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Robert S. Zemetra - One of the best experts on this subject based on the ideXlab platform.
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jointed goatgrass Aegilops Cylindrica a review
Weed Science, 2018Co-Authors: Carol A Mallorysmith, Drew J Lyon, Andrew R Kniss, Robert S. ZemetraAbstract:In 1994, the National Jointed Goatgrass Research Program was initiated with funding from a special USDA grant. The 15-yr program provided $4.1 million to support jointed goatgrass (Aegilops Cylindrica Host.) research and technology transfer projects in 10 western states. These projects resulted in approximately 80 refereed manuscripts, including journal articles and extension publications. The research covered various topics related to the biology and ecology of jointed goatgrass as well as its management and control in wheat (Triticum aestivum L.) production systems. This review summarizes the research on jointed goatgrass published after Donald and Ogg's 1991 review, most of which was conducted as part of the USDA-funded National Jointed Goatgrass Research Program. Specific topics that were studied and reviewed here include A. Cylindrica genetics, especially as it relates to gene flow and hybridization rates with wheat and fertility of the resulting hybrids; vernalization requirements; seed dormancy, longevity, and germination requirements; competitiveness with wheat; and herbicide resistance acquired through evolution or gene flow from wheat. With respect to management, a wide variety of practices were evaluated, including various tillage types and frequencies; crop rotations, especially diversified wheat production systems that include spring-seeded annual crops; competitive wheat cultivars, seeding dates, seeding density, and row spacing; fertility management, including nitrogen application timing and placement; and field burning. Finally, many studies evaluated the use of herbicides, especially the introduction of imazamox in imidazolinone-resistant wheat cultivars, as well as comparison of adjuvant systems and application timings. In addition to the many management practices that were studied individually, several integrated management systems were evaluated that combined crop rotations, tillage, and herbicide programs. Between 1993 and 2013, weed scientists in 14 western states estimated that jointed goatgrass infestations decreased by 45% to 55% and attributed the reduction to the implementation of more diverse crop rotations, improved cultural practices, and use of imazamox-resistant wheat technology. This is evidence that the practical implications of the National Jointed Goatgrass Research Program have been successfully implemented by growers throughout the western United States.
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impact of transgene genome location on gene migration from herbicide resistant wheat triticum aestivum l to jointed goatgrass Aegilops Cylindrica host
Pest Management Science, 2017Co-Authors: Maqsood Rehman, Carol A Mallorysmith, Jennifer L. Hansen, Robert S. ZemetraAbstract:BACKGROUND Wheat (Triticum aestivum) (ABD) and jointed goatgrass (Aegilops Cylindrica) (CD) can cross and produce hybrids that can backcross to either parent. Such backcrosses can result in progeny with chromosomes and/or chromosome segments retained from wheat. Thus, a herbicide resistance gene could migrate from wheat to jointed goatgrass. In theory, the risk of gene migration from herbicide-resistant wheat to jointed goatgrass is more likely if the gene is located on the D genome and less likely if the gene is located on the A or B genome of wheat. RESULTS BC1 populations (jointed goatgrass as a recurrent parent) were analyzed for chromosome numbers and transgene transmission rates under sprayed and non-sprayed conditions. Transgene retention in the non-sprayed BC1 generation for the A, B and D genomes was 84, 60 and 64% respectively. In the sprayed populations, the retention was 81, 59 and 74% respectively. CONCLUSION The gene transmission rates were higher than the expected 50% or less under sprayed and non-sprayed conditions, possibly owing to meiotic chromosome restitution and/or chromosome non-disjunction. Such high transmission rates in the BC1 generation negates the benefits of gene placement for reducing the potential of gene migration from wheat to jointed goatgrass. © 2016 Society of Chemical Industry
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selection pressure effects on the proportion and movement of resistance alleles introgressed from wheat in Aegilops Cylindrica
Weed Research, 2016Co-Authors: B A B Martins, Robert S. Zemetra, J M Leonard, L Sun, Carol A MallorysmithAbstract:Summary In winter wheat in the USA, Aegilops Cylindrica is one of the most troublesome weeds, while the pathogen Oculimacula spp. causes foot rot disease. Imazamox-resistant (IR) and foot rot-resistant (FR) wheat cultivars represent effective tools to control the weed and prevent disease infection. However, resistance allele (RA) movement between wheat and A. Cylindrica facilitates the introgression process under herbicide and disease selection pressure. Field experiments using IR and FR A. Cylindrica plants intermixed with susceptible plants were conducted to measure the proportion of the RAs in the progeny and RA movement with and without herbicide and disease selection. Yield components of A. Cylindrica plants were determined across treatments. The herbicide RA proportion in the progeny was greater when plants were treated with the herbicide imazamox in both years. Disease RA proportion was greater with disease occurrence only in one year. Herbicide RA movement from resistant to susceptible plants was greater with herbicide than without it only in one year. Plants carrying the RAs had greater total spikelet weight and 1000-spikelet weight compared with susceptible plants with or without selection. However, susceptible plants produced more spikelets than the resistant ones in the absence of selection. If plants within an A. Cylindrica population acquire the herbicide RA, its proportion will increase each generation under selection. These findings contribute to the understanding of crop allele introgression into related species and the evolution of increased weediness, with weed management implications.
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hybridization between wheat and jointed goatgrass Aegilops Cylindrica under field conditions
Weed Science, 2006Co-Authors: Harish Gandhi, Robert S. Zemetra, Carol A Mallorysmith, Isabel M Vales, Christy J W Watson, Oscar RieralizarazuAbstract:Abstract Jointed goatgrass is an important weed of wheat in the United States and other parts of the world. Under field conditions, wheat and jointed goatgrass can hybridize and produce backcross derivatives, a situation that may allow gene flow between these two species. In order to gain a better understanding of the factors governing gene flow, a study to characterize patterns of mating between these two species was undertaken. Chloroplast and nuclear microsatellite markers were used to evaluate the parentage of 413 first-generation backcross (BC1) seeds obtained from 127 wheat–jointed goatgrass F1 hybrids, produced naturally under field conditions. Of the 127 hybrids evaluated, 109 (85.8%) had jointed goatgrass as the female parent, whereas the remaining 18 F1 plants (14.2%) had wheat as the female parent. Of the 413 BC1 plants analyzed, 358 (86.7%) had wheat and 24 (5.8%) had jointed goatgrass as the male backcross parent. The male parentage of 31 BC1 (7.5%) plants could not be determined. Under natur...
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Introgression of an imidazolinone-resistance gene from winter wheat (Triticum aestivum L.) into jointed goatgrass (Aegilops Cylindrica Host).
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 2006Co-Authors: Alejandro Perez-jones, Carol A. Mallory-smith, Jennifer L. Hansen, Robert S. ZemetraAbstract:Imidazolinone-resistant winter wheat (Triticum aestivum L.) is being commercialized in the USA. This technology allows wheat growers to selectively control jointed goatgrass (Aegilops Cylindrica Host), a weed that is especially problematic because of its close genetic relationship with wheat. However, the potential movement of the imidazolinone-resistance gene from winter wheat to jointed goatgrass is a concern. Winter wheat and jointed goatgrass have the D genome in common and can hybridize and backcross under natural field conditions. Since the imidazolinone-resistance gene (Imi1) is located on the D genome, it is possible for resistance to be transferred to jointed goatgrass via hybridization and backcrossing. To study the potential for gene movement, BC2S2 plants were produced artificially using imidazolinone-resistant winter wheat (cv. FS-4) as the female parent and a native jointed goatgrass collection as the male recurrent parent. FS-4, the jointed goatgrass collection, and 18 randomly selected BC2S2 populations were treated with imazamox. The percentage of survival was 100% for the FS-4, 0% for the jointed goatgrass collection and 6 BC2S2 populations, 40% or less for 2 BC2S2 populations, and 50% or greater for the remaining 10 BC2S2 populations. Chromosome counts in BC2S3 plants showed a restoration of the chromosome number of jointed goatgrass, with four out of four plants examined having 28 chromosomes. Sequencing of AHASL1D in BC2S3 plants derived from BC2S2-6 revealed the sexual transmission of Imi1 from FS-4 to jointed goatgrass. Imi1 conferred resistance to the imidazolinone herbicide imazamox, as shown by the in vitro assay for acetohydroxyacid synthase (AHAS) activity.
Ahmad Arzani - One of the best experts on this subject based on the ideXlab platform.
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polyphenols flavonoids and antioxidant activity involved in salt tolerance in wheat Aegilops Cylindrica and their amphidiploids
Frontiers in Plant Science, 2021Co-Authors: Razieh Kiani, Ahmad Arzani, S Mirmohammady A M MaibodyAbstract:Aegilops spp. is the closest genus to wheat (Triticum spp.), which makes Aegilops great candidates to exhibit precursors of wheat features. Aegilops Cylindrica Host displays excellent salt tolerance. In the current study, biochemical and phytochemical compounds in the leaves of two wheat cultivars, one hyper-salt tolerant Ae. Cylindrica genotype and their amphidiploids (derived from "Chinese Spring" × Ae. cilindrica and "Roshan" × Ae. Cylindrica), grown under control and saline field conditions, were assessed. These compounds included total protein content, proline content, electrolyte leakage, total flavonoid content, total phenolic content, DPPH radical scavenging activity, and reducing power. In addition, phenolic components were also identified using HPLC analysis. Chlorogenic acid, ellagic acid, ferulic acid, syringic acid, vanillic acid, p-coumaric acid, caffeic acid, and gallic acid were the most abundant phenolic acids. Luteolin, apigenin, and rutin were the most abundant flavonoids in the leaves. Salt stress significantly increased all biochemical variables, with the exceptions of reducing power and p-coumaric acid. Interestingly, amphidiploid genotypes exhibited intermediate levels of most of the detected phenolic compounds between the two parental species. As demonstrated by bivariate correlations luteolin, chlorogenic acid, caffeic acid and apigenin could predict inhibition percentage by DPPH assay, suggesting a possible role in the cellular defense against oxidative stress in wheat. The amphidiploids and their wild parent performed significantly better than wheat cultivars on phenolic constituents, flavonoids, and maintaining redox homeostasis under salt stress conditions.
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Morpho-physiological and gene expression responses of wheat by Aegilops Cylindrica amphidiploids to salt stress
Plant Cell Tissue and Organ Culture (PCTOC), 2021Co-Authors: Razieh Kiani, Ahmad Arzani, S. A. M. Mirmohammady Maibody, Mehdi Rahimmalek, Khadijeh RazaviAbstract:A synergistic interaction between HKT1;5 , NHX1 , and SOS1 genes was hypothesized to be positively and significantly associated with the Na+ homeostasis in A. Cylindrica and amphidiploid plants subjected to salt stress. Aegilops Cylindrica Host is one of the most salt-tolerant species in the Triticeae tribe. Amphidiploid plants derived from hybridization of ‘Roshan’ × Aegilops Cylindrica and ‘Chinese Spring’ × Ae. Cylindrica genotypes contrasting in salt tolerance were assessed for their morpho-physiological responses and the expression patterns of two genes related to ion homeostasis under 250 mM NaCl. Results showed that salt stress caused significant declines in both their morphological and phenological traits. Moreover, salt stress reduced not only their chlorophyll content but also their root and shoot K contents and K/Na ratios, while it led to significant enhancements in the remaining traits. Similar to Ae. Cylindrica , the amphidiploids subjected to salt stress exhibited significantly higher H_2O_2 levels, root and shoot K contents, and root and shoot K/Na ratios accompanied by lower root and shoot Na contents and MDA concentrations when compared with the same traits in the wheat parents. Quantitative Real-Time PCR showed significant differential expression patterns of the HKT1;5, NHX1 , and SOS1 genes between the amphidiploids and their parents. The transcript level of HKT1;5 was found to be higher in the roots than in the shoots of both the amphidiploids and Ae. Cylindrica while NHX1 exhibited a higher expression in the shoot tissues. The consistency of these data provides compelling support for the hypothesis that active exclusion of Na from the roots and elevated vacuolar sequestration of Na in the leaves might explain the declining Na levels in the shoots and roots of both the amphidiploids and Ae. Cylindrica relative to those measured in wheat parents. It is concluded that the hybridized amphiploids are potentially valuable resources for salt improvement in bread wheat through the backcrossing approach.
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morpho physiological and gene expression responses of wheat by Aegilops Cylindrica amphidiploids to salt stress
bioRxiv, 2020Co-Authors: Razieh Kiani, Ahmad Arzani, Mehdi RahimmalekAbstract:Aegilops Cylindrica Host is one of the most salt-tolerant species in the Triticeae tribe. Amphidiploid plants derived from hybridization of Roshan x Aegilops Cylindrica and Chinese Spring x Ae. Cylindrica genotypes contrasting in salt tolerance were assessed for their morpho-physiological responses and the expression patterns of three genes related to ion homeostasis under 250 mM NaCl. Results showed that salt stress caused significant declines in both their morphological and phenological traits. Moreover, salt stress reduced not only their chlorophyll content but also their root and shoot K contents and K/Na ratios, while it led to significant enhancements in the remaining traits. Similar to Ae. Cylindrica, the amphidiploids subjected to salt stress exhibited significantly higher H2O2 levels, root and shoot K contents, and root and shoot K/Na ratios accompanied by lower root and shoot Na contents and MDA concentrations when compared with the same traits in the wheat parents. Quantitative Real-Time PCR showed significant differential expression patterns of the HKT1;5, NHX1, and SOS1 genes between the amphidiploids and their parents. The transcript level of HKT1;5 was found to be higher in the roots than in the shoots of both the amphidiploids and Ae. Cylindrica while NHX1 exhibited a higher expression in the shoot tissues. The consistency of these data provides compelling support for the hypothesis that active exclusion of Na from the roots and elevated vacuolar sequestration of Na in the leaves might explain the declining Na levels in the shoots and roots of both the amphidiploids and Ae. Cylindrica relative to those measured in wheat parents. It is concluded that the hybridized amphiploids are potentially valuable resources for salt improvement in bread wheat through the backcrossing approach.
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expression profiles of p5cs and dreb2 genes under salt stress in Aegilops Cylindrica
Russian Journal of Plant Physiology, 2019Co-Authors: Mahbube Arabbeigi, Ahmad Arzani, Mohammad Mahdi MajidiAbstract:Aegilops Cylindrica Host. is a salt-tolerant wild relative of wheat. The expression of AecDREB2 and AecP5CS genes involved in salinity tolerance was investigated. Salt stress caused significant upregulation of AecDREB2 expression while it did not affect the transcripts of AecP5CS. Despite no significant difference in the AecDREB2 expression in the root and shoot tissues, the AecP5CS transcription profiles of the shoots was much higher than the roots supporting our data of proline accumulation in these tissues. In addition, the homology between AecP5CS and TaP5CS as well as between AecDREB2 and AetDREB2 may suggest the location of our studied genes in the D genome of Ae. Cylindrica and a clear orthologous relationship. It is concluded that proline did not play an explicit role in the adaptation response of Ae. Cylindrica to a high level of salt stress, while DREB2 plays a pivotal role in the regulatory network of salt tolerance in this species.
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Expression pattern of salt tolerance-related genes in Aegilops Cylindrica
Physiology and Molecular Biology of Plants, 2017Co-Authors: Mahbube Arabbeigi, Badraldin Ebrahim Sayed-tabatabaei, Mohammad Mahdi Majidi, Ahmad Arzani, Prasenjit SahaAbstract:Aegilops Cylindrica, a salt-tolerant gene pool of wheat, is a useful plant model for understanding mechanism of salt tolerance. A salt-tolerant USL26 and a salt-sensitive K44 genotypes of A. Cylindrica, originating from Uremia Salt Lake shores in Northwest Iran and a non-saline Kurdestan province in West Iran, respectively, were identified based on screening evaluation and used for this work. The objective of the current study was to investigate the expression patterns of four genes related to ion homeostasis in this species. Under treatment of 400 mM NaCl, USL26 showed significantly higher root and shoot dry matter levels and K+ concentrations, together with lower Na+ concentrations than K44 genotype. A. Cylindrica HKT1;5 (AecHKT1;5), SOS1 (AecSOS1), NHX1 (AecNHX1) and VP1 (AecVP1) were partially sequenced to design each gene specific primer. Quantitative real-time PCR showed a differential expression pattern of these genes between the two genotypes and between the root and shoot tissues. Expressions of AecHKT1;5 and AecSOS1 was greater in the roots than in the shoots of USL26 while AecNHX1 and AecVP1 were equally expressed in both tissues of USL26 and K44. The higher transcripts of AecHKT1;5 in the roots versus the shoots could explain both the lower Na+ in the shoots and the much lower Na+ and higher K+ concentrations in the roots/shoots of USL26 compared to K44. Therefore, the involvement of AecHKT1;5 in shoot-to-root handover of Na+ in possible combination with the exclusion of excessive Na+ from the root in the salt-tolerant genotype are suggested.
R. Guadagnuolo - One of the best experts on this subject based on the ideXlab platform.
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molecular analysis cytogenetics and fertility of introgression lines from transgenic wheat to Aegilops Cylindrica host
Genetics, 2006Co-Authors: N. Schoenenberger, R. Guadagnuolo, Dessislava Savovabianchi, Philippe Kupfer, Francois FelberAbstract:Natural hybridization and backcrossing between Aegilops Cylindrica and Triticum aestivum can lead to introgression of wheat DNA into the wild species. Hybrids between Ae. Cylindrica and wheat lines bearing herbicide resistance (bar), reporter (gus), fungal disease resistance (kp4), and increased insect tolerance (gna) transgenes were produced by pollination of emasculated Ae. Cylindrica plants. F1 hybrids were backcrossed to Ae. Cylindrica under open-pollination conditions, and first backcrosses were selfed using pollen bags. Female fertility of F1 ranged from 0.03 to 0.6%. Eighteen percent of the sown BC1s germinated and flowered. Chromosome numbers ranged from 30 to 84 and several of the plants bore wheat-specific sequence-characterized amplified regions (SCARs) and the bar gene. Self fertility in two BC1 plants was 0.16 and 5.21%, and the others were completely self-sterile. Among 19 BC1S1 individuals one plant was transgenic, had 43 chromosomes, contained the bar gene, and survived glufosinate treatments. The other BC1S1 plants had between 28 and 31 chromosomes, and several of them carried SCARs specific to wheat A and D genomes. Fertility of these plants was higher under open-pollination conditions than by selfing and did not necessarily correlate with even or euploid chromosome number. Some individuals having supernumerary wheat chromosomes recovered full fertility.
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Introgression of wheat DNA markers from A, B and D genomes in early generation progeny of Aegilops Cylindrica Host × Triticum aestivum L. hybrids
Theoretical and Applied Genetics, 2005Co-Authors: N. Schoenenberger, F. Felber, D. Savova-bianchi, R. GuadagnuoloAbstract:Introgression from allohexaploid wheat ( Triticum aestivum L., AABBDD) to allotetraploid jointed goatgrass ( Aegilops Cylindrica Host, CCDD) can take place in areas where the two species grow in sympatry and hybridize. Wheat and Ae. Cylindrica share the D genome, issued from the common diploid ancestor Aegilops tauschii Coss. It has been proposed that the A and B genome of bread wheat are secure places to insert transgenes to avoid their introgression into Ae. Cylindrica because during meiosis in pentaploid hybrids, A and B genome chromosomes form univalents and tend to be eliminated whereas recombination takes place only in D genome chromosomes. Wheat random amplified polymorphic DNA (RAPD) fragments, detected in intergeneric hybrids and introgressed to the first backcross generation with Ae. Cylindrica as the recurrent parent and having a euploid Ae. Cylindrica chromosome number or one supernumerary chromosome, were assigned to wheat chromosomes using Chinese Spring nulli-tetrasomic wheat lines. Introgressed fragments were not limited to the D genome of wheat, but specific fragments of A and B genomes were also present in the BC1. Their presence indicates that DNA from any of the wheat genomes can introgress into Ae. Cylindrica . Successfully located RAPD fragments were then converted into highly specific and easy-to-use sequence characterised amplified regions (SCARs) through sequencing and primer design. Subsequently these markers were used to characterise introgression of wheat DNA into a BC1S1 family. Implications for risk assessment of genetically modified wheat are discussed.
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introgression of wheat dna markers from a b and d genomes in early generation progeny of Aegilops Cylindrica host triticum aestivum l hybrids
Theoretical and Applied Genetics, 2005Co-Authors: N. Schoenenberger, Dessislava Savovabianchi, Francois Felber, R. GuadagnuoloAbstract:Introgression from allohexaploid wheat (Triticum aestivum L., AABBDD) to allotetraploid jointed goatgrass (Aegilops Cylindrica Host, CCDD) can take place in areas where the two species grow in sympatry and hybridize. Wheat and Ae. Cylindrica share the D genome, issued from the common diploid ancestor Aegilops tauschii Coss. It has been proposed that the A and B genome of bread wheat are secure places to insert transgenes to avoid their introgression into Ae. Cylindrica because during meiosis in pentaploid hybrids, A and B genome chromosomes form univalents and tend to be eliminated whereas recombination takes place only in D genome chromosomes. Wheat random amplified polymorphic DNA (RAPD) fragments, detected in intergeneric hybrids and introgressed to the first backcross generation with Ae. Cylindrica as the recurrent parent and having a euploid Ae. Cylindrica chromosome number or one supernumerary chromosome, were assigned to wheat chromosomes using Chinese Spring nulli-tetrasomic wheat lines. Introgressed fragments were not limited to the D genome of wheat, but specific fragments of A and B genomes were also present in the BC1. Their presence indicates that DNA from any of the wheat genomes can introgress into Ae. Cylindrica. Successfully located RAPD fragments were then converted into highly specific and easy-to-use sequence characterised amplified regions (SCARs) through sequencing and primer design. Subsequently these markers were used to characterise introgression of wheat DNA into a BC1S1 family. Implications for risk assessment of genetically modified wheat are discussed.
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gene flow from wheat triticum aestivum l to jointed goatgrass Aegilops Cylindrica host as revealed by rapd and microsatellite markers
Theoretical and Applied Genetics, 2001Co-Authors: R. Guadagnuolo, Dessislava Savovabianchi, Francois FelberAbstract:In order to estimate the potential of gene flow between wheat (Triticum aestivum L.) and jointed goatgrass (Aegilops Cylindrica Host.), we carried out mixed pollinations in experimental and natural conditions. A set of species-specific RAPD (random amplified polymorphic DNA) and microsatellite markers were used to detect the presence of parental markers in the progeny of the plants used in these experiments. No hybrids were found within the offsprings of the plants used for the greenhouse experiments, while 85 Ae. Cylindrica×T. aestivum hybrids were found within 2400 analyzed F1 plants resulting from the field pollinations. The hybridization rates for individuals of different populations of the wild species differed considerably: 1% for two populations known for more than 90 years versus 7% for a newly discovered population. Most of the hybrids were completely sterile, but five of them produced 13 seeds (BC1) by backcross with Ae. Cylindrica. Twelve seeds germinated and generated viable and partly fertile plants. About 25% of the wheat specific RAPD markers were found in the BC1 plants, indicating that introgression of wheat DNA into Ae. Cylindrica is possible. In addition, one microsatellite marker, known to be situated on the D genome (a genome shared by both species), was also found in the BC1 plants.
Carol A Mallorysmith - One of the best experts on this subject based on the ideXlab platform.
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jointed goatgrass Aegilops Cylindrica a review
Weed Science, 2018Co-Authors: Carol A Mallorysmith, Drew J Lyon, Andrew R Kniss, Robert S. ZemetraAbstract:In 1994, the National Jointed Goatgrass Research Program was initiated with funding from a special USDA grant. The 15-yr program provided $4.1 million to support jointed goatgrass (Aegilops Cylindrica Host.) research and technology transfer projects in 10 western states. These projects resulted in approximately 80 refereed manuscripts, including journal articles and extension publications. The research covered various topics related to the biology and ecology of jointed goatgrass as well as its management and control in wheat (Triticum aestivum L.) production systems. This review summarizes the research on jointed goatgrass published after Donald and Ogg's 1991 review, most of which was conducted as part of the USDA-funded National Jointed Goatgrass Research Program. Specific topics that were studied and reviewed here include A. Cylindrica genetics, especially as it relates to gene flow and hybridization rates with wheat and fertility of the resulting hybrids; vernalization requirements; seed dormancy, longevity, and germination requirements; competitiveness with wheat; and herbicide resistance acquired through evolution or gene flow from wheat. With respect to management, a wide variety of practices were evaluated, including various tillage types and frequencies; crop rotations, especially diversified wheat production systems that include spring-seeded annual crops; competitive wheat cultivars, seeding dates, seeding density, and row spacing; fertility management, including nitrogen application timing and placement; and field burning. Finally, many studies evaluated the use of herbicides, especially the introduction of imazamox in imidazolinone-resistant wheat cultivars, as well as comparison of adjuvant systems and application timings. In addition to the many management practices that were studied individually, several integrated management systems were evaluated that combined crop rotations, tillage, and herbicide programs. Between 1993 and 2013, weed scientists in 14 western states estimated that jointed goatgrass infestations decreased by 45% to 55% and attributed the reduction to the implementation of more diverse crop rotations, improved cultural practices, and use of imazamox-resistant wheat technology. This is evidence that the practical implications of the National Jointed Goatgrass Research Program have been successfully implemented by growers throughout the western United States.
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impact of transgene genome location on gene migration from herbicide resistant wheat triticum aestivum l to jointed goatgrass Aegilops Cylindrica host
Pest Management Science, 2017Co-Authors: Maqsood Rehman, Carol A Mallorysmith, Jennifer L. Hansen, Robert S. ZemetraAbstract:BACKGROUND Wheat (Triticum aestivum) (ABD) and jointed goatgrass (Aegilops Cylindrica) (CD) can cross and produce hybrids that can backcross to either parent. Such backcrosses can result in progeny with chromosomes and/or chromosome segments retained from wheat. Thus, a herbicide resistance gene could migrate from wheat to jointed goatgrass. In theory, the risk of gene migration from herbicide-resistant wheat to jointed goatgrass is more likely if the gene is located on the D genome and less likely if the gene is located on the A or B genome of wheat. RESULTS BC1 populations (jointed goatgrass as a recurrent parent) were analyzed for chromosome numbers and transgene transmission rates under sprayed and non-sprayed conditions. Transgene retention in the non-sprayed BC1 generation for the A, B and D genomes was 84, 60 and 64% respectively. In the sprayed populations, the retention was 81, 59 and 74% respectively. CONCLUSION The gene transmission rates were higher than the expected 50% or less under sprayed and non-sprayed conditions, possibly owing to meiotic chromosome restitution and/or chromosome non-disjunction. Such high transmission rates in the BC1 generation negates the benefits of gene placement for reducing the potential of gene migration from wheat to jointed goatgrass. © 2016 Society of Chemical Industry
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selection pressure effects on the proportion and movement of resistance alleles introgressed from wheat in Aegilops Cylindrica
Weed Research, 2016Co-Authors: B A B Martins, Robert S. Zemetra, J M Leonard, L Sun, Carol A MallorysmithAbstract:Summary In winter wheat in the USA, Aegilops Cylindrica is one of the most troublesome weeds, while the pathogen Oculimacula spp. causes foot rot disease. Imazamox-resistant (IR) and foot rot-resistant (FR) wheat cultivars represent effective tools to control the weed and prevent disease infection. However, resistance allele (RA) movement between wheat and A. Cylindrica facilitates the introgression process under herbicide and disease selection pressure. Field experiments using IR and FR A. Cylindrica plants intermixed with susceptible plants were conducted to measure the proportion of the RAs in the progeny and RA movement with and without herbicide and disease selection. Yield components of A. Cylindrica plants were determined across treatments. The herbicide RA proportion in the progeny was greater when plants were treated with the herbicide imazamox in both years. Disease RA proportion was greater with disease occurrence only in one year. Herbicide RA movement from resistant to susceptible plants was greater with herbicide than without it only in one year. Plants carrying the RAs had greater total spikelet weight and 1000-spikelet weight compared with susceptible plants with or without selection. However, susceptible plants produced more spikelets than the resistant ones in the absence of selection. If plants within an A. Cylindrica population acquire the herbicide RA, its proportion will increase each generation under selection. These findings contribute to the understanding of crop allele introgression into related species and the evolution of increased weediness, with weed management implications.
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a short growing season negatively affects progeny vigor in jointed goatgrass Aegilops Cylindrica
Agricultural sciences, 2015Co-Authors: Lynn M Ingegneri, Michael P Quinn, Andrew G Hulting, Carol A MallorysmithAbstract:Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorter growing season experienced by a maternal jointed goatgrass plant similarly affected seedling vigor in the progeny. Seed mass, percent germination, emergence, seedling height and biomass, including roots, were recorded or evaluated on progeny that were produced from three jointed goatgrass populations grown under a long or short growing season in a common garden experiment in eastern Oregon, an area where jointed goatgrass is known to commonly infest natural resources, including winter wheat. Seeds produced under a shorter growing season weighed less, were slower to germinate, and displayed lower percent germination compared with seeds produced under a long growing season. Seedlings from a short growing season were slower to emerge, and produced less shoot biomass compared to seedlings produced under a long growing season. Seedling roots and shoots were shorter when seeds were produced under a short growing season. A shorter growing season negatively affected jointed goatgrass seedling vigor. If resources for jointed goatgrass management are limited, strategies should focus on controlling plants that emerge in the fall, because they have the potential to produce more vigorous seedlings compared to plants that emerge in late winter or early spring.
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hybridization between wheat and jointed goatgrass Aegilops Cylindrica under field conditions
Weed Science, 2006Co-Authors: Harish Gandhi, Robert S. Zemetra, Carol A Mallorysmith, Isabel M Vales, Christy J W Watson, Oscar RieralizarazuAbstract:Abstract Jointed goatgrass is an important weed of wheat in the United States and other parts of the world. Under field conditions, wheat and jointed goatgrass can hybridize and produce backcross derivatives, a situation that may allow gene flow between these two species. In order to gain a better understanding of the factors governing gene flow, a study to characterize patterns of mating between these two species was undertaken. Chloroplast and nuclear microsatellite markers were used to evaluate the parentage of 413 first-generation backcross (BC1) seeds obtained from 127 wheat–jointed goatgrass F1 hybrids, produced naturally under field conditions. Of the 127 hybrids evaluated, 109 (85.8%) had jointed goatgrass as the female parent, whereas the remaining 18 F1 plants (14.2%) had wheat as the female parent. Of the 413 BC1 plants analyzed, 358 (86.7%) had wheat and 24 (5.8%) had jointed goatgrass as the male backcross parent. The male parentage of 31 BC1 (7.5%) plants could not be determined. Under natur...
Francois Felber - One of the best experts on this subject based on the ideXlab platform.
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molecular analysis cytogenetics and fertility of introgression lines from transgenic wheat to Aegilops Cylindrica host
Genetics, 2006Co-Authors: N. Schoenenberger, R. Guadagnuolo, Dessislava Savovabianchi, Philippe Kupfer, Francois FelberAbstract:Natural hybridization and backcrossing between Aegilops Cylindrica and Triticum aestivum can lead to introgression of wheat DNA into the wild species. Hybrids between Ae. Cylindrica and wheat lines bearing herbicide resistance (bar), reporter (gus), fungal disease resistance (kp4), and increased insect tolerance (gna) transgenes were produced by pollination of emasculated Ae. Cylindrica plants. F1 hybrids were backcrossed to Ae. Cylindrica under open-pollination conditions, and first backcrosses were selfed using pollen bags. Female fertility of F1 ranged from 0.03 to 0.6%. Eighteen percent of the sown BC1s germinated and flowered. Chromosome numbers ranged from 30 to 84 and several of the plants bore wheat-specific sequence-characterized amplified regions (SCARs) and the bar gene. Self fertility in two BC1 plants was 0.16 and 5.21%, and the others were completely self-sterile. Among 19 BC1S1 individuals one plant was transgenic, had 43 chromosomes, contained the bar gene, and survived glufosinate treatments. The other BC1S1 plants had between 28 and 31 chromosomes, and several of them carried SCARs specific to wheat A and D genomes. Fertility of these plants was higher under open-pollination conditions than by selfing and did not necessarily correlate with even or euploid chromosome number. Some individuals having supernumerary wheat chromosomes recovered full fertility.
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introgression of wheat dna markers from a b and d genomes in early generation progeny of Aegilops Cylindrica host triticum aestivum l hybrids
Theoretical and Applied Genetics, 2005Co-Authors: N. Schoenenberger, Dessislava Savovabianchi, Francois Felber, R. GuadagnuoloAbstract:Introgression from allohexaploid wheat (Triticum aestivum L., AABBDD) to allotetraploid jointed goatgrass (Aegilops Cylindrica Host, CCDD) can take place in areas where the two species grow in sympatry and hybridize. Wheat and Ae. Cylindrica share the D genome, issued from the common diploid ancestor Aegilops tauschii Coss. It has been proposed that the A and B genome of bread wheat are secure places to insert transgenes to avoid their introgression into Ae. Cylindrica because during meiosis in pentaploid hybrids, A and B genome chromosomes form univalents and tend to be eliminated whereas recombination takes place only in D genome chromosomes. Wheat random amplified polymorphic DNA (RAPD) fragments, detected in intergeneric hybrids and introgressed to the first backcross generation with Ae. Cylindrica as the recurrent parent and having a euploid Ae. Cylindrica chromosome number or one supernumerary chromosome, were assigned to wheat chromosomes using Chinese Spring nulli-tetrasomic wheat lines. Introgressed fragments were not limited to the D genome of wheat, but specific fragments of A and B genomes were also present in the BC1. Their presence indicates that DNA from any of the wheat genomes can introgress into Ae. Cylindrica. Successfully located RAPD fragments were then converted into highly specific and easy-to-use sequence characterised amplified regions (SCARs) through sequencing and primer design. Subsequently these markers were used to characterise introgression of wheat DNA into a BC1S1 family. Implications for risk assessment of genetically modified wheat are discussed.
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gene flow from wheat triticum aestivum l to jointed goatgrass Aegilops Cylindrica host as revealed by rapd and microsatellite markers
Theoretical and Applied Genetics, 2001Co-Authors: R. Guadagnuolo, Dessislava Savovabianchi, Francois FelberAbstract:In order to estimate the potential of gene flow between wheat (Triticum aestivum L.) and jointed goatgrass (Aegilops Cylindrica Host.), we carried out mixed pollinations in experimental and natural conditions. A set of species-specific RAPD (random amplified polymorphic DNA) and microsatellite markers were used to detect the presence of parental markers in the progeny of the plants used in these experiments. No hybrids were found within the offsprings of the plants used for the greenhouse experiments, while 85 Ae. Cylindrica×T. aestivum hybrids were found within 2400 analyzed F1 plants resulting from the field pollinations. The hybridization rates for individuals of different populations of the wild species differed considerably: 1% for two populations known for more than 90 years versus 7% for a newly discovered population. Most of the hybrids were completely sterile, but five of them produced 13 seeds (BC1) by backcross with Ae. Cylindrica. Twelve seeds germinated and generated viable and partly fertile plants. About 25% of the wheat specific RAPD markers were found in the BC1 plants, indicating that introgression of wheat DNA into Ae. Cylindrica is possible. In addition, one microsatellite marker, known to be situated on the D genome (a genome shared by both species), was also found in the BC1 plants.