Field pea （Pisum sativum var. arvense L.） is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomyces root rot...Field pea （Pisum sativum var. arvense L.） is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomyces root rot （ARR）, caused by the soil-borne oomycete Aphanomyces euteiches Drechs. （A. euteiches）, is a major threat to pea production in many pea-growing regions including Canada; it can cause severe root damage, wilting, and considerable yield losses under wet soil conditions. Traditional disease management strategies, such as crop rotations and seed treatments, cannot fully prevent ARR under conditions conducive for the disease, due to the longevity of the pathogen oospores, which can infect field pea plants at any growth stage. The development of pea cultivars with partial resistance or tolerance to ARR may be a promising approach to analyze the variability and physiologic specialization ofA. euteiches in field pea and to improve the management of this disease. As such, the detection of quantitative trait loci （QTL） for resistance is essential to field pea-breeding programs. In this paper, the pathogenic characteristics of A. euteiches are reviewed along with various ARR management strategies and the QTL associated with partial resistance to ARR.展开更多
Aphanomyces root rot(ARR) of field pea(Pisum sativum), caused by Aphanomyces euteiches, can cause severe root damage, wilting, and large yield losses under wet soil conditions. To identify ways to manage this disease,...Aphanomyces root rot(ARR) of field pea(Pisum sativum), caused by Aphanomyces euteiches, can cause severe root damage, wilting, and large yield losses under wet soil conditions. To identify ways to manage this disease, the effect of A. euteiches inoculum density on field pea was studied under greenhouse and field conditions in 2015 and 2016. Increases in inoculum density reduced seedling emergence, root nodulation, and plant vigor, and resulted in increased root rot severity in both field and greenhouse tests. Seed treatments with the fungicides Apron Advance(thiabendazole + fludioxonil + metalaxyl) + Vibrance(difenoconazole + metalaxylM + sedaxane), INTEGO Solo(ethaboxam), BAS 516F(boscalid + pyraclostrobin), BAS 720F(metalaxyl + pyraclostrobin + fluxapyroxad), and BAS 516F + BAS 720F(3:1) were evaluated for their efficacy against ARR. All seed treatments except Apron Advance + Vibrance reduced root rot severity under controlled conditions. BAS 516F, BAS 720F and INTEGO Solo improved plant vigor and all treatments reduced seedling blight to varying degrees under greenhouse conditions, but not in the field. A collection of 22 pea genotypes was evaluated for resistance to root rot in field plot experiments. Line 00–2067 showed the least severe root rot symptoms,whereas ‘Spring D' showed the lowest reduction in yield. The results suggest that there may be an opportunity to combine partial host resistance and fungicidal seed treatments to adequately manage ARR of field pea.展开更多
Fish mycotic disease outbreaks occur due to infections with oomycete pathogens such as Saprolegnia spp.and Aphanomyces invadans,and cause large-scale fish production losses.Despite its negative impact on aquaculture,l...Fish mycotic disease outbreaks occur due to infections with oomycete pathogens such as Saprolegnia spp.and Aphanomyces invadans,and cause large-scale fish production losses.Despite its negative impact on aquaculture,little is known about the diversity of oomycete pathogens.The aim of this study was to identify the diversity of pathogenic oomycetes causing infections in major aquaculture zones of Mymensingh and Jessore regions in Bangladesh.A total of 449 water and infected fish samples were collected from 28 fish farms in both regions of which 29 samples were able to grow out with mycelia on the Potato Dextrose Agar(PDA)/Glucose Peptone Yeast Agar(GPYA)plates.Sequence database searches using the rRNA Internal Transcribed Spacer(ITS)region revealed that 15 belonged to Pythium spp.,12 were Aphanomyces invadans and two corresponded to Saprolegnia parasitica.Five isolates of Pythium spp.were identified to the species level:one was closely related to Pythium catenulatum,four to Pythium rhizo-oryzae,rest were identified up to genus.The Pythium spp.were only isolated from water samples whereas A.invadans and S.parasitica were found in fish lesions.Phylogenetic analysis revealed that a single A.invadans clone exists in the sampled area.The results obtained confirm the existence of pathogenic oomycetes in Bangladesh fish farms and this will pave future research on diversity,prevention and control measures.展开更多
基金funding support received from Agriculture and Agri-Food Canadathe Saskatchewan Pulse Growers Association+1 种基金the Manitoba Pulse and Soybean Growers through the Growing Forward 2the Pest Management and Surveillance Implementation Program
文摘Field pea （Pisum sativum var. arvense L.） is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomyces root rot （ARR）, caused by the soil-borne oomycete Aphanomyces euteiches Drechs. （A. euteiches）, is a major threat to pea production in many pea-growing regions including Canada; it can cause severe root damage, wilting, and considerable yield losses under wet soil conditions. Traditional disease management strategies, such as crop rotations and seed treatments, cannot fully prevent ARR under conditions conducive for the disease, due to the longevity of the pathogen oospores, which can infect field pea plants at any growth stage. The development of pea cultivars with partial resistance or tolerance to ARR may be a promising approach to analyze the variability and physiologic specialization ofA. euteiches in field pea and to improve the management of this disease. As such, the detection of quantitative trait loci （QTL） for resistance is essential to field pea-breeding programs. In this paper, the pathogenic characteristics of A. euteiches are reviewed along with various ARR management strategies and the QTL associated with partial resistance to ARR.
基金Funding support from Agriculture and Agri-Food Canada, the Saskatchewan Pulse Growersthe Manitoba Pulse and Soybean Growers through the Growing Forward 2 Program
文摘Aphanomyces root rot(ARR) of field pea(Pisum sativum), caused by Aphanomyces euteiches, can cause severe root damage, wilting, and large yield losses under wet soil conditions. To identify ways to manage this disease, the effect of A. euteiches inoculum density on field pea was studied under greenhouse and field conditions in 2015 and 2016. Increases in inoculum density reduced seedling emergence, root nodulation, and plant vigor, and resulted in increased root rot severity in both field and greenhouse tests. Seed treatments with the fungicides Apron Advance(thiabendazole + fludioxonil + metalaxyl) + Vibrance(difenoconazole + metalaxylM + sedaxane), INTEGO Solo(ethaboxam), BAS 516F(boscalid + pyraclostrobin), BAS 720F(metalaxyl + pyraclostrobin + fluxapyroxad), and BAS 516F + BAS 720F(3:1) were evaluated for their efficacy against ARR. All seed treatments except Apron Advance + Vibrance reduced root rot severity under controlled conditions. BAS 516F, BAS 720F and INTEGO Solo improved plant vigor and all treatments reduced seedling blight to varying degrees under greenhouse conditions, but not in the field. A collection of 22 pea genotypes was evaluated for resistance to root rot in field plot experiments. Line 00–2067 showed the least severe root rot symptoms,whereas ‘Spring D' showed the lowest reduction in yield. The results suggest that there may be an opportunity to combine partial host resistance and fungicidal seed treatments to adequately manage ARR of field pea.
基金The authors would like to express deepest sense of gratitude and sincere appreciation for the financial support of the International Foundation for Science,Sweden(IFS:A/5788-1)COMSTECH as well as the Ministry of Science and Technology,Bangladesh(BS-57,2015–2016)TN acknowledges NST fellowship Ministry of Science and Technology,Bangladesh.The authors would also like to acknowledge the contribution of the Head of the department,Department of Fisheries Biology and Genetics,and Central Laboratory,Bangladesh Agricultural University for providing equipment and technical supports during the research.
文摘Fish mycotic disease outbreaks occur due to infections with oomycete pathogens such as Saprolegnia spp.and Aphanomyces invadans,and cause large-scale fish production losses.Despite its negative impact on aquaculture,little is known about the diversity of oomycete pathogens.The aim of this study was to identify the diversity of pathogenic oomycetes causing infections in major aquaculture zones of Mymensingh and Jessore regions in Bangladesh.A total of 449 water and infected fish samples were collected from 28 fish farms in both regions of which 29 samples were able to grow out with mycelia on the Potato Dextrose Agar(PDA)/Glucose Peptone Yeast Agar(GPYA)plates.Sequence database searches using the rRNA Internal Transcribed Spacer(ITS)region revealed that 15 belonged to Pythium spp.,12 were Aphanomyces invadans and two corresponded to Saprolegnia parasitica.Five isolates of Pythium spp.were identified to the species level:one was closely related to Pythium catenulatum,four to Pythium rhizo-oryzae,rest were identified up to genus.The Pythium spp.were only isolated from water samples whereas A.invadans and S.parasitica were found in fish lesions.Phylogenetic analysis revealed that a single A.invadans clone exists in the sampled area.The results obtained confirm the existence of pathogenic oomycetes in Bangladesh fish farms and this will pave future research on diversity,prevention and control measures.
