Search Results (189)

Maize (Zea may L.) is one of the most important crops worldwide, but ear rot poses a significant threat to its production. Diverse pathogens cause ear rot in China, with Fusarium spp. being predominant, especially Fusarium graminearum and Fusarium verticillioides. Current methods for the control of ear rot are limited, making the use of resistant germplasm resources an effective and economical management strategy. Earlier research focused on resistance to Fusarium ear rot (FER; caused by F. verticillioides) and Gibberella ear rot (GER; caused by F. graminearum), but assessing maize resistance to multiple major Fusarium spp. is critical in ensuring maize production. Thus, the resistance of 343 maize germplasm resources to ear rot caused by six Fusarium spp. (F. verticillioides, F. graminearum, F. proliferatum, F. meridionale, F. subglutinans, and F. temperatum) was evaluated in this study. Over three years, 69 and 77 lines resistant to six and five ear rot diseases, respectively, and 139 lines resistant to both FER and GER were identified. Moreover, the 343 germplasm resources were divided into eight heterotic groups, of which PH4CV was the most resistant one, whereas NSS and Pioneer Female were the least resistant ones. These findings provide a basis for the development of maize cultivars with broad-spectrum ear rot resistance. Full article

Fusarium root rot, caused by Fusarium equiseti, poses a significant threat to soybean production. This study aimed to explore the genetic basis of resistance to Fusarium equiseti root rot (FERR) by evaluating the resistance phenotype of 346 soybean germplasms and conducting a genome-wide association study (GWAS) using 698,949 SNP markers obtained from soybean germplasm resequencing data. GWAS analysis identified 101 SNPs significantly associated with FERR resistance, distributed across nine chromosomes, with the highest number of SNPs on chromosomes 13 and 20. Further gene-based association and allele variation analyses identified candidate genes whose mutations are closely related to FERR resistance. To accelerate soybean FERR resistance breeding screening, we developed CAPS markers S13_14464319-CAPS1 and S15_9215524-CAPS2, targeting these SNP sites, and KASP markers based on the S15_9205620-G/A, providing an effective tool for marker-assisted selection (MAS). This study offers a valuable theoretical foundation and molecular marker resources for the functional validation of FERR resistance genes and soybean disease resistance breeding. Full article

Polyploidy in plants can enhance stress resistance and secondary metabolite production, offering potential benefits for Clausena lansium (L.) Skeel, a medicinally valuable species. However, systematic studies of polyploidy-induced morphological, anatomical, and metabolic changes in this species are lacking. This study aimed to induce and characterize polyploid C. lansium lines, assess ploidy-dependent variations, and evaluate their impact on bioactive metabolite accumulation. Three cultivars were hybridized, treated with colchicine, and bred, yielding 13 stable polyploid lines confirmed by flow cytometry and chromosome counting. The polyploids exhibited distinct traits, including larger pollen grains, altered leaf margins, increased leaflet numbers, enlarged guard cells with reduced stomatal density, and thicker leaf tissues. Metabolomic analysis revealed that tetraploids accumulated significantly higher levels of flavonoids, alkaloids, and phenolic acids compared to diploids, while triploids showed moderate increases. These findings demonstrate that polyploidization, particularly tetraploidy, enhances C. lansium’s medicinal potential by boosting pharmacologically active compounds. The study expands germplasm resources and supports the development of high-quality cultivars for pharmaceutical applications. Full article

Introduction: Scattering of kernels due to angular dehiscence is a key bottleneck in mechanized harvesting of oilseed rape. Materials and Methods: In this study, a dual-track “genotype–phenotype” screening strategy was established by innovatively integrating high-throughput KASP molecular marker technology and a standardized random collision phenotyping system for the complex quantitative trait of angular resistance. Results: Through the systematic evaluation of 634 oilseed rape hybrid progenies, it was found that the KASP marker S12.68, targeting the cleavage resistance locus (BnSHP1) on chromosome C9, achieved a 73.34% introgression rate (465/634), which was significantly higher than the traditional breeding efficiency (<40%). Phenotypic characterization screened seven excellent resources with cracking resistance index (SRI) > 0.6, of which four reached the high resistance standard (SRI > 0.8), including the core materials NR21/KL01 (SRI = 1.0) and YuYou342/KL01 (SRI = 0.97). Six breeding intermediate materials (44.7–48.7% oil content, mycosphaerella resistance MR grade or above) were created, combining high resistance to chipping and excellent agronomic traits. For the first time, it was found that local germplasm YuYou342 (non-KL01-derived line) was purely susceptible at the S12.68 locus (SRI = 0.86), but its angiosperm vascular bundles density was significantly increased by 37% compared with that of the susceptible material 0911 (p < 0.01); and the material 187308 (SRI = 0.78), although purely susceptible at S12.68, had a 2.8-fold downregulation in expression of the angiosperm-related gene, BnIND1, and a 2.8-fold downregulation of expression of the angiosperm-related gene, BnIND1. expression was significantly downregulated 2.8-fold (q < 0.05), indicating the existence of a novel resistance mechanism independent of the primary effector locus. Conclusions: The results of this research provide an efficient technical platform and breakthrough germplasm resources for oilseed rape crack angle resistance breeding, which is of great practical significance for promoting the whole mechanized production. Full article

Drought stress has a significant impact on cotton growth, development, and productivity. This study conducted drought stress treatment and normal water treatment (control group) on 502 cotton accessions and analyzed data on eight phenotypic traits closely related to drought stress tolerance. The results showed that all indicators changed significantly under drought stress conditions compared to the control group, with varying degrees of response among different indicators. To comprehensively evaluate the drought resistance of cotton during the germination period, the values of drought resistance comprehensive evaluation (D-value), weight drought resistance coefficient (WDC-value), and comprehensive drought resistance coefficient (CDC-value) were calculated based on membership function analysis and principal component analysis. Cluster analysis based on the D-value divided the germplasm into five drought-resistant grades, followed by the selection of one extreme material, each from the strongly drought-resistant and strongly drought-sensitive groups. An evaluation model was established using stepwise regression analysis, including the following effective indicators: Relative Fresh Weight (RFW), Relative Hypocotyl Length (RHL), Relative Seeds Water Absorption Rate (RAR), Relative Germination Rate (RGR), Relative Germination Potential (RGP), and Relative Drought Tolerance Index (RDT). The validation of the D-value prediction model based on the Best Linear Unbiased Prediction (BLUP) showed that the results obtained from two independent biological replicates were highly consistent. The comprehensive evaluation system and screening indicators established in this study provide a reliable method for identifying drought tolerance during the germination period. Full article

Maize is an essential staple food, and its genetic diversity plays a central role in breeding programs aimed at developing climate-adapted cultivars. Constructing a representative core germplasm set is necessary for the efficient conservation and utilization of maize genetic resources. In this study, we analyzed 588 cultivated maize accessions using agronomic traits such as plant morphology and yield traits such as ear characteristics and single-nucleotide polymorphisms (SNPs) to assess molecular diversity and population structure and to construct a core collection. Nineteen phenotypic traits were evaluated, revealing high genetic diversity and significant correlations among most quantitative traits. The optimal sampling strategy was identified as “Mahalanobis distance + 20% + deviation sampling + flexible method.” Whole-genome genotyping was conducted using the Maize6H-60K liquid phase chip. Population structure analysis, principal component analysis, and cluster analysis divided the 588 accessions into six subgroups. A core collection of 172 accessions was selected based on both phenotypic and genotypic data. These were further evaluated for salt–alkali tolerance during germination, and cluster analysis classified them into five groups. Sixty-five accessions demonstrated salt–alkali tolerance, including 18 with high resistance. This core collection serves as a valuable foundation for germplasm conservation and utilization strategies. Full article

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat to global rice productivity. Although hybrid rice breeding has significantly enhanced yields, persistent genetic vulnerabilities within restorer lines continue to compromise BB resistance. This study addresses this challenge by implementing functional marker-assisted selection (FMAS) to pyramid two broad-spectrum resistance (R) genes, Xa21 and Xa23, into the elite, yet BB-susceptible, restorer line K608R. To enable precise Xa23 genotyping, we developed a novel three-primer functional marker (FM) system (IB23/CB23/IR23). This system complements the established U1/I2 markers used for Xa21. This recombination-independent FMAS platform facilitates simultaneous, high-precision tracking of both homozygous and heterozygous alleles, thereby effectively circumventing the linkage drag limitations typical of conventional markers. Through six generations of marker-assisted backcrossing followed by intercrossing, we generated K608R2123 pyramided lines harboring both R genes in homozygous states, achieving a recurrent parent genome recovery rate of 96.93%, as determined by single nucleotide polymorphism (SNP) chip analysis. The pyramided lines exhibited enhanced resistance against six virulent Xoo pathogenic races while retaining parental yield performance across key agronomic traits. Our FMAS strategy overcomes the historical trade-off between broad-spectrum resistance and the preservation of elite phenotypes, with the developed lines exhibiting resistance coverage complementary to that of both introgressed R genes. This integrated approach provides breeders with a reliable molecular tool to accelerate the development of high-yielding, disease-resistant varieties, demonstrating significant potential for practical deployment in rice improvement programs. The K608R2123 germplasm represents a dual-purpose resource suitable for both commercial hybrid seed production and marker-assisted breeding programs, and it confers synergistic resistance against diverse Xoo races, thereby providing a pivotal breeding resource for sustainable BB control in epidemic regions. Full article

Soybean frogeye leaf spot (FLS) disease has been reported globally and is caused by the fungus Cercospora sojina, which affects the growth, seed yield, and quality of soybean. Among the 15 physiological microspecies of C. sojina soybean in China, Race 7 is one of the main pathogenic microspecies. A few genes are involved in resistance to FLS, and they cannot meet the need to design molecular breeding methods for disease resistance. In this study, a soybean recombinant inbred line (RIL3613) population and a germplasm resource (GP) population were planted at two sites, Acheng (AC) and Xiangyang (XY). Phenotypic data on the percentage of leaf area diseased (PLAD) in soybean leaves were obtained via image recognition technology after the inoculation of seven physiological species and full onset at the R3 stage. Quantitative trait loci (QTLs) and quantitative trait nucleotides (QTNs) were mapped via linkage analysis and genome-wide association studies (GWASs), respectively. The resistance genes of FLS were subsequently predicted in the linkage disequilibrium region of the collocated QTN. We identified 114 QTLs and 18 QTNs in the RIL3613 and GP populations, respectively. A total of 14 QTN loci were colocalized in the two populations, six of which presented high phenotypic contributions. Through haplotype–phenotype association analysis and expression quantification, three genes (Glyma.06G300100, Glyma.06G300600, and Glyma.13G172300) located near molecular markers AX-90524088 and AX-90437152 (QTNs) are associated with FLS Chinese Race 7, identifying them as potential candidate resistance genes. These results provide a theoretical basis for the genetic mining of soybean antigray spot No. 7 physiological species. These findings also provide a theoretical basis for understanding the genetic mechanism underlying FLS resistance in soybeans. Full article

This study aimed to investigate the cracking characteristics of various sweet potato germplasm resources, explore their genetic associations, and identify crack-resistant varieties. Using 40 sweet potato varieties as experimental materials, we systematically analyzed their cracking traits and assessed 24 parameters. The results indicated that genotypic differences significantly influenced sweet potato cracking (p = 1.11 × 10⁻¹⁶). Correlation analyses revealed that skin thickness (r = −0.81, p < 0.01), skin hardness (r = −0.50, p < 0.01), and starch content (r = −0.51, p < 0.01) were highly significantly negatively correlated with cracking incidence. Microscopic observations of the cell structure revealed that the development quality of the cork cambium and vascular cambium during the secondary growth stage plays a crucial role in maintaining the structural stability of the tuber skin, whereas the internal expansion force during the rapid growth phase is a direct factor that induces cracking. A multiple regression prediction model (R² = 0.85) was established based on ten core indices. Furthermore, a comprehensive evaluation system for sweet potato cracking resistance was developed by integrating principal component analysis and the entropy-weighted TOPSIS model (kappa = 0.752, p = 5 × 10⁻⁶), identifying seven extremely crack-resistant and nine crack-resistant varieties. This study is the first to construct a multidimensional evaluation system for cracking traits in sweet potato, offering a reference for breeding crack-resistant varieties and developing cultivation, prevention, and management strategies. Full article

Seed deterioration is an inevitable process during storage, characterized by a gradual loss of germination capacity and eventual seed death, which poses challenges to seed longevity and the preservation of genetic resources. Understanding the molecular mechanisms driving seed aging and inherent resistance pathways, alongside developing innovative rejuvenation strategies for deteriorated seeds, is crucial for agricultural sustainability and germplasm banking. This review systematically examines (1) redox-regulated deterioration pathways involving reactive oxygen species (ROS) and macromolecular damage cascades, (2) anti-deterioration mechanisms mediated by the antioxidant system and macromolecular repair mechanisms, (3) genetic–epigenetic networks governing seed aging resistance, particularly ABA- and IAA-mediated signaling through ABI3/ABI5/LEC1 regulons, and (4) technological advances in seed priming that restore aged seeds via metabolic resetting and repair potentiation. By integrating multi-omics insights with physiological evidence, we propose a hierarchical model of seed deterioration and establish mechanistic links between priming interventions and longevity enhancement. These insights offer a theoretical framework for cultivating anti-deterioration crop varieties and developing seed longevity-enhancement technologies. Full article

Common beans (Phaseolus vulgaris L.) are considered a socially and economically important crop, with the biggest growers in India, Myanmar, and Brazil. Traditionally, common beans are also grown in most parts of Europe, including Latvia, where cultivation areas have remained relatively constant since the middle of the last century. This is explained by the plant’s higher thermal requirements compared to peas and faba beans more widely grown here. Despite this, landraces adapted to local conditions have been developed, whose origin and potential relationship with another European common bean germplasm is very limited. Therefore, the study aimed to characterise the morphology of the common bean germplasm collected and grown in Latvia to identify the most valuable material for further crop development and evaluate the local landraces in the European common bean germplasm context. The 28 genotypes representing Latvian landraces and European reference genotypes were phenotyped using 26 traits of bean seeds, pods, leaves, flowers, and stems, which were evaluated according to an internationally applied methodology. Latvian varieties showed phenotypical variability and characteristics that were different from those found in other European regions, showing the significance of the germplasm under study and highlighting the need for conservation. Local varieties (landraces) are reservoirs of unique genetic traits. Their adaptability to local environmental conditions, resistance to pests and diseases, and their potential to enhance nutritional quality make them invaluable resources for in situ conservation efforts and targeted genetic improvement programmes. Emphasising the utilisation of these landraces can contribute to sustainable agriculture, climate resilience, and food security. Full article

Salinity stress poses a major challenge to agricultural productivity worldwide, including for pumpkin, a globally cultivated vegetable crop with great economic value. To deal with salt stress, plants exhibit an array of responses such as changes in their root system architecture. However, the root phenotype and gene expression of pumpkin in response to different concentrations of NaCl remains unclear. To this end, this study evaluated the effects of salinity stress on root architecture in C. moschata (Cmo-1, Cmo-2 and Cmo-3) and C. maxima (Cma-1, Cma-2 and Cma-3), as well as their hybrids of C. moschata and C. maxima (Ch-1, Ch-2 and Ch-3) at the germination and seedling stages. The results showed that the total root length and the number of root tips decreased by more than 10% and 5%, respectively, under 180 mM NaCl conditions compared to those under the 0 mM NaCl conditions. In contrast, the total root length and the number of root tips were increased or decreased under 60 mM NaCl conditions. Meanwhile, salt stress was considered severe when treated with more than 120 mM NaCl, which could be used to evaluate the salt tolerance of the germplasm resources of pumpkin. In addition, the transcriptional changes in the roots of both Cmo-3 and Cma-2 under salt stress were analyzed via RNA-sequencing. We found 4299 and 2141 differential expression genes (DEGs) in Cmo-3 and Cma-2, respectively. Plant hormone signal transduction, Phenylpropanoid biosynthesis and the MAPK signaling pathway were found to be the significant KEGG pathways. The expression of ARF (auxin response factor), B-ARR (type-B response regulator) and PYR (pyrabactin resistance)/PYL (PYR-LIKE) genes was downregulated by NaCl treatment. In contrast, the expression of SnRK2 (sucrose non-fermenting-1-related protein kinase 2) and AHP (histidine-containing phosphotransmitter) genes was downregulated in Cmo-3 and upregulated in Cma-2. These findings will help us better understand the mechanisms of salt tolerance in pumpkins and potentially provide insight into enhancing salt tolerance in crop plants. Full article

Bacterial leaf streak (BLS) is one of the internationally significant quarantine diseases in rice. Effectively utilizing BLS resistance genes from wild rice (Oryza rufipogon Griff.) to breed new varieties offers a fundamental solution for BLS control. This study focused on the fine mapping of the BLS resistance gene bls2 and the development of closely linked molecular markers for breeding BLS-resistant lines. Using a Guangxi common wild rice accession DY19 (carrying bls2) as the donor parent and the highly BLS-susceptible indica rice variety 9311 as the recipient parent, BLS-resistant rice lines were developed through multiple generations of backcrossing and selfing, incorporating molecular marker-assisted selection (MAS), single nucleotide polymorphism(SNP) chip genotyping, pathogen inoculation assays, and agronomic trait evaluation. The results showed that bls2 was delimited to a 113 kb interval between the molecular markers ID2 and ID5 on chromosome 2, with both markers exhibiting over 98% accuracy in detecting bls2. Four stable new lines carrying the bls2 segment were obtained in the BC₅F₄ generation. These four lines showed highly significant differences in BLS resistance compared with 9311, demonstrating moderate resistance or higher with average lesion lengths ranging from 0.69 to 1.26 cm. Importantly, no significant differences were observed between these resistant lines and 9311 in key agronomic traits, including plant height, number of effective panicles, panicle length, seed setting rate, grain length, grain width, length-to-width ratio, and 1000-grain weight. Collectively, two molecular markers closely linked to bls2 were developed, which can be effectively applied in MAS, and four new lines with significantly enhanced resistance to BLS and excellent agronomic traits were obtained. These findings provide technical support and core germplasm resources for BLS resistance breeding. Full article

The anther culture-based breeding of rice is a plant tissue culture technique that utilizes rice pollen to rapidly obtain haploid plants. In comparison with traditional breeding methods, this technique shortens the breeding cycle and enables the quick generation of homozygous plants, which is of great significance for the development of new rice varieties and the expansion of germplasm resources. With the advancement of technologies, the use of the anther culture technique in rice breeding has matured and has been applied to the development and utilization of new varieties with high yield, multiple resistances, and superior quality, in combination with other breeding methods. This technique has gained widespread attention globally, with many countries adopting it to create new germplasm resources. This study reviews advances in the rice anther culture technique, the factors influencing anther culture efficiency, and the progress in breeding rice varieties using this technique, as well as analyzes the current challenges and future prospects of anther culture breeding. Full article

Rice is a globally important food crop, and phosphorus is an essential nutrient element for rice growth. In many of China’s arable lands, there is a deficiency in available phosphorus content. Therefore, screening and breeding rice germplasm resources that are tolerant to low phosphorus can enhance the growth capability of rice in low-phosphorus soils. This study set up treatments with two phosphorus concentrations: H₂PO₄⁻ at 0.18 mmol/L, referred to as normal phosphorus (NP), and H₂PO₄⁻ at 0.009 mmol/L, referred to as low phosphorus (LP). Using hydroponic methods, 156 different genotype rice germplasms were treated for 35 days, after which the morpho-physiological traits of the rice seedling shoots, root morphology, and material content were measured. An analysis of the coefficient of variation (CV) for low phosphorus tolerance coefficients across different rice germplasm resources revealed that 16 indicators had CVs greater than 10%, which can be used as criteria for screening rice varieties with low phosphorus tolerance at the seedling stage. The relevant indicators and low-phosphorus resistance characteristics of different rice varieties were comprehensively evaluated using principal component analysis, correlation analysis, membership function, and cluster analysis methods. The results indicate that the principal component analysis transformed 23 indicators into 5 comprehensive indicators, with a cumulative contribution rate of 86.947%. The D value was evaluated in a comprehensive evaluation of low-phosphorus resistance, and 156 rice germplasm resources were divided into four types by cluster analysis. A scatter plot was created using the comprehensive phosphorus efficiency values of different rice germplasms under normal phosphorus and low phosphorus conditions. Through further verification, the germplasms with strong low-phosphorus tolerance finally selected through comprehensive screening were Y3-14, Y3-35, Y3-21, Jinnongda 705, Changjing 625, and Jinnongda 873. The germplasms with poor low-phosphorus tolerance were Jijing 338, Jingu 981, Tong 35, Y3-31, and Longdao 20. Full article