1994 - 2002年小麦品种(系)抗条锈性鉴定与监测

1994—2002年经对3822份小麦品种(系)材料抗条锈性鉴定结果表明,冬小麦抗条锈性优于春小麦,甘肃品种抗条锈性优于国内其它省区品种。田间抗条锈性监测结果表明,我国主要生产品种均表现感病,甘肃主要生产品种仅陇鉴127等少数几个品种抗病,抗源材料中也仅有中四等少数品种表现抗病,结合抗病性鉴定、监测结果及田间综合农艺性状观察,筛选出20余份可供育种利用的抗源材料。同时在针对今后抗条中31、32号等主要小种类型的抗病育种、抗病性监测等方面进行了讨论。     

2003-2013年小麦品种(系)抗条锈性鉴定及评价

2003-2013年在甘肃省农业科学院植物保护研究所兰州温室和甘谷试验站,分别对来自国内35个相关育种单位的冬春小麦品种(系)5001份,其中冬小麦4291份、春小麦710份,进行苗期混合菌、成株期分小种和混合菌抗条锈性接种鉴定,结果表明:全生育期表现免疫近免疫的有兰天31号等479份,高抗的有兰天23号等76份,中抗的有天选49等291份,分别占9.58％、1.52％和5.82％;成株期表现免疫近免疫的有天选50号等840份,高抗的有兰天27号等47份,中抗的有天选52等311份,分别占16.80％、0.94％和6.22％;苗期表现免疫近免疫的有兰天30号等964份,高抗的有天98102等122份,中抗的有00-30等273份,分别占19.28％、2.44％和5.46％.冬小麦有天选49号等914份材料表现全生育期抗病,占18.28％;有97-473等906份成株期表现抗病,占18.12％;有兰天20号等1225份苗期表现抗病,占24.50％.春小麦有定西41号等113份材料全生育期表现抗病,占2.26％;有陇春28号等125份成株期表现抗病,占2.50％;有0109-1等114份苗期对混合菌表现抗病,占2.28％.先后在甘肃天水汪川良种场对相关材料进行成株期抗条锈性评价,结果发现:1154份从小种圃筛选出的抗病材料中,表现抗病的有兰天31号等745份,占64.56％;105份甘肃陇南生产品种中,到2013年表现抗病的仅有兰天28号、中梁31号等30份材料,占28.57％;后备品系中,00-30-2-1、CP04-20、00127-2-3等抗性表现优异;抗源材料中,仅有贵农775、中四、T.Spelta albun、贵协1、贵协3等少数材料表现抗病,重要抗源材料贵农21、贵农22、南农92R、川麦42、Moro从2011年开始在田间表现感病,逐步失去利用价值.其衍生系品种材料如陇鉴9343、天选43号、中梁29号、兰天17号、兰天24号等也在田间逐步感病,条锈病发生流行压力持续增大.     

Molecular mapping reveals two independent loci conferring resistance to Albugo candida in the east European germplasm of oilseed mustard Brassica juncea

White rust caused by Albugo candida (Pers.) Kuntze is a major disease of the oilseed mustard Brassica juncea. Almost all the released varieties of B. juncea in India are highly susceptible to the disease. This causes major yield losses. Hence, there is an urgent need to identify genes for resistance to white rust and transfer these to the existing commercial varieties through marker-assisted breeding. While the germplasm belonging to the Indian gene pool is highly susceptible to the disease, the east European germplasm of B. juncea is highly resistant. In the present study, we have tagged two independent loci governing resistance to A. candida race 2V in two east European lines, Heera and Donskaja-IV. Two doubled haploid populations were used; the first population was derived from a cross between Varuna (susceptible Indian type) and Heera (partially resistant east European line) and the second from a cross between TM-4 (susceptible Indian type) and Donskaja-IV (fully resistant east European line). In both the resistant lines, a single major locus was identified to confer resistance to white rust. In Heera, the resistance locus AcB1-A4.1 was mapped to linkage group A4, while in Donskaja-IV, the resistant locus AcB1-A5.1 was mapped to linkage group A5. In both the cases, closely linked flanking markers were developed based on synteny between Arabidopsis and B. juncea. These flanking markers will assist introgression of resistance-conferring loci in the susceptible varieties.     

A multi-generation analysis of the stability of transgenic virus resistance in doubled-haploid tobacco lines

Plants can be genetically engineered for virus resistance by transformation with a viral gene. We transformed tobacco with the tomato spotted wilt virus (TSWV) nucleocapsid gene from the Hawaiian L isolate in order to obtain TSWV resistant breeding lines. Doubled-haploid lines were produced from primary transgenic plants that were selected for resistance to the virus. Several of these lines showed very high levels of resistance and were symptomless after inoculation with the Hawaiian L isolate of TSWV. The accumulation of only low levels of full-length transgene RNA and protein observed in these lines is consistent with an RNA-mediated mechanism of resistance. The lines that were highly resistant to the Hawaiian L isolate of TSWV were also found to be highly resistant to several other isolates of TSWV, while lines that were only moderately resistant to the Hawaiian L isolate were often susceptible to the other isolates. The highly resistant lines were advanced over several generations by self-pollination. Although these lines were fully homozygous, several lines lost resistance in later generations, indicating that the resistance was unstable. Selection for resistance in these unstable lines did not prevent the occurrence of susceptible progeny in subsequent generations. Therefore, testing over several generations is required to determine the stability of resistance when breeding crops with transgenic virus resistance.     

Selection of parents for crossing based on genotyping and phenotyping for stripe rust (Puccinia striiformis) resistance and agronomic traits in bread wheat breeding

Bread wheat (Triticum aestivum L.) germplasm consisting of 45 genotypes were clustered phenotypically using ten morphological traits and Area Under Disease Progress Curve (AUDPC) as measure of stripe rust resistance. The clustering was ratified by using twenty three molecular markers (SSR, EST and STS) linked to stripe rust (Puccinia striiformis f. sp. tritici) resistant QTLs. The aim was to asses the extent of genetic variability among the genotypes in order to select the parents for crossing between the resistant and susceptible genotypes with respect to stripe rust. The Euclidian dissimilarity values resulted from phenotypic data regarding morphological traits and AUDPC were used to construct a dendrogram for clustering the accessions. Using un-weighted pair group method with arithmetic means, another dendrogram resulted from the similarity coefficient values was used to distinguish the genotypes with respect to stripe rust. Clustering based on phenotypic data produced two major groups and five clusters (with Euclidian dissimilarity ranging from 244 to 16.16) whereas genotypic data yielded two major groups and four clusters (with percent similarity coefficient values ranging from 0.1 to 46.0) to separate the gene pool into highly resistant, resistant, moderately resistant, moderately susceptible and susceptible genotypes. With few exceptions, the outcome of both type of clustering was almost similar and resistant as well as susceptible genotypes came in the same clusters of molecular genotyping as yielded by phenotypic clustering. As a result seven genotypes (Bakhtawar-92, Frontana, Saleem 2000, Tatara, Inqilab-91, Fakhre Sarhad and Karwan) of diverse genetic background were selected for pyramiding stripe rust resistant genes as well as some other agronomic traits after hybridization.     

Hypersensitive lignification response as the mechanism of non-host resistance of wheat against oat crown rust

Seven-day-old seedlings of the near-isogenic wheat ( Triticum aestivum L.) lines Prelude and Prelude-Sr5, susceptible and resistant to wheat stem rust, respectively, were inoculated with uredospores of the oat crown rust fungus Puccinia coronata Cda. f. sp. avenae Fraser & Led. Fluorescence microscopy revealed that the majority of colonies developed intercellular infection structures including haustorial mother cells and haustoria after penetration of wheat mesophyll cells. All penetrated cells became necrotic, and exhibited bright yellow autofluorescence. This autofluorescence was not extractable with alkali, and fluorescent cells stained positively with phloroglucinol/HCI, suggesting that hypersensitive cell death was correlated with cellular lignification. Accordingly, the lignin biosynthetic enzymes phenylalanine ammonia-lyase (EC4.3.1.5). 4-coumarate:CoA ligase (EC6.2.1.12), cinnamyl-alcohol dehydrogenase (EC1.1.1.149), and peroxidases (EC1.11.1.7) increased in activity during the expression of resistance. The induced pattern of peroxidase iso/ymes closely resembled that observed for highly incompatible wheat/wheat stem rust interactions. Furthermore, an elieitor was extracted from oat crown rust germlings. which induces lignification when injected into the intercellular space of wheat leaves. This elieitor appears to be functionally similar to that isolated from wheat stem rust germlings. The results suggest that the non-host resistance of wheat to the xenopara-site oat crown rust closely resembles the race/cullivar-speeific resistant mechanism of highly resistant wheat varieties to wheat stem rust.     

亚蔬中心绿豆品种(系)抗白粉病评价

采用苗期人工接种鉴定法,在大棚种植条件下对12个亚蔬中心(AVRDC)绿豆品种白粉病抗性进行了鉴定评价。结果显示,VC1560C、V4785和VC2768A三个品种高抗(HR)白粉病,VC6173-14、V1132为中抗(MR)白粉病品种。其它品种对白粉病表现高度感病。在田间种植条件下对亚蔬中心16个抗豆象回交9代品系(BC9)进行了成株期白粉病抗性鉴定。与对照感病品种 VC1973、VC1178A 相比,VC6459-3-6-37和 VC6458-6-3-16对白粉病具有一定抗性,但白粉病感染程度仍很严重,其它14个 BC9品系均对白粉病表现高度感病。     

Phenotypic and Molecular Assessment of Wheat Genotypes Tolerant to Leaf Blight,Rust and Blast Diseases

Globally among biotic stresses, diseases like blight, rust and blast constitute prime constraints for reducing wheat productivity especially in Bangladesh. For sustainable productivity, the development of disease-resistant lines and high yielding varieties is vital and necessary. This study was conducted using 122 advanced breeding lines of wheat including 21 varieties developed by Bangladesh Wheat and Maize Research Institute (BAMRI) with aims to identify genotypes having high yield potential and resistance to leaf blight, leaf rust and blast diseases. These genotypes were evaluated for resistance against leaf blight and leaf rust at Dinajpur and wheat blast at Jashore under field condition. Out of 122 genotypes tested, 20 lines were selected as resistant to leaf blight based on the area under the diseases progress curve (AUDPC) under both irrigated timely sown (ITS) and irrigated late sown (ILS) conditions. Forty-two genotypes were found completely free from leaf rust infection, 59 genotypes were identified as resistant, and 13 genotypes were identified as moderately resistant to leaf rust. Eighteen genotypes were immune against wheat blast, 42 genotypes were categorized as resistant, and 26 genotypes were identified as moderately resistant to wheat blast. Molecular data revealed that the 16 genotypes showed a positive 2NS segment among the 18 immune genotypes selected against wheat blast under field conditions. The genotypes BAW 1322, BAW 1295, and BAW 1203 can be used as earlier maturing genotypes and the genotypes BAW 1372, BAW 1373, BAW 1297 and BAW 1364 can be used for lodging tolerant due to short plant height. The genotypes WMRI Gom 1, BAW 1349 and BAW 1350 can be selected for bold grain and the genotypes WMRI Gom 1, BAW 1297, BAW 1377 can be used as high yielder for optimum seeding condition but genotypes BAW 1377 and BAW 1366 can be used for late sown condition. The selected resistant genotypes against specific diseases can be used in the further breeding program to develop wheat varieties having higher disease resistance and yield potential.     

Population genetic diversity of Puccinia striiformis f. sp. tritici on different wheat varieties in Tianshui, Gansu Province

Population genetic diversity in Tianshui city was analyzed with SSR markers in 605 single-pustule isolates of the stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst), obtained from 19 varieties of wheat. Significant differences in genetic diversity among populations were defected. Genetic diversity was highest in population on Tian 863-13, a highly resistant variety, whereas genetic diversity was lowest in population on Huixianhong, a highly susceptible variety. Seven populations from seven varieties that carried the common Yr18 resistance gene were clustered as one sub-group at 0.88 similarity coefficient, which showed that resistance gene selection had close relation with pathogen??s component. The results of present study can provide a theoretical basis for integrated management of wheat stripe rust and effective deployment of resistance genes in Pst over-summering zones in China.     

Selection of parents for crossing based on genotyping and phenotyping for stripe rust (<Emphasis Type="Italic">Puccinia striiformis</Emphasis>) resistance and agronomic traits in bread wheat breeding

Bread wheat (Triticum aestivum L.) germplasm consisting of 45 genotypes were clustered phenotypically using ten morphological traits and Area Under Disease Progress Curve (AUDPC) as measure of stripe rust resistance. The clustering was ratified by using twenty three molecular markers (SSR, EST and STS) linked to stripe rust (Puccinia striiformis f. sp. tritici) resistant QTLs. The aim was to asses the extent of genetic variability among the genotypes in order to select the parents for crossing between the resistant and susceptible genotypes with respect to stripe rust. The Euclidian dissimilarity values resulted from phenotypic data regarding morphological traits and AUDPC were used to construct a dendrogram for clustering the accessions. Using un-weighted pair group method with arithmetic means, another dendrogram resulted from the similarity coefficient values was used to distinguish the genotypes with respect to stripe rust. Clustering based on phenotypic data produced two major groups and five clusters (with Euclidian dissimilarity ranging from 2.44 to 16.16) whereas genotypic data yielded two major groups and four clusters (with percent similarity coefficient values ranging from 0.1 to 46.0) to separate the gene pool into highly resistant, resistant, moderately resistant, moderately susceptible and susceptible genotypes. With few exceptions, the outcome of both type of clustering was almost similar and resistant as well as susceptible genotypes came in the same clusters of molecular genotyping as yielded by phenotypic clustering. As a result seven genotypes (Bakhtawar-92, Frontana, Saleem 2000, Tatara, Inqilab-91, Fakhre Sarhad and Karwan) of diverse genetic background were selected for pyramiding stripe rust lesistant genes as well as some other agronomic traits after hybridization.     

广西玉米种质资源对纹枯病的抗性鉴定

在人工接种条件下,对860份玉米材料进行了纹枯病抗性鉴定和评价,旨在为进一步开展玉米纹枯病抗性育种和分子生物学研究奠定基础。结果显示,在鉴定的860份玉米材料中,没有发现免疫的材料,高抗、抗、中抗、感和高感的比例分别为3.49%、28.60%、26.16%、10.35%和31.40%;在农家种、群体种和杂交种（组合）等杂合体中,抗病材料所占比例较大,而自交系等纯合体中,感病材料所占比例较大,表明玉米杂合体种质资源材料中可能蕴藏着不同的抗纹枯病基因,特别是广西农家种中可能存在对纹枯病具有稳定抗性的材料,值得进一步研究和利用。     

广西玉米种质资源对纹枯病的抗性鉴定

在人工接种条件下,对860份玉米材料进行了纹枯病抗性鉴定和评价,旨在为进一步开展玉米纹枯病抗性育种和分子生物学研究奠定基础。结果显示,在鉴定的860份玉米材料中,没有发现免疫的材料,高抗、抗、中抗、感和高感的比例分别为3．49％、28．60％、26．16％、10．35％和31．40％;在农家种、群体种和杂交种（组合）等杂合体中,抗病材料所占比例较大,而自交系等纯合体中,感病材料所占比例较大,表明玉米杂合体种质资源材料中可能蕴藏着不同的抗纹枯病基因,特别是广西农家种中可能存在对纹枯病具有稳定抗性的材料,值得进一步研究和利用。     

辽宁水稻品种抗灰飞虱鉴定及其抗性机制研究

为探明辽宁地区水稻品种对本地灰飞虱Laodelphax striatellus(Fallén)的抗性水平及其抗虫机制,本研究利用改进的苗期集团鉴定法,以IR36为抗虫对照品种、武育粳3号为感虫对照品种,对42份辽宁地区主栽水稻品种和研究待推广品种进行了水稻苗期对灰飞虱抗性鉴定,并从中选取20份不同抗性水平的品种进行了排趋性和抗生性的测定。结果表明:从42份水稻材料中仅筛选出1份抗虫材料辽优5218,中抗品种11份,其余均为感虫或高感品种。在不同水稻类型中,杂交稻的抗虫性普遍较常规稻强,而从水稻株型上看,抗性品种大多为披散型。抗虫机制研究发现,抗虫品种辽优5218和中抗品种港育129兼具排趋性和抗生性,是非常理想的抗性种质资源,中抗品种港源8号和粳优558具有很强的排趋性,也是较为理想的抗性资源,为抗性机制的深入研究提供了材料。但大部分省内主栽主推品种不具备对灰飞虱的抗性,应引起重视。     

Genes tagging and molecular diversity of red rot susceptible/tolerant sugarcane hybrids using c-DNA and unigene derived markers

Sugarcane is an important international commodity as a valuable agricultural crop especially in tropical and subtropical countries. Two bulked DNA used to screen polymorphic primers from commercial hybrids (varieties) with moderately resistant and highly susceptible to red rot disease. Among 145 simple sequence repeat and unigene primers screened, 37 (25%) were found to be highly robust and polymorphic with Polymorphism Information Content values ranging from 0.50 to 1.00 with the mean value of 0.82. Among these microsatellites, twenty one were used in the study of genetic relationships and marker identification in sugarcane varieties for red rot resistance. A total of 105 polymorphic DNA bands were identified, with their fragment size ranging from 54 to 1,280 bp. Jaccard’s similarity coefficient value recorded between closely related hybrids was 0.986 while lowest coefficient value of 0.341 was detected with distantly related hybrids. The average similarity coefficient among these hybrids was 0.663. Cluster analysis resulted in a dendrogram with two major clusters separating the moderately resistant varieties from highly susceptible varieties. Three group specific fragments amplified by unigene Saccharum microsatellite primers viz; two markers UGSM316₈₅₀ and UGSM316₆₀ were closely associated with moderately resistant varieties by appearing bands in this region but the bands were absent in highly susceptible varieties. Similarly UGSM316₄₀₀ marker was tightly linked with highly susceptible varieties by amplifying uniformly in sugarcane varieties showing highly susceptible reaction to red rot but it was absent in moderately resistant varietal groups. Validation of red rot resistance/susceptibility associated markers on a group of different mapping populations for red rot resistant/susceptible traits is in progress.     

Comparative analysis of Phytophthora infestans induced gene expression in potato cultivars with different levels of resistance

Differential gene expression was analyzed after infection with Phytophthora infestans in six potato cultivars with different levels of resistance to late blight. To verify the infection of the potato leaflets, the amount of phytopathogen mRNA within the plant material was quantified by real-time quantitative PCR. The expression of 182 genes selected from two subtracted cDNA libraries was studied with cDNA array hybridization using RNA from non-infected and infected potato leaflets. Gene up- and down-regulation were clearly detectable in all cultivars 72 h post inoculation. Gene expression patterns in susceptible cultivars differed from those in potato varieties with a higher level of resistance. In general, a stronger gene induction was observed in the susceptible cultivars compared to the moderately to highly resistant potato varieties. Five genes with the highest homology to stress and/or defence-related genes were induced specifically in the susceptible cultivars. Four genes responded to pathogen attack independently of the level of resistance of the cultivar used, and three genes were repressed in infected tissue of most cultivars. Even in the absence of P. infestans infection, six genes showed higher expression levels in the somewhat resistant cultivars Bettina and Matilda. Possible reasons for the different levels of gene expression are discussed.     

来自西尔斯山羊草的抗小麦白粉病基因Pm57抗性丧失突变体的筛选与鉴定

小麦近缘种属来源的抗白粉病基因是培育小麦抗病品种,防治白粉病危害的最重要基因来源。Pm57是位于西尔斯山羊草2S^s#l染色体长臂上的一个外源基因,对小麦白粉病具有苗期和成株期广谱抗性。为了创制Pm57白粉病抗性丧失突变体,利用基于基因突变体的植物抗病基因克隆新兴技术分离Pm57基因,选用0.625%的甲基磺酸乙酯(EMS)对1万粒小麦-西尔斯山羊草Pm57易位系89(5)69种子进行了诱变处理,M1大田密播种植,收获了1598个M2可育株系。初步对其中300个M2株系进行苗期白粉病抗性接种鉴定,并利用2个Pm57基因特异分子标记X2L4g9P4/HaeⅢ和X284274及小麦全国区试品系DUS测试所用的42对SSR核心引物对Pm57抗性丧失突变体进行鉴定,筛选出来自27个M2株系的真实抗性丧失突变体70个,Pm57基因抗性丧失突变体频率达到9.0%。本研究所获得的白粉病抗性丧失突变体为Pm57基因的后续克隆与抗白粉病分子机理研究提供了重要的材料基础。     

Screening Soybeans for Resistance to Reniform Nematode Disease in the Philippines

Sixty-five soybean varieties were tested in the field for resistance to Rotylenchulus reniformis. Criteria for resistance or susceptibility were root necrosis, nematode recovery from roots and soil, and egg production. Nine varieties were resistant, 13 moderately resistant, 26 moderately susceptible, and 17 susceptible. Linear correlations between resistance rating and each assessment parameter were highly significantly positive, suggesting that any of the parameters could be used to identify resistance. There were also highly significant positive linear correlations between any two combinations of parameters, indicating that they were reciprocally related.     

Screening of certain barley lines for resistance to root rot disease caused by Fusarium graminearum

This investigation was conducted in 2005/2006 and 2006/2007 to test 235 barley lines plus two varieties Giza 127 and Giza 128 for resistance and susceptibility to Fusarium graminearum. All screened barley lines showed varied significant degrees of infestation to root rot pathogen. A screening system is described for identifying barley lines which are effective in controlling resistant or susceptible lines. By detecting small but consistent differences in root rot severity, the bioassay proved effective in large-scale screening for partial resistance: already 335 barley lines and two varieties have been screened. We found five groups (7.12%), 22 barley lines and both varieties are resistant (R) (8.31%); 28 barley lines are moderately resistant (MR) (19.29%); 65 barley lines are moderately susceptible (MS) (27.89%); 94 barley lines are susceptible (S) and (37.39%) 126 barley lines are highly susceptible (HS). The high degree of precision makes this an invaluable tool in the understanding of pathogen aggressiveness, host specialisation and parasitic fitness. Disease scale was strongly negative and had moderate correlation with germination (?0.309?? and ?0.649??) under normal and disease treatment. The correlation between yield and normal and disease treatment during two seasons was strong and negative (?0.834?? and ?0.847??, respectively were detected).     

甘薯品种抗黑斑病鉴定及其遗传趋势

对2745份甘薯品种及育种材料的黑斑病抗性鉴定结果表明,高抗型占7．7％,抗病型占17．7％,中抗型占23.2％,感病型占27．2％,高感型占24．2％。对898份材料及其亲本的抗性分析表明,不同抗性组合后代中均可分离出高抗至高感类型的材料,杂交后代的抗性强弱随双亲抗性水平的增加而提高。相关分析显示,甘薯品种抗黑斑病性与其它主要经济性状间没有相关关系。采用品种阃杂交育种技术先后育成了一批高产、优质的抗病型优良品种。     

The mechanism and inheritance of adult plant leaf rust resistance in 12 wheat lines.

Twelve lines of wheat (Triticum aestivum L.) were developed that had susceptible infection types to leaf rust (Puccinia recondita Rob. ex Desm. f.sp. tritici) race UN 15 in the seedling stage but were resistant in the adult plant stage in the field. The lines were developed from four crosses, each involving four parents (eight in total) that had originally been selected for adult plant or field resistance to stem rust (Puccinia graminis Pers. f.sp. tritici Eriks, and Henn.). The objectives of the present study were to determine the mechanism of resistance to leaf rust and its inheritance in the 12 lines. The 12 lines were grown in an artificially inoculated field nursery in Saskatoon, coefficients of infection (CI) were determined at four dates, and the areas under the disease progress curve (AUDPC) were calculated. Four representative lines were grown in a growth chamber to measure the latent period and pustule size at the two-leaf and flag-leaf stages. Eight lines were crossed and backcrossed to a susceptible check and the parents, F1, F2, F3, and BC1F2 generations were grown in a field nursery. The 12 lines showed wide ranges in CI and AUDPC but all were significantly more resistant than the susceptible check. The four lines studied in the growth chamber had longer latent periods and smaller pustules than the susceptible check at both stages. The differences tended to be greater at the flag-leaf stage. The inheritance studied showed that resistance was recessive or partially recessive and was controlled by two or more genes in each line of the eight lines. In three of the eight lines, Lr34 may be one of the genes and in the other five both Lr13 and Lr34 could be present. However, additional genes are clearly involved. A single gene by itself had only a small effect, but in two and three gene combinations the effects appeared to be greater. This type of resistance appears to occur frequently and may be durable because its complex inheritance may make it more difficult for the rust fungus to overcome. It should be used in breeding wheat for areas where leaf rust is a major problem.