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Análisis de la sensibilidad de biotipos de Lolium multiflorum a herbicidas inhibidores de la enzima ALS, ACCasa y Glifosato Sensitivity analysis of Lolium multiflorum biotypes to Glyphosate, ACCase and ALS-inhibiting herbicides
P. Diez De Ulzurrun,M.I. Leaden
Planta Daninha , 2012, DOI: 10.1590/s0100-83582012000300024
Abstract: A pesar de los avances logrados en el control de las malezas con el uso de herbicidas, el manejo de las mismas no se simplificó, sino que, al contrario, surgieron nuevos desafíos, como la aparición de resistencia a herbicidas. En 2007, se reportó en Lolium multiflorum el segundo caso de resistencia a glifosato detectado en Argentina. En el sudeste de la provincia de Buenos Aires se registraron fallas de control a campo en poblaciones de Lolium multiflorum debido a su resistencia a distintos herbicidas de las familias de los inhibidores de ALS y de ACCasa y al herbicida glifosato. El objetivo de este estudio fue caracterizar el nivel de resistencia a ciertos herbicidas inhibidores de la ALS y de la ACCasa y al glifosato en una población de L. multiflorum de Lobería (Bs As, Argentina) supuestamente resistente (LmR). Se realizaron bioensayos en cajas de Petri y se determinó la GR50 mediante la variación en la longitud de coleoptile. Las curvas de dosis-respuesta se obtuvieron por medio de la ecuación log-logística. El biotipo LmR presentó resistencia múltiple a herbicidas con tres modos de acción diferentes: glifosato, inhibidores de ALS y de ACCasa. Dicho ensayo demostró la aparición de un biotipo de L. multiflorum con resistencia a múltiples principios activos. Despite progress in weed control using herbicides, management has not been simplified, but new challenges such as herbicides resistance have arisen. In 2007, a Lolium multiflorum population resistant to glyphosate was reported, as the second case of glyphosate resistant weeds in Argentina. In the southeast of Buenos Aires province, control failures in populations of L. multiflorum to different families of herbicide such as ALS and ACCase inhibitors and to glyphosate at field level have been registered. The aim of this study was to characterize the level of resistance to certain herbicides inhibitors of ALS, ACCase and glyphosate in a putatively resistant (LmR) population of L. multiflorum of Loberia (Buenos Aires, Argentina). Bioassays were conducted in Petri dishes and the GR50 was determined by the length of coleoptile. Curves dose-response were obtained using the log-logistic equation. The LmR biotype survived under multiple herbicides of three different modes of action, glyphosate, ALS and ACCase inhibitors. This test showed the appearance of a biotype of L. multiflorum with resistance to multiple active ingredients.
Resistência de azevém (Lolium multiflorum) ao herbicida glyphosate
Roman, E.S.;Vargas, L.;Rizzardi, M.A.;Mattei, R.W.;
Planta Daninha , 2004, DOI: 10.1590/S0100-83582004000200018
Abstract: italian ryegrass (lolium multiflorum) is cultivated as forage and/or cover crop in no-till system. however, it is also a serious weed in wheat and other winter cereals in southern brazil. experiments were conducted at greenhouse and field conditions to evaluate the susceptibility of two ryegrass biotype to glyphosate as well as the efficacy of other herbicides on the post-emergence control of the species for sowing wheat under no-till system. the experimental design was a completely randomized design for the greenhouse experiment and a completely randomized block design for the field experiment. herbicides with different mechanisms of action were evaluated on the weed control: glyphosate, glufosinate, clethodim, haloxyfop-r and diclofop, paraquat and paraquat+diuron. the results obtained under greenhouse conditions indicated the glyphosate susceptible biotype was controlled by the rate of 360 g e.a. ha-1. the resistant ryegrass biotype had no reduction in dry matter production and less than 15 % phytotoxicity caused by glyphosate up to 1,440 g e.a. ha-1. however, glyphosate rates between 1440 and 5,760 g e.a. ha-1 reduced dry matter accumulation and resulted in toxicities under45%. under field conditions, the best lolium multiflorum control was given by clethodim 79.2 g ha-1 and diuron + paraquat at 300+600 g ha1, respectively. the results obtained in these studies indicated that the population was composed predominantly by a biotype resistant to epsps inhibitor herbicides.
Transloca??o do glyphosate em biótipos de azevém (Lolium multiflorum)
Ferreira, E.A.;Santos, J.B.;Silva, A.A.;Oliveira, J.A.;Vargas, L.;
Planta Daninha , 2006, DOI: 10.1590/S0100-83582006000200021
Abstract: this work evaluated foliar absorption and glyphosate translocation in italian ryegrass (lolium multiflorum) susceptible and resistant biotypes, 14c-glyphosate was applied by using a precision micro syringe, and adding 10 μl of solution on the adaxial side of the first leaf with ligule totally visible, when italian ryegrass plants showed 3 tillers. the quantity of glyphosate absorbed and translocated was evaluated through a liquid scintilation spectrometer by measuring radiation emitted by 14c-glyphosate at 2, 4, 8, 16, 32 and 64 hours after application. the roots and aerial part were analyzed as well as the leaf where application was performed and the solution used to wash the leaf. glyphosate absorption speed was similar in both italian ryegrass biotypes, with over 50% of herbicide absorption in the first 8 hours after application. up to 64 hours, higher retention (81.64%)of glyphosate was observed in the resistant biotype, while only 55% was retained in the susceptible biotype. in the remaining aerial part and roots, a higher amount of glyphosate was absorbed by the susceptible biotype, indicating higher capacity of its translocation. after 64 hours of application, only 6%, of glyphosate was found in the plants, on average indicating that most of the product could be exuded. it could be concluded that italian ryegrass sensitivity to glyphosate can be attributed to higher translocation capacity of this herbicide by susceptible biotypes.
Suscetibilidade de genótipos de Lolium multiflorum ao herbicida glyphosate
Dors, C.A.;Christoffoleti, P.J.;Sanchotene, D.M.;Dias, A.C.R.;Manfron, P.A.;Dornelles, S.H.B.;
Planta Daninha , 2010, DOI: 10.1590/S0100-83582010000200020
Abstract: this work aimed to evaluate the degree of tolerance of italian ryegrass genotypes to the herbicide glyphosate. thus, four experiments were installed, one for each phenological stage (two leaves, four tillers, pre-flowering, and grain formation). the treatments consisted of the combination of the two genotypes and six rates of glyphosate (240; 480; 960; 1,920; 3,840 and 7,680 g a.e. ha-1) and a check without glyphosate application, in a complete randomized block design and four replications. the parameters analyzed were control percentage and shoot dry biomass. results were submitted to analysis of variance and subsequently adjusted to non-linear log of dose-response curves, and from these models control values were calculated at 50, 80, 90 and 99%. the italian ryegrass genotypes presented differential susceptibility to the herbicide glyphosate, with the tetraploid genotype being more tolerant to the herbicide than the diploid. the degree of differential tolerance, measured by the differential tolerance factor between the genotypes, is 1.6 times the glyphosate dose in the tetraploid genotype compared to the diploid genotype. the phenological stages of plant development of both the genotypes studied affected the degree of tolerance to glyphosate. the variable shoot dry biomass presented the same differential tendency between the diploid and tetraploid genotypes presented by the parameter visual control percentage.
Identifica??o de biótipos de azevém (Lolium multiflorum) resistentes ao herbicida glyphosate em pomares de ma??
Vargas, L.;Roman, E.S.;Rizzardi, M.A.;Silva, V.C.;
Planta Daninha , 2004, DOI: 10.1590/S0100-83582004000400017
Abstract: glyphosate is a wide spectrum herbicide used for over 15 years in apple orchards in vacaria-rs for weed control in rows of trees. usually, 3 to 4 applications per year are made at a rate of 720 to 1080 g a.e. glyphosate ha-1 (2 to 3 l ha-1 of commercial product). ryegrass (lolium multiflorum) is a common weed in orchards and traditionally sensitive to glyphosate. however, in the last years, some ryegrass plants have not been found to show significant toxicity symptoms after treatment with glyphosate, suggesting that they acquired resistance to this product. to evaluate the response of a ryegrass plant population to glyphosate, one field and two greenhouse experiments were carried out. the field experiment treatments had increasing rates of glyphosate (0; 360; 720; 1,440; 2,880; 5,760 and 11,520 g a.e. ha-1), in addition to the herbicides paraquat, glufosinate-ammonium, haloxyfop and diclofop-methyl as standards, sprayed at two different vegetative growth stages of ryegrass. the greenhouse experiments had increasing rates of glyphosate (0; 360; 720; 1,440; 2,880 and 5,760 g a.e. ha-1) plus the above listed check herbicides sprayed on biotypes considered resistant and on plants of one susceptible biotype. in the second greenhouse experiment, glyphosate rates (720; 1,440; 2,880; 720 + 720 and 720 + 1,440 g a.e. ha-1) were sprayed in single and sequential applications, in addition to the herbicides paraquat, glufosinate-ammonium, haloxyfop, clethodim, sethoxydim, diclofop-methyl, fenoxaprop, fluazifop, paraquat + diuron, atrazine + simazine, trifluralin, and metolachlor. toxicicity to the herbicides was assessed at 15, 30 and 45 dat (days after treatment). overall, the field and greenhouse experiment results showed that the susceptible biotype is easily controlled by glyphosate and by the other postemergence herbicides tested, independent of the vegetative growth stage. in addition, the results showed that the resistant biotype, similarly to the susceptible biotype, is
Heran?a da resistência de azevém (Lolium multiflorum) ao glyphosate
Vargas, L.;Moraes, R.M.A.;Berto, C.M.;
Planta Daninha , 2007, DOI: 10.1590/S0100-83582007000300016
Abstract: glyphosate is a non-selective herbicide used to control weeds. azevem plants, which are tolerant to glyphosate, have been identified in rio grande do sul, where they are rapidly becoming predominant. the objective of this work was to identify inheritance type, number of genes conferring resistance, and the degree of resistance in azevem plants. reciprocal crossings between sensitive and resistant plants have been carried out to obtain f1 seeds which were crossed among themselves to obtain f2 plants .herbicide containing 720 g ha-1 was applied on the f1, f2, rcr, rc and parent plants to estimate segregation. to evaluate the degree of resistance of the f1 plants, resistant and sensitive parents were sprayed with increasing rates of glyphosate (0, 360, 720, 1.440 and 2.880 g ha-1). f1 plants showed intermediate response to the resistant and sensitive biotypes, indicating that allelic interaction is of the incomplete dominance type. f2 plants showed a tendency for segregation 3:1, indicating that resistance to glyphosate is controlled by a semi-dominant gene.
Aspectos morfofisiológicos de biótipos de azevém (Lolium multiflorum) sensíveis e resistentes ao glyphosate
Galvan, J;Rizzardi, M.A;Scheffer-Basso, S;
Planta Daninha , 2011, DOI: 10.1590/S0100-83582011000500018
Abstract: ryegrass has a high potential for infestation in crops and orchads and its control with glyphosate has been limited due to the existence of herbicide-resistant biotypes. the objective of this work was to compare four ryegrass biotypes collected from different regions in the state of rio grande do sul, brazil, to test the hypothesis that morphophysiological aspects and phenology are linked to resistance. the experiment was conducted in a greenhouse, where four biotypes, one susceptible (b1s, passo fundo) and three resistant to glyphosate (b2r, santa maria; b3r, julio de castillos; b4r, vacaria) were collected at 126, 147, 168 and 189 days of age. biotype b1s showed 21 days in advance of flowering in relation to the other biotypes. biotype b4r produced significantly more leaves (43 per plant), tillers (14 per plant), ears (14 per plant), seeds (3484 per plant) and total dry matter (roots + shoot = 13.8 g per plant). it is concluded that sensitive biotypes cannot be distinguished from the resistant ones only by morphological aspects related to vigor.
Altera??o das características biológicas dos biótipos de azevém (Lolium multiflorum) ocasionada pela resistência ao herbicida glyphosate
Vargas, L.;Roman, E.S.;Rizzardi, M.A.;Silva, V.C.;
Planta Daninha , 2005, DOI: 10.1590/S0100-83582005000100018
Abstract: the identification of ryegrass biotypes resistant to glyphosate is causing changes in weed management in apple orchards. three experiments were carried out to determine the gr50 of the biotypes, to grass herbicides and dry matter accumulation. the first experiment tested different rates of glyphosate. their effects on gr50 dry matter accumulation by the biotype were assessed. in the second experiment different rates of glyphosate and grass herbicides were tested: glyphosate, haloxyfop-r, diclofop, fluazifop-p, fenoxaprop-p and paraquat. a third experiments was carried out under glasshouse conditions to determine the curve of dry matter accumulation. the results showed gr50 of 287.5 and 4,833.5 g e. a. ha-1 of glyphosate for the sensitive and resistant biotypes, respectively. the results showed that the resistant factor (rf) was 16.8 and that the resistance mechanism alters the biological characteristics of the resistant biotype affecting its sensitivity to grass herbicides.
Somatic embryogenesis in Lolium multiflorum suspension culture
Margarita Pavlova,Elizabeth Kordyum
Acta Societatis Botanicorum Poloniae , 1996, DOI: 10.5586/asbp.1996.007
Abstract: The embryogenic cell suspension was obtained from immature embryos of Lolium multiflorum through a callus culture. Somatic embryogenesis was induced by addition of 2,4-D, dicamba and picloram in 0,5 mg/l concentrations in MS liquid nutrient medium. It was shown that somatic embryos arised from single cells. In globular embryoids, the meristematic cells are characterized by the presence of phytoferritin inclusions in the leucoplasts.
Morphology and pollen viability of Lolium multiflorum Lam.
Nunes, Renata de Castro;Bustamante, Fernanda de Oliveira;Techio, Vania Helena;Mittelmann, Andréa;
Ciência e Agrotecnologia , 2012, DOI: 10.1590/S1413-70542012000200006
Abstract: study and characterization of pollen grains are essential for different areas, especially taxonomy, genetic improvement, phylogeny, and paleobotany. as yet, there are no reports on pollen morphology of genotypes of naturalized lolium multiflorum lam., introduced cultivars or breeding populations, diploid or polyploid. ten genotypes of annual ryegrass (l. multiflorum) were evaluated for the viability of pollen grains using propionic carmine and alexander's stains, while morphology was assessed by the acetolysis technique. measures of polar axis (p), equatorial diameter (e), exine thickness, and analysis of pollen grains were obtained by scanning electron microscopy (sem). all genotypes showed high rate of pollen viability (> 89%) for both stains. there were differences between genotypes in the following quantitative traits: polar axis, equatorial diameter, exine, endexine, ektexine, and p/e ratio. pollen grains were characterized as small, monoporates, with circular and non-prominent apertures. in addition to helping distinction of pollen grains, morphometric differences can be used later to compare ploidy levels, thus assisting in breeding programs of the species.
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