Wheat is among the most important staple crops worldwide; however, its yield and quality are severely threatened by stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). CH806 is a Thinopyrum intermedium-derived resistant breeding line developed in our laboratory that is highly resistant to the prevalent Chinese Pst races CYR32, CYR33, and CYR34 in field trials. A genetic population was developed by crossing CH806 with the susceptible cultivar Chuanmai 24. Phenotypic evaluation of the progeny under field conditions revealed segregation for stripe rust resistance in the F2 generation. On the basis of the resistance phenotypes of the F2 and F2:3 populations, homozygous resistant and homozygous susceptible F2 individuals were selected to construct resistant and susceptible DNA bulks, respectively, for genotyping using the Wheat 120K SNP array. Bulked segregant analysis indicated that the most significant SNPs were predominantly clustered on chromosome 4A. Subsequently, publicly available simple sequence repeat (SSR) markers on chromosome 4A and newly developed SSR markers within the candidate region that were enriched for polymorphic SNPs were used for linkage analysis. The resistance locus, temporarily designated YrCH806, was mapped to an interval flanked by markers Xwmc48/Xwmc89 and SSR4A-60, with genetic distances of 4.4 cM and 2.5 cM, respectively, corresponding to a physical position of 515.8–574.7 Mb on the wheat reference genome. The closest flanking marker, SSR4A-60, was successfully converted into a Kompetitive Allele-Specific PCR (KASP) marker. This high-throughput marker was subsequently utilized to screen a panel of wheat germplasms for the distribution of YrCH806. This study provides a novel resistance source and associated molecular markers for improving stripe rust resistance in wheat breeding programs.

Nitrogen is a crucial element that impacts rice yield and its constituent factors. The effects of reduced nitrogen levels on yield constitute is a complex quantitative trait that is controlled by multiple genes, and its genetic basis requires further exploration. In this study, 562 MAGIC line population and 284 germplasm varieties were used for genome-wide association analysis (GWAS) and haplotype analysis, aiming to detect quantitative trait loci (QTL) and candidate genes associated with tolerance to low nitrogen levels. The ratio of effective panicle number per plant (REPN), total number of grains per panicle (RTGN), seed setting rate (RSSR), thousand grain weight (RTGW), biomass (RBM), harvest index (RHI), and grain yield per plant (RGY) of low to normal nitrogen conditions were measured in this study. The RBM and RHI were directly closely related to RGY, while the RSSR indirectly and positively affected RGY through RHI, and the REPN and RTGN mainly indirectly and positively affected RGY through RBM. LOC_Os06g06440 was the most likely gene affecting low-nitrogen-tolerance-related traits in rice within the region, ranging from 2.898 Mb to 3.046 Mb (148 kb) on chromosome 6, and the haplotype AA, with a significantly larger mean RGY of 0.95 and 1.53 in the MAGIC and germplasm varieties, respectively, was the advanced allele of LOC_Os06g06440. Nine xian (indica) varieties (IRIS_313-11624, IRIS_313-10932, CX382, B067, B249, IRIS_313-8215, IRIS_313-10544, B052, and B233) carrying the superior haplotype (AA) of LOC_Os06g06440 and having a higher RGY were selected for the molecular marker-assisted selection of low nitrogen tolerance in rice. These results will enhance our knowledge of the genetic basis of tolerance to low levels of nitrogen and provide valuable information for improving tolerance to low levels of nitrogen in rice-breeding programs.

Abiotic stress has been a great challenge to global food security. To reduce its effects, breeding crops for tolerance to abiotic stresses is a promising strategy. Broomcorn millet is cultivated in arid and semiarid areas with a high degree of abiotic stress tolerance. However, due to the lack of efficient genetic transformation methods for broomcorn millet, the characterization of genes related to abiotic stress tolerance lags behind that of other crop species. Therefore, establishing efficient in vitro regeneration and genetic transformation methods for broomcorn millet is essential. In this study, we used mature seeds of the sequenced variety ‘Longmi 4’ as explants and optimized its in vitro regeneration and genetic transformation methods. The optimal hormone concentrations for embryogenic callus induction medium were 2.5 mg/L 2,4-dichlorophenoxyacetic and 0.5 mg/L 6-benzylaminopurine. The optimal hormone concentrations for shoot regeneration medium were 2 mg/L 6-benzylaminopurine and 0.5 mg/L a-naphthaleneacetic acid. Additionally, the co-cultivation time was 3 days, and the optimal hygromycin concentration for putative transgenic callus selection was 20 mg/L. The transformation efficiency was 21.25

The awn can contribute to photosynthesis and carbohydrates, enhancing grain yield in wheat. We mapped QAwn.sxau-5A, a major QTL for awn development in wheat (Triticum aestivum). This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A, which included the candidate gene encoding a zinc finger protein (TraesCS5A01G542800) as an awn length inhibitor (ALI). The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait. The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level, indicating the gene was regulated at the transcript level. However, the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region, resulting in a truncated protein compared to the functional Ali-A1 protein. The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motifs, one at the N terminus (EAR-N) and the other at the C terminus (EAR-C), and they were involved in interactions with the wheat co-repressor protein TOPLESS (TPL1). The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif, resulting in the attenuated ability to interact with TPL1. The tpl1 mutant produced a longer awn compared to the wild type. Ali-A1 repressed the transcription of two downstream genes, TaLRP-A1 and TaARF-B1, involved in endogenous auxin concentrations and auxin responses in wheat. We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.

Genome-wide association studies (GWASs) encounter limitations from population structure and sample size, restricting their efficacy. Though meta-analysis mitigates these issues, its application in rice research remains limited. Here, we report a large-scale meta-analysis of six independent GWAS experiments in rice to mine genes for key agronomic traits. By integrating a rice pan-genome graph to identify structural variants, we obtained 6,604,898 SNP and 42,879 PAV variants for the six panels (7765 accessions). Meta-analysis significantly improved quantitative trait loci (QTLs) detection and hidden heritability by up to 43 and 37.88%, respectively. Among 156 QTLs identified for six agronomic traits, 116 were exclusively detected through meta-analysis, highlighting its superior resolution. Two novel QTLs governing grain width and length were functionally validated through CRISPR/Cas9, confirming their candidate genes. Our findings underscore the utility and potential advantages of this pan-genome-based meta-GWAS approach, providing a scalable model for efficiently gene mining from diverse rice germplasms.

Common oat (Avena sativa L.) is one of the important minor grain crops in China, and drought stress severely affects its yield and quality. To investigate the drought resistance characteristics of oat seedlings, this study used Baiyan 2, an oat cultivar at the three-leaf stage, as the experimental material. Drought stress was simulated using polyethylene glycol (PEG) to treat the seedlings. The photosynthetic parameters and physicochemical indices of the treatment groups at 6 h and 12 h were measured and compared with the control group at 0 h. The results showed that drought stress did not significantly change chlorophyll content, but it significantly reduced net photosynthetic rate and other photosynthetic parameters while significantly increasing proline content. Transcriptome analysis was conducted using seedlings from both the control and treatment groups, comparing the two treatment groups with the control group using Tbtool software (v2.136). This analysis identified 344 differentially expressed genes. Enrichment analysis of these differentially expressed genes revealed significant enrichment in physiological pathways such as photosynthesis and ion transport. Ten differentially expressed genes related to the physiological process of photosynthetic carbon assimilation were identified, all of which were downregulated. Additionally, seven differentially expressed genes were related to ion transport. Through gene co-expression analysis combined with promoter region structure analysis, 11 transcription factors (from MYB, AP2/ERF, C2C2-dof) were found to regulate the expression of 10 genes related to photosynthetic carbon assimilation. Additionally, five transcription factors regulate the expression of two malate transporter protein-related genes (from LOB, zf-HD, C2C2-Dof, etc.), five transcription factors regulate the expression of two metal ion transporter protein-related genes (from MYB, zf-HD, C2C2-Dof), five transcription factors regulate the expression of two chloride channel protein-related genes (from MYB, bZIP, AP2/ERF), and two transcription factors regulate the expression of one Annexin-related gene (from NAC, MYB). This study provides a theoretical foundation for further research on the molecular regulation of guard cells and offers a molecular basis for enhancing drought resistance in oats.

Polyploidy, a prevalent event in plant evolution, drives phenotypic diversification and speciation. While transcriptional changes and regulation in polyploids have been extensively studied, the translational level impact remains largely unexplored. To address this gap, we conducted a comparative transcriptomic and translatomic analysis of cotton leaves from allopolyploid species G. hirsutum (AD1) and G. barbadense (AD2) relative to their model A-genome and D-genome diploid progenitors. Our data revealed that while allopolyploidization significantly affects the transcriptional landscape, its impact on translation was relatively modest, evidenced by a narrower expression range and fewer expression changes in ribosome-protected fragments than in mRNA levels. Allopolyploid-specific changes commonly identified in both AD1 and AD2 were observed in 7393 genes at either transcriptional or translational levels. Interestingly, the majority of translational changes exhibited concordant down-regulation in both ribosome-protected fragments and mRNA, particularly associated with terpenoid synthesis and metabolism (352 genes). Regarding translational efficiency (TE), at least one-fifth of cotton genes exhibit translational level regulation, with a general trend of more down-regulation (13.9–15.1%) than up-regulation (7.3–11.2%) of TE. The magnitude of translational regulation was slightly reduced in allopolyploids compared with diploids, and allopolyploidy tends to have a more profound impact on genes and functional associations with ultra-low TE. Moreover, we demonstrated a reduced extent of homeolog expression biases during translation compared with transcription. Our study provides insights into the regulatory consequences of allopolyploidy post-transcription, contributing to a comprehensive understanding of regulatory mechanisms of duplicated gene expression evolution.

The plant-specific NAC gene family is one of the largest transcription factor families, participating in plant growth regulation and stress response. Despite extensive characterization in various plants, our knowledge of the NAC family in oat is lacking. Herein, we identified 333 NAC genes from the latest release of the common oat genome. We provide a comprehensive overview of the oat NAC gene family, covering gene structure, chromosomal localization, phylogenetic characteristics, conserved motif compositions, and gene duplications. AsNAC gene expression in different tissues and the response to various abiotic stresses were characterized using RT-qPCR. The main driver of oat NAC gene family expansion was identified as segmental duplication using collinearity analysis. In addition, the functions of AsNAC109 in regulating abiotic stress tolerance in Arabidopsis were clarified. This is the first genome-wide investigation of the NAC gene family in cultivated oat, which provided a unique resource for subsequent research to elucidate the mechanisms responsible for oat stress tolerance and provides valuable clues for the improvement of stress resistance in cultivated oat.

Context Several high-quality reference genomes for oat (Avena sativa L. and relatives) have been published, with the prospect of many additional whole-genome assemblies emerging in the near future. Aims This has necessitated an effort by the International Oat Nomenclature Committee (IONC; all co-authors on this paper) to devise a universal system for naming oat genomes and subgenomes, chromosomes, genes, gene models and quantitative trait loci. Methods We evaluated existing naming practices, recent data from oat whole-genome sequencing, and the newly published convention for wheat nomenclature. Key results A framework for these rules has been posted on the GrainGenes database website (https://wheat.pw.usda.gov/GG3/oatnomenclature). The gene naming convention requires adoption of a numerical identifier for each genotype; we propose that these identifiers be assigned by contacting the GrainGenes curators, the curator of the Oat Newsletter, or a member of the IONC (as listed at the GrainGenes link above). Conclusions We encourage oat researchers to refer to these resources, policies, procedures and conventions, adopting them as an international nomenclature standard. Implications Adoption of these standards will facilitate communication and dissemination of oat research and allow programmatic access and data sharing across platforms, and will contribute to oat breeding and research worldwide.

Hemerocallis citrina is a popular vegetable crop in China, due to abundant nutrients in its edible flower buds. In March 2021, serious symptoms of leaf spot were observed on nearly 90% cultivated H. citrina seedlings in the fields of Dazhou city (31°17'56″ N, 107°31'59″ E), Sichuan, China. Symptomatic leaves were collected from 15 seedlings in five different sampling sites (3 seedlings per site). Small pieces (5 × 3 mm) of lesion margin were excised, surface disinfected in 70% ethanol for 20 s and 1% sodium hypochlorite (NaClO) for 40 s, washed, dried, placed on potato dextrose agar (PDA) amended with streptomycin sulfate (50 mg/L) and incubated in dark at 25 ℃ for two days. Finally, eight purified isolates, HHC-FL22, HHC-FL23, HHC-FL25, HHC-FL26, HHC-FL27, HHC-FL28, HHC-FL29 and HHC-FL30, showing similar morphology were obtained through transferring hyphal tips to fresh PDA plates. On PDA plates, mycelia were initially white but gradually became light yellow, and scarlet diffusible pigments were also produced with time. On carnation leaf agar, our isolates produced slightly curved macroconidia with 4 to 8 septa that measured 3.1 to 5.7 × 36.8 to 69.3 µm (n = 30). Microconidia and chlamydospores were not observed. Our isolates were initially identified as Fusarium species based on morphological features (Leslie and Summerell 2006). To further confirm accurate identity, primers EF1/EF2 (O'Donnell et al. 2010), TRI1015B/TRI1013E (Hao et al. 2017), RPB1-F5/RPB1-G2R (O'Donnell et al. 2010), and fRPB2-5F/fRPB2-11aR and RPB2-5f2/RPB2-7cr (O'Donnell et al. 2012) were used to amplify gene sequences of translation elongation factor-1 alpha (TEF1), 3-O-acetyltransferase (Tri101), and DNA-directed RNA polymerase II largest (RPB1) and second largest subunit (RPB2), respectively. Our sequences were deposited in GenBank under accession numbers OQ860946 to OQ860953 (TEF1), OR393245 to OR393252 (Tri101), OP131893 to OP131900 (RPB1), and OQ860954 to OQ860961 and OP131885 to OP131892 (RPB2), respectively. BLASTN searches of our sequences showed 99 ~ 100% identity with TEF1 (FJ240301.1), Tri101 (FJ240345.1), RPB1 (MW233297.1) and RPB2 (KM361666.1) of F. ussurianum NRRL 45681, and 99.05 ~ 100% identity with TEF1 (FJ240305.1) and Tri101 (FJ240349.1) of F. ussurianum NRRL 45833, respectively. Two independent maximum-likelihood phylogenetic trees based on different combined datasets of TEF1, Tri101, RPB1 and RPB2 of Fusarium species confirmed that our isolates were F. ussurianum. To test pathogenicity, conidial suspension from HHC-FL23 (106 conidia / mL) were sprayed to seedlings of cultivar "chuanhuanghua No.1" (n = 3) and incubated in a greenhouse (25°C under 90% relative humidity, 16/8 h light/dark cycle). Controls were treated with ddH2O. Ten days post-inoculation, natural symptoms appeared on leaves inoculated with HHC-FL23, but control group seedlings remained disease-free. This experiment was repeated three times. All re-isolated pathogens from diseased leaves were molecularly and morphologically identified using methods described above. Consequently, the re-isolated fungi were identical to these inoculated. The leaf spot disease could cause foliar damage and even drastic yield loss of flower buds under severe conditions. To our knowledge, this is the first report of F. ussurianum causing leaf spot in H. citrina worldwide. Our study will assist in monitoring causal agent diversity of leaf spot and breeding new resistant varieties in H. citrina.

Hemerocallis citrina is a popular vegetable crop. Its eatable flower buds contain abundant nutrients, especially lecithin (Guo et al., 2022). In March 2021, leaf spot disease was observed on 90% cultivated H. citrina seedlings in Dazhou city (31°17'56″ N, 107°31'59″ E), Sichuan, China. Totally, 15 diseased seedlings were sampled (three samples per 666 m2). The symptomatic leaves were cut into pieces (5 × 3 mm), superficially disinfected with 70% ethanol for 20 s and 1% Sodium hypochlorite (NaClO) for 40 s, and washed with sterile distilled water six times. The disinfected tissues were incubated on PDA amended with streptomycin sulfate (50 mg/L) in dark at 25 ℃. Two days later, hyphal tips from the edges of growing colonies were transferred to fresh PDA plates. Finally, 40 purified isolates were obtained. Using primer pairs ITS1/ITS4 (Glass & Donaldson, 1995), amplified rDNA internal transcribed spacer (ITS) regions indicated that these isolates belonged to different genera, mainly including Epicoccum, Fusarium and Colletotrichum. Six isolates of Epicoccum genus similar in morphology, named HHC46, HHC47, HHC491, HHC492, HHC51 and HHC58, were selected for identification. Cultured on oatmeal agar for 7 days, colonies were initially white and villose. Fourteen days later, mycelia started to secrete scarlet pigment. The NaOH spot test showed color changed from green to red, identical to that in Epicoccum species (Boerema et al., 2004). Meanwhile, colonies produced abundant conidia. Conidia were ellipsoidal, aseptate, and 4.1 to 6.5 × 1.3 to 2.9 µm (n = 30). Chlamydospores were also observed, globose to subglobose. The morphological features were similar to those of Epicoccum latusicollum (Xu et al., 2022). The DNA sequences of Beta-tubulin (TUB2) and DNA-directed RNA polymerase II second largest subunit (RPB2) of six isolates were amplified and sequenced, using primer pairs Bt2a/Bt2b (Glass & Donaldson, 1995), and RPB2-5f2/RPB2-7cr (O'Donnell et al., 2012), respectively. BLASTN searches indicated our ITS (OP107240 - OP107245), TUB2 (OP131865 - OP131870) and RPB2 (OP131871 - OP131876) sequences except one TUB2 (OP131867), showed 100% identity to the corresponding sequences of E. latusicollum CGMCC:3.18346 (KY742101, KY742343 and KY742174, respectively). There was a nucleotide divergence between OP131867 and reference sequence. Based on concatenated ITS, TUB2 and RPB2 sequences, the constructed phylogenetic tree of Epicoccum species, confirmed that our isolates were E. latusicollum. To test pathogenicity, 2-year-old healthy seedlings of cultivar "chuanhuanghua No.1" were sprayed with conidial suspension of HHC51 (105 conidia/mL), with controls treated with sterile distilled water. Each treatment (biological replicates = 3) was incubated in a greenhouse (at 25°C under 90% relative humidity, 16/8 h light/dark cycle). The experiment was repeated twice. After 18 days, leaf spot symptom in inoculated seedlings appeared. Whereas, non-inoculated controls showed no symptom. The pathogens were re-isolated from diseased leaves and identified as E. latusicollum, based on morphology and molecular methods described above. E. sorghinum was previously reported as causal agent of leaf spot in H. citrina (Ma et al., 2021). To our knowledge, this is the first report of E. latusicollum causing leaf spot in H. citrina worldwide. Our study will assist with monitoring disease distribution in H. citrina and host diversity of E. latusicollum (Chen et al., 2017).

This study determined the effects of arbuscular mycorrhizal (AM) fungi inoculation on the N and P contents in the soil–plant continuum and its subsequent effect on oat grain yield under drought stress. Separate experiments were conducted during the oat growing seasons (2020 and 2021) in which AM fungi inoculation with Rhizophagus intraradices was performed in soil with 75% and 55% relative water contents. In response to AM fungi inoculation under normal moisture, the infection rate was significantly higher than in water-limited regimes during both years. The AM fungi alleviated the negative effects of drought stress by influencing total N and P in oat soil, improving N contents in oat roots, stems, and ears, and accumulating more P in leaves. We also found that the promoting effect of AM fungi inoculation on accumulating N in various oat organs seemed to contribute more than that on P under drought stress. Above all, AM fungi significantly ameliorated the effects of drought stress and increased oat grain yield by 14.74% in 2020 and 14.20% in 2021. The soil total N was the key factor that affected oat grain yield, and N and P contents in various oat organs under drought stress and AM fungi inoculation. Based on these findings, AM fungi benefit oat nutrition and productivity and could improve oat performance in dryland agriculture.

为揭示喷硒对燕麦硒积累的影响,并评价筛选喷硒后燕麦产量和品质综合性状优良燕麦品种,以24份燕麦品种为材料,设置3个喷施浓度(亚硒酸钠用量为0、80、160g/hm2),抽穗期进行叶面喷硒.结果表明,燕麦成熟期叶片硒含量随喷硒浓度提高增幅最大,其次为籽粒.喷硒降低24份燕麦籽粒硒含量变异水平.喷硒下,籽粒硒含量差异最大,根硒含量差异最小.叶面喷施80g/hm2的亚硒酸钠时,籽粒硒含量最高的品种可达0.30mg/kg;喷施160g/hm2亚硒酸钠时,24份燕麦品种籽粒硒含量均超多数文献提到的食物或可食材料硒限量标准(0.300mg/kg).喷硒也会影响籽粒蛋白质、脂肪和β-葡聚糖含量的变异程度.在叶面喷施80g/hm2亚硒酸钠时,燕麦产量与未喷硒均无显著差异;燕麦籽粒硒含量与脂肪、β-葡聚糖含量存在显著正相关,相关系数分别为0.63和0.42;GYT双标图基于产量,兼顾硒、蛋白质、脂肪和β-葡聚糖含量,24份燕麦品种综合值排名前5位的依次为品燕1号、Banner、OA1576-4、白燕10号和品燕2号.

小麦是一种喜凉作物,但也容易受到寒害的威胁,利用近缘物种进行抗寒性改良是拓宽小麦遗传基础的有效方法.为了建立一种室内快速鉴定小麦苗期抗寒性强弱的方法,为小麦抗寒种质筛选服务,也为小麦抗寒育种及遗传研究提供新的种质资源,试验以苗期冷冻成活率为指标,结合田间越冬性调查,对29份源于中间偃麦草或长穗偃麦草的小偃麦衍生种质进行了抗寒性鉴定.结果表明,采用室内冷冻法可获得具有显著差异的抗寒性结果,试验材料的抗寒系数在0.77％～100％均有分布,其中有4份材料的苗期抗寒系数大于90％,分别为16W16-1、CH15132、CH7034、CH1677,其具有优良的苗期抗寒性.越冬性鉴定结果表明,田间冻害等级最大为6级,最小为2级,变异系数为31.04％;对田间冻害等级与室内冷冻成活率的相关性分析结果表明,二者的相关系数为-0.906,呈极显著负相关,表明采用室内冷冻法可有效鉴定小麦品种的抗寒性.抗寒系数与产量性状相关性分析结果表明,抗寒系数可显著影响品种的产量及其相关性状,且与产量呈正相关.

WRKY转录因子参与调控植物生长发育和多种胁迫应答,是一类非常重要的植物转录因子.为解析藜麦WRKY基因的进化特征及挖掘响应胁迫的WRKY基因,本研究利用系统的生物信息学方法在全基因组水平对WRKY基因进行了鉴定,并对其染色体定位、分组、系统进化、共线性分析以及多胁迫条件下的表达模式进行了分析.藜麦基因组中鉴定得到90个WRKY基因;划分为3组:Ⅰ组(18个)、Ⅱ组(46个)和Ⅲ组(12个),其中Ⅱ组成员进一步被划分为5个亚组:Ⅱ-a(9个),Ⅱ-b(4个),Ⅱ-c(13个),Ⅱ-d(10个)和Ⅱ-e(10个).另外,14个WRKY成员因为WRKYGQK短肽的缺失,以及锌指结构变异较大而未划分到任何分组.本研究分组与藜麦WRKY基因进化树中家族成员的聚类结果完全一致,进一步支持了成员分组的可靠性.此外,不同分组的WRKY成员的蛋白序列呈现出小组特异的氨基酸保守域组成.藜麦和祖先二倍体苍白茎藜、瑞典藜的同源基因组模块分析表明,藜麦WRKY基因数目的增加主要来自全基因组倍增.在干旱、高温、盐、低磷胁迫和花生褪绿扇形斑病毒(GCFSV)侵染下,大量WRKY基因的表达水平被显著性诱导或抑制,说明这些WRKY基因很可能参与了调控藜麦的逆境应答反应.研究结果可为藜麦的抗逆研究提供优良的候选WRKY基因,为藜麦的抗逆研究提供参考依据.

The number of spikelets per spike is an important trait that directly affects grain yield in wheat. Three quantitative trait loci (QTLs) associated with spikelet nodes per spike (SNS) were mapped in a population of recombinant inbred lines generated from a cross between two advanced breeding lines of winter wheat based on the phenotypic variation evaluated over six locations/years. Two of the three QTLs are QSns.sxau-2A at the WHEATFRIZZY PANICLE (WFZP) loci and QSns.sxau-7A at the WHEAT ORTHOLOG OF APO1 (WAPO1) loci. The WFZP-A1b allele with a 14-bp deletion at QSns.sxau-2A was associated with increased spikelets per spike. WAPO-A1e, as a novel allele at WAPO1, were regulated at the transcript level that was associated with the SNS trait. The third SNS QTL, QSns.sxau-7D on chromosome 7D, was not associated with homoeologous WAPO-D1 or any other genes known to regulate SNS. The favorable alleles for each of WZFP-A1, WAPO-A1, and QSns.sxau-7D are identified and incorporated to increase up to 3.4 spikelets per spike in the RIL lines. Molecular markers for the alleles were developed. This study has advanced our understanding of the genetic basis of natural variation in spikelet development in wheat.

Thinopyrum intermedium (JJJsJsStSt, 2n = 6x = 42), a member of tertiary gene pool of hexaploid wheat (Triticum aestivum L., AABBDD, 2n = 6x = 42), provides several beneficial genes for wheat improvement. In this study, line CH51 was developed from the BC1F8 progeny of a partial wheat-Th. intermedium amphiploid TAI8335 (2n = 56) and wheat cultivar (cv.) Jintai 170. Somatic metaphase chromosome counting showed that CH51 had stable 42 chromosomes. Genomic in situ hybridization (GISH) analysis showed that CH51 had 40 wheat chromosomes and two Th. intermedium chromosomes involving translocation between Js- and St-genome chromosomes. Non-denaturing fluorescence in situ hybridization (ND-FISH) analysis revealed that CH51 lacked a pair of wheat chromosome 6B. Wheat 55K SNP array analysis verified that chromosome 6B had the highest percentage of missing SNP loci in both CH51 and Chinese Spring (CS) nullisomic 6B-tetrasomic 6D (CS-N6BT6D) and had the highest percentage of polymorphic SNP loci between CH51 and cv. Jintai 170. We identified that CH51 was a wheat-Th. intermedium T6StS.6JsL (6B) disomic substitution line. Disease resistance assessment showed that CH51 exhibited high levels of resistance to the prevalent Chinese leaf rust and stripe rust races in the field. Therefore, the newly developed line CH51 can be utilized as a potential germplasm in wheat disease resistance breeding.

Wheat grain yield is affected by plant height, which is the total length of spike, the uppermost internode, and other elongated internodes. In this study, a population of recombinant inbred lines generated from a cross between two advanced winter wheat breeding lines were phenotyped over four locations/years and genotyped by using markers of genotyping-by-sequencing (GBS) and Diversity Array Technology (DArT) for mapping of genes for three traits, including spike length, the uppermost internode length, and plant height. Five genomic regions or quantitative trait loci (QTLs) were associated with candidate genes for these traits. A major QTL was associated with Q5A , and two novel haplotypes of Q5A were identified, one for a single nucleotide polymorphism (SNP) at position -2,149 in promoter region and the other for copy number variation. Compared with one copy Q5A on chromosome 5A in Chinese Spring, the novel haplotype of Q5A with two copies Q5A was found to generate spikes that are extremely compacted. A major QTL was associated with allelic variation in the recessive vrn-A1 alleles involving in protein sequences, and this QTL was associated with increased uppermost internode length but not with plant height. A major QTL for plant height was associated with Rht-B1b on chromosome 4B, but its effects could be compromised by two new minor QTLs on chromosome 7. Collectively, the favorable alleles from the four loci can be used to establish the optimal plant height in wheat.

[目的]在燕麦主产区对裸燕麦种质资源农艺性状和品质性状进行鉴定及综合分析,为优异种质资源创新利用提供可靠材料依据.[方法]本试验以收集的40份裸燕麦种质资源为材料,在山西省右玉县对其9个农艺性状和6个品质性状指标多样性进行调查和分析.[结果]农艺性状中穗粒重变异系数最大,达46.11％,其中ZY0000621穗粒重最高;株高的变异系数最低.品质性状中脂肪、β-葡聚糖含量的变异系数最高,分别达32.50％、15.65％,其中ZY000674脂肪含量最高,晋燕12号β-葡聚糖含量最高.脂肪含量与所有农艺性状无显著相关性,除穗枝梗数、穗铃数、穗粒数外,其他农艺性状与品质性状间存在互为促进或制约的关系.40份裸燕麦种质资源基于农艺性状聚类后形成的4个种质群可分别作为多 目标性状(20份),高秆大穗型(2份),农艺性状表现较好且稳定(7份),高秆饲草型及用于增加穗轮层数(11份)的种质创新利用群.基于品质性状聚类后形成的其中3个品质优良的种质群分别可作为高蛋白(12份),高脂肪、高总淀粉和高支链淀粉(10份),高β-葡聚糖和高直链淀粉(9份)种质创新利用群,且种质群Ⅱ综合品质性状突出.基于农艺性状与品质性状聚类后形成的3个种质群可分别作为选育大粒型、高β-葡聚糖(15份),高秆、主穗长、高蛋白、高总淀粉和高支链淀粉(13份),穗部性状优良、高脂肪和高直链淀粉(12份)种质创新利用群.GGE Biplot排序结果显示,ZY000621、ZY000671、坝莜18号资源的综合性状位列前三.[结论]40份裸燕麦种质资源农艺性状和品质性状变异程度有差异,从变异程度高的性状中鉴定出3个优异资源.40份裸燕麦种质资源被归为10个种质创新利用群.筛选到3个综合性状优良资源.

抗条锈病基因Yr69对我国小麦条锈菌(Puccinia striiformis f.sp.tritici)小种具有广谱抗性,在小麦抗条锈病育种中具有重要价值.为提高分子标记辅助选择育种的效率,加快Yr69在小麦抗病育种中的应用,本研究利用条锈菌小种CYR34对包含340个小麦家系的'Taichung29/CH7086'F9代RIL(Recombinant inbred line)群体进行接种鉴定,并利用BSA-SNP(Bulked segregant analysis-single nucleotide polymorphism)技术对其抗条锈病基因进行了重新定位.抗病鉴定结果显示,RIL群体中抗感病家系的数量呈双峰分布,'CH7086'的条锈病抗性受一个主效位点控制.BSA-SNP基因分型结果表明,多态性SNP主要集中于小麦2AS染色体末端0～30 Mb的染色体区段.在该基因组区段开发了208个SSR分子标记,利用抗感病小群体从中筛选到14个与Yr69连锁的分子标记.利用14个标记对340个RIL家系进行PCR扩增和分子作图,将Yr69定位于2AS111和2AS171之间约7.76 Mb的染色体区段,两侧连锁标记2AS111、2AS171与Yr69的连锁距离均为0.4 cM,并获得2个与Yr69共分离的分子标记2AS117和2AS127,可用于Yr69的分子标记辅助选择.