Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most destructive foliar diseases of wheat. In this study, we combined the bulked segregant RNA sequencing (BSR-seq) and comparative genomics analysis to localize the powdery mildew resistance gene in Chinese landrace Xiaomaomai. Genetic analysis of F1 plants from a crossing of Xiaomaomai × Lumai23 and the derived F2 population suggests that a single recessive gene, designated as pmXMM, confers the resistance in this germplasm. A genetic linkage map was constructed using the newly developed SNP markers and pmXMM was mapped to the distal end of chromosome 2AL. The two flanking markers 2AL15 and 2AL34 were closely linked to pmXMM at the genetic distance of 3.9 cM and 1.4 cM, respectively. Using the diagnostic primers of Pm4, we confirmed that Xiaomaomai carries a Pm4 allele and the gene function was further validated by the virus-induced gene silencing (VIGS). In addition, we systematically analyzed pmXMM in comparison with the other Pm4 alleles. The results suggest that pmXMM is identical to Pm4d and Pm4e at sequence level. Pm4b is also not different from Pm4c according to their genome/amino acid sequences. Only a few nucleotide variances were detected between pmXMM and Pm4a/b, which indicate the haplotype variation of the Pm4 gene.

由春季低温引发的倒春寒是严重威胁我国小麦生产安全的自然灾害之一.为准确评价倒春寒的危害程度与小麦植株发育阶段的关系,本研究以春性品种中麦8444为试验材料,在可控环境条件下,比较了不同幼穗分化发育阶段的小麦遭受低温后的冻害症状和生长发育情况.结果表明,小麦植株发育叶龄和幼穗分化阶段存在一定的对应关系.小麦植株的茎和叶片受冻害的程度随着温度降低和发育进程而呈现加重趋势,株高、穗长和结实率随着温度降低和发育进程而呈现降低趋势.二棱末期(S2.25)至小花原基分化期(S3.5)、药隔期(S5)至柱头羽毛突起期(S7)是幼穗发育过程中对低温敏感性发生明显变化的两个阶段.综合茎、叶、穗等器官对低温的耐受性,减数分裂期可以更全面地评价小麦的倒春寒抗性水平.

中麦6032是由中国农业科学院作物科学研究所选育的高产广适小麦新品种.该品种半冬性中熟,幼苗半匍匐、叶色深绿、分蘖力强,成穗率高;株高约80cm,株型松紧适中,茎秆粗壮、抗倒性强.产量三要素适中,亩穗数47.2万穗,穗粒数32.6粒,千粒重46.8g.该品种适应性广,2021年通过黄淮北片和安徽省审定,完成黄淮南片生产试验,进入冀中北水地组生产试验.黄淮北片2年区域试验每667m2平均产量586.8kg,比对照济麦22增产6.28％;生产试验平均产量587.4kg,比对照济麦22增产3.95％.黄淮北片区试2年抗病性鉴定,中感纹枯病、条锈病、叶锈病,高感赤霉病、白粉病.节水指数1.198、1.094,节水性较强.品质检测达到国家中强筋小麦品种标准.

中麦6052是由中国农业科学院作物科学研究所选育的高产抗逆小麦新品种.该品种半冬性中熟,幼苗半匍匐、苗壮,冬季抗寒性较好;春季发育稳健,耐倒春寒能力较好;株高约80cm,株型松紧适中,茎秆粗壮、抗倒性强.产量三要素适中,亩穗数44.2万穗,穗粒数33.2粒,千粒重42.5g.2年区域试验每667m2平均产量560.7kg,比对照周麦18增产3.9％;生产试验平均产量550.6kg,比对照周麦18增产6.2％.氮利用效率指数(NUI)为1.75,属氮高效品种.田间白粉病、叶锈病自然发病较轻,适宜在黄淮冬麦区南片种植.

Improvement of grain weight and size is an important objective for high-yield wheat breeding. In this study, 174 recombinant inbred lines (RILs) derived from the cross between Jing 411 and Hongmangchun 21 were used to construct a high-density genetic map by specific locus amplified fragment sequencing (SLAF-seq). Three mapping methods, including inclusive composite interval mapping (ICIM), genome-wide composite interval mapping (GCIM), and a mixed linear model performed with forward-backward stepwise (NWIM), were used to identify QTLs for thousand grain weight (TGW), grain width (GW), and grain length (GL). In total, we identified 30, 15, and 18 putative QTLs for TGW, GW, and GL that explain 1.1-33.9%, 3.1%-34.2%, and 1.7%-22.8% of the phenotypic variances, respectively. Among these, 19 (63.3%) QTLs for TGW, 10 (66.7%) for GW, and 7 (38.9%) for GL were consistent with those identified by genome-wide association analysis in 192 wheat varieties. Five new stable QTLs, including 3 for TGW (Qtgw.ahau-1B.1, Qtgw.ahau-4B.1, and Qtgw.ahau-4B.2) and 2 for GL (Qgl.ahau-2A.1 and Qgl.ahau-7A.2), were detected by the three aforementioned mapping methods across environments. Subsequently, five cleaved amplified polymorphic sequence (CAPS) markers corresponding to these QTLs were developed and validated in 180 Chinese mini-core wheat accessions. In addition, 19 potential candidate genes for Qtgw.ahau-4B.2 in a 0.31-Mb physical interval were further annotated, of which TraesCS4B02G376400 and TraesCS4B02G376800 encode a plasma membrane H+-ATPase and a serine/threonine-protein kinase, respectively. These new QTLs and CAPS markers will be useful for further marker-assisted selection and map-based cloning of target genes.

为了解120份小麦品种（系）重要性状功能基因的组成,本研究利用高通量的KASP标记技术对株高、抗叶锈病、抗条锈病、抗赤霉病、抗穗发芽和加工品质等性状相关的基因进行了检测。结果表明,供试材料的株高基因组成包含5种类型,分别是Rht-B1a/Rht-D1a （1份）、Rht-B1a/Rht-D1b （58份）、Rht-B1a+160/Rht-D1a （2份）、Rht-B1a+160/Rht-D1b （30份）和Rht-D1a/Rht-B1b （29份）。在抗病性方面,有69份材料含抗叶锈病基因Lr14a,3份材料含Lr68基因;抗叶锈病基因Lr21和Lr34、抗赤霉病基因Fhb1、抗条锈病基因Yr15在供试材料中均未发现。在抗穗发芽方面,68份材料为TaMFT-A1基因的Jagger-type抗穗发芽单倍型,21份材料为TaMoc-A1基因的Hap-H抗穗发芽单倍型,22份材料为TaSdr-D1基因的TaSdr-D1a抗穗发芽单倍型,84份材料为TaPHS1基因的Rio Blanco type抗穗发芽单倍型。在品质方面,83份材料为非1B/1R易位系,20份材料含高分子量麦谷蛋白亚基5+10,供试材料均不含Bx7OE。上述结果表明,对常规育种手段育成的高代品系进行KASP标记辅助选择可作为一种重要的分子育种策略,能显著地提高小麦育种效率。

中麦5051是中国农业科学院作物科学研究所育成的节水、抗寒、强筋小麦新品种.该品种曾在北京昌平、河北保定、安徽蚌埠、河南新乡等地参加多点观察,综合性状表现良好,特别适宜黄淮海北部及类似生态区节水轻简化栽培.该品种于2019年3月通过国家审定,在发展绿色优质小麦生产中具有广阔的应用前景.

Three major loci for pre-harvest sprouting tolerance (PHST) were mapped on chromosomes 1AL, 3BS, and 6BL, and two CAPS and one dCAPS markers were validated. Sixteen lines with favorable alleles and increased PHST were identified. Pre-harvest sprouting (PHS) significantly affects wheat grain yield and quality. In the present study, the PHS tolerance (PHST) of 192 wheat varieties (lines) was evaluated by assessment of field sprouting, seed germination index, and period of dormancy in different environments. A high-density Illumina iSelect 90K SNP array was used to genotype the panel. A genome-wide association study (GWAS) based on single- and multi-locus mixed linear models was used to detect loci for PHST. The single-locus model identified 23 loci for PHST (P < 0.0001) and explained 6.0–18.9% of the phenotypic variance. Twenty loci were consistent with known quantitative trait loci (QTLs). Three single-nucleotide polymorphism markers closely linked with three major loci (Qphs.ahau-1A, Qphs.ahau-3B, and Qphs.ahau-6B) on chromosomes 1AL, 3BS, and 6BL, respectively, were converted to two cleaved amplified polymorphic sequences (CAPS) and one derived-CAPS markers, and validated in 374 wheat varieties (lines). The CAPS marker EX06323 for Qphs.ahau-6B co-segregated with a novel major QTL underlying PHST in a recombinant inbred line population raised from the cross Jing 411 × Wanxianbaimaizi. Linear regression showed a clear dependence of PHST on the number of favorable alleles. Sixteen varieties showing an elevated degree of PHST were identified and harbored more than 16 favorable alleles. The multi-locus model detected 39 marker–trait associations for PHST (P < 0.0001), of which five may be novel. Six loci common to the two models were identified. The combination of the two GWAS methods contributes to efficient dissection of the complex genetic mechanism of PHST.

Shifting geographical ranges of crop pests and pathogens in response to climate change pose a threat to food security ( 1 , 2 ). The orange wheat blossom midge ( Sitodiplosis mosellana Géhin) is responsible for significant yield losses in China ( 3 ), the world’s largest wheat producer. Here we report that rising temperatures in the North China Plain have resulted in a mean northward range shift of 3.3° (58.8 km per decade) from the 1950s to 2010s, which accelerated to 91.3 km per decade after 1985 when the highly toxic pesticide hexachlorocyclohexane (HCH) was banned ( 4 ). Phenological matching between wheat midge adult emergence and wheat heading in this new expanded range has resulted in greater damage to wheat production. Around $286.5 million worth of insecticides were applied to around 19 million hectares in an attempt to minimize wheat midge damage to crops between 1985 and 2016. Despite use of these pesticides, wheat midge caused losses of greater than 0.95 million metric tons of grain during this period. Our results demonstrate the potential for indirect negative impacts of climate change on crop production and food security, and constitute the first large scale example of plant pest range shift due to global warming.

Low temperature (LT) stress in spring occurs frequently in the Huang-Huai Rivers Valley, resulting in yield loss of wheat. The objectives of this study were to understand the physiological responses of wheat cultivars to LT and determine suitable physiological indicator(s) for cold-tolerance selection. Three cultivars, Taishan 6426, Taishan 4033, and Jimai 22, were exposed to LT stress at standing, jointing and booting stages, and the yield-related traits, photosynthetic parameters as well as leaf cell struc-ture were compared among different cultivars. The agronomic traits of different cultivars changed in similar trends after LT treat-ment with the consistent result across years. Plant height received small influence of LT, especially LT at standing stage. In con-trast, spike number per plant decreased significantly compared with the control (normal temperature), but the reduced percentage varied across years. Grain number per spike and yield per plant showed significantly declined trends with delaying LT stress, and the maximum decrements were observed in the treatment of LT at booting stage. The grain number per spike was 90.5%–93.3% (2012–2013) and 91.9%–93.6% (2013–2014) lower, and the yield per plant was 87.9%–97.3% (2012–2013) and 91.5%–97.8% (2013–2014) lower in LT treatment at booting than in the control. Booting stage was secondly sensitive to LT in yield, whereas jointing stage was less influenced by LT. Grain yield loss under LT stress mainly resulted from the decrease of grain number per spike. Under LT at jointing or booting stage, the chlorophyll content decreased in the three cultivars, but the decrement varied across cultivars. Moreover, the photosynthetic rate, transpiration rate and stomata conductance decreased significantly and the intercellular CO2concentration increased greatly in the three cultivars, and those in Taishan 6426 had the minimum variations. LT also had inhibition in chlorophyll fluorescence parameters of wheat. For example, the Fv/Fmvalue was significantly lower in the treatment of LT at jointing or booting stage than in the control except for Taishan 6426. When exposed to LT stress, leaf epidermic cells were severely damaged, showing their loose arrangement and irregular structures of guard cell and accessory cell. Our results indicate that photosynthetic rate, transpiration rate, stomata conductance, intercellular CO2concentration and Fv/Fmcan be used as indicators to identify tolerance of wheat cultivars to spring coldness.

A novel TaGW2-A1 allele was identified from a stable, robust QTL region, which is pleiotropic for thousand grain weight, grain number per spike, and grain morphometric parameters in wheat. Thousand grain weight (TGW) and grain number per spike (GNS) are two crucial determinants of wheat spike yield, and genetic dissection of their relationships can help to fine-tune these two components and maximize grain yield. By evaluating 191 recombinant inbred lines in 11 field trials, we identified five genomic regions on chromosomes 1B, 3A, 3B, 5B, or 7A that solely influenced either TGW or GNS, and a further region on chromosome 6A that concurrently affected TGW and GNS. The QTL of interest on chromosome 6A, which was flanked by wsnp_BE490604A_Ta_2_1 and wsnp_RFL_Contig1340_448996 and designated as QTgw/Gns.cau-6A, was finely mapped to a genetic interval shorter than 0.538 cM using near isogenic lines (NILs). The elite NILs of QTgw/Gns.cau-6A increased TGW by 8.33%, but decreased GNS by 3.05% in six field trials. Grain Weight 2 (TaGW2-A1), a well-characterized gene that negatively regulates TGW and grain width in wheat, was located within the finely mapped interval of QTgw/Gns.cau-6A. A novel and rare TaGW2-A1 allele with a 114-bp deletion in the 5' flanking region was identified in the parent with higher TGW, and it reduced TaGW2-A1 promoter activity and expression. In conclusion, these results expand our knowledge of the genetic and molecular basis of TGW-GNS trade-offs in wheat. The QTLs and the novel TaGW2-A1 allele are likely useful for the development of cultivars with higher TGW and/or higher GNS.

TaMFT-3A on wheat chromosome 3AS, encoding a phosphatidyl ethanolamine-binding protein, was previously determined to be a candidate gene underlying the major quantitative trait locus (QTL) for pre-harvest sprouting (PHS) resistance. Three single nucleotide polymorphisms (SNPs) (−222, +646, and +666) and one insertion/deletion (InDel) variation at TaMFT-3A locus are associated with PHS resistance. In the present study, we detected a novel 33-bp InDel in the promoter (−194) of TaMFT-3A and developed a gene-specific marker (MFT-A2). Linkage mapping indicated that MFT-A2 co-segregated with a major QTL on chromosome 3AS for PHS resistance in the recombinant inbred line population from the cross of Annong 0711 × Henong 825, explaining 17.79 and 14.22% of phenotypic variations in 2016 and 2017, respectively. Association analysis also showed that the InDel was significantly associated with PHS resistance using 260 current wheat varieties (lines) and 183 Chinese mini-core wheat collections across environments. TaMFT-3A expression levels in genotypes with the resistance allele TaMFT-3Aa were significantly higher than those in varieties with the susceptible allele TaMFT-3Ab. Moreover, TaMFT-3A transcription was up-regulated in high-temperature and abscisic acid treatments, but down-regulated in low-temperature and gibberellic acid treatments. Notably, PHS resistance of varieties simultaneously carrying favorable haplotypes of SNP-222, SNP646/666, TaMFT-A1, and TaMFT-3A (designated Hap-11) was significantly higher than that of other haplotypes across environments. This study provides useful information for the use of the MFT-A2 marker for improvement of PHS resistance in wheat breeding, and for our better understanding of TaMFT-3A regulatory mechanism for PHS resistance.

Sprouting severely affects the quality of wheat in its mature stage.In this study,200 white wheat materials with different genetic backgrounds in Huanghuai western areas derived from commercial varieties were used to conduct the pre-harvest sprouting comparison experiment in laboratory and field,respectively.The results showed that Jimai series of varieties in Shandong were sprouting resistant under both conditions,because of their seed dormancy characteristics at maturity and favorable thick seed coat.On the other side,the Heguan 35 etc derived from Hebei appeared seriously sprouting problem,although they had been promoted widely in Henan.It is recommended to strengthen the breeding of parental sprouting resistant properties in this area.

Wheat yield can be enhanced by modifying the spike morphology and the plant height. In this study, a population of 191 F9 recombinant inbred lines (RILs) was developed from a cross between two winter cultivars Yumai 8679 and Jing 411. A dense genetic linkage map with 10,816 markers was constructed by incorporating single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) marker information. Five spike morphological traits and plant height were evaluated under nine environments for the RILs and parental lines, and the number of detected environmentally stable QTLs were 18 and three, respectively. The 1RS/1BL (rye) translocation increased both spike length and spikelet number with constant spikelet compactness. The QPht.cau-2D.1 was identical to gene Rht8, which decreased spike length without modifying spikelet number. Notably, four novel QTLs locating on chromosomes 1AS (QSc.cau-1A.1), 2DS (QSc.cau-2D.1), and 7BS (QSl.cau-7B.1 and QSl.cau-7B.2) were firstly identified in this study, which provide further insights into the genetic factors that shaped the spike morphology in wheat. Moreover, SNP markers tightly linked to previously reported QTLs will eventually facilitate future studies including their positional cloning or marker-assisted selection.

Winter freezing injury is one of the major natural disasters in wheat production. The effect ofVRN1genes on cold hardness was analyzed with phenotypic data and the allelic variations of VRN-A1,VRN-B1,VRN-D1in 71 wheat varieties grown in Yellow-Huai-Hai River Valley region. The results indicated that the cold hardiness of wheat was correlated with other stress toler-ances, and strong cold hardiness was found in most varieties showing good salinity tolerance, drought tolerance or water-saving fea-ture in production and the National Variety Regional Trial. VRN1 is a critical locus in the genetic network of wheat cold hardiness. The presence of the dominant geneVRN1was often accompanied with a significant decrease in cold hardiness, and weak cold hardi-ness was usually detected in the varieties with two or threeVRN1 genes. Coexistence of recessive genes vrn-A1,vrn-B1, andvrn-D1 was found to be an indispensable prerequisite for strong cold hardiness. Therefore, thevrn-A1vrn-B1vrn-D1 genotype is suggested in wheat production and variety improvement in the northern part of Yellow-Huai-Hai River Valley region of China.

Cytokinin oxidase (CKX) plays a crucial role in plant growth and development by reversibly inactivating cytokinin (CTK). Twenty-four primer pairs, designed from ESTs of the TaCKX genes family of common wheat, were used to identify their allelic variations associated with grain size, weight, and filling rate in 169 recombinant inbred lines (RIL) derived from Jing 411 × Hongmangchun 21. TaCKX6a02, a member of TaCKX gene family, amplified by primer pair T31-32, showed a close association with grain traits in this RIL population. Statistical analysis indicated that allelic variation of TaCKX6a02 had significant correlation with grain size, weight, and filling rate (GFR; P < 0.001) under varied environments. The TaCKX6a02-D1a allele from Jing411 significantly increased grain size, weight and grain filling rate, compared with TaCKX6a02-D1b from Hongmangchun 21. TaCKX6a02 was located on chromosome 3DS in the interval of Xbarc1119 and Xbarc1162, with a genetic distance of 1.4 cM. The location was further confirmed using Chinese Spring nulli-tetrasomic lines. A major QTL (quantitative trait locus) tightly linked to TaCKX6a02 was detected in the RIL population, explaining 17.1~38.2% of phenotype variations for grain size, weight, GFRmax and GFRmean in different environments. In addition, significant effects of variations of TaCKX6a02 on grain weight and GFR were further validated by association analysis among 102 wheat varieties in two cropping seasons. 12.8~35.1% of phenotypic variations were estimated for these genotypes. A novel 29-bp InDel behind the stop codon was detected by DNA sequence analysis between the two alleles of TaCKX6a02-D1. The gene-specific marker, TKX3D, was designed according to the novel variation, and can be used in marker-assisted selection (MAS) for grain size, weight, and GFR in common wheat.

区域试验是小麦新品种从选育到大面积应用推广过程中的重要中间环节,是鉴定和评价新品种产量、适应性、抗逆性和品质等性状及新品种宣传和示范推广的重要平台.根据多年承担区域试验工作的经验,提出区域试验工作应注意的事项.

Few Chinese high yielding white-grained wheat cultivars possess sufficient dormancy to avoid pre-harvest sprouting (PHS). Because the field evaluation of PHS is difficult, the identification of informative molecular markers is a priority for improving the level of dormancy. In this report, the effectiveness of phenotypic and genotypic selection was compared. Four microsatellite loci Xbarc57, Xbarc294, Xbarc310 and Xbarc321, mapped on the short arm of chromosome 3A, were used for selection in white-grained wheat F5 lines which were also selected on the basis of their grain filling rate (GFR). One of these (later designated cv. Zhongmai911) was further selected on the basis of its allelic constitution at the four SSR loci. This cultivar combines a high level of PHS resistance with high grain yield. The results suggested that rapid GFR and PHS resistance can be bred simultaneously.

To identify QTLs related to thousand-grain weight （TGW） and validate its＇ stability in mul- tiple ecological environments, the F9：10 generation of 142 recombinant inbred lines （RILs） derived from the cross between Yu 8679 （large spike） and Heshangmai （small spike） were planted in eight ecological environments in Beijing （2006 and 2007）, Hefei （2007, 2008）, Chengdu （2007, 2008） and Taian （2009, 2010）. A genetic map comprising 170 SSR and 2 EST markers （Tx23-24 and Tx37-38） was constructed based on the 142 RII.s. According to the genetic map and phenotypic data, quantita- tive trait loci were identified for TGW using the composite interval mapping （CIM） method. A total of 35 QTLs located on chromosomes 1A, 1B, 2A, 2D, 3A, 3B, 4A, 4D, 5A, 5B, 6D, and 7D for TGW were identified over eight environments, which accounted for variations of TGW by 4. 36O//oo 16.80~//00. Especially, three QTI.s on chromosomes 1B （QTgw. nfcri-lB）, 2A （QTgw. nfcri-2A） and 3B （QTgw. nfcri-3B） could be detected in the most environments and could explain high phenotypic variation, the three QTLs may be effective and useful for farther exact location and MAS for high yield breeding.