Search Results (162)

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

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), represents a major global threat to wheat (Triticum aestivum. L). Planting varieties with adult-plant resistance (APR) is an effective approach for long-term management of this disease. The Chinese winter wheat variety Lantian 25 exhibits moderate-to-high APR against stripe rust under field conditions. To investigate the genetic basis of APR in Lantian 25, a set of 219 F₆ recombinant inbred lines (RILs) was created from a cross between Lantian 25 (resistant parent) and Huixianhong (susceptible parent). These RILs were assessed for maximum disease severity (MDS) in Pixian of Sichuan and Qingshui of Gansu over the 2020–2021 and 2021–2022 growing seasons, resulting in data from four different environments. Genotyping was performed on these lines and their parents using the wheat Illumina 50K single-nucleotide polymorphism (SNP) arrays. Composite interval mapping (CIM) identified six quantitative trait loci (QTL), named QYr.gaas-2BS, QYr.gaas-2BL, QYr.gaas-2DS, QYr.gaas-2DL, QYr.gaas-3BS and QYr.gaas-4BL, which were consistently found across two or more environments and explained 4.8–12.0% of the phenotypic variation. Of these, QYr.gaas-2BL, QYr.gaas-2DS, and QYr.gaas-3BS overlapped with previous studies, whereas QYr.gaas-2BS, QYr.gaas-2DS, and QYr.gaas-4BL might be novel. All the resistance alleles for these QTL originated from Lantian 25. Furthermore, four kompetitive allele-specific PCR (KASP) markers, Kasp_2BS_YR (QYr.gaas-2BS), Kasp_2BL_YR (QYr.gaas-2BL), Kasp_2DS_YR (QYr.gaas-2DS) and Kasp_2DL_YR (QYr.gaas-2DL), were developed and validated in 110 wheat diverse accessions. Additionally, we identified seven candidate genes linked to stripe rust resistance, including disease resistance protein RGA2, serine/threonine-protein kinase, F-box family proteins, leucine-rich repeat family proteins, and E3 ubiquitin-protein ligases. These QTL, along with their associated KASP markers, hold promise for enhancing stripe rust resistance in wheat breeding programs. Full article

Corn smut, caused by Ustilago maydis, significantly threatens maize production. This study evaluated 199 maize inbred lines at the seedling stage under greenhouse conditions for resistance to U. maydis, identifying 39 highly resistant lines. A genome-wide association study (GWAS) using the mrMLM model detected 19 significant single-nucleotide polymorphism (SNP) loci. Based on a linkage disequilibrium (LD) decay distance of 260 kb, 226 candidate genes were identified. Utilizing the significant loci chr1_244281660 and chr5_220156746, two kompetitive allele-specific PCR (KASP) markers were successfully developed. A PCR-based sequence-specific oligonucleotide probe hybridization technique applied to the 199 experimental lines and 60 validation lines confirmed polymorphism for both markers, with selection efficiencies of 48.12% and 43.33%, respectively. The tested materials were derived from foundational inbred lines of domestic and foreign origin. Analysis of 39 highly resistant lines showed that the advantageous alleles carrying thymine/cytosine (T/C) predominated at frequencies of 94.87% and 53.84%, respectively. The genotype TTCC conferred high resistance, while CCTT was highly susceptible. The resistance exhibited high heritability and significant gene-by-environment interaction. This work systematically dissects the genetic basis of common smut resistance in maize, identifies favorable alleles, and provides a novel KASP marker-based strategy for developing disease-resistant germplasm. 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

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

The extension of genetic diversity is the basis for yield and adaptability improvements of winter wheat varieties under climate fluctuations. In the present study, an international collection consisting of 96 winter bread wheat accessions from Russia, Germany, Finland, Kazakhstan, Bulgaria, Turkey, the USA, and the international programme (Turkey–CIMMYT–ICARDA) was analysed under the conditions of Western Siberia during three growing seasons. Yield and yield-related traits were recorded following standard agronomy practices. Genotyping of the germplasm panel was conducted using 55 KASP markers at the Institute of Plant Biology and Biotechnology (Kazakhstan). The yield had a high correlation with the number of fertile tillers per unit area (0.68), which indicates significant yield reduction in wheat accessions from different origins that are not adaptive to the conditions of Western Siberia. The main stable QTLs associated with yield-related traits during two growing seasons, ippb_ta_1147 (1A), ippb_ta_107 (4A), ippb_ta_239 (5D), and ippb_ta_283 (6A), can be used in MAS for the improvement of yield and related traits. The outperforming genotypes Zhiva, Zolushka, Doneko, Line K 18918, Line 2293; CO13D1299, KS13DH0030-32, Gondvana//HBK0935-29-15/KS90W077-2-2/VBF0589-1… are recommended to be included in hybridisation programmes and represent promising sources for breeding high-yielding and climate-resilient winter wheat. Full article

Bacterial blight (BB) disease is a serious stress that affects up to 80% of rice yield. Utilizing an elite resistant variety was previously thought to be an alternative way to control disease outbreaks. The indigenous upland rice variety ULR207 is a high-potential donor for the BB resistance breeding program. However, the quantitative trait loci (QTLs) associated with bacterial blight resistance in this variety have not yet been discovered. Therefore, QTLs associated with BB resistance need to be identified. In this study, we identified the QTLs associated with BB resistance in the F_2:3 population crossed between the BB resistance variety ULR207 and Maled Phai, as well as a susceptible variety, via QTL-seq analysis and bulk-segregant analysis. We found a new QTL-associated BB resistance locus (qBBchr8) mapped on chromosome 8. Five positions were candidates, including Os08g0110700, Os08g0115200, Os08g0131300, Os08g0139500, and Os08g0163900. Afterwards, Kompetitive Allele-Specific PCR (KASP) markers specific to the SNP variant and the position of each gene were designed. These markers, associated with the disease lesion length phenotype, were validated with another 178 individual plants of the F₂ population via single-marker analysis. This analysis revealed that the position Os08g0110700 was the strongest locus, with a PVE of 15.00%. The results suggest that this KASP SNP marker could be used to improve elite rice for BB resistance. Full article

Wheat stripe rust (Puccinia striiformis f. sp. tritici, Pst) resistance and agronomic traits are crucial determinants of wheat yield. Elucidating the quantitative trait loci (QTLs) associated with these essential traits can furnish valuable genetic resources for improving both the yield potential and disease resistance in wheat. Lantian 31 is an excellent Chinese winter wheat cultivar; multi-environment phenotyping across three ecological regions (2022–2024) confirmed stable adult-plant resistance (IT 1–2; DS < 30%) against predominant Chinese Pst races (CYR31–CYR34), alongside superior thousand-kernel weight (TKW) and kernel morphology. Here, we dissected the genetic architecture of these traits using a total of 234 recombinant inbred lines (RILs) derived from a cross between Lantian 31 and the susceptible cultivar Avocet S (AvS). Genotyping with a 15K SNP array, complemented by 660K SNP-derived KASP and SSR markers, identified four stable QTLs for stripe rust resistance (QYrlt.swust-1B, -1D, -2D, -6B) and eight QTLs governing plant height (PH), spike length (SL), and kernel traits. Notably, QYrlt.swust-1B (1BL; 29.9% phenotypic variance) likely represents the pleiotropic Yr29/Lr46 locus, while QYrlt.swust-1D (1DL; 22.9% variance) is the first reported APR locus on chromosome 1DL. A pleiotropic cluster on 1B (670.4–689.9 Mb) concurrently enhanced the TKW and the kernel width and area, demonstrating Lantian 31’s dual utility as a resistance and yield donor. The integrated genotyping pipeline—combining 15K SNP discovery, 660K SNP fine-mapping, and KASP validation—precisely delimited QYrlt.swust-1B to a 1.5 Mb interval, offering a cost-effective model for QTL resolution in common wheat. This work provides breeder-friendly markers and a genetic roadmap for pyramiding durable resistance and yield traits in wheat breeding programs. Full article

To identify the key genes conferring resistance to soybean cyst nematode race 4 (SCN4, Heterodera glycines), this study utilized 280 recombinant inbred lines (RILs) derived from the resistant cultivar Huipizhiheidou (HPD) and the susceptible cultivar Jindou23 (JD23). Through phenotypic characterization and a genome-wide association study (GWAS), a genomic region (Gm18:1,223,546–1,782,241) on chromosome 18 was mapped, yielding 14 candidate genes. GmPDH1 was validated as a critical resistance gene using reverse transcription quantitative PCR (RT-qPCR) and Kompetitive Allele Specific PCR (KASP) marker M0526. RT-qPCR revealed that GmPDH1 expression in HPD roots was upregulated 9 days post-inoculation with SCN4 compared to uninoculated controls. KASP genotyping showed that marker M0526 efficiently distinguished between resistant and susceptible plants in natural populations: 71.05% of the resistant accessions exhibited resistant or moderately resistant genotypes, whereas 81.03% of the susceptible accessions showed susceptible or highly susceptible genotypes. Functional validation demonstrated that overexpression of GmPDH1 significantly enhanced SCN4 resistance in the susceptible cultivars JD23 and Jack, whereas CRISPR/Cas9-mediated knockout of GmPDH1 in HPD attenuated its resistance. This study confirmed GmPDH1 as a key gene governing SCN4 resistance and developed an efficient molecular marker, M0526, providing theoretical insights and technical tools for dissecting nematode resistance mechanisms and advancing soybean disease-resistant breeding. Full article

Hybrid necrosis in wheat is caused by an interaction between two genes, Ne1 and Ne2, that triggers the gradual death of plant tissue. This trait affects wheat breeding as the gene Ne2 is the same as the gene Lr13 for leaf rust resistance. We have built a three-marker haplotype that consists of single nucleotide polymorphism (SNP) marker information already available on genotyping arrays for the determination of the presence and absence of Ne2. In this work, test crosses of eight bread wheat varieties with known and unknown Ne1 carriers showed that six of them possessed Ne2. We analyzed a set of wheat varieties which had partial SNPs and phenotypic data, i.e., hybrid necrosis and leaf rust reactions, using Kompetitive Allele-Specific PCR (KASP) markers previously available for Ne2. The observed haplotypes of the SNP markers RAC875_c1226_652, Ra_c4397_542, and AX-110926324 perfectly matched the KASP marker variants for Ne2 and ne2. A prediction, based on these SNP haplotypes, of the distribution of Ne2 in wheat varieties, predominantly from Germany and released between 1900 and 2024, showed that breeding steadily increased the proportion of Ne2 in the German gene pool. Full article

Eggplant (Solanum melongena) is a significant vegetable in the Solanaceae family. Significant progress has been made in genetic diversity analysis and fingerprinting construction for crops such as tomatoes and peppers within the same family, but research on eggplants in these aspects remains relatively limited. Current germplasm identification using fingerprinting primarily relies on traditional SSR markers, which suffer from limited polymorphism and labor-intensive workflows. This study aimed to identify high-quality single nucleotide polymorphisms (SNPs), develop reliable Kompetitive Allele-Specific PCR (KASP) markers for eggplant genotyping, and then conduct fingerprint construction and genetic diversity analysis. The ultimate goals were to achieve a precise identification of eggplant varieties and deeply explore the genetic background and evolutionary patterns of eggplant germplasm. In this study, 49 representative eggplant accessions were re-sequenced. After data quality control, sequence alignment, and multiple rounds of screening, 224 high-quality SNPs were identified. Based on these SNPs, 96 SNPs were selected to develop KASP markers. These markers can provide abundant genetic markers for eggplant genetic research, which are used to deeply explore the genetic background and conduct genetic diversity analysis. After multiple rounds of rigorous verification, 32 core candidate markers were finally screened out. The average polymorphic information content (PIC) and gene diversity (GD) values were 0.36 and 0.46, respectively. Phylogenetic tree, population structure, and principal component analyses divided the 280 eggplant accessions into eight distinct groups. Through the analysis of minimal core markers and core germplasm, 23 core SNP markers and a subset of 56 core germplasm accessions were identified, leading to the establishment of a comprehensive fingerprinting system for all 280 accessions. Our findings provide a foundational genetic resource for eggplant germplasm identification and offer significant support for future breeding efforts. Full article

Maize is a crucial food crop and industrial raw material, significantly contributing to national food security. Aphids are one of the most prevalent and destructive pests in maize production, necessitating the exploration of pest-resistant germplasm and the development of resistant varieties as the most fundamental and effective strategy for mitigating aphid-induced damage. This study established an aphid resistance evaluation system and identified 17 elite resistant inbred lines through multi-year screening. A genome-wide association study (GWAS) revealed 22 significant single-nucleotide polymorphisms (SNPs) associated with aphid resistance, including genes involved in benzoxazinoid (Bx) biosynthesis (such as Bx2), insect resistance-related transcription factors (such as WRKY23), plant lectins, and other resistance pathways. RNA-seq analysis of the samples before and after aphid infestation detected 1037 differentially expressed genes (DEGs) in response to aphid infestation, with KEGG enrichment highlighting benzoxazinoid biosynthesis and starch/sucrose metabolism as primary response pathways. Integrating GWAS and RNA-seq results revealed the presence of several benzoxazinoid synthesis-related genes on the short arm of chromosome 4 (Chr4S). FMqRrm1, a Kompetitive Allele-Specific PCR (KASP) marker, was derived from the Chr4S region. We subsequently utilized this marker for marker-assisted selection (MAS) to introgress the Chr4S region from the aphid-resistant inbred line into two aphid-susceptible inbred lines. The results demonstrated that the Chr4S favorable allele significantly reduced aphid occurrence by 1.5 to 2.1 grades. This study provides a critical theoretical foundation and practical guidance for understanding the molecular mechanism of aphid resistance in maize and molecular breeding for aphid resistance. Full article

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a destructive disease of wheat worldwide. William Som (WS), an Argentinian spring wheat landrace, has consistently exhibited high-level resistance to stripe rust for over 20 years in our field evaluations in Washington state, USA. A previous study showed high-temperature adult-plant (HTAP) resistance in WS. To map the HTAP resistance quantitative trait loci (QTL) in WS, 114 F_5-8 recombinant inbred lines (RILs) from the cross AvS/WS were evaluated for their stripe rust response in seven field environments in Washington. The RILs and parents were genotyped with the Infinium 90K SNP chip. Four stable QTL, QYrWS.wgp-1BL on chromosome 1B (669–682 Mb), QyrWS.wgp-2AL on 2A (611–684 Mb), QyrWS.wgp-3AS on 3A (9–13 Mb), and QyrWS.wgp-3BL on 3B (476–535 Mb), were identified, and they explained 10.0–19.0%, 10.2–16.7%, 7.0–15.9%, and 12.0–27.8% of the phenotypic variation, respectively. The resistance in WS was found to be due to additive interactions of the four QTL. For each QTL, two Kompetitive allele-specific PCR (KASP) markers were developed, and these markers should facilitate the introgression of the HTAP resistance QTL into new wheat cultivars. Full article

Rye (Secale cereale), a cereal crop with high cold tolerance, serves as an ideal model for investigating plant cold adaptation mechanisms. Despite recent progress in identifying numerous genes and metabolic changes associated with cold tolerance, the detailed regulatory networks and coordinated interactions between metabolic pathways under low-temperature stress in rye remain unclear. In this study, we focused on the winter rye variety “Winter” and systematically explored its metabolic regulatory responses to cold stress through a combination of low-temperature treatments, phenotypic observations, antioxidant enzyme activity assays, and transcriptomic analysis. Four rye varieties (“Winter”, HZHM3, HZHM8, and “Victory”) were compared for cold tolerance, with the results indicating that “Winter” and HZHM3 exhibit superior cold tolerance. Physiological analysis revealed that after 12 h of exposure to −4 °C, the activities of catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) in “Winter” were significantly upregulated, displaying an initial increase followed by a decline over time. Transcriptomic sequencing identified 1643 differentially expressed genes (DEGs), and GO, KEGG, and GSEA enrichment analyses highlighted the critical roles of carbohydrate metabolism (ko00630) and amino acid metabolism (ko00250) pathways in the cold stress response. These pathways are interconnected through key metabolic intermediates such as L-glutamate, collectively regulating cold adaptation. Furthermore, based on the transcriptomic data, we identified and developed molecular markers associated with cold tolerance, detecting 10,846 EST-SSR and 250,116 EST-SNP markers. We successfully developed 13 EST-SSR primer pairs applicable to rye and 7 KASP markers. Notably, the KASP-665 marker effectively distinguishes between winter and spring rye, providing a reliable tool for marker-assisted selection in cold tolerance breeding. This study not only elucidates the metabolic regulatory mechanisms of rye under low-temperature stress but also provides a solid theoretical and technical foundation for future cold-tolerance breeding programs. Full article

A male sterile mutant, S201, was identified in Brassica napus. Genetic analysis revealed that the male sterility trait was controlled by a recessive nuclear gene, male sterility (MS), which was stably inherited. The results of microscopy showed that the main reason for male sterility was a defect in microspore development, resulting in the absence of typical exine and mature microspores. Bulked segregant analysis (BSA) and genotyping of an F₂ population showed that the MS gene was located in a 1.4 Mb region. Sequence analysis showed that the CYP704B1 gene in this region contained two non-synonymous SNPs, leading to substitutions of two amino acids. A high-throughput KASP marker was characterized to detect the presence of the ms gene in the breeding population. The data presented here indicate that the male sterile mutant S201 can be applied in rapeseed breeding by producing the male sterile line and that the KASP marker developed for male sterility will be useful in marker-assisted selection of male sterile individuals in rapeseed-breeding programs. Full article