通过组织培养筛选小麦抗赤霉病突变体的研究

选用中抗赤霉病的春小麦品种和品系的花药进行离体培养,以小麦赤霉病29号菌株产生的致病培养滤液为选择剂,结合物理诱变处理,进行抗病鉴定,用赤霉病菌分生孢子直接接种在愈伤组织和再生植株筛选抗病突变体。在83块愈伤中有53块抗病。在11株的再生植株中有9株均比未经培养滤液处理的对照提高了抗病性,从中选出4株抗病性接近或超过“苏麦3号”品种。     

抗病高淀粉甘薯品种徐薯26的选育及产量形成特点

抗病高淀粉甘薯新品种徐薯26是中国农业科学院甘薯研究所以徐781为母本,通过集团杂交放任授粉、多年多点综合鉴定选育而成。该品种2009年通过国家甘薯新品种鉴定,鉴定编号为国品鉴甘薯2009003。对徐薯26的形态特征、品质性状、抗病性、生产力和产量形成的生理特点等进行了研究,结果表明:徐薯26全生育期长势平稳,薯干品质和食味较好,抗根腐病和蔓割病,薯干和淀粉产量与徐薯18相比增产极显著,生长后期薯块干物质积累较快,经济系数较高,适宜早栽和密植。     

棉花黄萎病病原菌诱导侵染对转基因抗病棉花生理性状的影响

通过研究棉花黄萎病病原菌诱导侵染对转基因抗病棉花生理性状的影响,旨在为提高转基因抗病棉花抗病性提供理论依据。Byd、28p两品种棉花为供试材料,应用花粉管通道法将几丁质酶与β-1,3-葡聚糖双价抗病基因导入棉花株系中,多年筛选获得不同抗性水平的棉花株系;棉种经棉花黄萎病病菌侵染后,苗期测定棉株内的生理生化变化。结果显示,转基因抗病棉株体内的酶活性已达对照水平,而感病及耐病棉株内的酶活性均有不同程度的变化。所测定的棉株内的酶活性及脯氨酸含量的变化与棉株的抗病性相关。     

基于MAS的小麦抗赤霉病育种材料抗性评价

为了提高黄淮海麦区小麦育种材料的赤霉病抗性,采用分子标记辅助选择的方法,将来自望水白的4个抗赤霉病主效QTL 3B-QTL、4B-QTL、5A-QTL和6B-QTL导入不同的感病背景中,在后代BC1F3和BC1F4株系中评价它们的抗病效应和农艺性状回复情况。结果表明:(1)导入4个抗病QTL株系的平均病小穗率和病粒率分别为12.2%和6.3%,而受体亲本则分别达到59.1%和44.2%,抗病性显著提高;(2)病小穗数和病粒率与穗长及株高极显著负相关,但与可育小穗数、百粒重、旗叶长和旗叶宽等农艺性状指标没有显著相关性。因此,通过导入抗病主效QTL可以显著改善感病材料的抗性,为进一步选育高产抗病品种提供基础材料。不良农艺性状的紧密连锁阻碍着抗赤霉病主效QTL的高效利用,需要通过继续回交或与其他品种杂交来打破这种遗传连锁关系。     

豇豆优异种质综合评价

以60份具有早熟、矮秆、多荚、大粒、抗逆、抗病虫、高蛋白性状的优异种质为材料,在河北、河南与安徽进行多点农艺性状综合评价,评选出48份优异种质,其中34个品种达到一级优异种质标准。这些优异种质已结合鉴定繁种入国家中期库,以备科研与生产利用。     

转基因玉米株系纯合系选育及其农艺性状表现

目的：以携带水稻矮缩病毒（RDV）运动蛋白缺陷型（MP-）基因的转基因玉米种子T0为试验材料,通过分子分析、抗病鉴定及农艺性状筛选得到转基因纯合株系。方法：首先对转化种子进行潮霉素抗性筛选,其后对各代转基因材料进行PCR检测、农艺性状调查和抗病鉴定。结果：从645粒T0转化种子得到抗潮霉素植株246株,即T1转基因植株。T1、T2、T3、T4代材料的PCR检测阳性率分别为56.9%、83.9%、94.6%和99.8%,证明RDVMP-基因已被导入玉米自交系中,且目的基因可以稳定遗传到转基因植株及其后代。田间人工接种抗病鉴定结果表明,经过连续筛选,转基因后代植株（系）的抗病性不断提高,T1、T2、T3和T4代中的高抗病材料分别占总材料数的8.9%、31.5%、70.7%和100%;所选纯合系连续2年的发病率均为0,抗病性比相应对照株系提高4级。农艺性状调查结果表明,转基因株系的株高比对照株系高15.0～33.4cm,穗位高提高13.4～20.2cm,;穗长增加2.0～3.8cm,穗粒数增加10.2～22.8粒。结论：根据分子检测、田间抗病鉴定及农艺性状鉴定结果,选育到96C0502、96C0507和96C0513等抗矮花叶病转基因玉米纯合株系。     

抗黄矮病小麦新品系YW443的分子细胞遗传学鉴定

以小麦－中间偃麦草二体附加系Ｌ１衍生抗病系ＰＰ９－１为抗源,与小麦推广品种陕７８５９．丰抗８号杂交并自交,在Ｆ６代中选到农艺性状优良的高抗黄矮病小麦新品系ＹＷ４４３。对ＹＷ４４３及其亲本进行抗病性鉴定。结果表明：ＹＷ４４３高抗大麦黄矮病毒ＧＰＶ、ＧＡＶ株系。利用基因组原位杂交,ＲＦＬＰ分析和ＲＡＰＤ分析,研究诉遗传构成及其抗病基因染色体归属。结果表明：ＹＷ４４３（２ｎ＝４３）的遗传构成了４０条（２     

利用细胞工程技术筛选小麦抗根腐病突变体的研究

以小麦根腐病菌002号菌株产生的致病培养滤液为选择剂,选用春、冬小麦品种、品系以及杂种的花药和幼德进行离体培养,并结合物理诱变技术,已获得抗根腐病的植株,用根腐病菌分生孢子接种鉴定,再生植株50株中有12株抗病。     

离体筛选小麦抗赤霉病和根腐病突变体 I．小麦兼抗赤霉病和根腐病愈伤组织的筛选及其抗病性的鉴定

本文选用冬小麦和春小麦品种及其杂种后代的幼穗进行离体培养， 以赤霉病菌及根腐病菌的培养 滤液为选择剂，按不同的筛选方法筛选兼抗赤霉病和根腐病的突变体，用赤霉病菌和根腐病菌分生抱子 直接接种在经筛选的愈伤组织上，进行抗病性鉴定。试验结果表明：不同筛选方法对筛选兼坑赤霉病和 根腐病的愈伤组织的效果有明显差异，二步筛选法比混合筛选法效果好。供鉴定的120块愈伤组织中， 有村块愈伤组织具有兼抗赤霉病菌和根腐菌侵染的能力。     

小麦抗赤霉病利器——他山之石

赤霉病是我国乃至世界小麦(Triticum aestivum)产区的重要病害, 给农业生产和人畜健康造成重大威胁。分离鉴定优质抗病基因、培育抗病品种, 是控制我国麦区赤霉病的重要手段。最近, 山东农业大学孔令让团队完成了二倍体长穗偃麦草(Thinopyrum elongatum)基因组的组装, 并在此基础上通过精细定位和图位克隆分离得到来自长穗偃麦草的抗赤霉病基因Fhb7。他们发现Fhb7编码1个谷胱甘肽转移酶, 对禾谷镰孢菌(Fusarium graminearum)分泌的包括呕吐毒素等在内的多种毒素具有解毒作用, 是1个广谱持久抗病基因。他们还发现Fhb7很可能最初源于内生真菌, 经过基因水平转移进入到偃麦草基因组中。此外, Fhb7不影响其它农艺性状, 且其抗性不受小麦遗传背景影响。这一系列工作揭示了作物抗病演化中的全新机制, 对小麦抗赤霉病育种以及更好地利用长穗偃麦草的丰富基因资源都具有重要意义。     

Linkage of a RAPD marker with powdery mildew resistance

The aim of this study was to investigate the inheritance of powdery mildew disease and to tag it with a DNA marker to utilize for the marker-assisted selection (MAS) breeding program. The powdery mildew resistant genotype Fallon(er) and susceptible genotype 11760-3ER were selected from 177 genotypes by heavy infestation of germplasm with Erysiphe pisi through artificial inoculation. The F1 plants of the cross Fallon/11760-3 indicated the dominance of the susceptible allele, while F2 plants segregated in 3 : 1 ratio (susceptible : resistant) that fit for goodness of fitness by chi2 (P > 0.07), indicating monogenic recessive inheritance for powdery mildew resistance in Pisum sativum. A novel RAPD marker OPB18 (5'-CCACAGCAGT-3') was linked to the er-1 gene with 83% probability with a LOD score of 4.13, and was located at a distance of 11.2 cM from the er-1 gene.     

Specific Isozyme Marker of a Virus Resistant Barley Derived from Interspecies Cross Between Hordeum vulgare and H. bulbosum

A diploid barley cultivar "Supi 1" was crossed with a tetraploid Hordeum bulbosum “GBC141” to transfer the disease resistant traits. Eleven viable triploid F1 plants were produced by means of embryo rescue technique. The resulting triploid hybrids were backcrossed to diploid barley, and seven BC1 plants were obtained. One of the BC1 plants exhibited barley yellow mosaic virus (BaYMV) resistance when grown in the diseased nursery. Isozyme analysis of H. vulgate, H. bulbosum and their backcross hybrids were made via slab polyacrylamide gel electrophoresis technique. The primary results showed that zymogram variation could be obviously found between diploid barley "Supi 1' and tetraploid H. bulbosurn "GBC141”. A peroxidase isozyme (Rf=0.47) from H. bulbosum was detected in the peroxidase isozyme zymogram of young roots of backcross hybrid BC1-2. This peroxidase isozyme was related to the BaYMV resistance but the linkage relation will be determined by the genetic analysis of the F2 population in the future. The BaYMV resistant line of the backcross with isozyme marker is the important resource of barley disease-resistant breeding.     

秋海棠抗性育种初探

通过杂交育种提高秋海棠植物抗病性等抗逆能力。采用抗病亲本与具观赏性的易感病亲本杂交,F1自交两代使抗病性状纯合稳定,获得具观赏性、抗病的类型。连续回交将抗病性转移到具可看性而易感病的亲本中,培育出目的新品种;根据亲本性状互补的原则,结合杂种优势F1的利用,选择秋海棠属内不同组、不同生态型,抗逆性差异显著的原始材料进行远缘杂交,选育出观赏价值高、抗逆能力强的适应型新品种。通过30多个亲本组合的杂交选育,对6个典型组合亲本、子代的性状及表型分析研究,以及子代群体生长势、病情指数、抗性等级的测定,对秋海棠属植物的抗性育种作了初步探讨。     

小麦白粉病抗性基因的聚合及其分子标记辅助选择

采用了在早代进行抗性鉴定、淘汰感病株、保留抗病株继续种植、较晚世代（F4代）进行抗性鉴定结合分子标记辅助选择的策略,提高了选到聚合抗性植株的效率。利用与Pm2、Pm4α、Pm8、Pm21紧密连锁或共分离的RFLP标记和PCR标记（SCAR标记）,对含有这些基因的优良品系间配制的杂交组合的F4代进行了分子标记辅助育种选择,并结合抗性鉴定,筛选到14株Pm4α Pm2I的植株,16株Pm2 Pm4α的植株,6株Pm8 Pm21的植株。应该引起注意的是,Pm2 Pm4α对混合白粉病菌的抗性达到高抗至免疫水平,而Pm2和Pm4α单独存在时抗性较差,表明聚合抗病基因植株的抗性提高了,为培育具有持久性抗性的品系或品种提供了新思路,它在实践和理论研究上都将具有重要意义。     

Biochemical and genetic studies of two Heterodera avenae resistance genes transferred from <Emphasis Type="Italic">Aegilops ventricosa</Emphasis> to wheat

Two Heterodera avenae resistance genes, Cre2 from Aegilops ventricosa AP-1 and Cre5 from Ae. ventricosa #10, were shown to confer a high level of resistance to the Spanish pathotype Ha71. No susceptible plants were found in the F(2) progeny from the cross between the two accessions of Ae. ventricosa, suggesting that their respective resistance factors were allelic. However, genes Cre2 and Cre5 apparently were transferred to a different chromosomal location in the wheat line H-93-8 and in the 6M(v)(6D) substitution, respectively, as proved by F(2) segregation of their cross progeny. The induction of several defence responses during early infection by the same H. avenae pathotype in resistant lines carrying Cre2 or Cre5 genes was studied. Isoelectrofocusing (IEF) isozyme analysis revealed that peroxidase, esterase and superoxide dismutase activity increased after nematode infection, in roots of resistant lines in comparison with their susceptible parents. Differential induced isoforms were also identified when IEF patterns of resistant lines were compared. A DNA marker, absent in Cre5-carrying genotypes, was found to be linked, thought not very tightly, to the Cre2 gene in the H-93-8 line. The differences observed between the Cre2 and Cre5 genes with respect to their chromosomal location in wheat introgression lines, de-toxificant enzyme induction and behaviour against different pathotypes, suggest they are different H. avenae resistance sources for wheat breeding.     

A Monogenic Dominant Resistance of Tomato to Bacterial Wilt in Hawaii 7996 is Associated with Plant Colonization by Pseudomonas solanacearum

Hawaii 7996, a tomato cultivar resistant to bacterial wilt caused by P. solanacearum was crossed with Floradel, a susceptible cultivar and the F1 and F2 seeds were obtained. Inoculated plants were tested in the field for bacterial wilt resistance and colonization by P. solanacearum. The F1 did not wilt and a significant 3:1 segregation for non wilting: wilting was observed in the F2, indicating a monogenic dominant resistance in Hawaii 7996. In the F2 and in Hawaii 7996, resistance was, associated to the limitation of bacterial spread in the stem. The degree of resistance of Floradel, the F2 and Hawaï 7996 was correlated to colonization at midstem. The usefulness of plant colonization criteria for breeding programs is discussed.     

Effects of barley yellow mosaic disease resistant gene rym1 on the infection by strains of Barley yellow mosaic virus and Barley mild mosaic virus

Although a Chinese landrace of barley, Mokusekko 3, is completely resistant to all strains of Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), and is known to have at least two resistant genes, rym1 and rym5, only rym5 has been utilized for BaYMV resistant barley breeding in Japan. In order to clarify the effect of rym1 on BaYMV and BaMMV, and to utilize the gene for resistant barley breeding, the susceptibilities of only rym1 carrying breeding lines against BaYMV and BaMMV were investigated. In the assessment of resistance to BaYMV-I, 341 F(2) populations derived from a cross between the resistant line Y4 with only rym1 and the susceptible cv Haruna Nijo shows that the segregation loosely fits a 1R:3S ratio (0.05 > P > 0.01), suggesting that the resistance is controlled by a single recessive gene, rym1. Further, none of the F(3) lines derived from the nine resistant F(2) plants showed any disease symptoms in the field infected by BaYMV-I. The same nine F(3) lines showed almost the same agronomic characters in the field infected by BaYMV-III as those in the uninfected field, apart from the symptom of showing numerous mosaics. This result indicates that the gene rym1 has an acceptable level of resistance to BaYMV-III. In the assessment of resistance to BaYMV-II, BaMMV-Ka1 and -Na1, an artificial infection method was adopted and the susceptibilities to those viruses were investigated. Although the control varieties, Ko A and Haruna Nijo, were infected with all of them, the rym1 gene carrying BC(2)F(3) lines were completely resistant to all strains. In summary, rym1 is completely resistant to BaYMV-I, -II, BaMMV-Ka1 and -Na1, and has an acceptable level of resistance to BaYMV-III. This study concludes with a discussion of the reason why the important resistance gene rym1 was eliminated along with resistant cultivars during breeding for resistance to BaYMV.