山东地区小麦条锈病发生规律及防控措施

小麦是山东地区重要的粮食作物,小麦生产也是当地农民的主要的经济来源之一。近些年山东地区小麦条锈病呈现加重趋势,直接影响小麦产量,降低农民收入。因此,针对山东地区小麦条锈病发生规律以及相应的防控措施进行具体分析,以期提供参考。

Molecular Detection of Resistance Genes to Stripe Rust and Powdery Mildew in Common Wheat Cultivar Yunmai52

Yunmai52, developed by crossing with common wheat-Haynaldia villosa6AL/6VS translocation line 92R149 as a resistant parent in 1992, was a common wheat cultivar approved and released in 2007 in Yunnan Province, China, which is characterized by high resistance to powdery mildew and stripe rust. In this study,an F_2 population derived from a cross K78S/Yunmai52 was constructed to investigate the resistance genes, where K78 S is a wheat male sterile line susceptible to powdery mildew and stripe rust. Phenotypic identification of the parents, F_1 and F_2 populations and chi-square analyses showed that F_1 population was immune to stripe rust and powdery mildew; the segregation ratio of resistance and susceptibility to powdery mildew（χ~2=1.10χ~2_（1,0.05）=3.84） and stripe rust（χ~2=0.15χ~2_（1,0.05）=3.84） fit to a 3：1 ratio in F_2 population, indicating that Yunmai52 harbors a dominant stripe rust resistance gene and a dominant powdery mildew resistance gene. The individuals were further detected with a marker co-segregated with Pm21（SCAR_（1400）） and two markers closely linked with Yr26（XWe173 and Xbarc181）. The results showed that polymorphic bands could be amplified between the parents and between resistance and susceptibility gene pools at the same locus. Randomly 96 individuals of F_2 population were selected for verification. The results showed that the phenotype was significantly correlated with the genotype. The detection accuracy of markers SCAR_（1400）, XWe173 and Xbarc181 was 100%, 97.91% and 92.70%, respectively.Yunmai52 harbored powdery mildew resistance gene Pm21 and stripe rust resistance gene Yr26, which were both derived from 6AL/6VS translocation line 92R149.In addition, the results also demonstrate that Pm21 and Yr26 are two genes conferring durable resistance to powdery mildew and stripe rust in wheat.

Control of Wheat Stripe Rust and Ensuring High Yield of Crops under Planting of Wheat Variety Mixtures

Wheat stripe rust has become the most dangerous disease which threaten safe yield of wheat in Sichuan Province. It is meaningful to provide technique support for integrated disease control by exploring the effective control measures of wheat stripe rust. Wheat stripe rust dynamic developments of all-planting and mixed-planting have been systematically investigated in this study by taking different mixed-planting combinations among 6 wheat varieties with different resistance levels. The results of this experiment show that the mixed-plantings of 4 and 6 wheat varieties can delay the occurance of wheat stripe rust,slow the speed of disease and decline the damage of disease as well as stabilize yield of wheats.

Study on Epidemic Characteristics and Its Causes of Wheat Stripe Rust in Nanchong City

On basis of the research result of stripe rust for 16 years since 1999,the epidemic characteristics and trend of stripe rust in the city were determined.Namely,the earlier the initial stage appeared,the heavier the disease would be.Furthermore,stripe rust has two introduction infection peaks,of which the first peak plays a key role.In farmlands,there are one to three epidemic peaks,and the infection area of the first peak plays the key role on the epidemic area of that year.In addition,the accumulated areas of late January was in significantly positive correlation with annually total area,with a correlation coefficient of 0.769 2.In recent 16 years,the frequency of severe stripe rust was as high as 81.25% which was 50% higher than that before 1995.The slight stripe rust became just in 2013,with a frequency of 6.3%,which indicated that the city has become a region hit by severe stripe rust.The internal reason is the reduction or loss of wheat variety＇s resistance to tripe rust for a new physiological race of rust is becoming pathogenic stronger and be the major race.Big fluctuation of temperatures in warm winter and spring,foggy and dew days slants much would be the external reason.

Mapping of a Major Stripe Rust Resistance Gene in Chinese Native Wheat Variety Chike Using Microsatellite Markers

Chike （accession number Su1900）, a Chinese native wheat （Triticum aestivum L.） variety, is resistant to the currently prevailing physiological races of Puccinia striiformis Westend. f. sp. tritici in China. Genetic analysis indicated that resistance to the physiological race CY32 of the pathogen in the variety was controlled by one dominant gene. In this study, BSA （bulked segregant analysis） methods and SSRs （simple sequence repeats） marker polymorphic analysis are used to map the gene. The resistant and susceptible DNA bulks were prepared from the segregating F2 population of the cross between Taichung 29, a susceptible variety as maternal parent, and Chike as paternal parent. Over 400 SSR primers were screened, and five SSR markers Xwmc44, Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 on the chromosome arm 1BL were found to be polymorphic between the resistant and the susceptible DNA bulks as well as their parents. Genetic linkage was tested on segregating F2 population with 200 plants, including 140 resistant and 60 susceptible plants. All the five SSR markers were linked to the stripe rust resistance gene in Chike. The genetic distances for the markers Xwmc44, Xgwm259, Xwmc367, Xcfa2292, and Xbarc80 to the target gene were 8.3 cM, 9.1 cM, 17.2 cM, 20.6 cM, and 31.6 cM, respectively. Analysis using 21 nulli-tetrasomic Chinese Spring lines further confirmed that all the five markers were located on chromosome lB. On the basis of the above results, it is reasonable to assume that the major stripe rust resistance gene YrChk in Chike was located on the chromosome arm 1BL, and its comparison with the other stripe rust resistance genes located on 1B suggested that YrChk may be a novel gene that provides the resistance against stripe rust in Chike. Exploration and utilization of resources of disease resistance genes in native wheat varieties will be helpful both to diversify the resistance genes and to amend the situation of resistance gene simplification in the commercial wheat cultivars in China.

Assessment of Variabilities in Wheat Genotypes to Yellow and or Strip Rust, Puccinia striiformis in Glass House Conditions

Yellow/stripe rust caused by Puccinia striiformis is a major problem in the Middle East specially Iran. Virulence survey of cereal rust fungi have traditionally used differential host genotype and virulent physiologic race 134 E 134 AT was received to evaluate the segregating lines. A set of 35 segregating lines and three additional susceptible cultivars were added, making a total of 38 eultivars-lines. Spreader plants served as a source of inoculums. The plants were evaluated after two months based on infection percentage and the disease scoring scales. The results indicated that, there are significant changes in susceptibility assessments of the segregating lines in contrast to cultivated varieties to the yellow rust P. striiformis as far as the disease incidence and rust development is concerned in these experiments. The selected differential genotypes associated with various levels of resistance. The infection percentages were varied on the lines and the varieties, whereas the severity percentages were entirely different. The lowest severity is of line 38 with 34.70% and the highest in line 1 with 93.49% indicating 2.7 folds reduction in severity. For discrimination among the lines, the results on scoring scales gave distinctions of five classes of resistance, in which, the highest score is 29.93 and the lowest one 11.46. The cluster analysis showed almost similar results and confirmed, the analysis by Duncan＇s Multiple-lest rang as the above five distinctive groups.

Wheat Stripe Rust Virulence and Varietal Resistance in the Foot Hill Himalayas of Nepal

Stripe rust, caused by Puccinia striiformis f. sp. tritici （Pst） is an important disease of wheat （Triticum aestivum） in Nepal, which is a part of the Himalayas stretching over the North of Nepal, India, Pakistan, Bhutan and beyond. Wheat production plays a crucial role in food security of the marginal hill farmers of Nepal. Frequent epidemics of the rust have caused huge loss in farmer＇s field. Periodic monitoring during 1980-2008 showed that changes in virulence occurred during this period. The objective of this study was to evaluate Pst resistance and its effective genes in wheat genotypes. For this, trap nurseries, wheat stripe rust differentials, commercial cultivars and advanced breeding lines were tested under artificial epiphytotic and natural hot spots conditions during 2005 to 2010. Four genes （Yr5, Yr10, Yr15 and YrSp） consistently showed resistance to the prevailing races. The gene Yr9 and Yr27 in combinations with Yrl8 were found effective. Other lines with combination of minor genes were also found effective. The genotypes Amadina, Kukuna, Tukuru, Kakatsi and Buck Buck widely used in breeding program were resistant. The cultivation of varieties WK1204, Gautam, Gaura and Dhaulagiri have ensured genetic diversity for the rust resistance and slowed down frequent occurrence of epidemics. The findings of these studies could help in developing effective varietal resistance program in the sub-continent.

Study Genetic Variation Using DNA Molecular Markers and Identification Physiological Races of Wheat Stripe （yellow） Rust Puccinia striiformis f.sp tritici during 2010-2014 in Some Regions of Syria

Yellow Rust （stripe） rust （Puccinia striiformis West. f. sp. tritici） is one of the most epidemic diseases infect wheat in cold and wet regions. In 1988, this disease caused a loss of seasonal production amounted 70% on wheat variety Mexipak in Syria, and recurrent infection in 2010, caused by a virulent race called Yr27, caused a considerable loss in the production of bread wheat cultivars （Cham 8, Cham 6 particularly） amounted 90%. Recently, 15 races of yellow rust had been addressed in Syria for seasons 2010-2014; 159E256, 166E254, 166E256, 255 E112, 0 E0, 64 E 6, 230 El50, 0 E 18, 198 El30, 166 El50, 102 El60, 128 E0, 126 El50, 214E150, and 6E16. The race 6E16 was the most frequent during the two seasons, while the race 255El12 was the most virulent, followed by the race 230E222 and the race 0E0 was the weakest one. This study revealed the presence of fourteen newly observed races in Syria. Molecular Variance Analysis of Molecular Variance （AMOVA） of 55 yellow rust Puccinia striiformis f.sp tritici isolates examined by Amplify Fragment Length Polymorphism （AFLP） revealed high genetic variation within population, and the dimensional scale analysis （MSD） and tree diagram showed that the Syrian yellow rust isolates were clustered in three groups： the first group contained isolates derived from durum wheat, the second one contained bread wheat isolates, but the third was made of isolates derived from both durum and bread wheat species.