Transmission of the Chromosome 1R in Winter Wheat Germplasm Aimengniu and Its Derivatives Revealed by Molecular Markers

In order to clarify the transmission of the rye chromosome 1R in winter wheat germplasm Aimengniu and its derivatives, 17 derivatives and 7 types of Aimengniu were examined through molecular-marker technology. The results showed that the chromosome arm 1RS of Neuzucht was transmitted to 5 of the 7 types of Aimengniu, i.e., Aimengniu Ⅱ and Aimengniu Ⅳ-Aimengniu VII, no segment of t RS was identified in Aimengniu Ⅰ or Aimengniu Ⅲ. As for the 17 derivatives, the 1RS chromosome arm of Aimengniu was transmitted to 11 derivatives, part segments of 1RS were found in 1 derivative, while no segment was found in the remaining 5 ones. The results provided the evidence that molecular-marker technology was an efficient approach and suitable for analysis of the transmission of chromosome 1R.

Novel and favorable genomic regions for spike related traits in a wheat germplasm Pubing 3504 with high grain number per spike under varying environments

Grain number per spike （GNPS） is a major factor in wheat yield breeding. A new wheat germplasm Pubing 3504 shows superior features in spike traits. To elucidate the genetic basis of spike and yield related traits in Pubing 3504, 282 F2：3 families were generated from the cross Pubing 3504xJing 4839, and seven spike and yield related traits, including GNPS, spike length （SL）, kernel number per spikelet （KPS）, spikelet number per spike （SNS）, thousand-grain weight （TGW）, spike number per plant （SNP）, and plant height （HT） were investigated. Correlation analysis indicated significant positive correlations between GNPS and spike-related traits, including KPS, SNS, and SL, especially KPS. A genetic map was constructed using 190 polymorphic simple sequence repeat （SSR）, expressed sequence tag （EST）-SSR, and sequence- tagged-site （STS） markers. For the seven traits measured, a total of 37 quantitative trait loci （QTLs） in a single-environment analysis and 25 QTLs in a joint-environment analysis were detected. Additive effects of 70.3% （in a single environment） and 57.6% （in a joint environment） of the QTLs were positively contributed by Pubing 3504 alleles. Five important genomic regions on chromosomes 1A, 4A, 4B, 2D, and 4D could be stably detected in different environments. Among these regions, the marker interval Xmag834-Xbarc83 on the short arm of chromosome 1A was a novel important genomic region that included QTLs controlling GNPS, KPS, SNS, TGW, and SNP with stable environmental repeatability. This genomic region can improve the spike trait and may play a key role in improving wheat yield in the future. We deduced that this genomic region was vital to the high GNPS of Pubing 3504.

Development and Characterization of Wheat Germplasm with Combined Resistance to Russian Wheat Aphid and Stem Rust (Race “Ug99”) in Kenya

Wheat is the second most important cereal in Kenya. However, production is severely constrained by both abiotic and biotic stresses. Of the biotic stresses a devastating pest (Russian wheat aphid (RWA)) and a serious disease (stem rust race TTKS (“Ug99”)) are currently the biggest problem for wheat producers in Kenya. Severe infestations by RWA may result in yield losses of up to 90% while “Ug99” infected fields may suffer 100% crop loss. The two pests combined are seriously affecting wheat farmers’ incomes because of the heavy reliance on pesticides that increase the cost of production. This study attempted to develop and characterize wheat lines that are resistant to both RWA and “Ug99” by pyramiding two major resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to both RWA and “Ug99”;“Cook”, an Australian variety carrying stem rust resistance gene Sr36 conferring immunity to “Ug99”;and “KRWA9”, a Kenyan line with resistance to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1) was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale × KRWA9”. The DC F1 population was subjected to sequential screening for both RWA and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to obtain the F2 of the double cross (DC F2). The DC F2 progenies were sequentially screened against RWA and “Ug99” to yield a population that was resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were conducted to select homozygous resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Though races with virulence for Sr36 have been reported, the gene provides immunity to race “Ug99” and can still be effectively used as a component for “Ug99” resistance breeding together with other Sr genes.

Deciphering the evolution and complexity of wheat germplasm from a genomic perspective

Bread wheat provides an essential fraction of the daily calorific intake for humanity.Due to its huge and complex genome,progress in studying on the wheat genome is substantially trailed behind those of the other two major crops,rice and maize,for at least a decade.With rapid advances in genome assembling and reduced cost of high-throughput sequencing,emerging de novo genome assemblies of wheat and whole-genome sequencing data are leading to a paradigm shift in wheat research.Here,we review recent progress in dissecting the complex genome and germplasm evolution of wheat since the release of the first high-quality wheat genome.New insights have been gained in the evolution of wheat germplasm during domestication and modern breeding progress,genomic variations at multiple scales contributing to the diversity of wheat germplasm,and complex transcriptional and epigenetic regulations of functional genes in polyploid wheat.Genomics databases and bioinformatics tools meeting the urgent needs of wheat ge-nomics research are also summarized.The ever-increasing omics data,along with advanced tools and well-structured databases,are expected to accelerate deciphering the germplasm and gene resources in wheat for future breeding advances.

Evaluation of Pakistan wheat germplasms for stripe rust resistance using molecular markers

Wheat production in Pakistan is seriously constrained due to rust diseases and stripe rust (yellow) caused by Puccinia striiformis f.sp.tritici,which could limit yields.Thus development and cultivation of genetically diverse and resistant varieties is the most sustainable solution to overcome these diseases.The first objective of the present study was to evaluate 100 Pakistan wheat cultivars that have been grown over the past 60 years.These cultivars were inoculated at the seedling stage with two virulent stripe rust isolates from the United States and two from Pakistan.None of the wheat cultivars were resistant to all tested stripe rust isolates,and 16% of cultivars were susceptible to the four isolates at the seedling stage.The data indicated that none of the Pakistan wheat cultivars contained either Yr5 or Yr15 genes that were considered to be effective against most P.striiformis f.sp.tritici isolates from around the world.Several Pakistan wheat cultivars may have gene Yr10,which is effective against isolate PST-127 but ineffective against PST-116.It is also possible that these cultivars may have other previously unidentified genes or gene combinations.The second objective was to evaluate the 100 Pakistan wheat cultivars for stripe rust resistance during natural epidemics in Pakistan and Washington State,USA.It was found that a higher frequency of resistance was present under field conditions compared with greenhouse conditions.Thirty genotypes (30% of germplasms) were found to have a potentially high temperature adult plant (HTAP) resistance.The third objective was to determine the genetic diversity in Pakistan wheat germplasms using molecular markers.This study was based on DNA fingerprinting using resistance gene analog polymorphism (RGAP) marker analysis.The highest polymorphism detected with RGAP primer pairs was 40%,50% and 57% with a mean polymorphism of 36%.A total of 22 RGAP markers were obtained in this study.RGAP,simple sequence repeat (SSR) and sequence tagged site (STS) markers were used to determine the presence and absence of some important stripe rust resistance genes,such as Yr5,Yr8,Yr9,Yr15 and Yr18.Of the 60 cultivars analyzed,17% of cultivars showed a RGAP marker band for Yr9 and 12% of cultivars exhibited the Yr18 marker band.No marker band was detected for Yr5,Yr8 and Yr15,indicating a likely absence of these genes in the tested Pakistan wheat cultivars.Cluster analysis based on molecular and stripe rust reaction data is useful in identifying considerable genetic diversity among Pakistan wheat cultivars.The resistant germplasms identified with 22 RGAP markers and from the resistance evaluations should be useful in developing new wheat cultivars with stripe rust resistance.

Detection of Allelic Variation in Chinese Wheat (Triticum aestivum L.) Germplasm with Drought ToleranceUsing SSR Markers

Allelic variation in two domestic wheat landraces, Pingyaobaimai and Mazhamai, two cornerstone breeding materials and their derived cultivars with drought tolerance was detected by SSR (simple sequence repeat) markers. The clustering of 25 accessions showed that the similarity between Pingyaobaimai and Yandal817, the latter was developed from the former, was 0.71, the highest one of all accessions, but the similarities were very low between these two accessions and other accessions including their derived cultivars. A similar situation was revealed between Mazhamai and its derived cultivars. Pingyaobaimai and its three derived cultivars shared three alleles at loci Xgwm526, Xgwm538 and Xgwm126 on chromosome arms 2BL, 4BL and 5AL, respectively. There were six shared alleles in Mazhamai and its derived cultivars, in order of Xgwm157, Xgwm126, Xgwm212, Xgwm626, Xgwm471 and Xgwm44 on chromosome arms 2DL, 5AL, 5DL, 6BL, 7AS and 7DC, respectively. Only one shared allele was detected between the pedigrees of Pingyaobaimai and Mazhamai. The difference of shared alleles in two cornerstone breeding materials and their derived cultivars revealed the diversity in Chinese wheat germplasm with drought tolerance and the complication in genetic basis of drought tolerance in wheat.

基于深度字词融合的小麦种质信息实体关系联合抽取

为获得结构化的小麦品种表型和遗传描述,针对非结构化小麦种质数据中存在的实体边界模糊以及关系重叠问题,提出一种基于深度字词融合的小麦种质信息实体关系联合抽取模型WGIE-DCWF(wheat germplasm information extraction model based on deep character and word fusion)。模型编码层通过深度字词融合和上下文语义特征融合,提高密集实体特征识别能力;模型三元组抽取层建立层叠指针网络,提高重叠关系的提取能力。在小麦种质数据集和公开数据集上的一系列对比实验结果表明,WGIE-DCWF模型能够有效提高小麦种质数据实体关系联合抽取效果,同时拥有较好的泛化性,可以为小麦种质信息知识库构建提供技术支撑。

麦穗干插花加工型小麦种质资源的筛选

本研究以麦穗干插花(以下简称麦穗花)加工企业认可的云生1号、云麦53号品种为对照,采用芒长、穗长和茎秆强度3个加工企业认为影响麦穗花加工和销售的重要指标,对42份长芒小麦种质资源进行性状筛选与评价,并利用文献报道的与小麦茎秆强度相关的SSR分子标记对参试资源进行茎秆强度辅助选择,挑选出在农艺性状和分子遗传学上都适合加工麦穗花的优异种质资源,为云南干花产业发展提供新的原材料。结果表明,通过两年的田间种植观测与数据分析,未发现3个性状都较两个对照优异的资源。其中,C6(小黑麦)两年的芒长都较两对照显著优异且穗长和茎秆强度差异不明显或也显著优异,是比两个对照更适合加工麦穗花的优异资源;其次是C3和C9,两年的穗长和茎秆强度都显著优于或与两个对照差异不显著,也是加工麦穗花的较理想资源;C4、C5、C7和C8的穗长较云麦53号显著优异,芒长和茎秆强度则差异不显著或也显著优异。对茎秆强度的SSR分子标记辅助选择结果表明,C4、C6可能携带有与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59位点,C3、C5、C8也可能携带与云麦53号相同的BARC59、BARC134和WMC48位点以及与云生1号相同的BARC59、BARC358位点,C9可能携带有与云麦53号相同的BARC59、BARC134位点以及与云生1号相同的BARC59、WMC48位点。但是,用这些引物获得的分子标记结果与表型评价结果之间的一致性都在50%及以下,可能这些分子标记都不适宜用作供试小麦材料茎秆强度的辅助筛选。今后还需进一步筛选适合评价麦穗花加工型小麦种质资源的指标及分子标记,为选育满足生产需求的优良小麦品种提供技术支持。

宁夏小麦种质资源研究现状与发展建议

作物种质资源作为品种培育、种业创新和农业高质量发展的“核心芯片”,对品种培育和保障粮食安全具有不可替代的基础性作用。基于此,阐述了作物种质资源研究的重要意义和国内小麦种质资源研究发展历程及现状,分析了存在问题及发展趋势,旨在为加强小麦种质资源研究、促进小麦育种提供理论依据。

小麦种质资源农艺性状的相关及聚类分析

研究小麦种质资源农艺性状,可为小麦亲本选配和杂种后代选择、小麦种质资源创新和新品种选育提供参考。该试验利用35份小麦种质材料,对其8个农艺性状进行相关分析、通径分析及聚类分析。研究表明,成穗率的变异系数最大,其他性状由高到低依次是株高、穗粒数、千粒重、有效穗、穗粒重、产量、生育期。穗粒数和穗粒重与产量呈显著正相关。通过通径分析,发现有效穗、株高、穗粒数、千粒重对小麦种质资源农艺性状呈正向贡献。从产量构成因素看,提高有效穗、穗粒重和千粒重能提高产量。欧氏距离为80可将35份种质材料分为4类。本研究表明,这些小麦种质资源变异类型丰富,可以根据性状间的相关性进行选择。

小麦种质资源保护工作探析

小麦是世界重要粮食作物之一,对保障全球粮食供应至关重要。然而,由于小麦的遗传基础相对狭窄,导致其品种改良受到限制。因此,需要加快小麦种质资源收集、保护及创新利用等研究工作。本文阐述了小麦种质资源保存现状,分析了小麦种质资源保护工作存在的问题,并提出了小麦种质资源保护工作对策,以期为提高小麦种质资源保护和利用水平、促进农业可持续发展提供参考。

小麦种质资源苗期耐盐性鉴定评价

土壤盐渍化是影响小麦生长的重要非生物胁迫之一,筛选培育耐盐小麦种质资源对开展盐碱地综合利用具有重要意义。本研究以19份杂交小麦和2份常规品种为试验材料,以蛭石为培养基质,设置NaCl含量分别为0、0.4%、0.8%、1.2%、1.6%、2.0%的6个处理,从播种时开始盐胁迫处理,分析测定生长相关的11项指标。采用多元统计分析方法对小麦种质资源进行苗期耐盐性评价,结果表明,在1.2%盐处理下,小麦种质资源大多数指标的耐盐系数四分位差最大,因此,1.2%盐被认为是耐盐鉴定最适浓度;利用主成分分析方法可将11项调查指标的耐盐系数简化为3个主成分;通过主成分贡献率和隶属函数分析进一步将3个主成分值简化成综合评价指标D值;根据D值利用聚类分析将21份小麦种质资源划分为5类,对应高耐、耐盐、中耐、敏感和高敏5个耐盐级别,苗期耐盐鉴定表明13份杂交小麦的综合评价D值高于捷麦19与济麦22;结合逐步回归分析获得11个调查指标耐盐系数与D值的最优回归方程:D=–0.743+0.779×PLL+0.372×TNL+1.273×PH+0.336×PLC+0.279×RL+0.558×RDW,由此回归方程可知倒二叶叶长(PLL)、总叶片数(TNL)、株高(PH)、倒二叶叶绿素(PLC)、根长(RL)和根干重(RDW)可作为1.2%持续盐胁迫下小麦种质资源苗期鉴定评价指标。

小麦抗旱性研究进展与展望

利用优异基因资源改良小麦抗旱性是应对干旱和保障粮食安全的重要途径。结合国内外小麦抗旱性研究的最新进展和本研究组的研究实践,概述了现行主要抗旱性鉴定方法的适用对象和评价指标,以及小麦抗旱种质创新、抗旱基因资源发掘与利用等方面的研究成果,同时提出未来小麦抗旱性研究的重点任务和发展方向,即建立基于高通量表型鉴定的抗旱性综合评价技术体系,建立基于高通量基因型鉴定的抗旱基因资源发掘平台,创建基于综合运用多学科技能的智慧育种策略,以期为加快小麦抗旱性遗传改良提供信息资源和理论参考。

中国小麦抗穗发芽种质资源的挖掘与创制

根据4年的表型数据,并结合实验室开发和鉴定的13个分子标记,对我国833份小麦种质资源(主要包括278份小麦微核心种质、124份地方品种和431份现代推广品种及高代品系)穗发芽抗性进行鉴定。结果表明,13个分子标记鉴定的抗/感穗发芽等位类型间相对发芽指数(RGI)差异均达显著或极显著水平,其中TaMFT-222和TaMFT-194标记鉴定的差异最大,U值分别为14.98^(**)和11.30^(**),均达极显著水平,其优异等位类型可以降低相对发芽指数0.21~0.32。其次是Sdr2A、CNGC2AL、Vp1-b2、TaMKK3-A、PM19、CAPS-2AL、A17-19和EX06323标记,其等位类型间穗发芽抗性差异也均达极显著水平;Qsd1和Barc321标记也能显著区分穗发芽抗性。共计鉴定出63份穗发芽抗性较好的种质资源,其中达到抗的有41份,多为红皮品种和地方品种;达到中抗的有22份,白皮半冬性居多。利用分子标记辅助选择,并结合杂交聚合,创制出12份穗发芽抗性水平达到中抗和抗的种质资源,至少携带3个抗穗发芽基因/位点。该结果为抗穗发芽新品种选育提供重要遗传资源。

Analysis of HMW-GS in Pedigree of Longdong Dryland Winter Wheat Varieties

The composition of high molecular weight glutenin subunits( HMW-GS) was analyzed using SDS-PAGE with 70 Longdong dryland winter wheat germplasm resources as experimental materials.The results showed that Longdong dryland winter wheat germplasm resources had N,7 + 8,2 + 12 as the dominant HMW-GS composition( 42.86%),while the dominant HMW-GS composition in the introduced germplasms was N,7 + 9,2 + 12( 36.84%).On the Glu-B1 locus of Longdong dryland germplasms,subunit 7 + 8 had the highest frequency,accounting for 65.71%,and on the Glu-B1 locus of the introduced germplasms,subunit7 + 9 had the highest frequency,accounting for 57.89%.Whether subunit 7 + 8 is related to drought resistance in varieties still needs further study.On Glu-D1 locus,high-quality subunit 5 + 10 appeared in the introduced resources for 5 times,accounting for 13.16% of all the introduced lines,and appeared in Longdong dryland winter wheat germplasm resources for 2 times,only accounting for 2.86% of all the resources,suggesting that Longdong dryland germplasms lack high-quality subunits and need further improvement.

220份四川小麦条锈病抗性鉴定与评价

【目的】了解四川小麦条锈病抗性水平及抗性基因本底,为实现小麦生产抗性多基因布局、可持续利用抗病基因提供依据。【方法】利用条锈病流行生理小种对220份四川小麦进行条锈病抗性表型鉴定并结合已知Yr基因进行分子检测。【结果】29份育成品种和27份农家种对CYR34表现苗期抗性;40份农家种和53份育成品种表现出稳定成株期抗性。2、35、66、72、37和20份种质分别携带Yr10、Yr17、Yr18、Yr24/26、Yr41和Yr48;41份种质携带2个及以上Yr基因。【结论】四川农家种对我国优势条锈菌具有较高比例抗性;农家种以携带Yr18为主,育成品种主要携带Yr17、Yr24/26和Yr41;推测4个具有全生育期抗性的育成种质可能携带其他已知或未知Yr基因或组合,可供进一步Yr基因遗传解析和育种利用。

基于原始种质的小麦育种技术体系

【目的】作物野生近缘物种、地方品种以及利用它们创制的育种原始种质,具有大量未被育种利用的遗传变异。但是,由于普遍具有明显缺陷、产量潜力低,育种家不愿意用,从而限制了其大规模应用。育种原始种质的利用效率不高,仍然是亟待解决的重要问题。【方法】根据人工合成六倍体小麦和以地方品种为遗传背景的染色体工程材料的育种实践,总结建立原始种质的高效育种利用技术体系。【结果】建立了“育种原始种质-顶交-两段选择”育种体系,利用小群体选育出7个新品种,同时利用6RS.6AL易位系选育的含黑麦抗白粉病基因Pm56的新品系参加了四川省区域试验。【结论】顶交可以导入原始种质的有利位点、同时改良综合性状,有利于重组累积不同品种亲本中的有利位点、赶上育种家的遗传改良步伐,也有利于原始种质与其他亲本间不同遗传变异的协调匹配。两段选择降低了选择难度、提高了选择效率,尤其是第一段选择聚焦于淘汰遗传上相对简单的关键缺陷性状,选择标准简单、易操作,而且符合中选标准的植株少,从而选择难度小、工作量小。育种实践表明,基于原始种质的小麦育种技术体系提高了育种效率。

新疆冬小麦种质资源主要农艺性状遗传多样性分析

【目的】研究新疆冬小麦种质资源主要农艺性状遗传多样性。【方法】分析232份冬小麦种质资源的株高、有效分蘖数、千粒重等9个主要农艺性状,进行遗传多样性、相关性和聚类综合评价。【结果】新疆232份小麦品种遗传多样性指数较高,9个农艺性状的多样性指数介于1.68~2.10,变异类型丰富,变异系数幅度为10.3%~43.6%,各农艺性状变异系数顺序为单株产量>有效分蘖数>主穗粒重>主穗长>主穗粒数>最多粒数>株高>小穗数>千粒重;主要农艺性状与单株产量的相关程度为:有效分蘖数(0.838)>主穗粒重(0.564)>主穗粒数(0.559)>最多粒数(0.301)>千粒重(0.269)>主穗长(0.224)>株高(-0.196)>小穗数(-0.102),有效分蘖数、主穗粒重、主穗粒数、千粒重对单株产量的直接通径系数和相关系数均达显著水平;在欧式距离为16的位置将232个品种划分为5个类群,分析各类群的9个农艺性状特征发现,类群间存在较大差异。【结论】新疆冬小麦种质资源主要农艺性状变异较大,且遗传多样性丰富。有效分蘖数、主穗粒重、主穗粒数、千粒重对单株产量的影响是直接且正向的,可以作为提高单株产量的筛选指标,且有效分蘖数这一性状应优先选择。

利用转基因技术和基因编辑技术改良小麦进展

小麦籽粒营养丰富,其面粉可制作成多种食品,是全球超过三分之一人口的主食。随着病虫害加重、环境恶化(干旱、高温、盐碱)等生物和非生物逆境的影响,全球小麦安全生产受到的威胁越来越大。为保障全球粮食安全供给和人民生活对优质产品的需要,提高小麦产量和改进小麦品质仍将是重要的育种目标,要求不断创新育种技术和种质资源。近10年来,转基因和基因编辑等生物技术发展迅速,逐步在小麦改良中发挥重要作用。建立了小麦高效遗传转化体系和基因编辑体系,利用农杆菌转化模式基因型的转化效率50%以上,利用CRISPR/Cas9编辑部分基因的编辑效率40%~70%,利用再生相关基因基本克服了转基因和基因编辑研究中基因型的依赖性。通过转基因和基因编辑改良了小麦抗病性、抗逆性、特性品质、产量潜力和生长发育等多个性状,创制了抗白粉病、条锈病、赤霉病、花叶病毒病、穗发芽,以及耐旱、耐盐、低醇溶蛋白、高谷蛋白、高千粒重和雄性不育系、单倍体诱导系等小麦新材料,丰富了小麦种质资源。本研究旨在综述小麦转基因和基因编辑的最新研究进展,并探讨目前研究中存在的问题和可能的解决途径。

成株期抗纹枯病小麦种质的发掘

小麦纹枯病是一种危害小麦茎基部的土传真菌病害,近年来在我国长江中下游和黄淮麦区发生日趋严重,限制了小麦的高产稳产。当前生产上推广品种对纹枯病的抗性普遍较差且抗病育种进展缓慢,究其主要原因是纹枯病抗源匮乏。为发掘小麦纹枯病稳定抗源,本研究采用土表接菌法和滚动鉴定的方式,连续10年在3个环境(南京大田、六合大棚和水泥池)下,对共计384份小麦种质资源进行了成株期纹枯病抗性鉴定。结果表明,携带小麦近缘种属遗传物质的近缘种质抗性较好,国外引进种质次之,国内育成品种(系)抗性较差。鉴定出成株期对纹枯病呈稳定抗性的种质3份,分别为小黑麦09R1-29、美国引进种质Glacier和Steele;鉴定出呈稳定中抗的种质44份,包括淮麦920等育成品种(系)11份,辉县红等地方品种2份,Scout等引进种质11份,来源于黑麦、簇毛麦、偃麦草、人工合成小麦等的近缘种质20份。这些小麦成株期纹枯病新抗源可为抗纹枯病研究和抗病新品种培育提供种质资源。