Genetic and pathogenic diversity within Ascochyta rabiei(Pass.) Lab. populations in Pakistan causing blight of chickpea (Cicer arietinum L.)     

F. F. Jamil  N. Sarwar  M. Sarwar  J. A. Khan  J. Geistlinger  G. Kahl 《Physiological and Molecular Plant Pathology》2000,57(6):243

Pathogenic and genetic diversity in Ascochyta rabiei populations in Pakistan were evaluated. Biological pathotyping of 130 A. rabiei isolates (obtained from hierarchically collected samples) was conducted on a set of three chickpea differentials, i.e. ILC 1929 (susceptible), ILC 482 (tolerant) and ILC 3279 (resistant), under controlled conditions. Disease severity data were recorded 12 days after inoculation. Statistical analysis grouped the isolates into three pathotype classes. Four isolates belonged to pathotype I (least aggressive), 79 isolates to pathotype II (medium aggressive) and 47 isolates to pathotype-III (highly aggressive).Genetic analysis was performed using RAPDs and oligonucleotide fingerprinting, where Hinf I-digested DNA was hybridized to the³²P-endlabeled oligonucleotide probes (CAA)₅, (GAA)₅, (GA)₈, (CA)₈and (GATA)₄. Dendrograms produced by cluster analysis discriminated 46 genotypes in the A. rabiei population of Pakistan. Genetic distances and relatedness between isolates were calculated. At a genetic distance of 0.3, genotypes were divided into six distinct genotype groups A, B, C, D, E and F containing 16, 11, 2, 5, 5 and 7 isolates, respectively. Most of the genotypes were area specific or predominated in certain areas but did not belong to a distinct pathotype, while most of the aggressive isolates (pathotype III) occurred in Northern Punjab and in the North Western Frontier Province.  相似文献   

The severity of diseases of faba bean depending on sowing rate and variety     

Margit Olle  Pille Sooväli 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2020,70(7):572-577

ABSTRACT

Little research has been published about the occurrence of diseases in faba bean such as chocolate spot, ascochyta blight, or rust in Northern Europe. There is also little data about the impact of sowing rate or variety on disease development. Therefore, the purpose of this study was to assess the impact of variety and seeding rate on disease severity at Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie (BBCH) 75 (which is when 50% of pods have reached full length). Five varieties were tested from multiple Northern European countries: Bauska (Latvia), Jõgeva (Estonia), Gloria (Sweden), Julia (Sweden) and Lielplatones (Latvia). Two sowing rates were used: 30 seeds m^-2 (100%) and 36 seeds m^-2 (120%). The sowing rate did not influence disease severity. The varieties which were most damaged by chocolate spot were Gloria and Jõgeva and the varieties least damaged were Julia and Lielplatones. Variety did not influence the severity of ascochyta blight. The variety most damaged by rust was Gloria and the variety least damaged was Julia. The varieties most susceptible to disease Gloria and Jõgeva while Julia was least susceptible. Thus, Julia can be recommended for faba bean production in Northern Europe.  相似文献   

Methods for screening resistance in chickpea to Ascochyta blight     

R. Pieters  A. Tahiri 《Euphytica》1986,35(3):1007-1010

Summary In Morocco, Ascochyta blight is a major limiting factor in chickpea production. The best long term solution to the problem seems to be the production of chickpea lines with durable resistance to the disease. Because of the nature of durable resistance, screening methods assessing resistance quantitatively had to be developed. Four methods are described: a seedling test, a germination test, a score of the percentage infected pods and a hair density score. With these screening methods a quantitative assessment of resistance in chickpea to blight appeared possible.Mr Pieters is with the FAO Plant Protection and Production division. Mr Tahiri is with the Service de Contrôle des Semences et Plants in Morocco.  相似文献   

Diallel analyses reveal the genetic control of resistance to ascochyta blight in diverse chickpea and wild Cicer species     

N. Danehloueipour  G. Yan  H. J. Clarke  K. H. M. Siddique 《Euphytica》2007,154(1-2):195-205

Ascochyta blight is a major fungal disease affecting chickpea production worldwide. The genetics of ascochyta blight resistance was studied in five 5 × 5 half-diallel cross sets involving seven genotypes of chickpea (ICC 3996, Almaz, Lasseter, Kaniva, 24B-Isoline, IG 9337 and Kimberley Large), three accessions of Cicer reticulatum (ILWC 118, ILWC 139 and ILWC 184) and one accession of C. echinospermum (ILWC 181) under field conditions. Both F₁ and F₂ generations were used in the diallel analysis. The disease was rated in the field using a 1–9 scale. Almaz, ICC 3996 and ILWC 118 were the most resistant (rated 3–4) and all other genotypes were susceptible (rated 6–9) to ascochyta blight. Estimates of genetic parameters, following Hayman’s method, showed significant additive and dominant gene actions. The analysis also revealed the involvement of both major and minor genes. Susceptibility was dominant over resistance to ascochyta blight. The recessive alleles were concentrated in the two resistant chickpea parents ICC 3996 and Almaz, and one C. reticulatum genotype ILWC 118. The wild Cicer accessions may have different major or minor resistant genes compared to the cultivated chickpea. High narrow-sense heritability (ranging from 82% to 86% for F₁ generations, and 43% to 63% for F₂ generations) indicates that additive gene effects were more important than non-additive gene effects in the inheritance of the trait and greater genetic gain can be achieved in the breeding of resistant chickpea cultivars by using carefully selected parental genotypes.  相似文献   

Presowing Hardening of the Host with Phenolic Acids Reduces Induction of Seed Germination in the Root Parasite Striga asiatica     

Bharathalakshmi  Jayachandra 《国际虫害防治杂志》2013,59(3):309-312

Abstract

Striga asiatica (L.) Kuntze, a root parasite, causes severe loss of yield in sorghum and several other crops. The seeds of the parasite are induced to germinate by a stimulant in the host root exudate. Presowing hardening of the host with vanillic acid, caffeic acid and ferulic acid (25 ppm) reduces the induction of seed germination in the parasite by the host root exudate. The treatment causes a slight improvement in the dry matter production in the host and in addition, increases the phenolics level in the host root exudate. The latter effect might be responsible for reducing germination in Striga. If the treatment remains effective under field conditions also, it reduces significantly the incidence of Striga in cultivated fields.  相似文献   

Distribution of Mating Types and Diversity in Virulence of <Emphasis Type="Italic">Didymella rabiei</Emphasis> in Israel     

J.?Lichtenzveig  E.?Gamliel  O.?Frenkel  S.?Michaelido  S.?Abbo  A.?Sherman  D.?ShtienbergEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(1):15-24

The distribution of mating types and diversity in virulence of Didymella rabiei populations were studied in Israel from 1997 to 1999. Forty-one monoconidial D. rabiei isolates from 18 commercial fields distributed among all the chickpea production areas of the country were paired with MAT1-1 and MAT1-2 mating type tester isolates of D. rabiei. Both mating types were found in all chickpea production areas of the country. Of the 18 fields sampled, MAT1-1 was observed in 44%, and MAT1-2 in 88% of the sites. In some sites both mating types were present in close proximity, suggesting that sexual reproduction of the pathogen was feasible. The contribution of sexual reproduction of the fungus to virulence diversity was tested on detached leaves of six differential chickpea cultivars. Nine isolates were derived from different well separated foci (derived from ascospores as inoculum) and eight isolates were derived from a single, well defined infection focus (derived from sister conidia). In the analyses of variance the cultivar × isolate interaction showed no significant (P of F>0.09) effect on disease incidence; the chickpea cultivars differed significantly (P of F<0.0001) in their response to D. rabiei; and the isolate effect was highly significant (P of F = 0.0007) for the conidial population, but not significant (P of F>0.1) among isolates of the ascosporic population. Nevertheless, when comparing a cultivar at a time, the ascosporic and conidial populations did not differ significantly (P of F>0.1) in their virulence diversity. Virulence of 41 isolates collected from the different chickpea fields was tested on detached leaves of four Israeli cultivars that differ in their field response to D. rabiei. The cultivar × isolate interaction showed no significant effect (P of F = 0.95) on disease incidence. The main effects of cultivar and isolate on disease incidence were highly significant (P of F<0.0001). Accordingly, our data do not support the hypothesis that there is pathogenic specialization in the D. rabiei–C. arietinum pathosystem in Israel.  相似文献   

Determination of agronomic practices for the management of blight of chickpea caused by <Emphasis Type="Italic">Ascochyta rabiei</Emphasis> in Turkey: 1. Appropriate sowing date     

F. Dusunceli  K. Meyveci  L. Cetin  M. Avci  D. Surek  S. Albustan  Z. Mert  K. Akan  M. Karacam  R. N. Strange 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(4):449-456

In order to determine the most appropriate dates for planting chickpea in central Anatolia, Turkey, six cultivars were planted at three sites that differed in disease pressure. In two of the sites, disease pressure from Ascochyta rabiei was promoted by spreading infected chickpea debris on the soil surface at the time of planting and, at one of these, sprinkle irrigation was applied. In the third site, where conditions were dryer, no artificial inoculum was provided. Plants from seeds sown in early March had the most disease and in the sprinkle irrigated plots the disease severity ranged from 7.8 on the most susceptible cv. Canitez to 3.3 on the least susceptible Gokce as scored on the 1–9 scale where 1 = no disease and 9 represents a plant killed by the fungus. There was an inverse relationship between disease severity and yield, production from blight resistant cultivars of around 2,000 kg ha⁻¹ being more than twice that of susceptible ones. Delaying planting for 3–5 weeks reduced the severity of ascochyta blight but also reduced the yields in four of the six cultivars. In contrast, reduction in disease severity by delayed sowing resulted in yield increases for the susceptible cvs Canitez and Local, although yield level was not as much as those of the less susceptible cvs sown early. Delay of 6–9 weeks almost eliminated ascochyta blight but yields of all cultivars were seriously compromised by drought stress. In consequence, chickpea farmers are recommended to use resistant or tolerant cultivars and sow early in March. For less resistant cultivars, sowing in early April is recommended. Further delay is not recommended unless irrigation is provided and fungicide spraying is recommended where signs of infection are present under conditions conducive to the disease.  相似文献   

Development of ascochyta blight (Ascochyta rabiei) in chickpea as affected by host resistance and plant age     

A. K. Basandrai  D. Basandrai  S. Pande  M. Sharma  Sanjay K. Thakur  H. L. Thakur 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):77-86

Ascochyta blight caused by Ascochyta rabiei, is the most destructive disease in many chickpea growing countries. Disease development varies with the growth stage and host resistance. Hence, disease development was studied in cvs ICCX 810800 (resistant), ICCV 90201 (moderately resistant), C 235 (moderately susceptible), ICCV 96029 and Pb 7 (susceptible) under controlled environment (ICRISAT, Patencheru) and field conditions (Dhaulakuan, Himachal Pradesh) at seedling, post-seedling, vegetative, flowering and podding stages. Under controlled environment, the incubation period and terminal disease reaction (TDR) did not vary significantly at different growth stages against virulent isolate AB 4. Cultivars ICCX 810800, ICCV 90201 and C 235 showed a significantly longer incubation period than the susceptible cv. Pb 7. Cultivar ICCX 810800 showed slow disease progress and the least TDR. Field experiments were conducted during the 2003–2004 and 2004–2005 growing seasons. During 2003–2004, TDR was higher in plants inoculated at podding and the flowering stage and the lowest disease reaction was recorded in ICCX 810800. A severe epidemic during 2004–2005 was attributed to the favourable temperature, humidity and well distributed high rainfall. TDR did not differ significantly at any of the growth stages in susceptible cvs ICCV 96029 and Pb 7. With respect to seeding date and cultivar, the highest yield was recorded in the early-sown crop (1,276.7 kg ha⁻¹) and in ICCV 90201 (1,799.3 kg ha⁻¹), respectively. The yields were greatly reduced in all the cultivars during 2004–2005 and the highest yield was recorded in ICCX 810800 (524.7 kg ha⁻¹). Integrated disease management using resistant cultivars, optimum sowing period and foliar application of fungicides will improve chickpea production. The experiment under controlled environment and field conditions (during the epidemic year) showed a similar disease development.  相似文献   

The role of seedling infection in epiphytotics of ascochyta blight on chickpea     

R. B. E. Kimber  D. Shtienberg  M. D. Ramsey  E. S. Scott 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(2):141-152

Didymella rabiei, the causal agent of ascochyta blight, survives on infected seeds and seedlings. Diseased seedlings originating from infected seeds occasionally serve as the source for primary infection in chickpea crops. Experiments carried out independently in Australia and in Israel provided quantitative information on the temporal and spatial distribution of ascochyta blight from initial infections and on the relationship between the amount of initial infection and the intensity of subsequent epiphytotics for cultivars differing in susceptibility to the pathogen. Disease spread over short distances (<10 m) from individual primary infections, was governed by rain and wind, and was up to five times greater down-wind than up-wind. Cultivar response to D. rabiei significantly affected the distance and area over which disease spread and the intensity of the disease on infected plants. At onset of the epiphytotic, the relationship between disease spread and time was exponential (P < 0.05; R ² > 0.95) and the area of the resulting foci was over 10 times greater in susceptible cultivars than in resistant cultivars. Regression equations showed the relationship between disease severity and the distance from the focus-plants was inverse-linear for all cultivars tested (P < 0.05). A simulation model based on the experimental data revealed that even if primary infection is infrequent (less than 1% of plants), the consequences are potentially devastating when susceptible cultivars are used. The epidemiological information and simulation model generated by this study provide an increased understanding of the development of an epiphytotic in which the primary foci of disease originate from infected chickpea seedlings.  相似文献   

Mating type, pathotype and RAPDs analysis inDidymella rabiei, the agent of ascochyta blight of chickpea     

J. A. Navas-Cortés  E. Pérez-Artés  R. M. Jiménez-Diaz  A. Llobell  B. W. Bainbridge  J. B. Heale 《Phytoparasitica》1998,26(3):199-212

Eleven pathotype groups (A-K), including five not previously reported, ofDidymella rabiei (anamorphAscochyta rabiei), representing isolates of the pathogen from Ascochyta blight-affected chickpeas mainly from India, Pakistan, Spain and the USA, were characterized using 44 single-spore isolates tested against seven differential chickpea lines. Of 48 isolates tested for mating type, 58% belonged to MAT 1-1 and 42% to MAT 1-2. Thirty-nineD. rabiei isolates, as well as two isolates ofAscochyta pisi and six isolates of unrelated fungi, were analyzed using Randomly Amplified Polymorphic DNAs (RAPDs) employing five primers (P2 at 40°C, and OPA3, OPC1, OPC11 and OPC20 at 35°C). Computer cluster analysis (UPGMA / NTSYS-PC) detected a relatively low level of polymorphism among all theD. rabiei isolates, although atca 7% dissimilarity,ca 10 RAPD groups [I-X] were demarcated, as well as subclustering within the larger groups. By the same criteria, the maximum dissimilarity for the whole population ofD. rabiei isolates wasca 13%. No correlation was found between different RAPD groups, pathotype, or mating type ofD. rabiei, although some evidence of clustering based on geographic origin was detected. The use of RAPDs enabled us to identify specific DNA fragments that may have a potential use as genetic markers in sexual crosses, but none which could be used as virulence markers.  相似文献