水稻两用核不育系龙S抗稻瘟病主效基因的定位

龙S是一个广谱抗稻瘟病的水稻两用核不育系,利用分子标记技术精细定位其主效抗性基因,对于培育抗稻瘟病水稻新品种具有重要意义。采用来自国内外的41个稻瘟病菌系通过接种鉴定方式对龙S进行了稻瘟病抗谱分析,结果显示龙S的抗性频率为100%,对其中39个菌系表现高水平抗性,与Pi9的携带品种75-1-127抗性频率和抗病级别基本相当。群体遗传分析表明龙S的抗性基因表现为显性遗传方式,对于不同菌系龙S表现出不同的抗病遗传模式,其中龙S对稻瘟菌系318-2的抗性由单基因控制。通过抗病亲本龙S与感病亲本日本晴构建F₂分离群体,采用BSA (bulk segregant analysis)及RCA (recessive class analysis)分析方法,将龙S的主效抗病基因精细定位于第9染色体上的SSR标记M1-M2所在的1.31 cM区间,与已克隆的广谱抗稻瘟病基因Pi5位于相邻的染色体区域。抗谱分析表明,龙S与Pi5、Pii单基因系的抗性频率差异明显,抗谱较后二者更广。龙S主效抗性基因的精细定位,为进一步揭示其与Pi5、Pii的等位关系以及通过分子标记辅助选择培育抗病水稻新品种奠定了基础。     

一个粳稻来源抗稻瘟病基因的鉴定、遗传分析和基因定位

7001S是一个广谱抗稻瘟病的粳稻两用核不育系,对来自全国不同稻区的22株稻瘟病菌系均表现为高度抗性。通过构建7001S/80-4B F2群体的遗传分析和初步定位表明,F2分离单株对稻瘟病菌的抗性呈明显的抗、感双峰分布,抗感分离符合3﹕1的理论比例,说明粳稻7001S对稻瘟病菌的抗性由1对显性核基因或一个显性QTL位点控制,并将该基因初步定位于第11染色体长臂末端。进一步通过扩大遗传群体和分子标记开发,利用基于BSA的隐性群体分析技术,将目的基因精细定位于P21-2415和RM27322之间约310 kb的范围内,并获得了可用于分子标记辅助选择的紧密连锁和共分离分子标记,同时对目标基因所在区域进行基因预测,初步确定了候选基因。为进一步开展该抗稻瘟病基因的克隆、功能验证和抗病机理研究,以及通过分子标记辅助选择技术培育抗稻瘟病水稻新品种等工作奠定了基础。     

水稻材料IR65482抗稻瘟病基因鉴定与定位

水稻材料IR65482对不同地区的稻瘟菌小种具有广谱抗性,已知其第6号染色体上具有一个抗稻瘟病病基因Pi40(t)。本研究应用极端分离混合池重测序策略,对IR65482抗稻瘟病基因进行鉴定,并在其第11号染色体上鉴定到另一个抗稻瘟病基因。进一步利用IR65482与日本晴配置的F2群体进行基因定位,将IR65482抗稻瘟病基因定位在水稻第11染色体末端InDel标记OSL3-2和OSL3-5之间约425 kb的区间。本研究结果对利用IR65482开展水稻抗稻瘟病育种具有指导意义,也为后续克隆IR65482的抗病基因提供了理论依据。     

子预44中抗稻瘟病基因Pi-zy3(t)的定位

稻瘟病是影响水稻高产、稳产、优质的重要病害。广谱持久抗瘟品种的培育和利用是防治稻瘟病最经济有效的措施之一,但广谱持久抗性分子机制还不清楚。子预44是一具有广谱持久稻瘟病抗性的云南地方粳稻品种,对其抗瘟基因的鉴定将有助于揭示其抗瘟分子机制。本研究通过利用子预44和感病水稻江南香糯杂交构建F2遗传群体,稻瘟病菌株LP33苗期喷雾接种亲本预44、江南香糯及F2代单株,对其抗性进行评价和主效抗瘟基因定位。研究结果显示:子预44表现高抗,江南香糯高感;F2群体稻瘟病抗感分离符合3:1的分离比,即子预44对LP33的抗性为单显性基因控制的抗性遗传,并将该基因暂定名为Pi-zy3(t)。进一步利用SSR分子标记将Pi-zy3(t)定位在水稻第六号染色体RM276到RM3827之间,为进一步的基因克隆和抗病机分子制研究奠定了基础,同时也为利用子预44进行抗病分子育种提供了辅助选择的分子标记。     

Basmatic370突变体BTX抗稻瘟病遗传分析及基因标记定位

BTX是由Basmatic370突变而来的优质抗源籼稻品种,它对稻瘟病菌(Mangnaporthe grisea(Hebert)Barr)具有广谱抗性.为了挖掘和定位BTX含有的稻瘟病抗性基因,首先利用7个对丽江新团黑谷(LTH)致病,但对BTX非致病的稻瘟病菌株95-59a、98-288a、00-193a、05-20a、05-135a、06-138a和RB6分别接种以BTX为抗性供体、LTH为感病亲本获得的102个重组自交系(recombinant inbred lines,RILs).其中3个菌株95-59a、98-288a和05-20a在RILs后代群体的抗感比率符合R:S=3:1,其抗性由两对显性基因控制;而其余4个菌株00-193a、05-135a、06-138a和RB6在RILs后代群体的抗感比率符合1R:IS,它们的抗性由一对基因控制.本研究选用致病谱较广的菌株00-193a进行抗性基因标记定位,旨在鉴定出对华南稻区具有广谱抗性的稻瘟病基因.用菌株00-193a接种由BTX和LTH杂交获得的F2群体后代个体,F2后代群体的抗感比率符合R:S=3:1,表明BTX对接种菌株的抗性受一对显性主效基因控制.并由此构建了由400个极端感病个体组成的作图群体用于基因的分子定位.选用250个平均分布于水稻12条染色体上的SSR标记对由00-193a接种的RILs群体构建的抗病池和感病池进行筛选和连锁分析.结果发现,位于第11染色体上的1个微卫星标记RM224与抗性基因连锁.进一步连锁分析表明,共有5个标记RM27181、RM27272、RM224、RM27334和RM37363与目的抗性基因Pibt(t)连锁,遗传距离分别为7.74 cM、1.50 cM、0.25 cM、10.59 cM和13.24 cM.基因被初步定位于RM224和RM27334之间约10.84 cM的遗传区域.     

广东地方稻种沾叶独枝抗稻瘟病遗传分析及基因鉴定

沾叶独枝来源于广东陆丰籼型地方稻种,它对华南稻区稻瘟病菌具有广谱抗性。为了挖掘和鉴定沾叶独枝含有的稻瘟病抗性基因,利用对五丰B(WB)致病、对沾叶独枝非致病的稻瘟病菌代表菌株GD08-T19接种以沾叶独枝为抗性供体、WB为感病亲本获得的F2群体。菌株GD08-T19在F2后代群体的抗感比率为15R:1S,其抗性由两个显性基因控制。利用已开发的Pi1,Pi2,Pi9,Pii,Pish,Pita等抗稻瘟病基因功能标记分别检测了沾叶独枝,研究表明沾叶独枝含有Pita基因。为了鉴定沾叶独枝另一抗性基因,选用300个平均分布于水稻12条染色体上的SSR标记对由GD08-T19接种的F2代群体构建的抗病池和感病池进行筛选和连锁分析。发现位于第6染色体上的2个SSR标记RM19769和RM19959与抗性基因连锁。进一步的定位区域扩充标记连锁分析表明,有6个标记RM19792、RM19804、GDAP41、RM19818、ESR6、RM19844与目的抗性基因连锁。目的基因被初步定位于Pi2/Pi9/Pi50区域。目标区域的Pi50等位基因测序表明沾叶独枝的另一目的抗稻瘟病基因为Pi50本身。     

黄淮稻区推广水稻品种稻瘟病抗性基因Pi9和Pi-ta的分子鉴定

为明确Pi9和Pi-ta 2个稻瘟病抗性主效基因在黄淮稻区种植水稻品种中的分布状况,利用分子标记对60个水稻品种进行Pi9和Pi-ta抗稻瘟病基因的分子鉴定。结果表明,60个检测品种中31个含有Pi9抗性基因,9个含有Pi-ta抗性基因,郑稻18、豫农粳12号、豫稻16、泰香2号、武香粳14号和武运粳21号等6个品种携带2个抗病基因。黄淮稻区水稻育种Pi9基因利用广泛,Pi-ta基因利用较少,今后应加强Pi-ta及更多主效广谱抗稻瘟病基因的聚合利用。     

水稻抗稻瘟病基因Pi47的精细定位和候选基因分析

不断挖掘和克隆抗稻瘟病新基因, 是解析水稻抗病分子遗传机制和培育抗稻瘟病新品种的重要基础。Pi47是笔者从广谱、持久抗稻瘟病湖南地方品种湘资3150中鉴定的稻瘟病抗性基因, 前期研究将其初步定位于第11染色体标记RM224和RM5926间。本研究利用3个Pi47单基因系与感病亲本CO39杂交F₂群体1687个感病单株对Pi47精细定位, 利用6个STS标记对3个单基因系进行背景分析, 采用生物信息学方法进行了候选基因分析。结果表明, Pi47被精细定位于CAPS标记S32与K33间0.24 cM区域的171.2 kb物理区间内, 背景分析将Pi47进一步缩小至SC12和K33间67.8 kb的区间内; 该区间含有8个结构基因, 其中2个编码NBS-LRR抗病类似蛋白, 为Pi47的候选功能基因。稻瘟菌抗谱比较分析发现, Pi47单基因系与其定位区间内4个Pik位点的等位基因Pik、Pikm、Pikh和Pikp的近等基因系抗谱不同。这些结果为进一步克隆Pi47和利用其进行分子标记辅助选择培育抗稻瘟病水稻新品种奠定了基础。     

利用MAS技术改良水稻两用核不育系C815S的稻瘟病抗性

为了改良水稻两用核不育系C815S的稻瘟病抗性,本研究以75-1-127(Pi9)、谷梅2号(Pi25)、谷梅4号(Pigm)、天津野生稻(Pi2-1和Pi51(t))、湘资3150(Pi47和Pi48)和魔王谷(Pi49)共6个广谱抗稻瘟病水稻品种为供体亲本,通过分子标记辅助选择育种技术,将稻瘟病抗性基因回交导入C815S。结果表明:改良的6个BC3F1群体除每穗粒数较轮回亲本极显著增加外,其他性状均与轮回亲本保持一致。利用稻瘟病菌株110-2和CHL506对BC3F2改良株系接种鉴定,发现导入了抗病基因的单株抗性增强,表明抗病基因已成功导入到受体亲本中并稳定表达,证实本研究中分子标记辅助选择抗稻瘟病基因是有效的。改良的系列两用核不育系,一方面可用于配制稻瘟病抗性增强的两系法杂交稻新组合,另一方面为进一步培育聚合多个抗稻瘟病基因的不育系提供了材料基础。     

直播稻品种‘旱27号’抗稻瘟病基因的定位

稻瘟病严重威胁水稻生产,利用抗稻瘟病基因选育抗病品种是防控该病的有效途径。直播稻品种‘旱27号’(H27)在辽宁地区多年来一直对稻瘟病表现高抗,但其所携带的抗稻瘟病基因并不清楚。本研究以其与感病水稻品种‘辽星1号’(LX1)为亲本杂交构建的重组自交系群体为试验材料,在田间稻瘟病诱发圃中对该RIL群体各单系对叶瘟和穗颈瘟的抗性进行鉴定,并基于水稻8K SNP芯片鉴定各单系的基因型,利用ICIMMapping 4.0软件进行抗稻瘟病基因定位。结果表明,在第12染色体14.46～14.84 Mb之间及5.49～7.74 Mb分别鉴定到1个与叶瘟抗性相关和1个与穗瘟抗性相关的QTL,其增效位点均来自‘旱27号’。本研究对北方粳稻抗稻瘟病水稻新品种选育及该病的防控具重要应用价值。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.