediate morphology were confirmed as hybrids between their putative parental species. All hybrids involving S. purpurea (native to Mexico) appear to be F₁ generation. The recently described S. bahiensis is shown to have originated from hybridization between S. tuberosa and S. venulosa. The other ‘umbu-cajá’ taxon found in Northeastern Brazil is revealed to be the result of hybridization between S. mombin and S. tuberosa. Both the northern ‘umbu-cajá’ taxon and S. bahiensis appear to be well-established hybrid lineages and not early-generation hybrids. Additionally, some introgression and backcrossing processes between S. bahiensis and one of the parents was also observed. Our findings confirm the hybrid origins of the domesticated Spondias taxa found in Northeastern Brazil. Full article

Drought stress is a major limiting factor for canola production in arid and semi-arid regions, particularly during seed germination, seedling and flowering stages. In this study, we evaluated drought responses of doubled haploid (DH) lines derived from interspecific hybrids of B. napus × B. rapa and their parental cultivars under simulated (PEG-6000) and soil-based drought conditions. Drought stress significantly reduced germination, growth, and physiological performance in all genotypes; however, DH lines consistently exhibited superior tolerance. Under PEG-induced osmotic stress, DH lines maintained higher germination rates, root elongation, and relative water content compared with parental genotypes. During seedling and flowering stages drought, DH lines showed lower accumulation of hydrogen peroxide and malondialdehyde, alongside markedly higher antioxidant enzyme activities (CAT and POD) and improved photosynthetic efficiency (Fv/Fm). Gene expression analysis revealed strong induction of drought-responsive genes, including WRKY28, MYB, LTP, WSP, metallothionein, and protein kinase family genes, particularly in DH lines at prolonged stress exposure. Multivariate analyses (PCA and correlation) confirmed a close association between enhanced antioxidant capacity, transcriptional activation, and drought tolerance traits. Overall, our results demonstrate that homozygous doubled haploid lines derived from distant hybridization between B. napus and B. rapa exhibit enhanced drought tolerance at both early and reproductive stages. These genotypes represent valuable genetic resources for breeding drought-tolerance canola cultivars. Full article

The conservation and genetic improvement of rare and endangered tree species are crucial for sustainable forest management. Liriodendron chinense, a relict species with limited distribution in China, exhibits high cross-compatibility with Liriodendron tulipifera, providing opportunities for interspecific hybrid breeding. In this study, 29 Liriodendron hybrids were established in a progeny trial plantation in Fujian Province, China, and subjected to multi-year evaluation of tree height, diameter at breast height (DBH), and individual stem volume. Significant differences (p < 0.01) among hybrids and hybrid × replicate interactions were detected for all traits across all assessment years, with individual stem volume showing the highest phenotypic coefficient of variation (35.30–40.56%). The mean annual increment in tree height increased during the early years, peaking at 1.50 m in the fourth year. Broad-sense and narrow-sense heritabilities for growth traits were consistently high (0.4073–0.7253 and 0.3410–0.6501, respectively), and the ratio of narrow-sense to broad-sense heritability ranged from 0.64 to 0.99, supporting the feasibility of early hybrid and individual selection. At a 10% selection intensity, hybrids No. 39, No. 59, and No. 74 were identified as elite, with selection based on individual stem volume providing the highest predictive accuracy and genetic gain (26.54–34.69%). Individual selection at a 1% intensity yielded genetic gains of 95.55–107.12% for stem volume. These results demonstrate substantial potential for early and efficient genetic improvement in Liriodendron hybrids, providing a theoretical foundation for the selection and deployment of elite hybrids and individuals in subtropical forest plantations. Full article