Assessment of molecular markers and marker-assisted selection for drought tolerance in barley(Hordeum vulgare L.)

This review updates the present status of the field of molecular markers and marker-assisted selection(MAS),using the example of drought tolerance in barley.The accuracy of selected quantitative trait loci(QTLs),candidate genes and suggested markers was assessed in the barley genome cv.Morex.Six common strategies are described for molecular marker development,candidate gene identification and verification,and their possible applications in MAS to improve the grain yield and yield components in barley under drought stress.These strategies are based on the following five principles:(1)Molecular markers are designated as genomic‘tags’,and their‘prediction’is strongly dependent on their distance from a candidate gene on genetic or physical maps;(2)plants react differently under favourable and stressful conditions or depending on their stage of development;(3)each candidate gene must be verified by confirming its expression in the relevant conditions,e.g.,drought;(4)the molecular marker identified must be validated for MAS for tolerance to drought stress and improved grain yield;and(5)the small number of molecular markers realized for MAS in breeding,from among the many studies targeting candidate genes,can be explained by the complex nature of drought stress,and multiple stress-responsive genes in each barley genotype that are expressed differentially depending on many other factors.

Molecular Marker Assisted Selection for Yield-Enhancing Genes in the Progeny of Minghui63 x O. rufipogon

Two yield-enhancing genes (yld1.1 and yld2.1) are located on chromosomes 1 and 2 respectivelyin a weedy relative of cultivated rice, Oryza rufipogon. SSR markers RM9 and RM166 are closelylinked with the two loci respectively. Minghui63 (MH63) has been a widely used restorationline in hybrid rice production in China during the past two decades. The F1 of cross 'MH63O.rufipogon' was backcrossed with MH63 generation by generation. RM9 and RM166 were used toselect the plants from the progeny of the backcross populations. The results were as follows:(1) In BC2F1 population, the percentage of the individuals which have RM9 and RM166 amplifiedbands simultaneously was 12.2%, while in the BC3F1 population, that was 16.3%. (2) Among 400individuals of BC3F1, four yield-promising plants were obtained, with yield being 30% more thanthat of MH63. (3) The products amplified by primer RM166 in O. rufipogon and MH63 weresequenced. It was found that the DNA fragment sequence amplified by RM166 from MH63 was 101 bpshorter than that from O. rufipogon. The 101bp sequence is a part of an intron of the PCNA(proliferating cell nuclear antigen) gene.

Application of the New Gene Gm6 Against Rice GallMidge in Resistance Breeding Through PCR-BasedMarker Aided Selection

The research results of marker aided selection(MAS)for resistant varieties and lines against rice gall midge Orseolia oryzae Wood-Mason successfully in 1999 - 2002 were reported in the present paper. The molecular markers linked to the gene Gm6 against rice gall midge were used to select and breed the resistant varieties and lines. The RAPD marker OPM06 was used to verify the existence actually of gene Gm6 in ten developed varieties resistant to gall midge such as Duokang1, Duokang2, Kangwen2, Kangwen3, Kang-wen5, Duokangzaozhan, Kangwenqinzhan, which were derived from Daqiuqi. For resistance breeding through PCRbased marker aided selection(MAS), the polymorphisms in the resistant and susceptible parents were i-dentified by RG476/Alu I and RG476/Sca I respectively. The RAPD marker OPM06(1.4 kb)was used to i-dentify 15 new resistance lines from F3 lines of Fengyinzhan1/Daqiuqi in 1999. 21 and 7 resistance lines were selected from F4 and F6 lines of KWQZ/Gui99(restored line of hybrid rice)using RG476/Alu I in 2000-2001 respectively. The Gm6 gene was transferred into the restored line of hybrid rice. In 2001 - 2002, RG214/ Hha I and G214/Sca I were used for selecting 11 and 5 resistance lines from F3 lines of KWQZ/IR56 and AXZ/KWQZ successfully. The application of the resistance gene through PCR-based marker aided selection is a new and effective approach in resistance breeding.

A Co-Dominant Marker BoE332 Applied to Marker-Assisted Selection of Homozygous Male-Sterile Plants in Cabbage (Brassica oleracea var.capitata L.)

The dominant genic male sterility （DGMS） gene CDMs399-3 derived from a spontaneous mutation in the line 79-399-3 of spring cabbage （Brassica oleracea var. capitata L.）, has been successfully applied in hybrid seed production of several cabbage cultivars in China. During the development of dominant male sterility lines in cabbage, the conventional identification of homozygous male-sterile plants （CDMs399-3/CDMs399-3） is a laborious and time-consuming process. For marker-assisted selection （MAS） of the gene CDMs399-3 transferred into key spring cabbage line 397, expressed sequence tag-simple sequence repeats （EST-SSR） and SSR technology were used to identify markers that were linked to CDMs399-3 based on method of bulked segregant analysis （BSA）. By screening a set of 978 EST-SSRs and 395 SSRs, a marker BoE332 linked to the CDMs399-3 at a distance of 3.6 cM in the genetic background of cabbage line 397 were identified. 7 homozygons male-sterile plants in population P1170 with 20 plants were obtained finally via MAS of BoE332. Thus, BoE332 will greatly facilitate the transferring of the gene CDMs399-3 into the key spring cabbage line 397 and improve the application of DGMS in cabbage hybrid breeding.

Adaptive path selection for the improved distributed mobility management

Current mobility management schemes usually represent centralized or hierarchical architectures,which force data traffic to be processed by a centralized mobility anchor.This allows the mobile node(MN)to be reachable anywhere and provides an efficient method for seamless session continuity.However,all of the signal messages and data traffic converge on particular mobility anchor,which causes excessive signaling and traffic at the centralized mobility anchor and single point of failure issues as data traffic increases.To overcome these limitations and handle increasing data traffic,the distributed mobility management(DMM)scheme has emerged as an alternative solution.Although previous researches have been conducted on DMM support,because their schemes employ an unconditional way to make direct paths after handover,they have some drawbacks,such as several signaling and chain of tunneling problems.Therefore,this paper introduces a new DMM scheme which adaptively creates a direct path.To support it,we present the path selection algorithm,which selects the most efficient path between a direct path and no direct path based on routing hops and traffic load.Through the performance analysis and results,we confirm that the proposed scheme is superior in terms of signaling and packet delivery costs.

利用MAS技术培育水稻多抗、优质强恢复系桂恢663

【目的】培育新的兼抗稻瘟病、白叶枯病和细菌性条斑病,且米质较优的水稻强恢复系,为选育抗病、高产、优质的杂交稻组合提供良好的亲本材料。【方法】以抗稻瘟病品种合丰占为母本,与抗白叶枯病品系粤泰占杂交,通过分子标记辅助选择(MAS),获得多个抗病基因聚合的优良单株,再经过多代自交选育,并进行田间抗性及米质鉴定、农艺性状考察及恢复力测试。【结果】培育出聚合了抗稻瘟病基因Pi-ta、Pib、Pi54和抗白叶枯病兼抗细条病基因xa5的多抗、优质强恢复系桂恢663。桂恢663对白叶枯Ⅳ型菌和强毒Ⅴ型菌表现为抗,对广西细条病优势菌株JZ-8表现为抗,对14个稻瘟病菌株,有12个达到1级抗性。桂恢663除直链淀粉含量偏低外,其余6个主要米质指标均达到国标2级标准,其与丰田1A所配抗病、高产、优质组合丰田优663通过广西品种审定。桂恢663和丰田优663谷粒具有香味。【结论】桂恢663兼抗稻瘟病、白叶枯病和细条病,且恢复力强、米质较优具有香味,是组配抗病、高产、优质杂交组合的优良亲本,同时为水稻提供重要遗传基础材料。

利用回交和MAS技术改良珍汕97B的白叶枯病抗性

以IRBB21为白叶枯抗病基因的供体亲本,珍汕97B为受体亲本,通过1次杂交、3次回交、1次自交,采用传统的回交育种和分子标记辅助选择技术相结合的方法获得了6个导入Xa21的珍汕97B导入系,其遗传背景恢复比例为92.8%-97.4%(平均为94.9%).

利用分子标记辅助选择育种(MAS)技术改良水稻恢复系粤恢826

【目的】改良杂交稻恢复系粤恢826,以提高其稻瘟病和白叶枯病抗性,改良米质,为选育抗病、优质的杂交稻组合提供良好亲本材料。【方法】以含稻瘟病抗性基因Pi1和Pi2、白叶枯病抗病基因Xa23及蜡质基因Wx的中间材料Z1103为供体亲本,杂交水稻强恢复系粤恢826为受体亲本,利用分子标记辅助选择(MAS)技术和系谱选育方法,聚合4个外源基因以改良粤恢826的抗病性和米质,并进行稻瘟病和白叶枯病抗性及米质鉴定。【结果】经SSR分子标记检测、田间抗病性及米质鉴定,获得以粤恢826为遗传背景且含有目标基因的6个改良株系,通过农艺性状筛选与恢复力测试,优选到一个含有Pi1、Xa23和Wx基因的纯合株系,其恢复力好,农艺性状优良,2014年早造定名为粤恢88,其田间鉴定稻瘟病抗性3级,白叶枯病抗性1级,米质为软米。2014年晚造与两系不育系Y58S配制杂交稻组合Y两优88,其在品比试验中产量达6543 kg/ha,比对照深两优58香油占增产4.97%,未达显著水平(P>0.05),且抗稻瘟病,中抗白叶枯病,米质鉴定为国优3级和省优3级。【结论】MAS技术可有效聚合多基因(Pi1、Xa23和Wx基因),使粤恢826的稻瘟病和白叶枯病抗性及米质明显改良,获得抗稻瘟病、高抗白叶枯病、米质为软米的新恢复系粤恢88,为选育抗病优质的杂交稻组合提供良好亲本材料。

利用回交和MAS技术改良优质两系不育系金山s-2的稻瘟病抗性

以水稻品系5173为抗性供体亲本,通过连续回交和MAS技术将稻瘟病抗性基因Pi-2导入优质低温敏核不育系金山s-2的遗传背景中。在各世代皆利用与Pi-2紧密连锁的SSR标记SRM24对目标基因进行"前景选择",并结合形态性状进行"背景选择",直至BC3F2,获得抗病标记纯合且其它性状与金山s-2非常相似的植株9株。在BC3F1,对中选的4个单株利用SRAP标记进行遗传背景分析表明,它们与受体亲本金山s-2具较高的遗传相似系数;对选育出的株系的温敏不育性特性观察表明,获得的4个近等基因系,它们保持了亲本育性稳定、临界温度低和可繁性好的特性;对BC3F1∶2株系抗病鉴定结果表明,通过标记选出的单株均表现抗病,说明利用SRM24对Pi-2基因进行选择是可靠的,能够满足需要。因此,在BC3F1决选出4个单株可望替代不抗病的金山s-2直接应用于生产。

棉花QTL定位及MAS育种进展与展望

近年来,随着现代分子生物学及统计分析方法的快速发展,育种工作者已定位了许多作物的重要性状QTLs。同时,基于QTL定位的标记辅助选择(MAS),已成为当前作物分子育种研究的热点。综述了近年来棉花重要性状包括产量、纤维品质、抗性、形态、生理、早熟性等QTL定位最新进展,以及标记辅助选择在一些性状上的初步应用,并对其发展前景进行展望。

含玉米pepc基因恢复系的MAS转育及其杂交稻的光合特性和杂种优势研究

用玉米pepc基因的特异性引物对转育pepc基因的后代材料进行分子标记辅助选育(MAS),成功地培育出与轮回亲本蜀恢881遗传相似度达97.09%～99.03%的改良蜀恢881,用此改良恢复系与3个不育系冈46A、776A、2480A形成组合。结果表明,(1)自行设计的pepc基因特异性引物能对基因进行准确的筛选,而且玉米pepc基因在新的遗传背景下能够稳定遗传和高水平表达;(2)含有pepc基因F1的PEPCase活力明显地高于对照,PEPCase活力与净光合速率(Pn)极显著正相关(0.6081**),表观量子效率、羧化效率等光合指标也显著好于对照;(3)含有pepc基因F1农艺性状表现各不相同,但千粒重和单株产量表现较为一致,且单株产量较对照平均增加41.48%;(4)776A、Line1和Line6的GCA较高,值得今后进一步考察与利用。

家畜育种中MAS的遗传标记与QTL

简要评述了在家畜育种中标记辅助选择（ＭＡＳ）所适用的遗传标记系统及对数量性状位点（ＱＴＬ）和标记的基本要求．对ＭＡＳ中遗传标记与ＱＴＬ的紧密连锁之意义进行了讨论，认为遗传标记与ＱＴＬ间的连锁程度是决定ＭＡＳ效能的关键因素．

MAS环境下支持产品设计的协同技术及系统研究

为了提高产品质量和开发效率,提出了基于MAS的采用网络技术和现代通信技术进行产品设计开发的新型设计模式——网络化协同设计和基于多Agent的协同设计系统框架及其流程。研究了协同设计过程中基于贝叶斯方法的任务逻辑推断、蚁群算法的伙伴选择以及基于Web的电子图纸显示等关键技术,并在理论研究的基础上开发了网络化协同设计原型系统,验证了网络化协同设计系统的可靠性、实用性和高效性。

应用MAS技术改良水稻特异种质大粒溪香的稻瘟病抗性

本研究以携带Pi1和Pi9抗病基因的BC_(4)F_(2)群体为基础材料,利用分子标记辅助选择(MAS)完成BC_(5)F_(5)株系的构建,并对其进行苗瘟接种鉴定及不同生态环境的田间自然鉴定。结果表明,大粒溪香的苗瘟病级为7级,而改良株系病级为2~6级。大粒溪香在湄潭和黎平两病圃叶瘟病病级为8级和7级,穗瘟病均为9级高感,其综合抗性指数为8.4,表现为高感稻瘟病;而改良株系在两病圃叶瘟病病级为1~7级,穗瘟病病级为5~9级,表现为感和高感,但穗瘟损失率病级较轻,相较对照大粒溪香8级穗瘟损失率,降低了3~7个病级。通过分子标记辅助选择获得改良株系抗性较原始亲本大粒溪香均有不同程度提升,明确了改良株系在不同生态区的稻瘟病抗性水平差异,筛选出一批可供育种利用的水稻新种质。

基于MAS的供应商选择系统分析与设计

在总结了供应链管理及智能代理基本理论的基础上,通过与传统供应商筛选方法之间的对比,构建了基于MAS的企业供应商筛选系统模型,并研究了供应商选择中的协调问题。其次,重点研究了数据采集Agent、决策支持Agent、动态评价Agent的组成框架及工作内容,并在此基础上阐述了各部分的运作模型、供应链框架的运行机制及框架中供应商的地位。然后,为了提高系统的学习性、自适应性和智能性,实现供应商的自动筛选,采用了自组织数据挖掘结合遗传算法优化本系统的学习能力。

利用MAS选育抗大豆花叶病毒病SC7新品种阜豆169

为培育黄淮海和长江流域大豆产区主要大豆花叶病毒流行株系SC7的抗性大豆品种,阜阳市农业科学院/国家大豆改良中心安徽分中心以郑97196为母本、科丰29为父本进行杂交,结合MAS方法选育出抗花叶病毒SC7株系夏大豆新品种阜豆169。两年试验平均粗蛋白含量40.96%,平均粗脂肪含量19.4%。抗性基因连锁分子标记BARCSOYSSR_02_0631鉴定和人工接种鉴定结果均表明,该品种对大豆花叶病毒SC3和SC7株系均表现抗病。对8个大豆疫霉菌株均表现抗病。2019年生产试验产量2668.05 kg·hm^(-2),较对照中黄13增产9.43%。苗期耐渍,后期耐旱,抗倒抗病,落叶性好,不裂荚,高产稳产。于2020年通过安徽省农作物品种审定委员会审定,审定编号为皖审豆20200001。此次MAS技术的应用实现了大豆品系抗花叶病毒SC7相关位点的早期子代选择鉴定,不仅突破了时空条件的限制,而且避免了传统方法接种鉴定时传播花叶病毒的情况,减少了后续工作量,缩短抗病高产大豆品种育种周期。

Deep genotyping of the gene GmSNAP facilitates pyramiding resistance to cyst nematode in soybean

Soybean cyst nematode(SCN)is a highly destructive pathogen.The soybean host genome harbors at least two major genes for resistance(rhg1 and Rhg4),as well as a minor locus(SCN3-11).In the present study,a splicing site in GmSNAP11,the potential causal gene of SCN3-11,was identified by comparison of the GmSNAP11 cDNA sequences generated from resistant and susceptible soybean accessions.The sequence information was used to design a codominant CAPS marker,GmSNAP11-2565,which was used to genotype a panel of 209 soybean accessions varying with respect to SCN resistance.Analyses of the effect of the haplotypes formed by GmSNAP11-2565 and another large-effect(nonsynonymous)locus,GmSNAP11-2307,previously identified in GmSNAP11,revealed linkage disequilibrium(P<0.0001)between the two loci,suggesting that GmSNAP11-2565 could be used as a marker for GmSNAP11.GmSNAP11-2565 was accordingly used,along with established markers for GmSNAP18(rhg1)and GmSHMT(Rhg4),to characterize the panel accessions.The mean SCN female index of accessions carrying only the GmSNAP11 allele associated with resistance(20.3%)was higher than that associated with accessions carrying alleles for resistance at both GmSNAP11 and GmSNAP18(12.4%),while the index for accessions carrying alleles for resistance at all of GmSNAP11,GmSNAP18,and GmSHMT was very low(1.9%).Selection on all three markers was effective for maintaining a high level of resistance to SCN race 3.

基于MA-EGARCH-t-Copula模型的金融市场相关关系的研究

构建MA-EGARCH-t-Copula模型研究深证综合指数和中小板指数相关关系.选取深证综合指数与中小板指数的日收盘指数序列,利用MA-EGARCH-t模型构建Copula函数的边缘分布,使用AIC准则确定模型阶数及参数,结合秩相关系数选取较优的Copula函数刻画深证综合指数与中小板指数的相关关系,进一步利用欧氏距离法进行拟合优度检验.结果表明,t-Copula可以较好地拟合深证综合股指和中小板股指的日收益率序列间关系,两股指日收益率序列呈现出较强的相关性以及对称尾部相关性.

Identification of QTLs Associated with Total Soyasaponin Content in Soybean (Glycine max (L.) Merr.)

Soyasaponins are valuable compounds in certain drugs, industry, food additives and surfactants. Selecting cultivars with higher-soyasaponin content along with agronomic traits is a main goal for many soybean breeders. The aim of the present study was to identify the quantitative trait loci （QTLs） associated with total soyasaponin content through a F2 population, which was derived from a cross between Ha 91016 （higher soyasaponin content cultivar, 16.8 mg gl） and N98-9445A （lower soyasaponin content, only 5.7 mg g-l）. A genetic linkage map including a total of 162 simple sequence repeat markers was constructed, which covered the total length 2 735.5 cM, and the average distance between markers was 16.96 cM. Two QTLs associated with total soyasaponin content were identified. One, qSAP1 （located in sat_044-satt102 of linkage group （LG） K）, could explain 12.6% of phenotypic variance. The other, qSAP_2, was located between satt368 and sat413 of LG Dla, which could explain 15.8% of phenotypic variance. It was concluded that the two QTLs would have some potential value for marker-assisted selection for high-soyasaponin content breeding in soybeans.

Development of Insect-Resistant Hybrid Rice by Introgressing the Bt Gene from Bt Rice Huahui 1 into Ⅱ-32A/B,a Widely Used Cytogenic Male Sterile System

Huahui 1 is an elite transgenic male sterile restorer line of wild rice abortive-type that expresses a Bacillus thuringiensis （Bt） δ-endotoxin and provides effective and economic control oflepidopteran insects. To exploit Huahui 1 to develop a new Bt rice, the insertion site of the Bt gene was determined by thermal asymmetric interlaced PCR （TAIL-PCR）. Bt was located in the promoter region ofLOC. Os10g10360, approximately 5.35 Mb from the telomere of the short arm of chromosome 10. For the first time, a Bt cytoplasmic male sterile （CMS） system was developed by introgressing Bt from Huahui 1. The recipient CMS system used consisted of Indonesia paddy rice-type II-32B （maintainer line） and II-32A （male sterile line）. Marker-assisted selection was used to increase selection efficiency in the backcrossing program. In BC5F1, the Bt plant 85015-8 was selected for further analyses, as it had the highest SSR marker homozygosity. In addition, the linkage drag of the foreign Bt gene in 85015-8 was minimized to 8.01-11.46 Mb. The foreign Bt gene was then delivered from 85015-8 into II-32A. The resultant Bt II-32A and Bt II-32B lines were both resistant to lepidopteran in field trials, and agronomic traits were not disturbed. The maintainability of II-32B, and the male sterility and general combining ability of II-32A, were not affected by the Bt introgression. This study demonstrates a simple and fast approach to develop Bt hybrid rice.