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J.f. Angus - One of the best experts on this subject based on the ideXlab platform.
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Arbuscular mycorrhizae in wheat and field Pea Crops on a low P soil: increased Zn-uptake but no increase in P-uptake or yield
Plant and Soil, 2003Co-Authors: M.h. Ryan, J.f. AngusAbstract:Few field studies have investigated the contribution of arbuscular mycorrhizal fungi (AMF) to agricultural systems. In this study, the role of AMF in nutrition and yield of dryland autumn-sown wheat and field Pea was examined through a 2-year crop sequence experiment on a red loam (Kandosol) in SE Australia. The soil was P-deficient and had low levels of root pathogens. In Year 1, levels of AMF were increased by growing subterranean clover or Linola^TM and decreased by growing canola or through maintenance of bare fallow with herbicides or tillage. In Year 2, hosts of AMF (wheat and field Pea) and non-mycorrhizal canola were grown with 0 P or 20 kg ha^−1 of P as superphosphate. Yields of all Year 2 Crops were increased by P-fertiliser. Year 1 treatment led to 2–3 fold variation in colonisation by AMF at each P-level for Year 2 wheat and field Pea. High colonisation did not correspond with greater crop growth, yield, or uptake of P, K, Ca, Cu or S in wheat or field Pea. However, total crop Zn-uptake and grain Zn concentration were positively correlated with colonisation by AMF, due to enhanced Zn-uptake after anthesis. For wheat, high colonisation also corresponded with reduced Mn-uptake and lower grain Mn concentrations. In a glasshouse experiment using a second P-deficient Kandosol, inoculation of wheat with Glomus intraradices and Scutellospora calospora enhanced uptake of Zn and P when no P-fertiliser was applied. We conclude that high colonisation by AMF is unimportant for productivity of the major field Crops grown on the Kandosol soils that occupy large areas of cropland in temperate SE Australia, even under P-limiting conditions. Investigation of the factors that control functioning of arbuscular mycorrhizae under field conditions, especially temperature, is required.
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arbuscular mycorrhizae in wheat and field Pea Crops on a low p soil increased zn uptake but no increase in p uptake or yield
Plant and Soil, 2003Co-Authors: M.h. Ryan, J.f. AngusAbstract:Few field studies have investigated the contribution of arbuscular mycorrhizal fungi (AMF) to agricultural systems. In this study, the role of AMF in nutrition and yield of dryland autumn-sown wheat and field Pea was examined through a 2-year crop sequence experiment on a red loam (Kandosol) in SE Australia. The soil was P-deficient and had low levels of root pathogens. In Year 1, levels of AMF were increased by growing subterranean clover or LinolaTM and decreased by growing canola or through maintenance of bare fallow with herbicides or tillage. In Year 2, hosts of AMF (wheat and field Pea) and non-mycorrhizal canola were grown with 0 P or 20 kg ha−1 of P as superphosphate. Yields of all Year 2 Crops were increased by P-fertiliser. Year 1 treatment led to 2–3 fold variation in colonisation by AMF at each P-level for Year 2 wheat and field Pea. High colonisation did not correspond with greater crop growth, yield, or uptake of P, K, Ca, Cu or S in wheat or field Pea. However, total crop Zn-uptake and grain Zn concentration were positively correlated with colonisation by AMF, due to enhanced Zn-uptake after anthesis. For wheat, high colonisation also corresponded with reduced Mn-uptake and lower grain Mn concentrations. In a glasshouse experiment using a second P-deficient Kandosol, inoculation of wheat with Glomus intraradices and Scutellospora calospora enhanced uptake of Zn and P when no P-fertiliser was applied. We conclude that high colonisation by AMF is unimportant for productivity of the major field Crops grown on the Kandosol soils that occupy large areas of cropland in temperate SE Australia, even under P-limiting conditions. Investigation of the factors that control functioning of arbuscular mycorrhizae under field conditions, especially temperature, is required.
M.h. Ryan - One of the best experts on this subject based on the ideXlab platform.
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Arbuscular mycorrhizae in wheat and field Pea Crops on a low P soil: increased Zn-uptake but no increase in P-uptake or yield
Plant and Soil, 2003Co-Authors: M.h. Ryan, J.f. AngusAbstract:Few field studies have investigated the contribution of arbuscular mycorrhizal fungi (AMF) to agricultural systems. In this study, the role of AMF in nutrition and yield of dryland autumn-sown wheat and field Pea was examined through a 2-year crop sequence experiment on a red loam (Kandosol) in SE Australia. The soil was P-deficient and had low levels of root pathogens. In Year 1, levels of AMF were increased by growing subterranean clover or Linola^TM and decreased by growing canola or through maintenance of bare fallow with herbicides or tillage. In Year 2, hosts of AMF (wheat and field Pea) and non-mycorrhizal canola were grown with 0 P or 20 kg ha^−1 of P as superphosphate. Yields of all Year 2 Crops were increased by P-fertiliser. Year 1 treatment led to 2–3 fold variation in colonisation by AMF at each P-level for Year 2 wheat and field Pea. High colonisation did not correspond with greater crop growth, yield, or uptake of P, K, Ca, Cu or S in wheat or field Pea. However, total crop Zn-uptake and grain Zn concentration were positively correlated with colonisation by AMF, due to enhanced Zn-uptake after anthesis. For wheat, high colonisation also corresponded with reduced Mn-uptake and lower grain Mn concentrations. In a glasshouse experiment using a second P-deficient Kandosol, inoculation of wheat with Glomus intraradices and Scutellospora calospora enhanced uptake of Zn and P when no P-fertiliser was applied. We conclude that high colonisation by AMF is unimportant for productivity of the major field Crops grown on the Kandosol soils that occupy large areas of cropland in temperate SE Australia, even under P-limiting conditions. Investigation of the factors that control functioning of arbuscular mycorrhizae under field conditions, especially temperature, is required.
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arbuscular mycorrhizae in wheat and field Pea Crops on a low p soil increased zn uptake but no increase in p uptake or yield
Plant and Soil, 2003Co-Authors: M.h. Ryan, J.f. AngusAbstract:Few field studies have investigated the contribution of arbuscular mycorrhizal fungi (AMF) to agricultural systems. In this study, the role of AMF in nutrition and yield of dryland autumn-sown wheat and field Pea was examined through a 2-year crop sequence experiment on a red loam (Kandosol) in SE Australia. The soil was P-deficient and had low levels of root pathogens. In Year 1, levels of AMF were increased by growing subterranean clover or LinolaTM and decreased by growing canola or through maintenance of bare fallow with herbicides or tillage. In Year 2, hosts of AMF (wheat and field Pea) and non-mycorrhizal canola were grown with 0 P or 20 kg ha−1 of P as superphosphate. Yields of all Year 2 Crops were increased by P-fertiliser. Year 1 treatment led to 2–3 fold variation in colonisation by AMF at each P-level for Year 2 wheat and field Pea. High colonisation did not correspond with greater crop growth, yield, or uptake of P, K, Ca, Cu or S in wheat or field Pea. However, total crop Zn-uptake and grain Zn concentration were positively correlated with colonisation by AMF, due to enhanced Zn-uptake after anthesis. For wheat, high colonisation also corresponded with reduced Mn-uptake and lower grain Mn concentrations. In a glasshouse experiment using a second P-deficient Kandosol, inoculation of wheat with Glomus intraradices and Scutellospora calospora enhanced uptake of Zn and P when no P-fertiliser was applied. We conclude that high colonisation by AMF is unimportant for productivity of the major field Crops grown on the Kandosol soils that occupy large areas of cropland in temperate SE Australia, even under P-limiting conditions. Investigation of the factors that control functioning of arbuscular mycorrhizae under field conditions, especially temperature, is required.
Didier Michot - One of the best experts on this subject based on the ideXlab platform.
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Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons.
Applied and Environmental Microbiology, 2016Co-Authors: G. Laloi, J. Montarry, M. Guibert, D. Andrivon, Didier Michot, C. Le MayAbstract:ABSTRACT Ascochyta blight, caused by the necrotrophic ascomycete Didymella pinodes, is responsible for severe losses in winter and spring Pea Crops. Despite different climatic conditions, epidemics on winter and spring Crops are due to a single population of D. pinodes, suggesting gene flow either between the two Crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two Crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520 D. pinodes strains throughout a growing season from winter and spring Pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring Crops and that the most aggressive isolates are selected as an epidemic progresses. IMPORTANCE Ascochyta blight, caused by Didymella pinodes, is responsible for severe losses in Pea Crops. While previous studies have shown that ascochyta blight epidemics on winter and spring Crops are due to a single population of D. pinodes, suggesting that isolates from the two Crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring Pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic.
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Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons
Applied and Environmental Microbiology, 2016Co-Authors: G. Laloi, J. Montarry, M. Guibert, D. Andrivon, Didier MichotAbstract:Unlabelled - Ascochyta blight, caused by the necrotrophic ascomycete Didymella pinodes, is responsible for severe losses in winter and spring Pea Crops. Despite different climatic conditions, epidemics on winter and spring Crops are due to a single population of D. pinodes, suggesting gene flow either between the two Crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two Crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520 D. pinodes strains throughout a growing season from winter and spring Pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring Crops and that the most aggressive isolates are selected as an epidemic progresses. Importance - Ascochyta blight, caused by Didymella pinodes, is responsible for severe losses in Pea Crops. While previous studies have shown that ascochyta blight epidemics on winter and spring Crops are due to a single population of D. pinodes, suggesting that isolates from the two Crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring Pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic.
Bernard Tivoli - One of the best experts on this subject based on the ideXlab platform.
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Effect and underlying mechanisms of Pea-cereal intercropping on the epidemic development of ascochyta blight
European Journal of Plant Pathology, 2010Co-Authors: Alexandra Schoeny, Stéphane Jumel, François Rouault, Emile Lemarchand, Bernard TivoliAbstract:Field experiments were conducted in western France for two consecutive years to investigate the effect of Pea-cereal intercropping on ascochyta blight, a major constraint of field Pea production world-wide. Disease pressure was variable in the experiments. Intercropping had almost no effect on disease development on stipules regardless of disease pressure. In contrast, disease severity on pods and stems was substantially reduced in the Pea-cereal intercrop compared to the Pea monocrop when the epidemic was moderate to severe. Therefore, a Pea-cereal intercrop could potentially limit direct yield loss and reduce the quantity of primary inoculum available for subsequent Pea Crops. Disease reduction was partially explained by a modification of the microclimate within the intercrop canopy, in particular, a reduction in leaf wetness duration during and after flowering. The effect of intercropping on splash dispersal of conidia was investigated under controlled conditions using a rainfall simulator. Total dispersal was reduced by 39 to 78% in Pea-wheat canopies compared to Pea canopies. These reductions were explained by a reduction in host plant density and a barrier or relay effect of the non-host plants.
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Effect and underlying mechanisms of Pea-cereal intercropping on the epidemic development of ascochyta blight
European Journal of Plant Pathology, 2010Co-Authors: Alexandra Schoeny, Stéphane Jumel, François Rouault, Emile Lemarchand, Bernard TivoliAbstract:Field experiments were conducted in western France for two consecutive years to investigate the effect of Pea-cereal intercropping on ascochyta blight, a major constraint of field Pea production world-wide. Disease pressure was variable in the experiments. Intercropping had almost no effect on disease development on stipules regardless of disease pressure. In contrast, disease severity on pods and stems was substantially reduced in the Pea-cereal intercrop compared to the Pea sole crop when the epidemic was moderate to severe. Therefore, a Pea-cereal intercrop could potentially limit direct yield loss and reduce the quantity of primary inoculum available for subsequent Pea Crops. Disease reduction was partially explained by a modification of the microclimate within the intercrop canopy, in particular, a reduction in leaf wetness duration during and after flowering. The effect of intercropping on splash dispersal of conidia was investigated under controlled conditions using a rainfall simulator. Total dispersal was reduced by 39 to 78% in Pea-wheat canopies compared to Pea canopies. These reductions were explained by a reduction in host plant density and a barrier or relay effect of the non-host plants.
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Host status and reaction of Medicago truncatula accessions to infection by three major pathogens of Pea (Pisum sativum) and alfalfa (Medicago sativa)
European Journal of Plant Pathology, 2007Co-Authors: Anne Moussart, Caroline Onfroy, Angélique Lesne, Magali Esquibet, Eric Grenier, Bernard TivoliAbstract:Ditylenchus dipsaci, the stem nematode of alfalfa (Medicago sativa), Mycosphaerella pinodes, cause of Ascochyta blight in Pea (Pisum sativum) and Aphanomyces euteiches, cause of Pea root rot, result in major yield losses in French alfalfa and Pea Crops. These diseases are difficult to control and the partial resistances currently available are not effective enough. Medicago truncatula, the barrel medic, is the legume model for genetic studies, which should lead to the identification and characterization of new resistance genes for pathogens. We evaluated a collection of 34 accessions of M. truncatula and nine accessions from three other species (two from M. italica, six from M. littoralis and one from M. polymorpha) for resistance to these three major diseases. We developed screening tests, including standard host references, for each pathogen. Most of the accessions tested were resistant to D. dipsaci, with only three accessions classified as susceptible. A very high level of resistance to M. pinodes was observed among the accessions, none of which was susceptible to this pathogen. Conversely, a high level of variation, from resistant to susceptible accessions, was identified in response to infection by A. euteiches
T. W. Bretag - One of the best experts on this subject based on the ideXlab platform.
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the epidemiology and management of bacterial blight pseudomonas syringae pv pisi of field Pea pisum sativum in australia a review
Crop & Pasture Science, 2007Co-Authors: G. J. Hollaway, T. W. Bretag, T V PriceAbstract:Bacterial blight caused by Pseudomonas syringae pv. pisi is an important, but sporadic, disease of field Peas (Pisum sativum) in Australia. The presence of P. syringae pv. pisi reduces the profitability of Peas due to yield loss and, in some cases, it also limits Australia’s export of Peas to some countries. Pseudomonoas syringae pv. pisi is primarily a seed-borne pathogen, but infected Pea trash can be an important source of inoculum. Alternative hosts and soil are not regarded as epidemiologically important sources of inoculum. P. syringae pv. pisi survives, multiplies and spreads epiphytically in Pea Crops. Epiphytic populations of P. syringae pv. pisi only become pathogenic following crop damage caused by frost or severe weather conditions. Frost damage is especially important because the ice nucleating activity of P. syringae pv. pisi initiates frost damage at higher temperatures than occurs in the absence of the bacterium. In addition early-sown Crops are more prone to damage from bacterial blight than Crops sown later in the season. Pseudomonas syringae pv. pisi consists of seven identified races. One of these (Race 6) lacks all avirulence genes and is common around the world and in Australia. Globally, Race 2 and Race 6 predominate; however, in Australia, Race 3 predominates due to the widespread cultivation of cultivars susceptible to Race 3, but resistant to Race 2. Resistance to Race 6 within P. sativum has not been found but attempts are being made to incorporate a race non-specific resistance identified from P. abyssinicum into field Pea. Bacterial blight can be successfully controlled using an integrated disease management strategy incorporating crop rotation, pathogen-free seed, avoidance of planting in areas prone to frequent frosts or extreme wet weather, crop hygiene and avoiding early sowing. Seed treatment and application of foliar bactericides have limited use in control of this disease.
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The occurrence of Pseudomonas syringae pv. pisi in field Pea (Pisum sativum) Crops in the Wimmera region of Victoria, Australia
Australasian Plant Pathology, 1995Co-Authors: G. J. Hollaway, T. W. BretagAbstract:Field Pea Crops in the Wimmera region of Victoria were surveyed for the presence of Pseudomonas syringae pv. pisi, the causal organism of bacterial blight. P. syn’ngae pv. pisi was isolated from 20% of the 130 Crops sampled. The results indicated that the true incidence of P. syringae pv. pisi in field Pea Crops of the Wimmera may be in excess of 30%. The presence of P. syringae pv, pisi in such a high proportion of Crops suggests that bacterial blight could be devastating to field Pea production in the Wimmera under conditions suitable for development of the disease