Improving Blast Resistance of a Thermo-Sensitive Genic Male Sterile Rice Line GD-8S by Molecular Marker-Assisted Selection

The broad-spectrum blast resistance gene Pi-1, from donor line BL122, was introduced into a thermo-sensitive genic male sterile rice line GD-8S, which possessed good grain quality but high susceptibility to rice blast, by using backcross breeding and molecular marker-assisted selection. Five elite improved male sterile lines, RGD8S-1, RGD8S-2, RGD8S-3, RGD8S-4 and RGD8S-5, were selected based on the results of molecular marker analysis, spikelet sterility, recovery rate of genetic background and agronomic traits. Thirty-three representative blast isolates collected from Guangdong Province,China were used to inoculate the improved lines and the original line GD-8S artificially. The resistance frequencies of the improved lines ranged from 76.47% to 100%, much higher than that of the original line GD-8S (9.09%). On the agronomic characters, there were no significant differences between the improved lines and GD-8S except for flag leaf length and panicle number per plant. The improved lines could be used for breeding hybrid rice with high blast resistance.     

利用分子标记辅助选择改良温敏核不育系GD-8S的稻瘟病抗性

以含有广谱稻瘟病抗性基因Pi 1的籼稻材料BL122为供体,优质感病温敏核不育系GD 8S为受体,通过杂交、多次回交和自交结合分子标记辅助选择技术,将Pi 1基因导入GD 8S中。综合目标基因的分子检测、育性镜检、田间农艺性状表现以及遗传背景的回复率,筛选获得5个改良株系RGD8S 1、RGD8S 2、RGD8S 3、RGD8S 4和RGD8S 5。采用广东省具有代表性的33个菌株进行人工接种抗性鉴定,5个改良株系的抗性频率为75.76%~100.00%,而对照仅为9.09%。农艺性状分析表明,除剑叶长和每株穗数外,其余性状改良株系与对照无显著差异。这些改良株系可用于进一步测配选育高抗稻瘟病杂交稻新组合。     

分子标记辅助选择改良水稻恢复系香5的病虫抗性

香5是由湖北省农科院选育的优质两系杂交稻恢复系,所配组合广两优5号(广占63-4S/香5)于2013年通过了湖北省审定.利用回交和分子标记辅助选择技术,将供体亲本MD12086-1351中的抗稻瘟病基因Pi9、抗褐飞虱基因Bph14、Bph15和抗白叶枯病基因Xa23渗入到香5背景中,育成了3个同时携带Pi9、Bph14、Bph15和Xa23基因的新株系.鉴定结果表明,新株系的叶瘟抗性明显提高,穗颈瘟抗性部分提高,苗期抗褐飞虱,分蘖盛期高抗白叶枯病;产量、主要农艺性状、香味和稻米品质主要指标与香5相似.新株系所配的组合在产量、主要农艺性状上与香5所配的组合相似.表明新株系可以作为香5的替代系用于培育抗稻瘟病、抗褐飞虱和抗白叶枯病的两系杂交稻新组合.     

Pigm特异性选择标记的开发及其在粳稻穗颈瘟抗性育种中的利用

【目的】Pigm是一个广谱的稻瘟病抗性基因,源自持久抗性品种谷梅4号,与Piz、Piz-t、Pi2、Pi9和Pi40等互为复等位基因但抗谱存在差异。为了更好地在分子辅助选择育种中利用Pigm基因,开发与Pigm特异性标记具有重要意义。【方法】在已有文献报道定位结果的基础上,通过随机测序获得了一段谷梅4号基因组的特异序列,并据此开发了一组用于筛选Pigm基因的分子标记,进一步选取江淮稻区3个不同生态型代表性粳稻品种作为受体,利用分子标记辅助选择结合对抗性基因的背景检测将Pigm基因导入受体品种。【结果】Pigm-4标记位于Pigm基因簇内部,与抗病功能元件PigmR紧密连锁,对不同类型的品种检测发现该标记特异性强,且利用该标记可将Pigm与Piz、Piz-t、Pi2、Pi9以及Pi40区分开来。对受体亲本稻瘟病抗性基因的检测和接种结果分析发现江淮稻区粳稻品种虽然携带了Pib、Pi54、Pita、Pb1中的2~3个基因,但是对强毒力的稻瘟病小种抗性普遍不强,而3种代表性粳稻背景下导入Pigm基因均可显著提高其对穗颈瘟的抗性水平。【结论】Pigm可以作为抗稻瘟病粳稻育种的有利基因资源加以利用,而Pigm-4是分子标记辅助筛选Pigm的优异标记。     

转基因小麦1Dx5基因沉默的遗传表达和品质效应分析

为了明确通过RNA干扰技术（RNAi）获得的转基因小麦品系“Glu1Dx5RNAi”中1Dx5基因的遗传规律,以“Glu1Dx5RNAi”为供体亲本,以弱筋品种扬麦18和扬麦13为轮回亲本进行回交, 采用半籽粒SDSPAGE法检测亲本、F₁、F₂和BC₁F₁籽粒的高分子量谷蛋白亚基（HMWGS）组成。结果表明,1Dx5基因的沉默效应在杂交后代中表现为显性遗传,在F₂和BC₁F₁世代1Dx5亚基不表达的种子数与1Dx5亚基表达的种子数的比例分别符合13∶3和3∶1的分离比例,说明转小RNA基因导致1Dx5基因沉默是单基因显性遗传。对转基因小麦“Glu1Dx5RNAi”及其受体品种Bobwhite进行品质测试表明,Glu1Dx5RNAi蛋白质含量（13.28%）比转化受体Bobwhite（12.83%）高0.45个百分点,硬度指数、微量SDS沉降值比受体品种分别降低3.13和3.7 mL。1Dx5基因沉默对弱筋小麦育种可能会有一定的利用价值。     

水稻Pi9基因序列标记的开发及其抗瘟育种应用

利用广谱抗稻瘟病基因Pi9的3'UTR序列设计特异DNA标记pi9utr,通过分子标记辅助选择和连续回交育种实践,改良7份籼稻亲本(316B、金23B、R207、R228、R288、R389、明恢86)的稻瘟病抗性。结果表明:pi9utr是一个高效显性分子标记,除R207外,在其余6份受体亲本与Pi9供体亲本75-1-127间均存在明显而稳定的多态;在室内接种后的316B×75-1-127 BC4F1群体和R288×775-1-127 BC6F1群体中随机取样,进行稻瘟病抗性表型和基因型鉴定及Pi9基因表达分析,证明pi9utr对两个组合回交后代个体的抗病性辅助选择效率均为100%,且在所有抗病单株中均能检测到Pi9基因的高效表达,在所有感病单株中均没有检测到Pi9基因的表达。利用pi9utr在回交世代中的连续辅助选择,获得了3个组合的BC4F1及3个组合的BC6F2代群体,为选育抗稻瘟病新品种打下了基础。     

Development and Identification of Novel Rice Blast Resistant Sources and Their Characterization Using Molecular Markers

To develop and characterize introgression lines for leaf and neck blast resistance, 326 introgression lines were developed using various accessions of six different AA genome wild species in the genetic background of elite Indian varieties like PR114 and Pusa 44 and were screened for blast resistance. Stringent phenotyping coupled with genotyping using gene based markers led to the identification of four resistant introgression lines, which showed promising resistance and do not possess any of the tested genes. Furthermore, multi-location screening confirmed the field resistance of the four introgression lines to both leaf and neck blast. Molecular characterization of these introgression lines using genome-wide simple sequence repeat markers revealed the presence of small percentage of wild Oryza genome introgrssion. So these lines can be used for mapping and identification of novel leaf and neck blast resistance genes. Thus, these four introgression lines can be considered as new genetic resources for blast resistance.     

Marker-Assisted Pyramiding of Genes Conferring Resistance Against Bacterial Blight and Blast Diseases into Indian Rice Variety MTU1010

Two major bacterial blight(BB) resistance genes(Xa21 and xa13) and a major gene for blast resistance(Pi54) were introgressed into an Indian rice variety MTU1010 through marker-assisted backcross breeding. Improved Samba Mahsuri(possessing Xa21 and xa13) and NLR145(possessing Pi54) were used as donor parents. Marker-assisted backcrossing was continued till BC2 generation wherein PCR based functional markers specific for the resistance genes were used for foreground selection and a set of parental polymorphic microsatellite markers were used for background selection at each stage of backcrossing. Selected BC2F1 plants from both crosses, having the highest recoveries of MTU1010 genome(90% and 92%, respectively), were intercrossed to obtain intercross F1(ICF1) plants, which were then selfed to generate 880 ICF2 plants possessing different combinations of the BB and blast resistance genes. Among the ICF2 plants, seven triple homozygous plants(xa13xa13Xa21Xa21Pi54Pi54) with recurrent parent genome recovery ranging from 82% to 92% were identified. All the seven ICF2 plants showed high resistance against the bacterial blight disease with a lesion lengths of only 0.53–2.28 cm, 1%–5% disease leaf areas and disease scoring values of ‘1' or ‘3'. The seven ICF2 plants were selfed to generate ICF3, which were then screened for blast resistance, and all were observed to be highly resistant to the diseases. Several ICF3 lines possessing high level of resistance against BB and blast, coupled with yield, grain quality and plant type on par with MTU1010 were identified and advanced for further selection and evaluation.     

聚合白背飞虱和褐飞虱抗性基因创制杂交水稻恢复系

【目的】为了创制兼抗白背飞虱和褐飞虱的水稻恢复系，【方法】分别以抗褐飞虱材料B5（携带褐飞虱抗性基因Bph14和Bph15）及携带白背飞虱抗性位点qsI-4的籼型恢复系福恢7011为供体亲本，以骨干恢复系福恢676为轮回亲本，应用低世代分离群体田间表型结合单株鉴定与高世代稳定株系室内筛选和分子标记辅助选择相结合的方法，并对抗虫株系及其测交后代进行考查和农艺性状分析。【结果】选育出聚合Bph14、Bph15 和qsI-4的恢复系材料3份，携带2个抗虫基因的恢复系材料3份。其中6份恢复系的褐飞虱抗性鉴定结果均表现中抗以上。通过抗性鉴定和杂交后代农艺性状分析筛选出具有生产应用潜力的恢复系材料2份。【结论】为褐飞虱和白背飞虱抗性聚合新种质的创制和应用提供了基础材料。     

利用分子标记辅助选择改良温恢117白叶枯病抗性

以恢复系温恢117为受体,以IRBB21为抗白叶枯病基因Xa21的供体,通过杂交、多次回交和自交,结合分子标记辅助选择技术,将Xa21基因导入温恢117中,结合抗性基因Xa21的分子检测和农艺性状表现,筛选出带有Xa21基因的15个恢复系株系.采用白叶枯病菌株的专化强毒菌系P6进行接种鉴定,各株系的白叶枯病抗性均强于受体亲本温恢117,其中株系M033抗性与IRBB21相当,而农艺性状与温恢117相近.     

聚合白背飞虱和褐飞虱抗性基因创制杂交水稻恢复系

【目的】为了创制兼抗白背飞虱和褐飞虱的水稻恢复系,【方法】分别以抗褐飞虱材料B5(携带褐飞虱抗性基因Bph14和Bph15)及携带白背飞虱抗性位点qsI-4的籼型恢复系福恢7011为供体亲本,以骨干恢复系福恢676为轮回亲本,应用低世代分离群体田间表型结合单株鉴定与高世代稳定株系室内筛选和分子标记辅助选择相结合的方法,并对抗虫株系及其测交后代进行考查和农艺性状分析。【结果】选育出聚合Bph14、Bph15和qsI-4的恢复系材料3份,携带2个抗虫基因的恢复系材料3份。其中6份恢复系的褐飞虱抗性鉴定结果均表现中抗以上。通过抗性鉴定和杂交后代农艺性状分析筛选出具有生产应用潜力的恢复系材料2份。【结论】为褐飞虱和白背飞虱抗性聚合新种质的创制和应用提供了基础材料。     

利用分子标记辅助育种技术育成优质高产抗病杂交稻国稻1号

国稻1号是中国水稻研究所利用分子标记辅助选择育种技术育成带有抗白叶枯病基因Xa21的恢复系中恢8006,再与印水型胞质不育系中9A组配的中晚兼用杂交稻新组合.该组合参加国家南方稻区区试、江西省区试和各地试种示范,表现高产稳产、米质优(国标3级)、抗性强(抗稻瘟病,中抗白叶枯病)、适应性广、易于制种等特点.于2004年3月通过江西省品种审定,2004年10月通过国家审定.     

利用分子标记辅助选择技术改良三系不育系荃9311A稻瘟病抗性的研究

为了提高三系不育系荃9311A的稻瘟病抗性,以含广谱稻瘟病抗性基因Pigm的水稻品种9311为供体,保持系荃9311B为受体和轮回亲本,通过分子标记辅助选择技术筛选抗性基因、剔除恢复基因和遗传背景筛选,在稻瘟病病区进行抗性鉴定,人工接种鉴定以及田间农艺性状考查,于BC2F2代获得有Pigm基因并剔除了恢复基因的改良株系,其后再与荃9311A杂交和连续回交,育成了农艺性状与荃9311A无显著差异而稻瘟病抗性明显增强的三系不育系K9311A及其保持系K9311B。     

444玉米回交导入系主要性状及对丝黑穗病的抗性评价

以玉米自交系444为轮回亲本和54个国内优良自交系为供体亲本构建高世代回交导入系(BC3F4),随机选取54份回交导入系进行主要性状及抗玉米丝黑穗病评价。结果表明,回交导入系J88、J107和J148在植株性状、产量及产量构成因素等多个性状上均优于轮回亲本444;54份回交导入系对丝黑穗病抗性差异较大,J15表现为高抗;J2、J7、J28、J31、J46、J88、J110和J148表现为抗病;J6、J55、J73、J76、J97、J102和J121表现为中抗。发病率低于444的有47个,占87.04%,表明回交导入系对玉米丝黑穗病的抗性水平较轮回亲本444有较大提升。J88和J148对丝黑穗病抗性、产量及产量构成因素均表现较好,明显优于轮回亲本444,可优先利用。     

Genetic Improvement of Japonica Rice Variety Wuyujing 3 for Stripe Disease Resistance and Eating Quality by Pyramiding Stv-b~i and Wx-mq

Japonica rice variety Kanto 194 as the donor of resistance gene Stv-b~i and low-amylose content gene Wx-mq was used to improve the resistance and eating quality of Wuyujing 3 by the breeding strategy of backcross. In continuous backcross and selfcross generations, the related molecular markers with Stv-b~i and Wx-mq genes were utilized for genotypic detection by associated with resistance identification of rice stripe disease and agronomic traits selection. Finally, 10 improved lines with homozygous genotype Stv-b~iStv-b~iWx-mq Wx-mq were obtained from BC_3F_4 generation. The results of comparative analysis indicated that most characters of these lines were consistent with those of recipient parent Wuyujing 3, except for the improved resistance, appearance and eating quality. By evaluation of the comprehensive performance of them, two excellent lines K01 and K04 were selected for further experiments.     

转基因小麦外源基因在主栽小麦种质中的遗传规律

为了研究转基因小麦中外源品质基因1D x 5在我国主栽小麦种质中的遗传规律,以转基因小麦B 72-8-11b为父本,主栽品种川89-107和鄂麦18为母本进行杂交,采用SDS-PAGE技术检测并分析各组合亲本、F1、F2、BC1F2、BC2F1、BC2F2代的HMW-GS组成。结果表明,外源基因有效地整合到主栽小麦的基因组中,并能够遵循孟德尔遗传模式稳定地遗传给下一代。     

水稻稻瘟病田间抗性的遗传与选种

 1982～1985年在辽宁省丹东市前阳水稻试验站对用三个田间抗性亲本配成的六个组合(银河/蒙古稻、蒙古稻/银河、誉锦/蒙古稻、蒙古稻/黎明、银河/水原300粒和银河/京越1号)的F_1、F+2和F_3代的表现做了调查。试验结果表明,单位叶面积上的侵染点数和感病病斑数、病斑在单位时间内的扩展速度、发病叶面积百分率(DLA)以及穗颈瘟百分率在F_2和F_3的分布都为连续正态或偏态分布,变异位于双亲之间,很少有超亲现象,证明这种田间抗性为多基因控制的数量性状,广义遗传力(平均)和狭义遗传力(平均)分别以单位叶面积上的感病病斑数(h_B~2=79.5%)和穗颈瘟百分率(h_N~2=65.3%)最高。各性状的亲子相关都达显著水平。文中提出,育种中田间抗性的选择,低世代(2—4代)以DLA为指标,高世代(5代以后)以感病病斑数和病斑扩展速度为指标。对叶瘟和穗瘟抗性的选择应分别进行。     

Genetic Improvement of Rice for Bacterial Blight Resistance: Present Status and Future Prospects

The production and productivity of rice has been challenged due to biotic and abiotic factors. Bacterial blight (BB) disease, caused by Xanthomonas oryzae pv. oryzae, is one of the important biotic stress factors, which reduces rice production by 20%–50%. The deployment of host plant resistance is the most preferred strategy for management of BB disease, and breeding disease resistant varieties remains a very economical and effective option. However, it is difficult to develop rice varieties with durable broad-spectrum resistance against BB using conventional approaches alone. Modern biotechnological tools, particularly the deployment of molecular markers, have facilitated the cloning, characterization and introgression of BB resistance genes into elite varieties. At least 46 BB resistance genes have been identified and mapped from diverse sources till date. Among these, 11 genes have been cloned and characterized. Marker-assisted breeding remains the most efficient approach to improve BB resistance by introducing two or more resistance genes into target varieties. Among the identified genes, xa5, xa13 and Xa21 are being widely used in marker-assisted breeding and more than 70 rice varieties or hybrid rice parental lines have been improved for their BB resistance alone or in combination with genes/QTLs conferring tolerance to other stress. We review the developments related to identification and utilization of various resistance genes to develop BB resistant rice varieties through marker-assisted breeding.     

Resistance Evaluation of Some Chinese Leading Rice Maintainer, Restorer lines and Their Hybrids to Magnaporthe grisea

Six isolates of Magnaporthe grisea were selected to inoculate on 10 Chinese leading maintainer lines (B-lines), 14 restorer lines (R-lines) and their F1 hybrid plants. In the tested rice materials, R-lines were proved to be more resistant to blast than B-lines. The resistance frequency of about 25% F1 hybrid plants was less than their parents. In addition, 26 isolates of M. grisea collected from different rice growing areas of China were inoculated on 13 new improved hybrid rice combinations. The resistance frequencies of 5 improved hybrids were better than those of the controls and leading varieties in rice production of China.     

Resistance Evaluation of Some Chinese Leading Rice Maintainer, Restorer lines and Their Hybrids to Magnaporthe grisea

Six isolates of Magnaporthe grisea were selected to inoculate on 10 Chinese leading maintainer lines (B-lines), 14 restorer lines (R-lines) and their F1 hybrid plants. In the tested rice materials, R-lines were proved to be more resistant to blast than B-lines.The resistance frequency of about 25% F1 hybrid plants was less than their parents. In addition, 26 isolates of M. grisea collected from different rice growing areas of China were inoculated on 13 new improved hybrid rice combinations. The resistance frequencies of 5 improved hybrids were better than those of the controls and leading varieties in rice production of China.