蚕豆和豌豆锈病病原菌的分子鉴定

为明确我国热带和亚热带地区蚕豆Vicia faba和豌豆Pisum sativum锈病的病原菌种类,通过致病性测定和ITS序列系统发育分析对来自我国云南省玉溪市的4份豌豆锈菌分离物及云南、广西、重庆和四川省(区、市)的5份蚕豆锈菌分离物进行系统鉴定。结果显示,分离自豌豆的锈菌WX1分离物对蚕豆和豌豆均具有高致病性,在侵染叶片上产生大量锈子器;分离自蚕豆的锈菌CX3分离物仅对蚕豆具有高致病性,能在叶片上产生大量夏孢子,而对豌豆的致病性相对较低,仅产生少量的夏孢子堆;分离物WX1和CX3对小扁豆和鹰嘴豆不具有致病性。基于ITS序列系统发育分析表明,所有不同寄主来源的蚕豆单胞锈菌分离物均聚类于一个系统发育组,但分离自蚕豆和豌豆的分离物分别聚类在不同的亚组。表明分离自云南省玉溪市豌豆上的蚕豆单胞锈菌Uromyces viciae-fabae应为豌豆专化型,定名为U. viciae-fabae ex P. sativaum,而来源于云南、广西、重庆和四川省(区、市)的蚕豆锈病病原菌为蚕豆专化型U. viciae-fabae ex V. faba。     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.     

Survey of faba bean (Vicia faba L.) for viruses in Morocco

A total of 52 faba-bean (Vicia faba L.) fields, located in the main growing areas in Morocco were surveyed for viruses. From 240 samples with symptoms suggestive of virus infection, the following viruses were detected using electron microscopy, serology, and biological indexing: Alfalfa mosaic virus (AMV), bean yellow mosaic virus (BYMV), broad bean mottle virus (BBMV), broad bean stain virus (BBSV), broad bean true mosaic virus (BBTMV), pea earlybrowning virus (PEBV), pea enation mosaic virus (PEMV), pea seed-borne mosaic virus (PSbMV), and a complex of luteoviruses including bean leafroll virus (BLRV). This is the first report of the occurrence of BBTMV, PEMV, PSbMV, and the luteoviruses (including BLRV) of faba bean in Morcco. The luteoviruses and BBMV were found to be the most prevalent. They were detected in 56 and 50%, respectively, of the surveyed fields; while AMV, BBSV, and PEBV were found in single fields only. The remaining viruses were less prevalent, and were detected in a range of 4 to 15% of the fields surveyed. The incidences per field of the prevalent viruses varied and ranged from 1 to 33% for BBMV and up to 20% in the case of luteoviruses. BBMV was found confined to the central and northern parts of the country, BBTMV and PEMV mainly occurred in the central area, while the luteoviruses and BYMV were spread over the faba-bean growing regions of the country.     

Broad bean mottle virus in Morocco; variability,interaction with food legume species,and seed transmission in faba bean,pea, and chickpea

Biological indexing of faba-bean samples collected during an earlier virus survey in Morocco revealed variation in symptom severity among isolates of broad bean mottle virus (BBMV). When seven selected isolates from Morocco and three from Algeria, Sudan, and Tunisia were further compared, they could be divided into mild, severe, and intermediate isolates, according to their pathogenicity on a number of food-legume genotypes tested. The Moroccan isolate SN1 and the Sudanese SuV256 were very mild, and deviant also in their effect onGomphrena globosa, whereas the Tunisian TV75-85 and the Moroccan VN5 were virulent. Representative isolates were indistinguishable, however, in coat-protein molecular weights, and they reacted similarly to the antisera to a Moroccan and a Syrian isolate in electro-blot immunoassay.Promising ICARDA breeding lines and accessions—ten each of pea and lentil, nine of chickpea, and twelve of faba bean-were all found vulnerable (susceptible and sensitive) to all isolates. Within each food-legume species, vulnerability varied from high to moderate, and no immunity was detected. Virus concentrations in faba-bean lines suggest that isolates differ in virulence rather than in aggressiveness, and that the differences in vulnerability among the lines are due to differences in sensitivity rather than in susceptibility.When pooled seed samples were germinated and seedlings were tested for BBMV in DASELISA, the virus was found seed-transmitted in faba bean, chickpea, and pea at transmission rates of ca 1.2, 0.9, and 0.1%, respectively. This is the first report on seed transmission of BBMV in faba bean, when occurring on its own, and the first record of such seed transmission in chickpea and pea.     

Broad bean mottle virus: Identification,host range,serology, and occurrence on faba bean (Vicia faba) in West Asia and North Africa

One of the faba bean viruses found in West Asia and North Africa was identified as broad bean mottle virus (BBMV) by host reactions, particle morphology and size, serology, and granular, often vesiculated cytoplasmic inclusions. Detailed research on four isolates, one each from Morocco, Tunisia, Sudan and Syria, provided new information on the virus.The isolates, though indistinguishable in ELISA or gel-diffusion tests, differed slightly in host range and symptoms. Twenty-one species (12 legumes and 9 non-legumes) out of 27 tested were systemically infected, and 14 of these by all four isolates. Infection in several species was symptomless, but major legumes such as chickpea, lentil and especially pea, suffered severely from infection. All 23 genotypes of faba bean, 2 of chickpea, 4 of lentil, 11 out of 21 ofPhaseolus bean, and 16 out of 17 of pea were systemically sensitive to the virus. Twelve plant species were found to be new potential hosts and cucumber a new local-lesion test plant of the virus.BBMV particles occurred in faba bean plants in very high concentrations and seed transmission in this species (1.37%) was confirmed.An isolate from Syria was purified and two antisera were produced, one of which was used in ELISA to detect BBMV in faba bean field samples. Two hundred and three out of the 789 samples with symptoms suggestive of virus infection collected in 1985, 1986 and 1987, were found infected with BBMV: 4 out of 70 (4/70) tested samples from Egypt, 0/44 from Lebanon, 1/15 from Morocco, 46/254 from Sudan, 72/269 from Syria and 80/137 from Tunisia. This is the first report on its occurrence in Egypt, Syria and Tunisia. The virus is a potential threat to crop improvement in the region.Samenvatting Eén van de in West-Azië en Noord-Afrika in faba-boon aangetroffen virussen werd geïdentificeerd als het tuinbonevlekkenvirus (broad bean mottle virus) op grond van waardplantreacties, deeltjesvorm en-grootte, serologische eigenschappen en granulaire, vaak gevacuoliseerde celinsluitsels. Verder onderzoek aan vier isolaten uit respectievelijk Marokko, Tunesië, Soedan en Syrië verschafte nieuwe informatie, over het virus.De in ELISA of gel-diffusietoetsen serologisch niet te onderscheiden isolaten verschilden enigszins in waardplantenreeks en symptomen. Van 27 getoetste plantesoorten werden 21 systemisch geïnfecteerd (12 vlinderbloemigen, en 9 niet-vlinderbloemigen) waarvan 14 door alle vier isolaten. In vele ervan was de infectie symptoomloos, maar belangrijke als gewas geteelde vlinderbloemigen, zoals erwt, linzen en kekererwt, leden ernstig onder aantasting. Alle 23 getoetste faba-boongenotypen, beide van kekererwt, alle vier van linzen, 11 van de 21 getoetste vanPhaseolus-boon en 16 van de 17 van erwt bleken systemisch gevoelig voor het virus. Twaalf plantesoorten, bleken nieuwe potentiële waardplanten en komkommer een nieuwe lokale-lesietoetsplant voor het virus te zijn.In faba-boneplanten kwam, het virus in hoge concentratie voor en overdracht met zaad (1.37%) in deze soort kon worden bevestigd.Een Syrisch isolaat werd gezuiverd en twee antisera werden bereid, waarvan één werd gebruikt voor de detectie van het virus in te velde verzamelde monsters. Van 789 in 1985 tot en met 1987 verzamelde bladmonsters, met symptomen die deden denken aan virusinfectie, bleken 203 het virus te bevatten en wel 4 van de 70 (4/70) uit Egypte, 0/44 uit Libanon, 1/15 uit Marokko, 46/254 uit Soedan, 72/269 uit Syrië en 80/137 uit Tunesië. Het virus was nog niet eerder aangetoond in Egypte, Syrië en Tunesië.De grote verbreiding, grote kunstmatige waardplantenreeks, overdracht met zaad, en pathogeniteit voor een aantal belangrijke vlinderbloemige gewassen maken het virus tot een potentiële bedreiging van de programma's tot verbetering van de teelt van de bedoelde gewassen in het betrokken gebied.     

Broad bean wilt virus: Host range,purification, serology,transmission characteristics,and occurrence in faba bean in West Asia and North Africa

A virus affecting faba bean in West Asia and Norht Africa was identified as broad bean wilt virus (BBWV) by host reactions, particle morphology and size, serology and transmission characteristics. An isolate from Syria (SV3-88) and one from Egypt (EV319-86) were found to be serologically identical and of serotype I. In host-range studies, the Syrian isolate infected systemically 59 out of 87 plant species tested. The virus was transmitted non-persistently by four aphid species naturally prevalent in Syria, but most efficiently byMyzus persicae. Inoculation of faba bean with SV3-88 14 weeks (pre-flowering) and 6 weeks after sowing (flowering) led to 25.8 and 1.8% yield loss and seed-transmission rates of 0.6 and 0.4%, respectively. The isolate SV3-88 was purified from systemically infected faba bean and yield 1.5–2 mg of partially purified virus per 100 g of leaves. When samples, with symptoms suggestive of virus infection, were collected during 1985–1989 from a number of countries in West Asia and North Africa and tested by ELISA, the virus was detected in 8 out of 127 samples tested (8/127) from Egypt, 0/44 from Lebanon, 1/23 from Morocco, 38/485 from the Sudan, 38/385 from Syria and 23/138 from Tunisia.Samenvatting Een virus uit veldboon of faba boon (Vicia faba) in West Azië en Noord-Afrika werd als tuinboneverwelkingsvirus (Fabavirus-groep) herkend aan zijn waardplantreacties, deeltjesvorm en grootte, serologie en wijze van overdracht. Een isolaat uit Syrië (SV3-88) en één uit Egypte (EV319-86) bleken serologisch identiek te zijn en te behoren tot serotype I van het virus. Met het Syrische isolaat kon in 59 van de 87 getoetste plantesoorten systemische infectie worden verkregen. Met vier veel in Syrië voorkomende bladluissorten kon het virus worden overgebracht, maar metMyzus persicae naar de meeste plantesoorten. Inoculatie van veldboon met SV3-88 vóór de bloei (14 weken na het zaaien) en tijdens de bloei (16 weken na het zaaien) gaf aanleiding tot respectivelijk 25,8 en 1,8% opbrengstreductie en tot 0,6 en 0,4% zaadoverdracht. Bij zuivering van isolaat SV3-88 uit systemisch geïnfecteerde fababoon was de opbrengst tot 1,5 à 2 mg gedeeltelijk gezuiverd virus per 100 g blad. Bij ELISA-toetsing in 1985–1989 van een groot aantal monsters afkomstig uit een aantal landen in West-Azië en Noord-Afrika werd het virus aangetoond in 8 van de 127 (8/127) monsters uit Egypte, 0/44 uit Libanon, 1/23 uit Marokko, 38/485 uit Soedan, 38/385 uit Syrië en 23/138 uit Tunesië.     

A mild strain of broad bean mottle virus from faba bean (Vicia faba L.) in the Sudan

A new strain of broad bean mottle virus, isolated from faba bean (Vicia faba L.) in the Sudan, is described. It differs considerably from known isolates by its nearly symptomless infection of faba bean in spite of high concentrations of the virus in infected plants. It does not differ from regular isolates in gel-diffusion serology, light and electron microscopy, host range and symptoms in major hosts other than faba bean. It may constitute a potential threat to other food legumes in the region.     

Life-table analysis of faba bean rust

In controlled near-optimum conditions (18 °C), monocyclic sporulation capacity and spore infection efficiency were assessed for faba bean rust on the first and second leaves of field bean. After a latency period of 8–10 days, lesions sporulated duringc. 50 days. Spore production on the second leaf,c. 9×10⁴ spores per lesion, was two times as high as spore production on the first leaf. Infection efficiency was similar for both leaf layers, with a mean value of 0.11 lesion per inoculated spore. Infection efficiency decreased strongly when spores originated from mother lesions older than 20 days. Three life-table statistics (the net reproduction numberR _o , the mean generation timeT _g , and the maximum relative growth rater _max ) were calculated.R _o was larger andT _g was longer for the second than for the first leaf, butr _max was nearly the same for both leaf layers (0.31–0.33 day^–1).r _max was compared with the exponential growth rater measured in a field experiment. From the difference between the two rates, the fraction of inoculum lost in field conditions was estimated at 0.54–0.94. The life-table statistics were also compared to those of other legume rusts, and implications of life-table analysis for comparative epidemiology were discussed.     

Analysis of genetic relations between <Emphasis Type="Italic">Broad bean wilt virus 1</Emphasis> and <Emphasis Type="Italic">Broad bean wilt virus 2</Emphasis>

We determined the complete nucleotide sequence of RNA-1 and the 5-terminal region of RNA-2 from Broad bean wilt virus 1 (BBWV-1) isolate PV132. This report is the first analysis of the genome organization of BBWV-1. We also determined the complete nucleotide sequence of RNA-1 from Broad bean wilt virus 2 (BBWV-2) isolate IP and analyzed the genetic relations between BBWV-1 and BBWV-2. Similar to the BBWV-2 isolates, both RNAs of PV132 encoded a single large polyprotein, which was predicted to contain some functional proteins in a manner similar to those of comovirus. With respect to the deduced amino acid sequences of the mature proteins, PV132 and IP had only 20%–40% homology to comovirus. On the other hand, IP was 73%–98% homologous to BBWV-2 isolates, but PV132 was 39%–67% homologous to the isolates. Although the extent of the homologies differed, the homologies were limited between BBWV-1 and BBWV-2 not only for the coat protein but also for the other proteins. These results clearly support the placement of BBWV-1 and BBWV-2 in the genus Fabavirus as distinct species, proposed on the basis of double immunodiffusion tests.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB084450 (RNA-1 of isolate PV132), AB084451 (RNA-2 of isolate PV132), and AB023484 (RNA-1 of isolate IP)     

Wheat/faba bean intercropping improves physiological and structural resistance of faba bean to fusaric acid stress

Fusarium oxysporum f. sp. fabae is the causal agent of fusarium wilt. Fusaric acid (FA), produced by F. oxysporum, plays an important role in the occurrence of disease, and intercropping is an effective measure for control of disease and for improving host resistance in plants. The objective of this study was to investigate the physiological and biochemical responses, and mechanisms of tissue structure resistance, of intercropped faba beans following exposure to different concentrations of FA. Results demonstrated that intercropping reduced the occurrence of fusarium wilt, and improved faba bean growth and yield. In addition, wheat intercropping significantly reduced red ink absorption of faba bean (33.2%), increased water content (3.1%), and increased activity of the root antioxidant enzymes peroxidase (POD) and catalase (CAT) (26.3% and 2.2.%, respectively). Furthermore, increased lignin content and callose deposition in plant vessels were observed (12.5% and 42.7%, respectively) when subjected to the highest concentration of FA stress (200 mg/L). Intercropping resulted in more intact root cell morphology, increased occurrence of intracellular vacuoles, increased cell wall thickness, and an increase in the number of mitochondria and rough endoplasmic reticulum. Intercropping alleviated the wilting effect of FA on faba bean via enhanced physiological, biochemical, and tissue structure resistance of faba bean root.     

First report of <Emphasis Type="Italic">Bean common mosaic virus</Emphasis> in yam bean [<Emphasis Type="Italic">Pachyrhizus erosus</Emphasis> (L.) Urban] in Indonesia

Severe mosaic with leaf malformation and green vein banding was observed on yam bean in West and Central Java, Indonesia. Virions of the causal virus were flexuous filaments, about 700 nm in length, with a coat protein of 30 kDa. The virus was transmitted by mechanical inoculation and by aphids in a nonpersistent manner. The nucleotide sequence of the coat protein gene had the highest identity with that of Bean common mosaic virus (BCMV, genus Potyvirus) isolate VN/BB2-5. Based on demarcation criteria, including the genome sequence and host range, we tentatively designate this isolate as BCMV-IYbn (Indonesian yam bean). The nucleotide sequence reported is available in the DDBJ/EMBL/GenBank databases under accession number AB289438.     

Broomrape control in faba bean (Vicia faba L.) with glyphosate and imazaquin

Field studies were carried out to evaluate the efficacy of imazaquin and glyphosate in controlling broomrape (Orobanche crenata Forsk. and O. aegyptiaca Pers.) in faba bean (Vicia faba L.) in Northern Syria. Several rates and times of application of the herbicides were tested. Nearly complete control of broomrape was achieved with both the herbicides when they were sprayed twice (when the broomrape attachments to the faba bean roots were at tubercle stage of develoment and 15 days later) at a rate of application of 80 g a.i. ha^?1 for glyphosate and 10 g a.i. ha^?1 for imazaquin. However, the yield of faba bean did not increase with these treatments, suggesting that the herbicides at these rates were still causing some physiological disorder in the plant that counteracted the beneficial effect of broomrape control on the performance of faba bean plants.     

Pea seed-borne mosaic virus: occurrence in faba bean (Vicia faba) and lentil (Lens culinaris) in West Asia and North Africa,and further information on host range,transmission characteristics,and purification

In a survey for viruses of cultivated legumes in West Asia and North Africa, pea seed-borne mosaic virus (PSbMV) was found in faba bean, lentil and pea. Using ELISA, it was detected in 107 out of 1554 faba bean samples and 40 out of 496 lentil samples with virus-like symptoms collected in Algeria, Egypt, Ethiopia, Jordan, Lebanon., Libya, Morocco, Sudan, Tunisia and Turkey.A pea isolate (SP9-88) from Syria was further characterized. Out of 57 plant species tested, 35 were found susceptible, 19 of which are newly reported hosts of the virus. The virus was transmitted efficiently in the non-persistent manner by five aphid species, especiallyMyzus persicae. Purification from systemically infected faba bean plants yielded 10–15 mg of purified virus per kg of infected tissue. Sap-inoculation of the food and forage legume species chickpea, faba bean, lentil, pea,Vicia narbonensis, V. sativa, Lathyrus ochrus andL. sativus at flowering stage led to 66.0, 40.5, 44.6, 49.2, 31.7, 7.5, 35.7 and 12.0% yield loss, respectively, and to seed-transmission, rates of 0.7, 6.0, 10.8, 1.1, 0.3, 0.2 and 0.4%, respectively. No transmission was detected in chickpea seed embryo axes. However, the virus was detected in the seed coat of SPbMV-infected chickpea at an estimated rate of 1.81%.     

Incidence of viruses in <Emphasis Type="Italic">Alstroemeria</Emphasis> plants cultivated in Japan and characterization of <Emphasis Type="Italic">Broad bean wilt virus-2, Cucumber mosaic virus</Emphasis> and <Emphasis Type="Italic">Youcai mosaic virus</Emphasis>

Alstroemeria plants were surveyed for viruses in Japan from 2002 to 2004. Seventy-two Alstroemeria plants were collected from Aichi, Nagano, and Hokkaido prefectures and 54.2% were infected with some species of virus. The predominant virus was Alstroemeria mosaic virus, followed by Tomato spotted wilt virus, Youcai mosaic virus (YoMV), Cucumber mosaic virus (CMV), Alstroemeria virus X and Broad bean wilt virus-2 (BBWV-2). On the basis of nucleotide sequence of the coat protein genes, all four CMV isolates belong to subgroup IA. CMV isolates induced mosaic and/or necrosis on Alstroemeria. YoMV and BBWV-2 were newly identified by traits such as host range, particle morphology, and nucleotide sequence as viruses infecting Alstroemeria. A BBWV-2 isolate also induced mosaic symptoms on Alstroemeria seedlings.     

Diversity and occurrence of chickpea chlorotic dwarf virus on legumes from Iran

Chickpea chlorotic dwarf virus (CpCDV; genus Mastrevirus, family Geminiviridae) is one of the most important legume-infecting viruses with a wide host range and geographic distribution in Africa and Asia. In Iran, CpCDV is common in chickpea (Cicer arietinum), but there is limited information about diversity and infections in plants of other legume species. In the current study, a total of 1671 leaf samples from different pulse crops with symptoms were collected in nine provinces of Iran, and the CpCDV infection status was tested by PCR and/or rolling circle amplification (RCA), resulting in the detection of CpCDV in samples of chickpea, lentil (Lens culinaris) and faba bean (Vicia faba) from different regions. Sequence analysis of complete genomes of 18 isolates recovered by digestion of RCA products revealed infection with isolates of the strains CpCDV-A and CpCDV-F in chickpea, lentil and faba bean. Phylogenetic analysis showed that the Iranian isolates of CpCDV were closely related to previously sequenced isolates of CpCDV-A and CpCDV-F. To the authors' knowledge, this is the first report of CpCDV-F in Iran. Using agroinoculation with infectious clones for one isolate each of CpCDV-A and CpCDV-F, infectivity was confirmed in both faba bean and chickpea, with plants developing leaf curling and/or yellowing. Both infectious clones also successfully infected Nicotiana benthamiana resulting in mild yellowing and intensive leaf curling for CpCDV-A, and dark-green mosaic, dwarfing and mild leaf curling for CpCDV-F.     

Tobacco streak virus in sunflower (Helianthus annuus)

Tobacco streak virus (TSV) was isolated from a plant of sunflower (Helianthus annuus) showing severe necrosis and chlorosis in the leaves. The virus was identified as TSV by serology and, to some extent, by host range. The type of symptoms varied with the host plant in which the virus had been propagated in successive transfers. Test plants inoculated with the virus propagated inNicotiana rustica produced symptoms which very much differed from those brought about by the virus from eitherN. clevelandii orChenopodium amaranticolor.The significance of the host-mediated variation in symptoms is discussed.Samenvatting Tabaksstrepenvirus (TSV) werd geïsoleerd uit zonnebloem (Helianthus annuus) die sterke necrose en chlorose van de bladeren vertoonde. De identiteit van het virus werd vastgesteld op grond van serologische reacties en, tot op zekere hoogte, de symptomatologie. Het type symptoom op de toetsplanten bleek echter sterk afhankelijk te zijn van de plant waarvan het inoculum afkomstig was. Was het virus verschillende malen achtereen vermeerderd inNicotiana rustica dan waren de symptomen op de toetsplanten zeer verschillend van die, welke werden veroorzaakt door virus vermeerderd inN. clevelandii ofChenopodium amaranticolor. De betekenis van deze door de waardplant bewerkstelligde variatie in symptomen wordt besproken.     

Granular formulation of Fusarium oxysporum for biological control of faba bean and tomato Orobanche

BACKGROUND: Orobanche spp. represent a serious threat to a wide range of crops. They are difficult targets for herbicides, and biological control could provide a possible solution. This work therefore aimed to formulate mycoherbicides of Fusarium with adequate shelf life and virulence against Orobanche but safe to faba bean and tomato. RESULTS: Only two isolates of Fusarium oxysporum Schlecht. (Foxy I and Foxy II) obtained from diseased Orobanche shoots were found to be pathogenic to Orobanche crenata Forsk. and Orobanche ramosa L. Conidial suspension of both isolates significantly decreased germination, attachments and tubercles of Orobanche. Microconidia and chlamydospores of both isolates were formulated as mycoherbicides encapsulated in a wheat flour–kaolin matrix (four different formulations). All formulations greatly diminished Orobanche emerged shoots, total shoot number, shoot height, attachment of emerged shoots, the germinated seeds that succeeded in emerging above the soil surface and dry weight. Meanwhile, disease incidence and disease severity of emerged shoots were enhanced. The shelf life was adequate, particularly for coarse, freshly prepared, low‐temperature‐stored, microconidia‐rich formulations. The induced growth reduction of Orobanche‐infected host plants seemed to be nullified by formulations, particularly at the highest dose. CONCLUSION: These formulations seemed to destroy Orobanche but appeared harmless to host plants. Hence, they could be efficiently used as mycoherbicides for biological control of Orobanche in faba bean and tomato. Copyright © 2008 Society of Chemical Industry     

Identification and pathogenicity of Pythium species causing damping-off of kidney bean

Five Pythium species (Pythium irregulare, P. mamillatum, P. myriotylum, P. spinosum and P. ultimum var. ultimum) were isolated from the hypocotyls and roots of kidney bean plants with damping-off from a commercial field and from experimental plots that have undergone either continuous cropping with kidney bean or rotational cropping with arable crops. In inoculation tests, all five Pythium species were pathogenic to kidney bean. This is the first report of damping-off of kidney bean caused by Pythium species; we named this disease damping-off of kidney bean. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB291811, AB291944 and AB291945.     

Effect of competition between Vicia faba and Camelina sativa as a model weed in breeding for organic conditions

Weeds can have a detrimental effect on faba bean (Vicia faba) crops in organic farming. Breeding for competitive cultivars is one option for weed control in organic conditions. The aim of this study was to analyse the impact of heterozygosity and heterogeneity levels and plant height on the competitive ability of faba bean genotypes. A set of 24 genotypes, classified as genotype groups (eight inbred lines, eight polycross progenies, two inbred line bulks, two hybrid bulks and four controls), was tested under two treatments: with and without a model weed. Each group of genotypes was equally composed of tall and short genotypes. The competitive ability of the faba bean genotypes was tested with Camelina sativa (false flax) as the model weed in two German locations over the course of 2 years. Yield loss due to weed competition, as recorded per faba bean genotype, was mainly dependent on the heterozygosity level of the genotypes; hybrid bulks were the most competitive genotype group with an average loss of yield of only 6%, whereas the inbred lines were the least competitive genotype group and recorded an average yield loss of 35%. Within the genotype group, no correlations were found between either the yield performance of the genotypes or their plant height and their competitive responses. The competitive ability of faba bean against weeds was mainly determined by their level of heterozygosity; thus, highly heterozygous cultivars should be promoted for breeding.     

Australian Uromyces viciae-fabae: Host and nonhost interaction among cultivated grain legumes

Uromyces viciae-fabae, rust of faba bean, parasitizes other legume crops such as lentils (Lens culinaris) and field peas (Pisum sativum) in some environments. In this study we examined the host range of two Australian isolates of U. viciae-fabae collected and purified from a faba bean crop and classified as U. viciae-fabae ex V. faba. Field pea (P. sativum), chickpea (Cicer arientinum), lupin (Lupinus spp.), lentil (L. culinaris), and mung bean (Vigna radiata) genotypes were tested with these isolates, as well as resistant and susceptible genotypes of the faba bean host. Race specificity for these two pathogen isolates was observed on Vicia faba, with two faba bean genotypes showing partial resistance. Both U. viciae-fabae isolates also colonized field pea seedlings and successfully produced uredinia under glasshouse conditions, despite this fungus not being known as a pathogen of Australian field pea crops. No sporulation of either isolate of U. viciae-fabae ex V. faba was observed on any of the remaining legume species tested. However, obvious differences in fungal growth were observed, ranging from small infection sites with very rare haustorium formation in mung bean to more extensive growth and the development of potential uredinial structures in chickpea. These observations are discussed in relation to the phylogenetic relationship of these host and nonhost species.