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John K Scott - One of the best experts on this subject based on the ideXlab platform.
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fungi pathogenic on wild Radish raphanus raphanistrum l in northern tunisia as potential biocontrol agents
Phytopathologia Mediterranea, 2009Co-Authors: Naceur Djebali, Marc Jourdan, John K Scott, Thouraya SouissiAbstract:The distribution and life cycle of wild Radish ( Raphanus raphanistrum L.) and a survey of the pathogens of this plant are reported for the northern regions of Tunisia. Wild Radish is a common weed of cereal crops and legumes. It germinates in early autumn (October), develops a rosette stage in November to December after which stem growth, fl owering and pod production occur through to May, with pod maturity completed in June. Fungus isolation from the foliar tissues exhibiting disease symptoms showed that wild Radish was infected with the fungi Albugo candida , Alternaria spp. including A. brassicicola , and A. raphani , Erysiphe cruciferarum , Stemphylium herbarum , Peronospora parasitica and Phoma lingam . Ascochyta spp., Cercospora armoraciae , Cladosporium cladosporioides and Colletotrichum higginsianum are here reported from wild Radish for the first time. Inoculation tests of pathogens on wild Radish plants showed that the most injurious fungi were Alternaria raphani and Phoma lingam . The remaining pathogens were weakly to moderately aggressive on this weed. To access the pathogenic effect of fungi spontaneously infecting natural populations of wild Radish, the weed was grown in a field experiment with and without the broad-spectrum systemic fungicide Carbendazim. Results showed a statistically significant two-fold decrease in the number and weight of seed pods in the non-treated plants, indicating that the reproductive potential of wild Radish was naturally reduced by fungal infection. Foliar pathogenic fungi have a potential in the integrated weed management of wild Radish, this role merits further investigations.
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pathogens on wild Radish raphanus raphanistrum brassicaceae in south western australia implications for biological control
Australasian Plant Pathology, 2008Co-Authors: Aaron Maxwell, John K ScottAbstract:Biological control options for wild Radish (Raphanus raphanistrum L.) were explored through a pathogen survey in south-western Australia, inoculation studies and a literature review. Twelve fungal species were isolated from diseased wild Radish, including an undescribed species of Mycosphaerella and Hyaloperonospora parasitica, which have not been previously recorded on wild Radish in Western Australia. H. parasitica was the most damaging and widespread pathogen of wild Radish. Phylogenetic analysis based on the internal transcribed spacer regions of the rRNA genes showed that the H. parasitica isolates from wild Radish are genetically distinct from the isolates found on Brassica species including canola. This finding opens up the possibility of developing a conservation or augmentative approach to the biological control of wild Radish using H. parasitica. The possibility of using other pathogens in a biocontrol strategy is remote because of likely nontarget effects on canola. Leptosphaeria biglobosa and L. maculans were widespread pathogens of wild Radish suggesting this weed may provide an inoculum source for blackleg disease on canola (Brassica napus) by providing a bridge to disease along roadsides and paddocks throughout grain-growing areas.
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Pathogens on wild Radish, Raphanus raphanistrum (Brassicaceae), in south-western Australia — implications for biological control
Australasian Plant Pathology, 2008Co-Authors: Aaron Maxwell, John K ScottAbstract:Biological control options for wild Radish (Raphanus raphanistrum L.) were explored through a pathogen survey in south-western Australia, inoculation studies and a literature review. Twelve fungal species were isolated from diseased wild Radish, including an undescribed species of Mycosphaerella and Hyaloperonospora parasitica, which have not been previously recorded on wild Radish in Western Australia. H. parasitica was the most damaging and widespread pathogen of wild Radish. Phylogenetic analysis based on the internal transcribed spacer regions of the rRNA genes showed that the H. parasitica isolates from wild Radish are genetically distinct from the isolates found on Brassica species including canola. This finding opens up the possibility of developing a conservation or augmentative approach to the biological control of wild Radish using H. parasitica. The possibility of using other pathogens in a biocontrol strategy is remote because of likely nontarget effects on canola. Leptosphaeria biglobosa and L. maculans were widespread pathogens of wild Radish suggesting this weed may provide an inoculum source for blackleg disease on canola (Brassica napus) by providing a bridge to disease along roadsides and paddocks throughout grain-growing areas.
Christopher J Hall - One of the best experts on this subject based on the ideXlab platform.
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investigation of mcpa 4 chloro 2 ethylphenoxyacetate resistance in wild Radish raphanus raphanistrum l
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Mithila Jugulam, Natalie Dimeo, Linda J Veldhuis, Michael J Walsh, Christopher J HallAbstract:The phenoxy herbicides (e.g., 2,4-D and MCPA) are used widely in agriculture for the selective control of broadleaf weeds. In Western Australia, the reliance on phenoxy herbicides has resulted in the widespread evolution of phenoxy resistance in wild Radish (Raphanus raphanistrum) populations. In this research the inheritance and mechanism of MCPA resistance in wild Radish were determined. Following classical breeding procedures, F1, F2, and backcross progeny were generated. The F1 progeny showed an intermediate response to MCPA, compared to parents, suggesting that MCPA resistance in wild Radish is inherited as an incompletely dominant trait. Segregation ratios observed in F2 (3:1; resistant:susceptible) and backcross progeny (1:1; resistant to susceptible) indicated that the MCPA resistance is controlled by a single gene in wild Radish. Radiolabeled MCPA studies suggested no difference in MCPA uptake or metabolism between resistant and susceptible wild Radish; however, resistant plants rapidly transloca...
Michael J Walsh - One of the best experts on this subject based on the ideXlab platform.
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Introgression of phenoxy herbicide resistance from Raphanus raphanistrum into Raphanus sativus
Plant Breeding, 2014Co-Authors: Mithila Jugulam, Michael J Walsh, John Christopher HallAbstract:Phenoxy herbicides such as 2,4-dichlorophenoxy acetic acid (2,4-D) and 4-chloro-2-methylphenoxy acetic acid (MCPA) are selective herbicides used extensively in agriculture for weed control. Wild Radish (Raphanus raphanistrum) is a problem weed across the globe and heavily infests crop fields in Australia. Phenoxy herbicides are used to selectively control dicot weeds, including wild Radish. As a result of selection, phenoxy-resistant wild Radish populations evolved in Western Australia. In this research, introgression of phenoxy resistance from wild Radish to cultivated Radish (Raphanus sativus) was investigated following classical breeding procedures. F1 progeny were generated by crossing MCPA-resistant R. raphanistrum and MCPA-susceptible R. sativus .F 1 hybrids were screened for MCPA resistance. The MCPA-resistant F1 hybrids were used to produce three generations of backcross progeny. Genetic analyses of F1 and backcross progeny demonstrated introgression of the MCPA-resistant trait from wild Radish to cultivated Radish. Implications of phenoxy resistance introgression into cultivated Radish include potential development of herbicidetolerant Radish cultivars or other members of the Brassicaceae family.
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investigation of mcpa 4 chloro 2 ethylphenoxyacetate resistance in wild Radish raphanus raphanistrum l
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Mithila Jugulam, Natalie Dimeo, Linda J Veldhuis, Michael J Walsh, Christopher J HallAbstract:The phenoxy herbicides (e.g., 2,4-D and MCPA) are used widely in agriculture for the selective control of broadleaf weeds. In Western Australia, the reliance on phenoxy herbicides has resulted in the widespread evolution of phenoxy resistance in wild Radish (Raphanus raphanistrum) populations. In this research the inheritance and mechanism of MCPA resistance in wild Radish were determined. Following classical breeding procedures, F1, F2, and backcross progeny were generated. The F1 progeny showed an intermediate response to MCPA, compared to parents, suggesting that MCPA resistance in wild Radish is inherited as an incompletely dominant trait. Segregation ratios observed in F2 (3:1; resistant:susceptible) and backcross progeny (1:1; resistant to susceptible) indicated that the MCPA resistance is controlled by a single gene in wild Radish. Radiolabeled MCPA studies suggested no difference in MCPA uptake or metabolism between resistant and susceptible wild Radish; however, resistant plants rapidly transloca...
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high frequency of chlorsulfuron resistant wild Radish raphanus raphanistrum populations across the western australian wheatbelt1
Weed Technology, 2001Co-Authors: Michael J Walsh, Ryan D Duane, Stephen B. PowlesAbstract:Abstract: In 1998, field populations of wild Radish suspected of being resistant to chlorsulfuron were collected and screened for resistance to this herbicide using the Quick-Test technique. This test successfully identified chlorsulfuron-resistant populations of wild Radish. Detailed dose–response experiments with the progeny of these populations confirmed their resistance and validated the use of the Quick-Test for a dicot species. Subsequently in 1999, a random survey was conducted employing this test to establish the current extent of chlorsulfuron resistance in wild Radish populations. The survey covered more than 200 fields in the northern, central, and eastern wheatbelt regions of Western Australia. Wild Radish plants were collected from wheat crops in 133 of these fields. The Quick-Test method was used to screen these plants with the acetolactate synthase (ALS)-inhibiting herbicide chlorsulfuron. Overall, 21% of randomly collected wild Radish populations were found to be resistant to chlorsulfuron...
Mithila Jugulam - One of the best experts on this subject based on the ideXlab platform.
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Introgression of phenoxy herbicide resistance from Raphanus raphanistrum into Raphanus sativus
Plant Breeding, 2014Co-Authors: Mithila Jugulam, Michael J Walsh, John Christopher HallAbstract:Phenoxy herbicides such as 2,4-dichlorophenoxy acetic acid (2,4-D) and 4-chloro-2-methylphenoxy acetic acid (MCPA) are selective herbicides used extensively in agriculture for weed control. Wild Radish (Raphanus raphanistrum) is a problem weed across the globe and heavily infests crop fields in Australia. Phenoxy herbicides are used to selectively control dicot weeds, including wild Radish. As a result of selection, phenoxy-resistant wild Radish populations evolved in Western Australia. In this research, introgression of phenoxy resistance from wild Radish to cultivated Radish (Raphanus sativus) was investigated following classical breeding procedures. F1 progeny were generated by crossing MCPA-resistant R. raphanistrum and MCPA-susceptible R. sativus .F 1 hybrids were screened for MCPA resistance. The MCPA-resistant F1 hybrids were used to produce three generations of backcross progeny. Genetic analyses of F1 and backcross progeny demonstrated introgression of the MCPA-resistant trait from wild Radish to cultivated Radish. Implications of phenoxy resistance introgression into cultivated Radish include potential development of herbicidetolerant Radish cultivars or other members of the Brassicaceae family.
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investigation of mcpa 4 chloro 2 ethylphenoxyacetate resistance in wild Radish raphanus raphanistrum l
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Mithila Jugulam, Natalie Dimeo, Linda J Veldhuis, Michael J Walsh, Christopher J HallAbstract:The phenoxy herbicides (e.g., 2,4-D and MCPA) are used widely in agriculture for the selective control of broadleaf weeds. In Western Australia, the reliance on phenoxy herbicides has resulted in the widespread evolution of phenoxy resistance in wild Radish (Raphanus raphanistrum) populations. In this research the inheritance and mechanism of MCPA resistance in wild Radish were determined. Following classical breeding procedures, F1, F2, and backcross progeny were generated. The F1 progeny showed an intermediate response to MCPA, compared to parents, suggesting that MCPA resistance in wild Radish is inherited as an incompletely dominant trait. Segregation ratios observed in F2 (3:1; resistant:susceptible) and backcross progeny (1:1; resistant to susceptible) indicated that the MCPA resistance is controlled by a single gene in wild Radish. Radiolabeled MCPA studies suggested no difference in MCPA uptake or metabolism between resistant and susceptible wild Radish; however, resistant plants rapidly transloca...
Aaron Maxwell - One of the best experts on this subject based on the ideXlab platform.
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pathogens on wild Radish raphanus raphanistrum brassicaceae in south western australia implications for biological control
Australasian Plant Pathology, 2008Co-Authors: Aaron Maxwell, John K ScottAbstract:Biological control options for wild Radish (Raphanus raphanistrum L.) were explored through a pathogen survey in south-western Australia, inoculation studies and a literature review. Twelve fungal species were isolated from diseased wild Radish, including an undescribed species of Mycosphaerella and Hyaloperonospora parasitica, which have not been previously recorded on wild Radish in Western Australia. H. parasitica was the most damaging and widespread pathogen of wild Radish. Phylogenetic analysis based on the internal transcribed spacer regions of the rRNA genes showed that the H. parasitica isolates from wild Radish are genetically distinct from the isolates found on Brassica species including canola. This finding opens up the possibility of developing a conservation or augmentative approach to the biological control of wild Radish using H. parasitica. The possibility of using other pathogens in a biocontrol strategy is remote because of likely nontarget effects on canola. Leptosphaeria biglobosa and L. maculans were widespread pathogens of wild Radish suggesting this weed may provide an inoculum source for blackleg disease on canola (Brassica napus) by providing a bridge to disease along roadsides and paddocks throughout grain-growing areas.
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Pathogens on wild Radish, Raphanus raphanistrum (Brassicaceae), in south-western Australia — implications for biological control
Australasian Plant Pathology, 2008Co-Authors: Aaron Maxwell, John K ScottAbstract:Biological control options for wild Radish (Raphanus raphanistrum L.) were explored through a pathogen survey in south-western Australia, inoculation studies and a literature review. Twelve fungal species were isolated from diseased wild Radish, including an undescribed species of Mycosphaerella and Hyaloperonospora parasitica, which have not been previously recorded on wild Radish in Western Australia. H. parasitica was the most damaging and widespread pathogen of wild Radish. Phylogenetic analysis based on the internal transcribed spacer regions of the rRNA genes showed that the H. parasitica isolates from wild Radish are genetically distinct from the isolates found on Brassica species including canola. This finding opens up the possibility of developing a conservation or augmentative approach to the biological control of wild Radish using H. parasitica. The possibility of using other pathogens in a biocontrol strategy is remote because of likely nontarget effects on canola. Leptosphaeria biglobosa and L. maculans were widespread pathogens of wild Radish suggesting this weed may provide an inoculum source for blackleg disease on canola (Brassica napus) by providing a bridge to disease along roadsides and paddocks throughout grain-growing areas.
