慢锈型抗性及其在育种中的应用

慢锈性(Slow—rustng resistance)是植物对锈病的一种抗性,对此,1970年已有报道和描述。燕麦、大麦、普通小麦、玉米、黍、饲用黑麦草和鸡脚草对叶锈、秆锈菌的抗性即属此类。小麦的慢叶锈抗性限制着病原菌的变异。在病害发展过程中,不表现褪绿或过敏性反应。具有这类抗性的植株因抑制着病原菌的扩展,因而病害发展速度明显低于易感品种植株。慢锈型抗性是众多因素共同作用结果的表现。例如,对抗病品种,病原菌很少穿透寄主植株组织,病害潜伏期延长,病斑小而少,夏     

利用免疫酶分析法研究小麦对叶锈病的不完全抗性

本文用免疫酶分析法进行比较,研究了小麦植株上叶锈病病原小种的发生速度及小麦对该病不完全抗性的差异。结果表明,具有不完全抗性品种之叶片病原菌发生速度比易感染植株缓慢得多。对所有研究的病原菌生物型小种的抑制程度大致相同。     

大豆对胞囊线虫抗性遗传与分子标记研究进展

大豆胞囊线虫是一种世界性的病害.已经证明大豆对胞囊线虫的抗性受多个基因控制.但由于抗性鉴定工作量大、易受环境因素影响以及大豆胞囊线虫群体本身的异质性,各个研究者的结果差异很大,具有抗源和组合特异性.Riggs等建立的生理小种鉴定模式虽被广泛采用,但鉴别寄主中抗性基因的重叠引起研究者的争议.分子标记结合经典遗传试验定位了2个抗性基因位点rbg1和Rhg4,rhg1在抗性遗传中贡献较大且具有非小种专化抗性,对抗病育种和基因克隆有重要意义,在G连锁群上许多与rhg1紧密连锁的分子标记已经找到,并证明在抗性鉴定中有很大的利用价值.Rhg4位于A连锁群上,距离i位点0.35 cM,与1、3号小种抗性有关.     

文摘

芥菜型油菜抗白锈病遗传 用一个抗性品种和两个感病品种杂交研究芥菜型油菜抗白锈病小种2号遗传。温室条件下进行接种试验,F_1对该病的反应与亲本相同表明,抗性呈显性,由核基因控制。F_1植株同抗性亲本回交,对该病的反应与抗性亲本相同,F_1植株同感病亲本回交,抗病与感病的分离比率为1:1。F_2植株的分离比率为3:1。本研究结果揭示,芥菜型油菜对白锈病小种2号的抗性为单基因遗传,可通过早期世代回交将抗性转     

抗病基因对大豆胞囊线虫3号生理小种的选择作用

为了解育成抗病品种抗性稳定性及胞囊线虫生理小种侵染力的变异,于2005～2008年,应用黑龙江省发生的大豆胞囊线虫3号生理小种及已经通过鉴定的抗大豆胞囊线虫3号生理小种的品种,哈尔滨小黑豆、灰皮支等8个品种和感病对照品种Lee68为材料,进行抗病基凶对大豆胞囊线虫3号生理小种选择作用研究.在盆栽条件下,强迫大豆胞囊线虫3号生理小种的群体在抗病品种上繁殖10代,选用5个标准鉴定大豆胞囊线虫生理小种的鉴别品种,重新鉴定经抗病基因选择后的大豆胞囊线虫的生理小种类型.结果表明:原来为3号生理小种的线虫群体,经在抗病品种抗线虫1号、抗线虫2号、抗线虫3号、抗线虫4号、抗线虫5号上连续选择10代之后,变为6号小种;经在厌皮支黑豆上选择之后变为10号小种;经在Peking上选择之后变为14号小种,经在哈尔滨小黑豆上选择之后变为15号小种.上述鉴定结果说明,原大豆胞囊线虫生理种群体,经过在抗病品种上连续强迫繁殖后,形成新的生理小种,并使原扰病品种变为感染品种,认为在生产上采用轮作方式是保持抗线品种抗性稳定性的有效途径.     

东农L-10对大豆胞囊线虫3号生理小种的遗传模型分析

为明确非小种特异性抗病大豆种质东农L-10对大豆胞囊线虫3号生理小种的抗性遗传模式,以东农L-10为共同父本,分别以感病品种黑农37、绥农10号和绥农14为母本,构建了3个F_(2∶10)重组自交系群体,利用酸性品红染色法对3个群体进行SCN 3号生理小种的抗性鉴定,结果表明:亲本间雌虫指数均存在较大差异,群体雌虫指数符合连续正态分布,后代中抗病株系不存在显著的超亲效应。利用主基因+多基因混合遗传模型对抗性鉴定数据进行遗传模型解析,发现东农L-10对抗大豆胞囊线虫3号生理小种的抗性符合主基因+多基因遗传模型,在不同遗传背景条件下,均存在2~3个主基因控制3号生理小种的抗性,以上研究结果为挖掘东农L-10的主效抗病位点和分子辅助选育高抗SCN 3号生理小种的大豆品种提供理论依据。     

尖孢镰孢霉种下分类鉴定新技术：营养体亲和性鉴定方法

尖孢镰孢是许多重要作物枯萎病的病原真菌。迄今已报道的专化型有８０多个，专化型下又划分为许多生理小种。专化型和生理小种的鉴别，对于抗病育种，植物检疫以及病害防治，具有重要的理论和实际意义，传统的鉴别方法是利用人工接种的办法，但这种方法较费时费工，易受环境条件和寄主因素的影响，营养体亲和性鉴定方法，是国外最近发明的一种新的变通技术，这种方法利用了突变体的互补性以及遗传关系接近的菌株才能形成异核体的原理     

美国大豆孢囊线虫生理小种及大豆品种抗性遗传育种研究进展

大豆孢囊线虫是美国大豆生产中造成损失最大的病害。目前从理论上用四个鉴别寄主把大豆孢囊线虫划分为１６个生理小种，但实际上未发现１１号、１２号和１３号生理小种。通过大规模品种资源筛选，已选出一大批抗源，较好的抗源有Ｐｅｋｉｎｇ、ＰＩ８８７８８和ＰＩ４３７６５４等。大豆品种对孢囊线虫的抗性由少数基因控制，在某些情况下与控制种皮颜色的基因有连锁，分子生物学研究表明，分子标记与大豆的抗性有关，ＲＦＬＰ和ＲＡ     

西南地区玉米大斑病菌生理小种鉴定

2008～2010年对采自西南地区的玉米大斑病标样经过单孢分离、纯化,共获得146个菌株。通过Ht单基因鉴别寄主进行生理小种鉴定,共鉴定出9个生理小种,分别为0、1、2、3、12、1N、2N、3N、N。0号小种占鉴定菌株的62.33%,为优势小种,其次为1号小种,占鉴定菌株15.07%。毒性频率分析表明,所有供试菌株对Ht1抗性基因的毒性频率最高,为20.99%;对Ht3抗性基因的毒性频率最低,为1.36%;对Ht2和HtN抗性基因的毒性频率分别为13.01%和9.57%。目前,西南地区玉米大斑病生理小种分化明显,并且产生了新的生理小种,对玉米生产存在潜在威胁。     

控制小麦条锈病的成株抗性(高温下)基因数量研究

Gaines,Nugaines和Luke冬小麦对条锈病的抗性,是持久性非专化小种抗性的最好例证.自从它们问世以来,在美国沿太平洋西北部地区对小麦条锈菌各生理小种,一直保持着成株期的抗性.1980年试验,对欧洲小种也有抗性.在大田中,这些品种的条锈病发育缓慢.在低(2-18℃)或高(10-30℃)昼夜温差条件下,Gaines和Nugaines的幼苗对该病菌所有小种都感病,Luke幼苗只对最流行的小种是感病的.它们在成熟时,高温差条件下发育的植株变得更抗病,低温差下发育的植株仍然感病.另一研究表明,这些品种的抗性基     

抗条纹叶枯病基因STV11的功能性分子标记建立及粳型抗源筛选

条纹叶枯病是水稻(Oryza sativa L.)上最严重的病害之一。STV11是从籼稻Kasalath中鉴定的条纹叶枯病抗性基因,根据Kasalath型条纹叶枯病基因STV11 KAS6个碱基缺失的功能性多态性序列差异,设计基于PCR的功能性分子标记qstv11。利用此标记对299份试验材料[5份抗病品种、5份感病品种、41份辽宁省育种材料、17份日本粳型材料、142份秋光/七山占重组自交系(群体A)、85份笹锦/Habataki//笹锦回交重组自交系(群体B)、群体亲本4份]进行基因型分析并进行抗病性鉴定。结果表明,qstv11能够较好区分抗感基因型,而且在测试材料中与条纹叶枯抗性整体呈现共分离。41份辽宁材料中鉴定出含有STV11-R(抗)材料1份;日本粳型材料该位点均为STV11-S(感);群体A和B中分别筛选出粳稻背景STV11-R型材料24份和6份。     

云南地方稻种Wx基因第一内含子供体+1位碱基变异与直链淀粉含量的关系

应用PCR一步法对来自云南省14个地州、55个市/县的220个籼、粳地方稻种Wx基因第一内含子供体+1位碱基G/T进行了检测,同时用PCR Acc I酶切法对其中的101份进行验证,结果表明两种方法检测结果一致。根据G/T碱基将220个供试材料分为GG、TT两种基因型。云南地方稻种以GG型占优势,有164个,占74.5%;TT型有56个,占255%;籼稻中80.5%属GG型,粳稻中67.0%属GG型。GG型直链淀粉含量较高,平均18.97%,TT型较低,均低于16%, GG、TT基因型之间的平均直链淀粉含量差异极显著。G/T与直链淀粉含量存在密切的联系,其相关系数为0733**。GG型品种中有33个直链淀粉含量较低（3.91%～15.93%）,多数为来源于云南西南部傣族地区的品种。籼稻中的GG型或TT型品种与粳稻中的GG型或TT型品种间平均直链淀粉含量无显著差异,表明GG/TT基因型在籼粳不同遗传背景下直链淀粉表达无显著差异。     

Current Status of Conventional and Molecular Interventions for Blast Resistance in Rice

Pyricularia oryzae anamorph of Magnaporthe oryzae is one of the most notorious fungal pathogens causing severe economic loss in rice production worldwide. Various methods, viz. cultural, biological and molecular approaches, are utilized to counteract this pathogen. Moreover, some tolerant or resistant rice varieties have been developed with the help of breeding programmes. Isolation and molecular characterization of different blast resistance genes now open the gate for new possibilities to elucidate the actual allelic variants of these genes via various molecular breeding and transgenic approaches. However, the behavioral pattern of this fungus breakups the resistance barriers in the resistant or tolerant rice varieties. This host-pathogen barrier will be possibly countered in future research by comparative genomics data from available genome sequence data of rice and M. oryzae for durable resistance. Present review emphasized fascinating recent updates, new molecular breeding approaches, transgenic and genomics approaches(i.e. mi RNA and genome editing) for the management of blast disease in rice. The updated information will be helpful for the durable, resistance breeding programme in rice against blast pathogen.     

一种水稻香味基因功能标记的开发

为了提高水稻香味基因的分子标记辅助选择的准确性,根据水稻隐性香型品种与非香型品种的BAD2基因（即香味基因）序列之间存在8 bp碱基缺失,设计出香味基因fgr的InDel功能标记GRFM04。利用该标记对粤丰B（香型）/振丰B（非香型）的F2分离群体和其他16份香稻品种和6份非香稻品种进行检测验证。依据其PCR扩增产物电泳带型,可以准确地区分出香型纯合基因型、非香型纯合基因型和杂合基因型3种带型,且3种带型与其植株或品种相应的香味性状表现完全呈一一对应关系。     

小麦品种（系）在白粉病圃中抗病性变化

１９９３～１９９９年,作者在小麦白粉病菌非自然越夏区陕西杨凌建立的模拟鉴定病圃中,对９个已知抗病基因鉴别材料和５个小麦常规品种苗期、成株期抗病性变化进行了系统观测。结果表明,病圃中小麦白粉病混合菌系组分复杂,年度间寄主反应有所变化。５个小麦品种中,淮阴８９４、阿勃、陕２２５等３个品种抗、感病性相对稳定,是较理想的参照品种。对如何延长抗病品种使用年限及抗病选育方法提出了商榷建议。     

Impact of tree species on nutrient stocks in the forest floors of a temperate forest ecosystem

To investigate the effect of silvicultural methods on forest floor C, N and elements stocks an experiment was carried out by sampling the forest floors of a 100-120-years-old species including beech, Norway spruce and mixed beech-spruce at the Solling forest, Germany. While the stocks of carbon and nitrogen in the forest floors of pure beech and spruce were significantly influenced by species specific differences of litter quality (p < 0.001), no significant differences were detected between pure and mixed species stands. Forest floor mass, some elements concentrations and C/nutrient ratios were significantly affected by tree species differences, while no clear dependency between pH and site specific effects was found among pure stands. Acid element concentrations in the forest floors of pure spruce were remarkably higher than the values obtained at beech stand, while the stocks were to some extent modified in mixed silviculture. The base-pump effect of beech significantly controlled variation between mono cultures on calcium stocks, while the acidifying effect of spruce in mixtures resulted in modification of Ca stocks of forest floors. The status of other nutrient elements at mixed species cultures due to variation in nutritional properties and composition of litter compared to pure species were between the range of values observed in mono cultures.     

Improvement of Bacterial Blight Resistance in Rice Cultivars Jyothi and IR50 via Marker-Assisted Backcross Breeding

Abstract

In pathogen population analysis of 208 Xanthomonas oryzae pv. oryzae(Xoo) strains that were assembled from different parts of India, 21 pathotypes were identified on the basis of disease reactions on near-isogenic lines (NILs) and 13 pathotypes, on rice differentials. Rice cultivars, Jyothi and IR50, which are high yielding but highly prone to bacterial blight (BB) caused by pathogen populations of Xanthomonas oryzae pv. oryzae in India, were chosen. To improve the BB resistance of these two varieties, a pyramid line, NH56, containing four R-genes, Xa4, xa5, xa13, and Xa21, was selected as the R-donor based on resistance to existing pathogen population. The four R-genes were successfully transferred to cultivars through a traditional backcross method and their presence was documented with marker-aided selection (MAS). Thirty BC₄F₂ plants derived from JxNH56 (cv. Jyothi) and 45 BC₄F₂ plants derived from IR50xNH56 (cv. IR50) had all four resistance genes (Xa4, xa5, xa13, and Xa21), which should be useful resistance donors for breeding other BB-resistant elite indica varieties.     

Effects of white clover cultivar and companion grass on winter survival of seedlings in autumn-sown swards

The aim was to study the effects of white clover cultivar and combinations with perennial ryegrass cultivars on seedling establishment in autumn‐sown swards and on winter survival of seedlings. Large‐leaved white clover cv. Alice and small‐leaved white clover cv. Gwenda, and an erect and a prostrate perennial ryegrass cultivar were sown in autumn in pure stands and as four binary grass‐clover mixtures. Mixtures of white clover cv. Huia and Aberherald with perennial ryegrass were also sown. Companion grasses had no significant impact on the establishment of white clover. The number of seedlings of white clover cv. Alice in mixtures (335 m^?2) was higher than cv. Gwenda (183 m^?2) and pure swards had similar white clover population densities as mixed swards. White clover cv. Huia tended to have more seedlings than Aberherald (355 and 205 m^?2 respectively). No stolons were produced prior to a severe winter, because of the late sowing date. Winter survival of clover seedlings was 0·56 in mixtures and 0·69 in pure stands, irrespective of white clover or companion grass cultivar. Stolon development of white clover in autumn is often considered essential for overwintering survival and spring growth. In this study, there was considerable survival of the non‐stoloniferous tap‐rooted seedlings of all four clover cultivars despite a severe winter.     

用SSR标记评估东北三省水稻推广品种的遗传多样性

 利用53个SSR标记和24个表型性状分析东北三省107个水稻推广品种,探讨东北水稻推广品种群体遗传多样性及不同育成年代、省份间的遗传多样性和互补性。结果表明,表型遗传多样性高于DNA水平,年代间表型与微卫星标记的遗传多样性具有较高的相似性,而地区间无明显相似性。东北水稻推广品种遗传多样性比较狭窄,随着时间推移增加的新等位基因多于消失的旧等位基因数。三省水稻推广品种遗传多样性呈现黑龙江>吉林>辽宁的趋势,但由于地区间频繁引种,东北水稻品种在区域上的遗传分化已不明显,其差异主要来源于品种间的基因型差异。不同省份存在较多的互补等位变异,最多的在黑龙江和辽宁之间。不同省份和不同年代间分别拥有各自特有和特缺的等位变异。参试品种可分为5个类群,每一类群均有两个以上年代（省份）品种分布。     

Virulence of the Populations of the Whitebacked Planthopper, Sogatella furcifera Reared on Different Resistant Rice Varieties

ARC and ND colony were obtained by rearing the whitebacked planthopper (WBPH), Sogatella furcifera(Horvath), exclusively on ARC10239 (ARC, carrying resistance gene Wbph2) and N‘Diang Marie (ND, carrying resistance gene WbphS) till 15 generations. Taichung Native 1 (TN1) and Rathu Heenati (RHT) served as susceptible and resistant check, respectively. The results of electronic recording revealed that duration of salivation and X-waveform of the two colonies on their corresponding hosts was short while the duration of phloem ingestion was long. The amount of honeydew excreted by ARC and ND colony did not differ on their corresponding host varieties from TN1 and was much higher than that of RHT. The number of eggs laid on their host varieties and TN1 were significantly higher than that on RHT. No distinct change was observed for these two colonies in term of percentage of developed eggs. The nymph survival rate of ND colony on its selection host was 45.0%, significantly different from that on TN1(71.4%0) and RHT(21.0%), while that of ARCcolony was 68. 3%, not significantly different from that on TN1(77.5%), but much higher than that on RHT(22.6%).The nymphal development duration of these two colonies on the corresponding hosts was not different from that on TN1, but significantly shorter than that on RHT. In brief, these two colonies had almost adapted to their corresponding host varieties based on feeding and oviposition, but the nymphal survival rate of ND colony was still low.