广西香蕉枯萎病菌生理小种鉴定及分布

[目的]明确广西香蕉种植区香蕉枯萎病菌生理小种的类型及分布范围,为发展其抗病育种技术及制定有针对性的综合防控措施打下基础.[方法]从广西香蕉主产区采集38份具典型香蕉枯萎病发病症状的病害样本,采用常规组织分离法分离病原菌,根据分离菌株的形态特征和特异引物PCR扩增结果确定香蕉枯萎病菌的生理小种类型.[结果]从38份病害样本中分离出35株尖孢镰刀菌(Fusarium oxysporum),经鉴定,有34株为尖孢镰刀菌古巴专化型(F.oxysporum f.sp.cubense),病菌检出率为89.47%,其中,9株为1号生理小种,25株为4号生理小种,检出率分别为26.47%和73.53%;4号生理小种均为热带4号生理小种.1号生理小种在广西香蕉种植区均有分布,4号生理小种主要分布于广西中东部和南部的香蕉种植区.[结论]热带4号生理小种为广西香蕉枯萎病菌的优势种群,在抗病育种中应以热带4号生理小种为靶标菌,且优先选择广西西部和北部的香蕉适生区作为新的香蕉种植地.     

中国水稻近等基因系的育成及其稻瘟病菌生理小种鉴别能力

 水稻品种丽江新团黑谷是一个普感品种。以它作为轮回亲本 ,日本清泽鉴别品种草笛、梅雨明、K1、Pi4号、K60和 BL1作为抗病性供体亲本 ,通过杂交、回交和抗性鉴定 ,培育了一套单基因的水稻近等基因系。这套近等基因系、它们的供体亲本、清泽鉴别品种、国际水稻研究所近等基因系等对菲律宾菌株的生理小种鉴别能力的比较研究结果为 :( 1 )近等基因系的生理小种鉴别能力比其供体亲本强。 ( 2 )中国近等基因系比清泽鉴别品种的小种鉴别能力高。 ( 3)中国近等基因系的生理小种鉴别能力与国际水稻研究所近等基因系相似或较强。但是国际水稻研究所的近等基因系不适用于鉴别粳稻区的稻瘟病菌生理小种 ;而中国近等基因系既适用于籼稻区 ,也适用于粳稻区 ,是可以在国际上通用的鉴别体系。     

广东省稻瘟菌生理小种变化研究

鉴别了1987～2003年广东省稻瘟菌(Magnaporthe grisea)标样3 865份,分离出有效单孢菌株2 621个,共鉴定出8群65个生理小种.结果表明,全省不同地区、不同年份间稻瘟菌生理小种的类型及其组成存在较大的变动.其中ZC群为优势菌群,出现频率平均达45.71%,ZB和ZG为次优势菌群,平均出现频率分别为20.87%和19.11%.ZC13一直是优势小种,出现频率达23.47%,其次ZG1、ZC15、ZF1和ZB13小种出现的频率也较高,分别为18.11%、12.18%、8.91%和7.37%.     

黑龙江省稻瘟病菌生理小种鉴定及外引水稻资源的抗瘟性筛选

本试验将2006年、2007年和2008年3年采集的478个单孢菌株,利用日本的12个鉴别寄主和中国的7鉴别寄主两套鉴别体系对黑龙江省稻瘟病菌致病型进行分类,鉴别出优势小种为77.7、377.7、737.5、100、ZE1、ZG1;强毒力小种为437、777.7、777.1、ZA9、ZA1、ZA13;利用优势菌群和240个供试单孢菌株对63份外引水稻资源进行抗瘟性筛选,筛选出抗谱80%以上的资源有G39、吉粳88、沈农9903,可以广为利用;同时得出利用优势小种和强毒力小种对水稻资源进行抗瘟性筛选,是一项简单而准确的初筛选技术。     

Indigenous highly virulent accessions of the sunflower root parasitic weed Orobanche cumana

Orobanche cumana (broomrape) is a severe constraint to sunflower production in southern and eastern Europe and the Middle East. Races A to E of this parasitic weed controlled by genes Or₁ to Or₅ have been described. A study of 38 seed accessions of O. cumana collected from different locations in Spain between 1983 and 2003 investigated the effect of long‐term storage in the laboratory on germination and infectivity and assessed their virulence on a number of sunflower cultivars. Only 18 infected the susceptible cultivar B117. Infectivity was maintained for up to 17 years of storage, but with a greatly decreased vigour as compared with that of recently collected seed. The 12 oldest viable accessions overcame the resistance of the gene Or₅ (in resistant line NR5). Seven out of them, in particular those collected in 1988 and 1989, were identified as race F. Three accessions were identified as race E allegedly holding components of higher virulence. Our results show evidence of the occurrence of race F prior to the use of sunflower hybrids resistant to race E, suggesting the former as indigenous to the country. This finding suggests the necessity of a continuous breeding of sunflower for resistance to O. cumana. The effectiveness and sustainability of genetic resistance must rely on the knowledge of the diverse virulence characteristics of O. cumana accessions.     

利用SSR分析四倍体棉种多态性

利用SSR标记对60份四倍体棉种材料进行遗传多样性分析,其中包括42份陆地棉野生种系。结果显示, 从1 050对SSR引物筛选出的95对SSR引物均能在60份材料间扩增出稳定明显的多态性条带,共检测出660个片段,其中多态性片段584个,占88.5%。每个位点的等位基因为2~12个,平均每对引物6.1个。UPGMA聚类分析显示, 42份材料的相似性系数(GS)在0.306~1.000之间,平均成对相似系数为0.493。95对引物的多态信息含量(PIC)的变幅为0.278~0.905,基因多样性(H¢)的变幅为0.451~2.451, 有效等位基因数(Ne)在1.385~10.490之间变动。SSR标记在陆地棉野生种系及四倍体棉种间均可反映丰富的遗传多样性信息,其中陆地棉与陆地棉野生种系中阔叶棉的亲缘关系最近,海岛棉和达尔文棉的亲缘关系非常相近,黄褐棉和毛棉相对较近,陆地棉与其他4个棉种的亲缘关系最远。     

水稻稻瘟病研究进展

从分子生物学在水稻遗传育种中的应用、稻瘟病菌生理小种的鉴别与变异和寄主与病原菌的互作关系三方面详细综述了稻瘟病防治的研究进展,并对未来的工作方向和前景进行了展望。     

Isozyme variation in some races of maize from Argentina

Summary Forty one populations of sixteen Argentine races of maize were studied with electrophoretic techniques. Seven isozyme systems coded by fifteen gene loci were used for studying the genetic variability within and among races and populations. In the whole sample was found that the variation within populations represented 78% of the isozymic variability, the variation among races was 14% while the variation among populations within races was only 8%. Cluster analysis and Principal Component analysis indicated that most races were closely related. Cateto Amarillo, Cravo and Perla Mediano were the most distinctive of the Argentine races.Germplasm Paper no. 10     

Leaf mold of tomato caused by races 4 and 4.11 of Passalora fulva in Japan

Leaf mold of tomato was found on cv. Momotaro-fight in 2003 in Ehime Prefecture. The symptoms were marginal indefinite yellowing on the upper leaf surface, and downy, gray to brown sporulation on the lower surface underneath the spots. The symptoms and morphology were the same as seen with Passalora fulva. The fungal isolates were identified as races 2.4, 2.4.11, 4, and 4.11 by inoculation tests. Races 4 and 4.11 have never before been found in Japan.     

浙江太湖稻区稻瘟病菌生理小种变化及毒性分析

】１９９１～１９９６年,从浙江太湖稻区８个县（市）的稻瘟病标样中分离到４８８个有效单孢菌株,经７个中国稻瘟病菌鉴别品种鉴定,共鉴定出７群１８个小种。其中,ＺＤ,ＺＡ,ＺＥ群为优势种群,出现频率分别为３９．３４％,２７．２５％和２４．８０％,优势小种为ＺＤ３,ＺＥ３,ＺＡ４９,ＺＤ１。主栽品种上的小种组成较为复杂,但主要小种与整个稻区的优势小种基本一致,小种与品种之间存在着特定的亲和性关系。病菌对该稻区已被更换或正在被更换的品种的毒力频率较高,对新育成和推广的秀水１７、秀水９３－６３等品种的毒力较弱。病菌小种类型和结构随着栽培品种的更换而发生较大的变化,反映了病原菌与寄主品种的协同进化关系。