Marker-Assisted Breeding of Thermo-Sensitive Genic Male Sterile Line 1892S for Disease Resistance and Submergence Tolerance

Rice line 1892S is an elite thermo-sensitive genic male sterile(TGMS)line for two-line hybrid rice production.However,1892S is susceptible to rice blast,bacterial blight and submergence.Here we reported the introduction of blast resistance(R)gene Pi9,bacterial blight R gene Xa21 and submergence tolerance gene Sub1A into 1892S genetic background through backcrossing and marker-assisted selection.The improved TGMS line 31892S and its hybrids conferred disease resistance to rice blast and bacterial blight,and showed submergence tolerance for over 14 d without significant loss of viability.The sterility-fertility conversion of 31892S was similar to that of 1892S.31892S and its derived hybrid rice had similar agronomic traits and grain quality with 1892S and the control hybrid rice,respectively.The newly developed 31892S provided an improved TGMS line for two-line hybrid rice production with disease resistance to rice blast and bacterial blight,and submergence tolerance with no yield penalty or change in grain quality.     

Marker-Assisted Selection of Xa21 Conferring Resistance to Bacterial Leaf Blight in indica Rice Cultivar LT2

Bacterial leaf blight of rice (BLB), caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive diseases in Asian rice fields. A high-quality rice variety, LT2, was used as the recipient parent. IRBB21, which carries the Xa21 gene, was used as the donor parent. The resistance gene Xa21 was introduced into LT2 by marker-assisted backcrossing. Three Xoo races were used to inoculate the improved lines following the clipping method. Eleven BC₃F₃ lines carrying Xa21 were obtained based on molecular markers and agronomic performance. The 11 lines were then inoculated with the three Xoo races. All the 11 improved lines showed better resistance to BLB than the recipient parent LT2. Based on the level of resistance to BLB and their agronomic performance, five lines (BC₃F₃ 5.1.5.1, BC₃F₃ 5.1.5.12, BC₃F₃ 8.5.6.44, BC₃F₃ 9.5.4.1 and BC₃F₃ 9.5.4.23) were selected as the most promising for commercial release. These improved lines could contribute to rice production in terms of food security.     

淹涝胁迫对水稻生长发育危害与耐淹性机理研究的进展

评述了淹涝胁迫对水稻生长发育的影响、水稻耐涝的生理机制、淹涝胁迫的基因型差异和耐淹性遗传与减灾措施等方面的一些研究进展,并简要提出了今后的研究方向。     

应用分子标记辅助选择培育抗稻瘟病恢复系R153

稻瘟病是危害水稻最严重的病害之一.培育抗稻瘟病的水稻品种是减少因病害损失的有效方法.本研究以携带稻瘟病抗性等位基因Pi25的品系BL108为供体、恢复系恢11-32为受体,应用该抗性基因的连锁标记Si13070C和功能标记CAP3/BglⅡ进行分子标记辅助选择,培育出携带Pi25抗性等位基因的恢复系R153,经福建省上...     

分子标记辅助选择降低籼稻057的直链淀粉含量

 以4种低直链淀粉含量（AC）的籼稻品种(R367、91499、盐恢559、恢527)作优质基因的供体，以产量配合力较强的三系籼稻恢复系057为受体轮回亲本，对高AC值的057进行回交改良。在回交改良中利用分子标记对控制AC值的基因型进行选择，并对分子标记鉴定的Wx基因3种表达类型（GG、TT、GT）植株稻米的AC值进行测定分析。结果显示，GG型植株的稻米AC值高于20%；GT型的变化较大，为17.71%~28.48%；TT型的小于18%。经最小显著差数法（LSR）检验，3种基因型间AC差异达极显著水平。表明这种分子标记对稻米AC值的辅助选择是可靠有效的。通过分子标记辅助选择有效降低了057的AC值。     

Development of Heat Tolerant Two-Line Hybrid Rice Restorer Line Carrying Dominant Locus of OsHTAS

In order to create novel germplasm resources for breeding heat tolerant variety,we transferred a dominant allele OsHTAS,previously characterized and cloned from a high-temperature tolerant local variety HT54,which was collected from the rice production area of southern China,into a high-temperature sensitive intermediate breeding line HT13 through six rounds of successive backcross by using marker-assisted selection.The molecular analysis showed that the recovery of genetic background of a resultant near isogenic line(NIL),MHT13,was around 99.8%.The OsHTAS gene introduced in the MHT13 expressed normally in the HT13 genetic background,mediating heat tolerance and phenotype similar to those of the donor parent HT54.The major agronomic traits of MHT13 resembled those of the recurrent parent HT13.Moreover,MHT13 had high general combining ability and its rice quality reached the grade 3 standard of edible high-quality rice issued by Ministry of Agriculture of the People’s Republic of China,which greatly improved its application value in rice production.     

水稻耐盐基因定位与克隆及品种耐盐性分子标记辅助选择改良研究进展

土壤盐渍化严重制约水稻生产发展,提高耐盐性已成为水稻育种的重要目标之一。挖掘水稻耐盐新基因,解析其分子作用机制可以为水稻耐盐性遗传改良奠定基础。本文从定位群体、耐盐性鉴定时期和鉴定方法、耐盐性评价指标、鉴定到的耐盐QTL、耐盐QTL的精细定位和图位克隆等方面,总结了近年来水稻耐盐QTL定位研究中所取得的进展;介绍了水稻耐盐/盐敏感突变体筛选和基因克隆以及耐盐性关联分析的研究近况;并对水稻耐盐性分子标记辅助选择改良的现状作了概述。     

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.     

Lowering Grain Amylose Content in Backcross Offsprings of indica Rice Variety 057 by Molecular Marker-Assisted Selection

To lower the amylose content （AC） of the indica rice restorer line 057 with high AC, backcrosses were made respectively by using four indica varieties （R367, 91499, Yanhui 559, Hui 527） as low AC donor parents and 057 as the recurrent parent. A molecular marker （PCR-Acc Ⅰ） was used to identify the genotypes （GG, TT and GT） of the waxy （Wx） gene. Plants with GT genotype were selected and used as female parent and crossed with 057 to advance generation. The ACs of rice grains harvested from plants with different Wx genotypes were measured and compared to analyze the efficiency of marker-assisted selection. The ACs of the rice grain, harvested from the plants of Wx genotypes GG, GT and TT, were higher than 20%, in the range of 17.7-28.5%, and less than 18%, respectively. The PCR-Acc Ⅰ marker could be used for efficiently lowering the AC of 057 through backcrossing, and there were some influence of parental genetic background on the AC of rice grains with the same Wx genotype.     

Identification for Heat Tolerance in Backcross Recombinant Lines and Screening of Backcross Introgression Lines with Heat Tolerance at Milky Stage in Rice

The present study aimed at breeding new rice germplasms with similar genome but significantly differed in heat tolerance during the grain filling stage.A total of 791 BC1F8 backcross recombinant lines,derived from the cross of Xieqingzao B /N22 //Xieqingzao B,were used as materials.Each rice line was separated evenly into two groups,and the heat tolerance of all rice lines were evaluated at natural high temperature in fields.The rice lines with heat tolerant index higher than 90% or lower than 40% were sele...     

分子标记辅助选择育成抗稻瘟病粳稻新品种扬农粳3091

通过杂交及不完全回交,结合分子标记辅助选择,育成携带广谱抗稻瘟病基因Pigm的粳稻新品种扬农粳3091。选育过程中的稻瘟病抗性鉴定结果显示,携带Pigm基因品系的抗性水平显著好于对照。该品种于2021年通过江苏省农作物品种审定委员会审定,具有综合抗性好、品质优、丰产稳产性好等特点。本文介绍了该品种的选育过程、特征特性及主要栽培技术要点。     

具抗稻瘟病基因Pi25杂交稻恢复系的分子标记辅助选育

 从组合中156/谷梅2号所衍生的重组自交系群体中选择携带抗稻瘟病基因Pi25的3个株系,分别与高产恢复系9308和3 11配组,通过单粒传法获得的6个F6重组自交系群体用于研究。在Pi25先前定位的遗传图谱上,新增加与该基因紧密连锁的分子标记RM3330和A7,并结合RM3330和A7分子标记辅助选择的结果,共筛选到了109个Pi25基因纯合的株系。用现有的与恢复基因连锁的标记对这109个株系进行二次筛选,最终获得20个Pi25基因和恢复基因均纯合的株系。对育性恢复力鉴定试验表明,选育出的抗病恢复系具有较好的恢复能力,并已应用于育种实践;人工稻瘟病接种试验证实,所用标记不同,分子标记辅助选择的效率差异显著,单个标记辅助选择符合率均不高,而采用目标基因两侧连锁的标记同时进行辅助选择,则可以明显提高分子标记辅助选择符合率。     

Breeding Rice Restorer Lines with High Resistance to Bacterial Blight by Using Molecular Marker-Assisted Selection

Rice bacterial blight, one of the major diseases of rice caused by Xanthomonas oryzae pv. oryzae, Xoo, jeopardizes rice diversely. It causes leaf wilting, affects photosynthesis and reduces 1000-grain weight and generally results in yield loss by 20-30 pe…     

Use of Major Quantitative Trait Loci to Improve Grain Yield of Rice

Further improvement of rice productivity remains a challenge. Breeding is perceived as an important option to increase rice yield. However, the genetic progress of grain yield in most rice breeding programs was slow in the last decades. Although great progress in rice genomics and molecular biology has been achieved, the effect of such technological innovations on rice breeding is far small. Marker-assisted selection （MAS） for a few target quantitative trait loci （QTLs） has significant effects in improving qualitative traits, such as disease resistance. The success of MAS has therefore motivated breeders to identify and use major QTLs for yield and yield component traits. In this review, we summarized the recent methods in QTL identification, including novel statistical methods for linkage and association mapping, special population types, and whole-genome sequencing. We reviewed the successful application of marker-assisted gene introgression and gene pyramiding to improve grain yield and discussed the design of efficient MAS schemes to further increase the success rate of breeding programs. The use of well-characterized major QTLs through introgression and gene pyramiding is proven effective in improving grain yield, particularly yield under abiotic stress. Major QTLs that are stable across genetic background and growing environments are often found in less adapted germplasms, such as landraces and wild relatives. Advanced backcross QTL analysis and introgression lines, which integrate QTL discovery and utilization, are important methods for exploiting major QTLs contained in such germplasms. Next-generation sequencing substantially increases mapping resolution and accelerates the identification of casual genes underlying major QTLs. Practical guidelines derived from theoretical and empirical studies are given to guide the design of efficient marker-assisted gene introgression and pyramiding schemes.     

通过分子标记辅助选择技术选育携有水稻白叶枯病抗性基因Xa23的水稻株系

 通过杂交和分子标记辅助选择技术,将亲本材料18113携有的水稻白叶枯病抗病基因Xa23导入亚种间恢复系H705和优质恢复系H706。利用EST标记C189检测目的基因,在18113/H705 F3和18113/H706 F3株系中,分别获得71和52份携有Xa23纯合基因型恢复系。采用水稻白叶枯病Ⅳ型小种代表菌株浙173进行剪叶接种,分别鉴定出61和44份抗病株系,它们的分子标记辅助选择准确率分别为85.92%和84.61%。研究结果表明,C189是检测Xa23基因的有效分子标记之一,不过,其假阳性的几率高于理论交换率的现象还有待于进一步研究。     

利用分子标记辅助育种技术选育高抗白叶枯病恢复系

通过常规回交育种结合分子标记辅助选择技术,已将来自IRBB24的2个抗白叶枯病基因, Xa21和Xa4, 聚合到感病的杂交稻恢复系绵恢７２５中。通过分子标记检测目标基因和亲本遗传背景差异分析快速获得了4个高抗白叶枯病的恢复系姊妹系R207 1、R207 2、R207 3和R207 4。采用与目标抗性基因相应的菲律宾菌系P1、P6 和7个中国病原型代表菌系（CⅠ~CⅦ）对4个姊妹系及其杂交组合进行田间接种。结果表明,这些姊妹系及所配制的杂交组合抗病性强、抗谱广,其中杂交组合G46A/R207 2具有良好的产量潜力,将R207 2定名为蜀恢207。     

分子标记辅助选择抗稻白叶枯病基因在选育水稻广亲和恢复系上的应用

 以IRBB21为Xa21基因供体,广亲和恢复系4183为受体，进行1次杂交并回交3次，逐代用分子标记检测手段，导入广谱抗白叶枯病基因Xa21,在保持广亲和恢复系4183优良经济性状的基础上，增强其抗白叶枯病的能力，育成抗白叶枯病的广亲和恢复系抗4183，其抗性达到了IRBB21的抗性水平，且保持了4183的广亲和性、恢复性及优良的经济性状。并就杂交水稻白叶枯病的抗性改良及育种对策进行了讨论。     

利用分子标记辅助选择培育优良食味、低谷蛋白香粳稻新品系

【目的】选育低谷蛋白新品种是功能性水稻育种的一个重要方向。为满足肾脏病患者对人体健康和稻米品质的需求,迫切需要在育种中加强对功能性和食味品质的协同改良。【方法】以具有低直链淀粉含量基因Wx^mp和香味基因fgr的优良食味粳稻品种南粳46与含低谷蛋白基因Lgc1的日本粳稻品种LGC-1杂交、回交,利用与目标基因共分离的分子标记进行跟踪检测并结合田间选择,在BC₂F₆获得5个新品系。以亲本南粳46和LGC-1为对照,对新品系的农艺、产量、品质性状进行分析。【结果】与LGC-1相比,新品系的谷蛋白含量和可吸收蛋白含量相当,食味品质得到显著提升,且综合性状优良,表现出较高的产量潜力,适宜在江苏不同稻区进行种植。【结论】分子标记辅助选择作为一种快速、准确、有效的方法,与常规育种技术紧密结合,能够显著提高优质、高产、低谷蛋白水稻品种的选育效率。     

利用分子标记技术降低协优57的直链淀粉含量

 为克服产量高、适应性广的中籼组合协优57的直链淀粉含量较高、蒸煮食味品质较差的缺点,对其父母本较高的直链淀粉含量特性进行了改良。先前利用PCR AccⅠ分子标记辅助选择对其父本057进行改良,育成了直链淀粉含量改良型057, 简称057(TT)。本研究以ND42为优质基因的供体,利用PCR AccⅠ分子标记对协青早B\[母本协青早A的保持系,简称协青早B(GG)\]进行改良,得到直链淀粉含量改良型协青早B,简称协青早B(TT)。然后用改良前、后的各亲本分别配组,分析各组合的基因型(GG、GT、TT)和食味品质。结果表明,改良单亲的GT型组合协青早B(GG)/057(TT)、协青早B(TT)/057(GG)杂交稻米的直链淀粉含量由原组合协青早B(GG)/057(GG)的26.1%分别降到19.3%和19.2%,但均一性较差。改良双亲的TT纯合型组合协青早B(TT)/057(TT)的杂交稻米,不仅直链淀粉含量降到中等偏低水平(12.5%)、胶稠度变得更软,而且直链淀粉含量的均一性也有了很大的提高。     

利用分子标记技术聚合3个稻瘟病基因改良金23B的稻瘟病抗性

以C101LAC和C101A51为稻瘟病抗性基因的供体亲本,金23B为受体亲本,通过杂交、复交及一次回交,在分离世代,利用分子标记辅助选择技术结合特异稻瘟病菌株接种鉴定和农艺性状筛选,获得6个导入Pi 1、Pi 2和Pi 33基因的金23B导入系,其中导入系W1对稻瘟病的抗病频率为96.7%,明显高于携带单个基因的C104LAC（Pi 1）、C101A51（Pi 2）和北京糯（Pi 33）。基因聚合后抗病频率提高,说明基因聚合是培育稻瘟病持久抗性的有效方法之一。