Yield Effects of Barley yellow dwarf virus in Soft Red Winter Wheat

ABSTRACT Three cultivars of soft red winter wheat were evaluated to determine the relationship between the incidence and time of infection by Barley yellow dwarf virus (BYDV) and yield. Wheat was planted in 1995, 1996, and 1997 in a split-plot design with six replicates at sites in Indiana and Illinois. Yield plots were infested with different amounts of viruliferous aphids, and the incidence of BYDV in each plot was measured. In a 2-year study in Illinois with cv. Clark and the PAV-IL isolate of BYDV, yields were assessed following aphid infestation in fall, early spring, and late spring. Early spring infections resulted in larger yield reductions than late spring infections in both years and larger than fall infections in one year. Regression analyses to relate incidence of infection and yield with data from fall and early spring infections provided R(2) values of 0.89 and 0.51 for the 1996 to 1997 and 1997 to 1998 seasons, respectively. An additional study at the same site in the 1996 to 1997 season compared the yield responses of cvs. Clark, Y88-3e, and PT8935b. Increases in the incidence of BYDV correlated with decreases in yield, with R(2) values of 0.80, 0.78, and 0.90 for the three cultivars, respectively. Estimated yield losses in both studies and all cultivars ranged from 27 to 45 kg/ha or 0.34 to 0.55% for each percent increase in virus infection. In a third study over a 2-year period in Indiana with the same three wheat genot ypes and a second BYDV isolate (PAV-P), BYDV treatments resulted in significant reductions in yield, but yield loss and the incidence of BYDV were not linearly correlated. Given the differences in yield reductions caused by the two BYDV isolates, PAV-P may be an attenuated strain of BYDV and may cross-protect plants from naturally occurring strains of the virus.     

A comparative study of the Barley yellow dwarf virus species PAV and PAS: distribution,accumulation and host resistance

This study investigated the distribution and characteristics of the Barley yellow dwarf virus (BYDV) species BYDV‐PAS, which was recently separated from BYDV‐PAV, the most commonly studied BYDV species. Throughout 3 years of experimental monitoring of BYDV incidence, PAS was the most frequently occurring species infecting cereals and grasses in the Czech Republic. Furthermore, Rhopalosiphum maidis and Metopolophium dirhodum were recorded as BYDV‐PAS vectors, even though M. dirhodum does not usually transmit BYDV‐PAV. In field experiments with barley and wheat, where virus accumulation, symptoms and effect on the yield were tested, BYDV‐PAV was more severe than PAS. Infection with the BYDV‐PAV isolate resulted in greater expression of symptoms and also in a greater reduction in plant height and grain weight per spike than BYDV‐PAS. In a sensitive cultivar of barley (Graciosa), the amount of viral RNA of BYDV‐PAV was also significantly higher than that of BYDV‐PAS. In a tolerant line (Wbon‐123), however, no such differences were found. In conclusion, although BYDV‐PAS seems to be dominant in the Czech Republic, BYDV‐PAV has the potential to cause more significant crop losses in barley and wheat.     

The incidence of strains of barley yellow dwarf virus in perennial ryegrass crops in south-west and central Scotland

The incidence of barley yellow dwarf virus (BYDV) in perennial ryegrass ( Lolium perenne ) crops in four areas of south-west and central Scotland was investigated between March 1988 and February 1989. BYDV was detected in 93·8% of the grass swards using an indirect enzyme-linked immunosorbent assay (ELISA). This enabled the seasonal periodicity of the BYDV strains to be monitored over 12 months for the first time in Scotland. The incidence of the RPV, PAV and MAV strains of BYDV declined between March and July 1988, before gradually rising in August. Incidence increased markedly in September, especially of the RPV and MAV strains, and then gradually decreased over the winter months, before stabilizing in February 1989. The incidence of the different strains in perennial ryegrass leys varied between geographical areas and between fields within areas. Most ryegrass samples contained a mixture of the three strains of BYDV. RPV was the most common strain in Ayrshire, while the incidence of PAV was highest in Wigtownshire and that of MAV was highest in Dumfriesshire and Stirlingshire. The incidence of BYDV increased with the age of the sward. The role of perennial ryegrass as a source of virus for the infection of cereals is discussed.     

兼抗麦长管蚜和大麦黄矮病毒的小麦种质田间鉴定筛选

为鉴定筛选兼抗麦长管蚜和大麦黄矮病毒(Barley yellow dwarf virus, BYDV)的小麦种质,采用自然感蚜/感病系数法,对36个外引和远缘杂交选育的小麦种质材料进行了2年的田间鉴定,并分析了感虫性与感病性的相关关系。结果表明,2年中均兼抗麦长管蚜和BYDV的种质仅有KOKIPPCAS、KOK、Amigo-3和PI137739共4个材料,占总鉴定材料的11.11%;对二者均敏感的有98-10-35q-9、186Tm39、Tam200e12-14a、Tam200(27)7、小偃22、西农1376和小偃6号共7个材料,占19.44%。其它材料仅抗虫或仅抗病,或仅在一年中表现抗病或抗虫,如材料98-10-30和98-10-35a8抗麦长管蚜,但对BYDV敏感;材料Tam200(13)G和PIG23(2)C感蚜,但对BYDV有抑制作用。BYDV发生普遍率(发病株率)和严重度(病情指数)与有蚜株率显著相关,严重度还与感蚜指数显著相关,但感病植株的病级均值与有蚜株率无显著相关性。表明自然界长期的进化和选择使许多抗病虫基因得以保存下来,但较多抗性基因只在抗病或抗虫的某一方面表现有效,需给予更多关注。     

晋南冬麦区大麦黄矮病毒流行株系监测及防治策略探讨

连续5年(1996～2000年)采集晋南冬麦区小麦黄矮病标样,采用生物学和血清学(酶联免疫吸附法)相结合的诊断方法对该地区的大麦黄矮病毒流行株系进行了鉴别。结果表明,该小麦黄矮病流行区近五年以GAV株系为主流株系,兼有少量GPV、PAV和混合株系存在。同时对小麦抗黄矮病新品种“临抗1号”进行了GPV和GAV两种株系的抗性测定,明确了该品种兼抗GPV和GAV两种株系。根据小麦黄矮病发生现状,提出了一套以选育推广抗耐病品种为主,以药剂防治为辅的综合防治措施。以期为当地小麦生产服务。     

蛋白质激发子Hrip1对小麦黄矮病的诱抗作用

小麦黄矮病是由大麦黄矮病毒（barley yellow dwarf virus,BYDV）引起的一种小麦病毒病,其传播介体是小麦蚜虫,在小麦生产中造成巨大的经济损失。近年来,植物诱导抗性作为一种新兴的植物病虫害防治措施引起了广泛的关注。蛋白质激发子Hrip1可以激活多种植物的免疫防御反应诱导植物产生广谱抗性。本研究评价了Hrip1对小麦黄矮病的诱抗效果。用30 μg/mL的Hrip1溶液进行小麦浸种和幼苗喷雾,随后接种BYDV,接种后第14 d,Hrip1对小麦黄矮病控制效果在50%以上,接种后第21 d控制效果仍在30%以上。实时荧光定量PCR检测结果显示,在Hrip1处理的小麦幼苗体内,BYDV外壳蛋白mRNA的数量显著低于对照组;EPG结果显示,在Hrip1处理的小麦幼苗上,麦二叉蚜寻找叶片刺吸位点和韧皮部取食位点的时间增加。以上结果表明：Hrip1能够有效地抑制BYDV在小麦体内的增殖;影响传毒媒介麦二叉蚜的取食行为,抑制其传毒能力。此外,Hrip1处理小麦能有效缓解BYDV引起的叶片黄化和植株矮化的症状。因此,Hrip1可以作为生物诱导剂综合控制小麦黄矮病。     

Occurrence of barley yellow dwarf virus in pastures of western France

As pasture grasses are preponderant in the agriculture of western France, their role as reservoirs of barley yellow dwarf virus (BYDV) and its aphid vectors has been studied from 1984 to 1986. Aphids were observed on most crops of five pasture grass species (brome grass, cocksfoot, tall fescue, Italian and perennial ryegrass) but in very low numbers. Rhopalosiphum padi was the most numerous species. The incidence of BYDV was high, with levels of infection ranging from 6 to 80% depending on the species of pasture grasses. Fescue pastures were highly infected with BYDV, whereas the virus was not detected in cocksfoot pastures. PAV-, RPV-, MAV-like isolates of BYDV were detected in pasture grasses, but RPV- and MAV-like isolates were only detected from ryegrass and brome grass, respectively. The role of these grasses as source of viruliferous aphids infecting cereals is discussed.     

Barley yellow dwarf virus in ryegrass and its detection by ELISA

The enzyme-linked immunosorbent assay (ELISA) effectively detected PAV- and MAV-like strains of barley yellow dwarf virus (BYDV) in ryegrass. MAV-like BYDV was found in a large proportion of ryegrass plants with foliar symptoms. There was a poor association between foliar symptoms and PAV-like virus, which occurred with similar frequency in plants with and without symptoms. By August 1982, plots of perennial, Italian and hybrid ryegrass sown at Auchincruive in 1980 were extensively infected with PAV- and MAV-like strains of BYDV. Tests on samples from 1981- and 1982-sown plots in August 1983 also indicated early invasion by BYDV. Infection levels of 7–80% were found in 13 commercial crops of perennial ryegrass surveyed near Auchincruive in May 1983. PAV-like BYDV occurred with greater frequency than did MAV-like strains of the virus.     

BYDV PREDICTOR: a simulation model to predict aphid arrival, epidemics of Barley yellow dwarf virus and yield losses in wheat crops in a Mediterranean-type environment

BYDV PREDICTOR, a simulation model, was developed to forecast aphid outbreaks and Barley yellow dwarf virus (BYDV) epidemics in wheat crops in the grainbelt region of southwest Australia, which has a Mediterranean-type climate. The model used daily rainfall and mean temperature to predict aphid ( Rhopalosiphum padi ) buildup in each locality before the commencement of the cereal-growing season in late autumn, and to forecast the timing of aphid immigration into crops. The introduction of BYDV by aphid immigrants, aphid buildup within the crop, spread of BYDV, and yield losses were predicted for different sowing dates. The model simulations were validated with 10 years' field data from five different sites in the grainbelt, representing a wide range of scenarios. When first aphid arrival dates ranging from 1 June to 2 September were compared with predictions, 65% of the variation between sites and years was explained. Progress curves for the predicted percentage of plants infected with the serotype BYDV-PAV closely resembled the starting point and shape of those recorded in 14 out of 18 scenarios. Sensitivity analysis confirmed that the combination of a high proportion of immigrants vectoring BYDV, early sowing of crops and early start to aphid arrival relative to sowing date led to the most BYDV spread and greatest yield loss. The model was incorporated into a decision support system used by farmers in targeting sprays against aphids to prevent virus spread in autumn and winter. BYDV PREDICTOR could serve as a template for modelling similar virus/aphid vector pathosystems in other regions of the world, especially those with Mediterranean-type climates.     

New experimental hosts of Barley yellow dwarf virus among wild grasses,with implications for grassland habitats

Barley yellow dwarf virus (BYDV), an economically important virus, infects small grain cereal crops and over 150 other Poaceae species. BYDV infection plays an important role in competition among grasses in non‐managed systems, but many grasses remain unexamined as potential BYDV hosts. This study examined grass species that have not been reported as BYDV hosts but are commonly encountered in non‐managed grasslands throughout the United States and Canada. Laboratory inoculations with BYDV‐PAV using the aphid vector Rhopalosiphum padi were performed to examine the ability of 13 grass species and barley to be infected with the virus; eight of the grass species were not documented previously as virus hosts. Serological and molecular assays were used to confirm BYDV‐PAV infection. Plant height, number of leaves, number of tillers and weight were recorded to evaluate susceptibility or sensitivity to BYDV. Infection with BYDV was experimentally achieved for the first time on Achnatherum lettermanii, Achnatherum occidentale, Achnatherum thurberianum, Danthonia intermedia, Poa fendleriana, Sporobolus airoides and Sporobolus cryptandrus, but not on Alopecurus pratensis and Elymus wawawaiensis. Infection was confirmed in Bromus inermis, Elymus elymoides, Poa bulbosa, Poa secunda and Hordeum vulgare, which served as controls. BYDV infection caused reductions in plant height on P. bulbosa and P. fendleriana. BYDV‐infected P. secunda had more leaves per plant compared to healthy plants of the same species. BYDV‐infected A. lettermanii exhibited reduced dry weight in both below‐ground and above‐ground tissue. These findings have implications for the management and conservation of grassland habitats.     

Effects of barley yellow dwarf and ryegrass mosaic viruses alone and in combination on the productivity of perennial and Italian ryegrasses

Moderately severe strains of barley yellow dwarf virus (BYDV) and ryegrass mosaic virus (RMV) significantly reduced the heights and yields of perennial ( Lolium perenne ) and Italian (L. multifiorum) ryegrasses. BYDV caused greater reductions in perennial ryegrass than in Italian, whereas the converse was true of RMV. Both viruses together rarely caused greater damage than the most damaging virus on its own. BYDV reduced the aggressiveness of perennial ryegrass more than of Italian, whereas with RMV the converse was true. In mixtures of perennial and Italian ryegrasses, the perennial was suppressed by the Italian when only BYDV was present, the Italian was suppressed by the perennial when only RMV was present, and the status quo was maintained when both viruses were present, even though they reduced the yield of the mixture by over 16%.     

抗黄矮病小麦新品系的分子标记检测研究

本研究对以小麦-中间偃麦草异附加系L1和小麦-中间偃麦草部分双二倍体‘无芒中4’为抗源选育出的抗黄矮病小麦新品系进行分子检测和抗病性鉴定.通过应用RAPD、SSR、SCAR 3种分子标记OPF15、Xgwm37、SC-W37进行分子检测,并采用人工接种和大田自然感病的方式进行抗黄矮病鉴定,筛选到了‘93646’、‘2003-2’等高抗黄矮病的小麦新品系.分子检测抗黄矮病基因与田间抗病鉴定结果基本一致,应用的3种PCR标记都可以检测出抗病材料,但SCAR标记SC-W37特异性强、稳定性好,可在小麦抗黄矮病育种早代选择过程中发挥重要作用.     

231份麦类种质资源对大麦黄矮病毒的田间抗性鉴定

为明确不同麦类种质资源对大麦黄矮病毒(Barley yellow dwarf viruses,BYDV)的抗性差异,于2015—2016年连续两年采用堆测法在田间人工接种鉴定了231份麦类种质资源的抗病性。结果表明,不同麦类种质资源对BYDV引起的黄矮病的抗性存在较大差异,2015—2016年,克群、加麻白芒麦、墨沙、绿见口和灰木头的平均病情指数分别为20.40、22.28、23.08、22.34和13.08,对黄矮病表现出较好的抗性;团结红壳麦-K、红矮子、定兴寨、旱地小麦、小红狼、榔头麦、峥白毛、金包银、红四楞、赤壳须麦及和穗板麦的平均病情指数分别为74.68、71.62、70.36、68.44、65.17、64.74、63.29、60.97、55.78、56.42和53.21,均大于50.00,表现为高感;其余种质资源的平均病情指数在25.00~50.00之间,表现为感病。此外,长芒芒、冰糖色小麦、苏麦、红皮麦、小红穗和青兰麦初期表现感病,后期可恢复健康,有一定的耐病性。抗病性不同的麦类种质资源感染BYDV后,对产量的影响差异很大,其中抗病资源绿见口的产量损失率最低,为8.87%,耐病资源长芒芒、冰糖色小麦、苏麦、红皮麦、小红穗和青兰麦的产量损失率依次为16.90%、17.40%、15.04%、13.13%、18.94%和11.57%,而感病资源和穗板麦的产量损失率达43.57%。     

The role of Poa annua in the epidemiology of barley yellow dwarf virus in autumn-sown cereals

Studies of cereal aphids and barley yellow dwarf virus (BYDV) from 1989 to 1992 revealed that Poa annua is an abundant weed of commercial winter barley crops during the summer months. P. annua was frequently infected with BYDV, and there were usually similarities with the BYDV infection of the surrounding barley crop. These P. annua weeds were often infested by cereal aphids both in July (pre-harvest) and in September (in cereal stubble fields). Poa -infested cereal stubbles may be major local sources of viruliferous aphids, increasing the risk of BYDV in nearby winter cereals. P. annua plays an important role in the epidemiology of S. avenae -transmitted BYDV.     

Barley yellow dwarf viruses in Japanese pasture grasses and lack of correlation with the presence of fungal endophytes

Pasture grasses from temperate Japan were tested for infection with barley yellow dwarf viruses (BYDVs) and fungal endophytes. BYDVs from both the MAV and RPV subgroups were detected, but no symptoms attributable to BYDV infection were observed. Not all isolates from the MAV subgroup could be clearly discriminated as MAV or PAV solely on ELISA results, and may have been intermediate serotypes or mixed infections. BYDVs were found to infect fescue ( Festuca arundinacea : 17%), ryegrass ( Lolium perenne : 41%), timothy ( Phleum pratense : 94%) and Poa spp. (20%). Fescue and ryegrass were predominantly infected with RPV and PAV, respectively. The small collections of Poa spp. were only infected with PAV, while timothy was only tested for MAV subgroup viruses. In fescue 26% of tillers were infected with Acremonium coenophialum , and 60% of ryegrass tillers from an ecotype collection were infected with Acremonium lolii. There was no correlation between BYDV infection and the presence of endophytes for the above species or for Epichloe typhina -infected (50%) timothy. An ELISA test for A. lolii did not detect A. coenophialum in fescue or E. typhina in timothy but showed good agreement with epidermal staining of A. lolii in ryegrass leaf sheaths.     

小麦品种抗耐黄矮病性鉴定初步研究

1983—1987年田间人工鉴定4211份主要小麦品种资源材料,对黄矮病的反应虽有不同程度差异,但无免疫品种。症状表现最为抗病并且较为稳定的是远缘杂交小麦品种中4、中5、多年生1号及普通小麦品种复壮30号。小麦品种抗耐黄矮病性与其症状表现不一定一致,需结合被害损失综合鉴定。     

Identification of barley yellow dwarf virus and cereal aphid Infestations In winter wheat by aerial photography

In 1976 distinctive patterns were identified on aerial photographs of winter wheat crops in East Anglia. The patterns consisted of numerous dark foci which were found to be associated with sooty moulds (mostly Cladosporium spp.) in the crops. Both green and mature crops were photographed in 1977 and the patterns were matched with crop inspection data. These suggested that barley yellow dwarf virus (BYDV) was the cause of the patterns and that sooty moulds secondarily invaded the infected plants. A different type of focal pattern appeared to be associated with damage caused by aphid feeding. All crops showing the pattern associated with BYDV were sown before 13 October but there was no relationship with sowing date for the crops damaged directly by aphids. Yield losses within foci were estimated by sampling and the total crop areas affected were calculated using an image analysis computer: yield losses were estimated to range from 10% (BYDV) to 2% (aphid feeding). The epidemiology of BYDV is discussed and reasons are suggested for the development and appearance of the foci.     

Occurrence of barley yellow dwarf virus in cereals and grasses of the low-rainfall wheatbelt of South Australia

South Australia is in the dry temperate zone where most cereal crops are grown in an area of low rainfall, with a crop-free season from December to April. The incidence of barley yellow dwarf virus (BYDV) was assessed by ELISA from 1989 to 1991 in wheat crops and irrigated pastures of South Australia. The incidence of BYDV was low in most wheat crops of the low-rainfall area in 1989 and 1990 (less than 1% of plants infected), but moderate levels of infection (1–10%) were observed in some early-sown crops. BYDV infection was more widespread in the high-rainfall area (south east of South Australia). A high incidence of BYDV was observed in the irrigated pastures of the three areas surveyed (4–86%). Of the five previously described strains, the Rhopalosiphum padi/Sitobion avenae strain (PAV) was the most common in wheat samples (> 90%). PAV and the R. padi-specific strain (RPV) were found in pasture grasses, alone or in mixed infection. Virus incidence was greater in Festuca spp. (56%) and Lolium perenne (30%) than in other species (2-–9%).     

The invasive weed Ventenata dubia is a host of Barley yellow dwarf virus with implications for an endangered grassland habitat

Ventenata dubia (African wiregrass), a winter annual weed, is a non‐native species invading grasslands, rangelands and pastures throughout the USA. Limited information is available on its suitability as a host to pathogens and insects in its invaded range. The barley/cereal yellow dwarf virus (B/CYDV) complex occurs ubiquitously in Poaceae species. In non‐managed grasslands, BYDV infection influences competitive dynamics between native and invasive grasses and facilitates invasion by non‐native annual weeds. The Palouse prairie of south‐eastern Washington and northern Idaho, USA, is an endangered ecosystem. Surveys of V. dubia in Palouse prairie and neighbouring Conservation Reserve Program (CRP) habitats were conducted to determine whether B/CYDV viral species are present. Laboratory tests examined the suitability of V. dubia to host BYDV‐PAV and serve as an inoculum source. Plant growth and weight parameters were measured to gauge the impact of BYDV‐PAV on V. dubia. Infection of V. dubia in Palouse prairie and CRP habitats with two species of BYDV, PAV and SGV, was detected for the first time. The ability of BYDV‐PAV to infect V. dubia in the laboratory and transmission from infected V. dubia to barley were demonstrated. BYDV‐PAV‐infected V. dubia showed reductions in plant height, number of leaves and tillers per plant, and above‐ground dry weight, suggesting that V. dubia is sensitive to BYDV. Results demonstrate that V. dubia is a host to BYDV and may serve as a virus inoculum source with potential implications for its management, competitive dynamics between invasive and native grasses and future conservation of endangered grasslands.     

A simple test for evaluation of transmission efficiency of barley yellow dwarf virus by aphids

Barley yellow dwarf virus (BYDV) transmission test systems involve the use of clip-cages or of whole plants in cages, which are both labor-intensive methods and require large controlled environment units. Employing detached leaves for assessment of the inoculation efficiency of aphids proved reliable for assessing transmission of a BYDV PAV-like isolate byRhopalosiphum padi. One use of the system could be for the rapid determination of the infectivity of field-collected aphids, an essential part of any epidemiological study of BYDV. http://www.phytoparasitica.org posting Aug. 14, 2002.