Effect of maleic hydrazide on parasitic fitness of Puccinia striiformis f. sp. tritici in wheat

As a growth inhibitor of the apical meristem in the plant stem, Maleic hydrazide plays an important role in modulation of plant growth. In this research, Puccinia striiformis f. sp. tritici and its host for reproduction was employed to characterize the effect of maleic hydrazide on parasitic fitness of the strain. Growth inhibition of the secondary leaves of wheat by maleic hydrazide was demonstrated. Results showed that root irrigation by maleic hydrazide at the seedling stage significantly increased the parasitic fitness of Puccinia striiformis f. sp. tritici, leading to the increase in sporulation amount, sporulation period, and germination rate of urediniospores. In addition, the ultrastructure of Puccinia striiformis f. sp. tritici urediniospores was not affected by maleic hydrazide treatment. Out data indicate that the optimal concentration and dose for the use of maleic hydrazide is 0.35 g?l^?1 and 1.5 ml/cm², respectively, facilitating the widespread application in wheat stripe rust studies.     

Genetic diversity of Puccinia striiformis from cereals in Alberta,Canada

Stripe rust of wheat caused by Puccinia striiformis f. sp. tritici has recently become a production problem on wheat in Alberta, Canada, and stripe rust of barley caused by P. striiformis f. sp. hordei occurs regularly. A total of 261 isolates of P. striiformis were collected from wheat, barley, Hordeum jubatum and triticale plants in Alberta, Canada from 2007 to 2012, and compared to isolates from other provinces and the USA. The genetic diversity of the pathogen was assessed using 11 simple sequence repeat (SSR) markers and by examining a length polymorphism in the ribosomal DNA (rDNA) intergenic spacer 1 (IGS1) region. A total of 28 SSR genotypes were detected within Alberta. The 13 genotypes common on wheat (P. striiformis f. sp. tritici) were distinct from the 15 genotypes common on barley (P. striiformis f. sp. hordei). Four SSR genotypes, two within each forma specialis, represented 85% of the isolates recovered. Genotypic diversity was low, population genetic analysis indicated a clonal structure, and the genotypes were widely dispersed. In both formae speciales, the dominant genotype varied between years. The second most common P. striiformis f. sp. hordei genotype was found to be more closely related to older P. striiformis f. sp. tritici genotypes from the USA than to other P. striiformis f. sp. hordei genotypes.     

小麦锈菌蛋白激酶基因家族的鉴定与生物信息学分析

为深入分析锈菌结构基因组,阐明锈菌毒性变异的分子机制,本研究通过生物信息分析方法,对3种小麦锈菌蛋白激酶(protein kinases,PKs)超家族预测基因进行了系统分析,利用COG(clusters of orthologous groups of proteins)、KEGG(Kyoto encyclopedia of genes and genomes)、GO(gene ontology)和PHI(pathogen-host interactions)数据库进行注释分析,并对小麦锈菌MAPK基因的蛋白质互作网络进行预测。结果表明,条锈菌Puccinia striiformis、叶锈菌P.triticina和秆锈菌P.graminis的PKs基因数量分别为221、159和159个,不同PKs基因家族类型在3种锈菌中的数量分布上表现出很高的保守性。注释分析表明,PKs家族预测功能涉及病原菌生长发育中的调控作用和病原菌-寄主互作机制,包括信号传导和致病因子等。PKs家族核心基因数目在蛋白激酶基因中占比大于1/3。MAPK基因的催化结构域序列呈现高度相似性。以STRING数据库的酿酒酵母蛋白质互作网络信息为参考,对小麦锈菌MAPK基因的蛋白质互作网络进行预测,共鉴定出25个互作关系,包含29个MAPK基因。研究表明这3种锈菌之间MAPK互作蛋白质分布不均衡,这可能反映了锈菌基因组进化的特殊复杂性。     

中国小麦农家品种红锁条和白蚂蚱的抗条锈性遗传分析

为明确小麦农家品种所含抗条锈病基因组成及其抗病性和遗传特点,通过接种中国小麦条锈菌生理小种CYR31、CYR32和CYR33,对红锁条和白蚂蚱2个农家品种进行抗病性鉴定、基因推导及系谱分析和苗期抗病性遗传分析。结果显示,红锁条和白蚂蚱苗期均高抗3个流行小种CYR31、CYR32和CYR33,成株期高抗CYR32;红锁条和白蚂蚱均含有未知抗条锈病基因;红锁条对CYR31和CYR32的抗病性由2对隐性独立或重叠遗传基因控制,对CYR33的抗病性由1对隐性基因控制;白蚂蚱对CYR31的抗病性由2对显性互补基因控制,对CYR32的抗病性由1对显性基因控制,对CYR33的抗病性由2对隐性独立或重叠基因控制。农家品种红锁条和白蚂蚱含有抗条锈病基因,可以为抗病育种提供新抗源。     

African wheat germplasm – a valuable resource for resistance to rust diseases

Known and unknown genes conferring seedling and adult plant resistance (APR) to leaf rust, stem rust and stripe rust were detected either singly or in combination in a set of 136 African wheat genotypes using multi-pathotype tests with characterized Australian Puccinia triticina (Pt), P. graminis f. sp. tritici (Pgt) and P. striiformis f. sp. tritici (Pst) pathotypes. Lines Beladi 132, IYN 68/9.44, Kenya Kifaru and Kenya Mbweha were postulated to carry resistance against multiple pathotypes of Pt, Pgt and Pst, whereas IAR/W/163-3, Grano Di Moggio Tipo 44 and Trigo 48 had resistance against all pathotypes tested in the current study. Field evaluation with the three rust pathogens detected low to high APR in more than 50% of lines, and while most tested positive with markers linked to known APR genes (csLV34, csLV46G22, TM10KASPAR, csGS, Cfb5006 and csSr2), many carried unidentified and useful resistance to all three rusts. Genetic analysis of F₃ mapping populations based on seven genotypes showed either monogenic or digenic inheritance of APR to leaf rust, stem rust and stripe rust. The lines postulated to carry effective uncharacterized seedling genes and APR genes are of great potential value in diversifying resistance to help achieve durable control of all three rust diseases of wheat.     

甘肃省甘谷县小麦条锈菌群体遗传结构分析

为明确我国小麦条锈菌Puccinia striiformis f. sp. tritici主要越夏地区的群体遗传结构及演变情况,利用SSR荧光检测技术,对甘肃省甘谷县2013—2015年期间连续5个小麦生长季采集的141株小麦条锈菌单孢系基因组DNA进行分子标记分析,对小麦条锈菌季节亚群的遗传多样性进行分析。结果表明,甘谷地区小麦条锈菌的遗传多样性丰富,有效等位基因数为1.71,Shannon信息指数为0.66,2014年秋季(2014A)亚群体的基因型多样性低于其余亚群体。分子变异方差分析结果显示,小麦条锈菌季节亚群体间变异仅占21%,变异主要出现在亚群体内部,表明甘谷地区各季节亚群体间遗传分化水平差异较小,小麦条锈菌群体在一个小范围内基本能维持稳定状态。主坐标分析(PCoA)、遗传分化、基因流以及共享基因型分析均表明2014年秋季(2014A)亚群体的遗传结构与相邻季节亚群体存在一定差异,表明越夏过程对甘谷地区个别年份小麦条锈菌群体周年稳定性造成较大的影响,越冬过程对小麦条锈菌群体的影响相对较小,春季受外来菌源干扰的可能性较低。     

Temperature adaptation in Australasian populations of Puccinia striiformis f. sp. tritici

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the major fungal pathogens of wheat. A new pathotype was introduced to Australia in 2002 and several derivative pathotypes were detected in subsequent seasons. It has been suggested that the severity of stripe rust outbreaks in Australia since 2002 could be as a result of traits other than virulence in the pathogen population. This study was conducted to investigate the hypothesis that the stripe rust pathogen population dominant in Australia since 2002 was better adapted to warm temperature conditions compared to previous pathogen populations. Sixteen pathotypes were selected to examine the influence of two contrasting temperature regimes during the 24 h incubation (10°C and 15°C) and the subsequent post‐inoculation (17°C and 23°C) periods on latent period and infection efficiency on four susceptible wheat cultivars. In addition, the effect of two contrasting incubation temperatures on urediniospore germination was examined. The results indicated that pathotypes of P. striiformis f. sp. tritici detected after 2002 did not show evidence of adaptation to high temperatures, which suggests that other factors contributed to the observed increased aggressiveness.     

The development of a PCR-based method for detecting <Emphasis Type="Italic">Puccinia striiformis</Emphasis> latent infections in wheat leaves

Stripe rust of wheat caused by Puccinia striiformis f. sp. tritici is one of the most important diseases on wheat worldwide, especially in temperate regions with cool moist weather conditions. A rapid and reliable detection of the pathogen in latent infected wheat leaves during overwintering of the fungus in the dormant stage will contribute to determine the initial inoculum potential and thus to predict early outbreak and to improve effective management of the disease. To achieve this aim, a PCR-based method was developed for specific and sensitive detection of P. striiformis. Specific primers were designed according to a genome-specific sequence of P. striiformis. To evaluate the specificity of the primers, seven different isolates and races of P. striiformis as well as six other pathogens of wheat were tested. All isolates of P. striiformis yielded a distinct band of a fragment of 470 bp, while using DNA of the other wheat pathogens as a template no amplification product was detected. The sensitivity of the primers was tested using serial dilutions of total DNA from P. striiformis; the limit of detection was 10 pg of DNA. Using extracts from P. striiformis-infected wheat leaves, the fungus could be determined in the leaves before symptoms appeared. The stripe rust could also be detected in the dormant stage by the PCR assay in samples of wheat leaves taken during the winter season. The application of the PCR assay may be useful for rapid and reliable detection of P. striiformis in latent infected leaves of overwintering wheat plants.     

Disease development and genotypic diversity of Puccinia graminis f. sp. avenae in Swedish oat fields

The disease development and population structure of Puccinia graminis f. sp. avenae, which causes stem rust on oats, were studied to investigate if sexual reproduction plays an important role in the epidemiology of the disease. The genetic population structure of P. graminis f. sp. avenae in Sweden was investigated by sampling 10 oat fields in July and August 2008 and seven fields during the same period in 2009. Nine single‐pustule isolates were first used to test simple sequence repeat (SSR) markers developed for P. graminis f. sp. tritici. Eleven of the 68 tested SSR markers were useful for genotyping P. graminis f. sp. avenae. For the main study, DNA from single uredinia was extracted and the SSR markers were used to genotype 472 samples. Both allelic and genotypic diversity were high in all fields, indicating that P. graminis f. sp. avenae undergoes regular sexual reproduction in Sweden. No significant relationship between genetic and geographic distances was found. Disease development was studied on two farms during 2008 and 2009. The apparent infection rates ranged between 0·17 and 0·55, indicating the potential for rapid disease development within fields. The incidence of oat stem rust has increased recently in Sweden. One possible explanation is a resurgence of its alternate host, barberry (Berberis spp.), after the repeal of the barberry eradication law in 1994. Barberry is present in several grain‐producing areas in Sweden, which supports the conclusion that P. graminis f. sp. avenae undergoes regular sexual reproduction there.     

A soluble carbohydrate elicitor from Blumeria graminis f. sp. tritici is recognized by a broad range of cereals

Wheat plants rapidly recognize pathogenic and non-pathogenic conidia of the powdery mildew fungusBlumeria (syn. Erysiphe)graminis on their leaf surfaces. This suggests that a chemical signal emanates from conidia at the pre-penetration stage of infection. Conidia of B. graminis f. sp. tritici were found to contain an elicitor that was easily washed off their surface. The elicitor activity is heat stable and could not be removed by phenol extraction. By contrast, elicitor activity is sensitive to periodate oxidation and partial acid hydrolysis suggesting that the elicitor activity resides in a carbohydrate moiety. Analysis of carbohydrates revealed mostly glucose, with smaller amounts of xylose and mannose. The glucosyl residues of the B. graminis elicitor were found to be linked (1 → 2)-, (1 → 4), and (1 → 6)-, with (1 → 4, 1 → 6)- branch point residues, and no 3-linked glucose residues were detected. As treatment with β -mannanase significantly reduced elicitor activity, mixed-linkage (1 → 4), (1 → 6)-mannosyl residues appeared to be important for elicitor activity. The B. graminis elicitor induced the expression of all defence-related genes tested in wheat and also induced resistance to subsequent attack by B. graminis f. sp. tritici. In contrast, a hypersensitive response was not induced by the elicitor in the absence or the presence of a challenging inoculum of B. graminis f. sp. tritici. The elicitor also induced the accumulation of thaumatin-like proteins in barley, oat, rye, rice and maize, but did not induce necrosis in any of these species. This suggests that the B. graminis elicitor represents a host non-specific determinant of non-self recognition in cereals activating general defence responses other than the hypersensitive reaction.     

模拟酸雨对小麦条锈病流行学组分的影响

为明确酸雨对小麦条锈病菌孢子萌发及病害流行学组分的影响,采用不同酸度的模拟酸雨(p H值分别为2.5、3.5、4.5和5.6)处理小麦条锈病菌Puccinia striiformis f.sp.tritici生理小种CYR32和CYR33的夏孢子,并将不同酸度模拟酸雨处理后的夏孢子接种小麦感病品种铭贤169,采用组分分析法研究酸雨对病害发展过程的影响。结果表明,随着模拟酸雨酸度的增强,生理小种CYR32和CYR33的夏孢子萌发率均显著降低,萌发24 h后对照组生理小种CYR32和CYR33的夏孢子萌发率分别为93.7%和79.8%,在p H 3.5模拟酸雨处理后萌发率仅为13.1%和8.6%。温室内接种试验结果显示,不同酸度模拟酸雨对生理小种CYR32和CYR33的侵染概率、潜育期和病情指数均有显著影响,对生理小种CYR32和CYR33病斑扩展率影响不显著;与对照相比,p H 3.5模拟酸雨处理后生理小种CYR32和CYR33的侵染概率分别下降79.9%和79.8%。结果表明强酸雨(p H 3.5)显著延长小麦条锈菌潜育期,减少病斑产孢量,降低病情指数和病害进展曲线下面积。     

Genetic analysis and molecular mapping of resistance to Puccinia striiformis f. sp. pseudo‐hordei in common wheat

This is the first genetic study reporting on the interaction and molecular mapping of resistance to the barley grass stripe rust pathogen (Puccinia striiformis f. sp. pseudo‐hordei, Psph) in common wheat. Seedlings of 638 wheat accessions were tested and it was determined that wheat is a near‐nonhost to Psph based on rare susceptibility observed in <2% of commercial cultivars and <5% of wheat landraces. As previously observed for P. striiformis f. sp. tritici (Pst), the Australian cultivar Teal was highly susceptible to Psph. In contrast, a selection of cv. Avocet carrying complementary resistance genes Yr73 and Yr74 (Avocet R; AvR) was resistant. The Teal × AvR (T/A) doubled haploid (DH) population was used to map resistance in AvR to Psph. Infection types on the T/A DH lines inoculated with Psph and Pst indicated that all DH lines carrying both Yr73 and Yr74 were also resistant to Psph; however, fewer DH lines were susceptible to Psph than expected, suggesting the resistance was more complex. QTL analysis using 9053 DArT‐Seq markers determined that resistance to Psph was polygenically inherited and mapped to chromosomes 3A, 3D, 4A and 5B. The 3DL and 5BL markers co‐located with Yr73 and Yr74, suggesting an overlap between host and non‐host resistance mechanisms.     

Differential response of phytohormone signalling network determines nonhost resistance in rice during wheat stem rust (Puccinia graminis f. sp. tritici) colonization

Stem rust caused by Puccinia graminis f. sp. tritici is one of the most devastating diseases of wheat. Breakdown of host resistance under field conditions triggered by the evolution of new pathogenic races and pathotypes is a perennial threat for wheat cultivation. Rice, often grown in a rice–wheat cropping system, is immune to rust infection. Our microscopic studies revealed that P. graminis f. sp. tritici, although displaying nearly identical uredospore germination, stomatal entry, and epi- and endophytic mycelial growth in rice and wheat, failed to sporulate to cause rust disease in rice. We identified 18 key defence signalling genes in rice and unravelled their elicitation dynamics in time-course studies during infection. ICS1, NPR1-3, PRs, EDS1, PAD4, FMO1 (salicylic acid [SA] signalling), and ethylene-related genes (ACO4 and ACS6) were strongly elicited in rice. However, genes from the jasmonic acid (JA) signalling pathway (LOX2, AOS2, MYC2, PDF2.2, JAZ8, JAZ10) showed a delayed response during colonization in rice compared to an early or no induction in wheat. However, the JA/ethylene marker gene PDF2.2 was strongly induced in wheat as early as 12 hr postinoculation. Furthermore, rice and wheat displayed specific profiles of accumulation of various phenolic acids during P. graminis f. sp. tritici 40A infection. We propose a model where a differential modulation of the SA/JA-dependent defence network may modulate nonhost resistance. A deeper understanding of the molecular mechanism governing differential elicitation of defence signalling may provide a novel resistance mechanism for the sustainable management of rust diseases.     

Characterization of the cytochrome b gene fragment of Puccinia species responsible for the binding site of QoI fungicides

The fragment of the cytochrome b (cyt b) gene responsible for the binding site of QoI fungicides was sequenced for different Puccinia species by using DNA and RNA as template for PCR and RT-PCR, respectively. Degenerated primers for the cyt b gene amplified in P. recondita f.sp. tritici a 450 bp fragment, which was cloned and sequenced. At cDNA level, several Thermal Asymmetric InterLaced (TAIL)-PCR cycles were needed to produce a 996 bp long fragment, which corresponded to almost the whole cyt b gene (about 1160-1180 bp, without introns). This fragment was sequenced and specific primers were designed. Amplification with cyt b specific primers using genomic DNA as template revealed the presence of an intron of about 1500 bp length after the codon for glycine at amino acid position 143. By using the same primer pair, the cyt b gene fragment was amplified and sequenced both at cDNA and genomic DNA level also for other rust species, including P. graminis f.sp. tritici (length: 506 bp), P. striiformis f.sp. tritici (755 bp), P. coronata f.sp. avenae (644 bp), P. hordei (660 bp), P. recondita f.sp. secalis (687 bp), P. sorghi (709 bp), and P. horiana (478 bp). At the same position as for P. recondita f.sp. tritici, an intron of about 1500-1600 bp length was detected also in all other Puccinia species. High homologies were observed among all Puccinia species for both the exonic and intronic fragments of the cyt b gene. Specific primers for the cyt b gene of all eight Puccinia species were developed, which easily amplified the fragment of the gene including all possible mutations known to confer resistance to QoIs in several plant pathogens. However, in all tested isolates of the Puccinia species included in this study, the sequence of cyt b gene fragment did not contain any point mutations.     

Gene-based analysis of <Emphasis Type="Italic">Puccinia</Emphasis> species and development of PCR-based marker to detect <Emphasis Type="Italic">Puccinia striiformis</Emphasis> f. sp. <Emphasis Type="Italic">tritici</Emphasis> causing yellow rust of wheat

Stripe rust is considered as the current major rust disease affecting winter cereal production across the world. A quick, reliable PCR-based marker was developed here to detect, identify and rapidly monitor Puccinia striiformis f. sp. tritici (Pst) in wheat-growing areas. Three respective sets of primers, designed from β-tubulin, squalene monooxygenase and ketopantoate reductase genes selected from the full genome of Puccinia striiformis f. sp. tritici, amplified sequences of 239, 358 and 1518 bp, respectively, in Pst pathotypes. A fragment of 1518 bp unique to Pst pathotypes was amplified using primer set PstKeto F1_30/Pst KetoR1_1547 and distinguished the pathogen clearly from different Puccinia spp. and other fungal pathogens. The detection limit of the marker (KetoPstRA₁₅₀₀, accession no. KU240073) by conventional PCR assay was 10 pg. This marker could detect the pathogen in the host before symptom expression. The sensitivity and utility of the marker were further enhanced in a qPCR-based assay that was developed with a newly designed primer set PstKeto F1_1246/Pst KetoR1_1547, which amplified a product of 302 bp and detected as little as 10 fg of DNA. This PCR/qPCR based marker is suitable for studying cultivar resistance, which requires accurate quantification of the pathogen in diseased host tissue.     

中国不同春麦区小麦地方种质抗条锈病评价及抗性基因分析

为明确中国不同春麦区小麦地方种质对当前小麦生产上流行的条锈病菌Puccinia striiformis f.sp.tritic的抗性水平及其所含抗性基因,利用条锈病菌生理小种条中32（CYR32）和条中34（CYR34）及混合生理小种（致病类群）对来自5个春麦区的196份小麦地方种质进行苗期、成株期抗性鉴定,并通过6个已知条锈病抗性基因Yr9、Yr18、Yr26、Yr48、Yr65和Yr67对其所含重要抗性基因进行分子标记检测。结果显示,在苗期,有11份小麦地方种质对CYR32表现出抗性,有12份对CYR34表现出抗性,分别占供试种质总数的5.61%和6.12%;有6份对CYR32和CYR34均表现出抗性;在成株期,有59份小麦地方种质在5个田间诱导环境下表现出稳定的抗性。有119份小麦地方种质检测到含抗性基因,其中有3份携带Yr9,有50份携带Yr18,有43份携带Yr48,有54份携带Yr65,所有供试种质均未检测到Yr26和Yr67,抗性基因的组合分析发现,共有31份小麦地方种质携带4种抗性基因组合类型Yr9+Yr18、Yr18+Yr48、Yr18+Yr65和Yr48+Yr65。表明来自中国5个春麦区的小麦地方种质条锈病抗性表型呈多样性,且携带目前在小麦抗病育种和生产上有效的条锈病抗性基因（组合）,建议加大对小麦地方种质的保护和应用力度。     

Morphology of infection structures of puccinia striiformis var. dactylidis

The yellow rust fungusPuccinia striiformis var.dactylidis of cocksfoot differs clearly in the morphology of infection structures from both the nominate form, var.striiformis of wheat, barley andElymus and var.striiformis f. sp.poae affectingPoa pratensis. The observations are in accordance with the idea that var.dactylidis and var.striiformis f.sp.poae are two distinct not closely related taxa withinP. striiformis.Samenvatting In de morfologie van de infectiestructuren verschilt de gele-roestschimmelPuccinia striiformis var.dactylidis van kropaar duidelijk van zowel de nominaatvorm, var.striiformis van tarwe, gerst en kweekgras, als van var.striiformis f.sp.poae die beemdgrassen aantast. De waarnemingen steunen de opvatting dat var.dactylidis en var.striiformis f.sp.poae twee onderscheiden en niet nauwverwante taxa zijn binnenP. striiformis.     

Charakterisierung der Virulenz einer Braunrost-Feldpopulation (Puccinia triticina f. sp. tritici) und Nachweis effektiver Braun-rost-resistenz-gene in Weizen (Triticum aestivum)

Puccinia triticina f. sp. tritici, the causal agent of leaf rust causes yield losses in wheat up to 60%. In order to avoid such losses, leaf rust resistance (Lr-) genes have been incorporated into wheat cultivars. The Lr- genes confer mostly vertical resistance, i.e. they are race specific. Therefore, knowledge of still effective resistance genes is required for efficient breeding of resistant cultivars. To get information on these virulences, a leaf rust population was monitored in field experiments in 2010. For this purpose naturally infection at three different timepoints of wheat development was monitored on Thatcher near isogenic lines (NILs) carrying 37 and accessions carrying 6 additional Lr-genes. Thatcher-NILs carrying Lr2a, Lr9, Lr19, Lr22a, Lr23, Lr24, Lr35, Lr38 and Lr49 showed a significantly lower infection with Puccinia triticina than the susceptible cultivar Thatcher. Thatcher-NILs carrying Lr13, Lr16, Lr37 and Lr46 showed no significant differences in comparison to Thatcher. In order to get information on the effectiveness of resistance genes, P. triticina isolates were collected from the NILs analysed in field trials and a leaf segment test was conducted followed by microscopic analyses. In the field and in the leaf segment test Lr9, Lr19, Lr24 and Lr38 and to some extent Lr3a turned out to be the most effective genes. By microscopic analyses, the infection process as well defense reactions activated before macroscopic symptoms are visible were monitored. By counting haustorial mother cells, it could be demonstrated which Lr-genes provide resistance, which were overcame and whether P. triticina isolates exist already at a low frequency, which may overcome a certain Lr-gene in the future. Thus microscopy offers a timesaving and effective method to detect susceptible or resistant plants and the upcoming of virulent races prior to typical symptom expression.     

林芝地区小麦条锈菌与气象因子的关系及流行动态模型的构建

为了解西藏林芝地区气象因子对小麦条锈病的影响及其流行动态,2016年采用五点取样法对林芝地区小麦条锈病的发病情况进行监测,通过相关性分析、逐步回归C(p)统计法和线性回归等方法,分析了病情指数与气象因子的关系,并结合时间和病情指数建立了病害预测模型。结果表明,在林芝地区,温度X_1、湿度X_2均与小麦条锈病病情指数Y呈极显著相关,降雨量X_3与病情指数Y呈显著相关;线性回归方程为:Y=-482.5991+19.7494X1+3.7974X2-0.8439X3。根据模拟情况选择的病害流行动态方程为Y=1/e~((0.914t+0.385)),决定系数为0.952,模型的拟合效果较好,表明该模型能够为林芝地区小麦条锈病的预测预报提供有效的参考依据。