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Tomas, Maria Andrea - One of the best experts on this subject based on the ideXlab platform.
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Prospective genetic gain to improve salinity tolerance in a population of Panicum coloratum var. coloratum with two different selection methods
'Centro Internacional de Agricultura Tropical', 2021Co-Authors: Pittaro Gabriela, Lifschitz, Mauro Ezequiel, Otondo Jose, Bustos, Dolores Angela, Sanchez, Miguel Alejandro, Tomas, Maria AndreaAbstract:Panicum coloratum var. coloratum is a subtropical grass for potentially increasing forage production in lowly productive environments where cattle-raising activities have been relocated. Heritability was estimated for characters related to salinity tolerance under saline and non-saline conditions to explore the possibility of improving tolerance by selection. From a base germplasm collected in a very harsh environment, heritability and gain after selection were calculated using 2 recombination units: individual and phenotypic family mean (PFM). Heritability estimates were very low for all characters both in saline and non-saline conditions, suggesting a complex genetic control of salinity tolerance, with a high proportion of non-additive genetic effects. Estimates were higher using individual selection than with PFM and expected genetic gains were higher for individual selection. When compared in both saline and non-saline conditions, predicted means were greater than for plants of cv. Klein, the most common cultivar in use. It appears that the analyzed germplasm would be a valuable source of genes to be included in breeding programs to increase salinity tolerance in Panicum coloratum.Panicum coloratum var. coloratum es una gramínea forrajera subtropical adecuada para incrementar la producción de forraje en ambientes de baja productividad donde la ganadería ha sido relocalizada. En un estudio realizado en Buenos Aires y Córdoba, Argentina, se estimó la heredabilidad para caracteres relacionados a la tolerancia a salinidad en condiciones salinas y no salinas para explorar la posibilidad de mejorar la tolerancia por selección. A partir de un germoplasma base recolectado de un ambiente con condiciones restrictivas de crecimiento, la heredabilidad y la ganancia genética luego de un ciclo de selección fueron calculadas usando dos unidades de recombinación: individual y media fenotípica familiar (PFM en inglés). Las estimaciones de heredabilidad fueron bajas para todos los caracteres tanto en condiciones salinas como no salinas sugiriendo un complejo control genético de la tolerancia a salinidad con alta proporción de efectos genéticos no aditivos. Las estimaciones fueron superiores usando la selección individual en comparación con la media fenotípica familiar. La ganancia genética esperada fue mayor para la selección individual. Tanto en condiciones salinas como en no salinas, la media predicha fue superior al cv. Klein, el cultivar más común de la variedad. El germoplasma analizado sería un buen recurso para ser incluido en programas de mejoramiento para incrementar la tolerancia a salinidad en Panicum coloratum.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Pittaro, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Lifschitz, Mauro Ezequiel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Lifschitz, Mauro Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Sanchez, Miguel Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Bustos, Dolores Angela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Otondo, José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Tomas, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin
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Combined effect of salinity and hypoxia in seedlings of two varieties of Panicum coloratum: morphology, root system architecture, oxidative damage and antioxidant response
'Wiley', 2021Co-Authors: Lifschitz, Mauro Ezequiel, Grunberg Karina, Tommasino, Exequiel Arturo, Zabala, Juan Marcelo, Ramos, Julio Cesar, Tomas, Maria AndreaAbstract:The effect of the combination of salinity and waterlogging may be additive, or alternatively, more or less detrimental than effects of them separately. Our objective was to evaluate the effects of waterlogging, salinity and the combination of both on seedlings of Panicum coloratum, a subtropical forage grass. Seedlings of cultivars Kapivera-INTA (KA) and Klein (KL) were exposed to treatments in a controlled hydroponic experiment and several morphological and physiological variables evaluated. The effect of hypoxia was almost null when the plants were already in salinity. KA showed lower reduction than KL in shoot biomass. Both varieties showed synergistic effect of stresses, indicating that biomass production was less affected under the combined treatment than predicted from them separately. Root length, tips, forks and volume were reduced by saline exposure, while no differences in root architecture was noticeable between cultivars. Plants of KA increased leaf temperature in salinity. Non-enzymatic oxidative response and the activity of antioxidant enzymes increased in saline conditions and were lower in KA than in KL. Oxidative damage was equivalent between cultivars and among stress conditions. Proline content was comparable to control in hypoxia but increased significantly in saline conditions, with a higher response in KL than in KA. Increases in Na+ (over 900%) and decreases in K+ (50%) tissue concentration in salinity occurred only in KA. In general, P. coloratum proved more tolerant to hypoxia than to salinity or their combination, Kapivera-INTA being more tolerant than Klein. Findings provide basis to deepen research into tolerance mechanisms.EEA RafaelaFil: Lifschitz, Mauro Ezequiel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; ArgentinaFil: Lifschitz, Mauro Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea; ArgentinaFil: Tommasino, Exequiel Arturo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina.Fil: Zabala, Juan Marcelo. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Zabala, Juan Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Grunberg, Karina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina.Fil: Grunberg, Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA); ArgentinaFil: Grunberg, Karina. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Grunberg, Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Ramos, Julio Cesar. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Ramos, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias Agropecuarias del Litoral; ArgentinaFil: Tomas, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; Argentina; ArgentinaFil: Tomas, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea; Argentin
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Phenotypic plasticity to drought in seedlings of the warm season grass Panicum coloratum is related to collection site
'Wiley', 2019Co-Authors: Giordano, Mabel Cristina, Grimoldi, Agusti Alberto, Tomas, Maria AndreaAbstract:Phenotypic plasticity is the ability of organisms to modify their phenotype in response to environmental changes. We estimated and compared the amount of phenotypic plasticity in response to drought in seedlings of different accessions of two varieties (var. makarikariense and var. coloratum) of Panicum coloratum, an allogamous warm season perennial grass, introduced and collected in sites in Argentina with different precipitation regimes. Amount of phenotypic plasticity was quantified in shoot/root biomass, blade/sheath biomass, specific leaf area and leaf area ratio (leaf area/total biomass) and mean phenotypic plasticity was estimated. The two genetically distinct varieties differed in the phenotypic plasticity of leaf area ratio (p = 0.008, F‐test), with var. makarikariense showing higher phenotypic plasticity. Accessions within varieties differed in phenotypic plasticity of leaf area ratio, specific leaf area, blade/sheath biomass and mean phenotypic plasticity (p
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Panicum coloratum seed yield components in a farmer's field under diverse fertilization
2019Co-Authors: Mattera Juan, Giordano, Mabel Cristina, Tomas, Maria Andrea, Lifschitz, Mauro Ezequiel, Pacente, Ezequiel MartinAbstract:Kleingrass (Panicum coloratum var. coloratum) is widely adapted to Argentinian Central La Pampa region, with desirable traits including persistence and high nutrition value. Despite this, Kleingrass utilization by growers has been limited due to seed scarcity and erratic success in pasture establishment. The objective of this study was to compare seed yield components and forage remaining after harvest under different rates of N fertilization in a farmer ’s field.EEA PergaminoFil: Mattera, Juan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino. Forrajeras; ArgentinaFil: Tomás, María Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Lifschitz, Mauro Ezequiel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Giordano, Mabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Pacente, Ezequiel. Estación Experimental Agropecuaria Pergamino. Forrajeras; Argentin
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Variability for salt tolerance in a collection of Panicum coloratum var. makarikariense during early growth stages = Variabilidad en tolerancia a la salinidad en una colección de Panicum coloratum var. makarikariense durante las etapas tempranas de c
'Centro Internacional de Agricultura Tropical', 2018Co-Authors: Cardamone Luisina, Cuatrin Alejandra, Grunberg Karina, Tomas, Maria AndreaAbstract:Our aim was to investigate variability for salt tolerance in a collection of Panicum coloratum var. makarikariense of INTA EEA Rafaela, Argentina. Panicum coloratum is a C4 perennial grass to be potentially used to increase forage production in areas affected by abiotic factors which reduce their productivity. We evaluated the response of half-sib families from different accessions to increasing salt concentrations under growth chamber conditions. Germination percentage (GP), GP (% of control) and index of germination decreased with increasing salinity, while mean germination time increased (P˂0.001). After being exposed to saline conditions ungerminated seeds were able to recover in distilled water and many germinated. Salt tolerance was more variable between families within accessions than between accessions in all evaluated variables. At the seedling stage, morphological and physiological variables allowed differentiation among families on the basis of salt tolerance. Molecular characterization by ISSR molecular markers demonstrated variability within parent material and grouped families by accessions. A positive but low correlation between morphological and molecular distances was detected (r = 0.24; P = 0.032). Nonetheless, even after selection, enough molecular variability remained within tolerant families grouped by principal components analysis. In summary, materials of P. coloratum var. makarikariense from INTA EEA Rafaela showed both morphological and genetic variability for salinity tolerance and the contrasting genotypes could be used as parent materials to conduct breeding studies to improve salt tolerance in this species.El objetivo del trabajo fue determinar la variabilidad en tolerancia a la salinidad en una colección de Panicum coloratum var. makarikariense existente en la estación experimental (EEA) Rafaela, INTA, Argentina. Panicum coloratum es una gramínea perenne tipo C4 con potencial para incrementar la productividad ganadera en zonas afectadas por factores abióticos. En el estudio se evaluó la respuesta de familias de medios hermanos de diferentes accesiones de P. coloratum al incremento de la concentración salina. El porcentaje de germinación, la germinación con respecto al tratamiento control y el índice de germinación, disminuyeron con el incremento de la salinidad mientras el tiempo medio de germinación se incrementó (P
José Augusto Imaz - One of the best experts on this subject based on the ideXlab platform.
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Efectos del forraje diferido como cobertura de invierno en el crecimiento primaveral de las gramíneas tropicales Chloris gayana y Panicum coloratum
Centro Internacional de Agricultura Tropical, 2017Co-Authors: José Augusto Imaz, Víctor Merani, M A Benvenutti, O. Hernandez, Daniel Dos Santos, Daniel O. Giménez, Jose Ignacio ArroquyAbstract:En La Plata, Buenos Aires, Argentina, en un experimento en macetas a aire libre (condiciones de luz y temperatura naturales) se evaluó el efecto del forraje diferido como cobertura invernal en 2 gramíneas tropicales C4 (Chloris gayana y Panicum coloratum). Plantas adultas fueron extraídas de un establecimiento ganadero, trasplantadas a macetas en un jardín experimental y después de crecer durante 111 días (2 de Febrero al 23 de Mayo) sometidas a los tratamientos: (1) control [sin remoción del forraje diferido de otoño (DF)]; y (2) remoción del forraje diferido de otoño (DFR) a 15 cm del suelo. Se utilizaron 10 repeticiones por tratamiento y una planta por maceta (unidad experimental). Las plantas fueron cosechadas el 27 de Septiembre (después del invierno) y nuevamente en Noviembre para medir la biomasa del rebrote primaveral en los estratos superior (>15 cm) e inferior (<15 cm sobre el suelo), láminas, vainas y estolones. Se realizó un análisis alométrico para dilucidar la incidencia del estrés por frio y se registraron la temperatura del aire, la humedad relativa y la ocurrencia de heladas. Las plantas con forraje diferido alcanzaron una mayor biomasa (55‒80%) que aquellas con remoción del forraje. Panicum coloratum mostró un ajuste significativo entre la biomasa total y la biomasa de los diferentes estratos para ambos tratamientos, mostrando buena tolerancia al estrés por frio. Por otro lado, C. gayana mostró falta de ajuste de la biomasa y un mayor estrés por la remoción del forraje, mientras que las plantas sin remoción presentaron menor daño por frío y un mayor ajuste. La cobertura invernal del forraje diferido podría mejorar la productividad y supervivencia de estas especies forrajeras cuando son utilizadas en sistemas pastoriles templados. Estos resultados preliminares deben ser evaluados en condiciones de campo durante un mayor número de años, considerando diferentes estrategias de pastoreo. Palabras clave: Cobertura invernal, daño por frío, manejo de pasturas, protección de heladas
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effects of deferred forage as winter cover on spring growth of the tropical grasses chloris gayana and Panicum coloratum
Tropical Grasslands - Forrajes Tropicales, 2016Co-Authors: José Augusto Imaz, Víctor Merani, D. O. Giménez, Daniel Dos A Santos, M A Benvenutti, O. Hernandez, Jose Ignacio ArroquyAbstract:En La Plata, Buenos Aires, Argentina, en un experimento en macetas a aire libre (condiciones de luz y temperatura naturales) se evaluo el efecto del forraje diferido como cobertura invernal en 2 gramineas tropicales C4 ( Chloris gayana y Panicum coloratum ). Plantas adultas fueron extraidas de un establecimiento ganadero, trasplantadas a macetas en un jardin experimental y despues de crecer durante 111 dias (2 de Febrero al 23 de Mayo) sometidas a los tratamientos: (1) control [sin remocion del forraje diferido de otono (DF)]; y (2) remocion del forraje diferido de otono (DFR) a 15 cm del suelo. Se utilizaron 10 repeticiones por tratamiento y una planta por maceta (unidad experimental). Las plantas fueron cosechadas el 27 de Septiembre (despues del invierno) y nuevamente en Noviembre para medir la biomasa del rebrote primaveral en los estratos superior (>15 cm) e inferior (<15 cm sobre el suelo), laminas, vainas y estolones. Se realizo un analisis alometrico para dilucidar la incidencia del estres por frio y se registraron la temperatura del aire, la humedad relativa y la ocurrencia de heladas. Las plantas con forraje diferido alcanzaron una mayor biomasa (55‒80%) que aquellas con remocion del forraje. Panicum coloratum mostro un ajuste significativo entre la biomasa total y la biomasa de los diferentes estratos para ambos tratamientos, mostrando buena tolerancia al estres por frio. Por otro lado, C. gayana mostro falta de ajuste de la biomasa y un mayor estres por la remocion del forraje, mientras que las plantas sin remocion presentaron menor dano por frio y un mayor ajuste. La cobertura invernal del forraje diferido podria mejorar la productividad y supervivencia de estas especies forrajeras cuando son utilizadas en sistemas pastoriles templados. Estos resultados preliminares deben ser evaluados en condiciones de campo durante un mayor numero de anos, considerando diferentes estrategias de pastoreo. Palabras clave : Cobertura invernal, dano por frio, manejo de pasturas, proteccion de heladas.
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Effects of deferred forage as winter cover on spring growth of the tropical grasses Chloris gayana and Panicum coloratum
Tropical Grasslands-Forrajes Tropicales, 2016Co-Authors: José Augusto Imaz, Víctor Merani, D. O. Giménez, M A Benvenutti, O. Hernandez, Daniel Andrés Dos Santos, Jose Ignacio ArroquyAbstract:This pot study assessed the effects of deferring forage during autumn and leaving as winter cover on reducing cold damage to plants of 2 tropical (C4) grasses ( Chloris gayana and Panicum coloratum ) in a temperate environment in La Plata, Buenos Aires, Argentina. Mature plants were subjected to the following treatments: (i) autumn-deferred forage retained (DF) as control; and (ii) autumn-deferred forage removed (DFR) cutting at 15 cm from soil level at beginning of winter. This experiment had 10 replicates per treatment and 1 plant per pot (experimental unit). Plants of both species were extracted from a commercial beef farm and transplanted into an experimental garden in pots where they grew outdoors from 2 February to 23 May (111 days) when treatments were applied. After winter, both grasses were cut to 15 cm in early spring (27 September) and spring growth was measured in November. Shoot biomass was harvested at ground level and separated into lower and upper layers (above and below 15 cm), leaf blades, sheaths and stolons. Daily air temperature, relative humidity and frost events were registered. Allometric analysis of shoot biomass was performed to determine the stress incidence by cold. DF plants achieved 55‒80% higher shoot biomass than DFR plants during spring in both species. The allometric analysis revealed for P. coloratum significant relationships between shoot biomass from plant compartments (lower and upper layers, leaf blade and sheath) and total shoot biomass in both treatments, indicating good cold tolerance. However, for C. gayana, unlike DF plants, DFR plants were strongly stressed, showing a lack of shoot biomass fit. These results suggest that deferring autumn forage growth and retaining as winter cover may improve survival during winter and productivity during spring of these two tropical grasses in temperate pastoral systems. However, the study needs to be repeated under field conditions and under grazing or cutting over a number of years in different situations to verify these preliminary results. Keywords : Winter cover, cold damage, frost protection, pasture management.
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ability to recover overrides the negative effects of flooding on growth of tropical grasses chloris gayana and Panicum coloratum
Crop & Pasture Science, 2015Co-Authors: José Augusto Imaz, D. O. Giménez, Gustavo G Striker, Agustin A GrimoldiAbstract:This study assessed the flooding tolerance of the tropical grasses Chloris gayana Kunth and Panicum coloratum L. at different times of the year: (i) late winter flooding for 50 days (WF), (ii) early spring flooding (SF) for 20 days, and (iii) long-term flooding covering both periods (WF + SF, 70 days). A growth period under well-watered conditions was allowed after each flooding event to assess recovery of plant species. Plants were harvested after each flooding event and at the end of the recovery period. Panicum coloratum had higher tolerance to WF than C. gayana. Treatment WF did not affect biomass in P. coloratum, whereas it reduced biomass of flooded plants by 38% in C. gayana. Treatment SF did not differentiate the species for tolerance; both registered moderate reduction in their growth (20–30%). Under WF + SF, C. gayana showed additional reduction in its growth over that observed when subjected separately to either WF or SF, whereas P. coloratum did not. Both species displayed remarkably fast recovery from flooding when temperatures rose during early summer, attaining biomass equivalent to that of non-flooded plants 1 month after water subsided. Therefore, although P. coloratum appears slightly more tolerant during flooding than C. gayana, both species are promising for introduction in temperate lowland grasslands.
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the effects of submergence on anatomical morphological and biomass allocation responses of tropical grasses chloris gayana and Panicum coloratum at seedling stage
Crop & Pasture Science, 2012Co-Authors: José Augusto Imaz, D. O. Giménez, Agustin A Grimoldi, Gustavo G StrikerAbstract:Submergence is a major factor affecting seedling recruitment in lowland grassland ecosystems. Our aim was to evaluate the tolerance to increasing flooding intensity of the seedlings of tropical grasses Chloris gayana K. and Panicum coloratum L., whose use as a forage species is increasing in humid grasslands. For this purpose, 2-week-old seedlings of C. gayana and P. coloratum were subjected to control, partial submergence (PS) and complete submergence (CS) in clear water for 14 days and allowed to grow for a subsequent 12-day period to assess their recovery. The following responses were assessed: generation of root aerenchyma, morphological changes and emergence from water, biomass allocation in relation to plant size, and biomass accumulation. Results showed that constitutive root aerenchyma was high in both species. Under PS and CS, root aerenchyma increased by up to 50–55% in C. gayana and up to 40–48% in P. coloratum. Under PS, the increase in seedling height for both species was the same as for controls. Under CS, C. gayana further increased its height and emerged more quickly from water; P. coloratum was not able to increase its height, and therefore the seedlings always remained underwater. The escape-from-water response of C. gayana was associated with preferential biomass allocation towards shoots and with a marked lengthening of leaf blades. By contrast, there was no change in allocation in P. coloratum, and its leaves were shorter under CS. The final biomass of C. gayana under CS was similar to that under PS, and equivalent to 54% of its controls. In P. coloratum, biomass under PS and CS were 64 and 21% of its controls (respectively), which indicates that injury caused by CS persisted during the post-submergence period. In conclusion, both species are tolerant to PS at the seedling stage. However, when flood depth increases by submerging the seedlings, C. gayana is able to escape from water while P. coloratum is not, thus strongly affecting its recovery. Therefore, C. gayana appears to be a more promising species for cultivation in lowland grasslands prone to flooding of unpredictable intensity.
Jose Ignacio Arroquy - One of the best experts on this subject based on the ideXlab platform.
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Efectos del forraje diferido como cobertura de invierno en el crecimiento primaveral de las gramíneas tropicales Chloris gayana y Panicum coloratum
Centro Internacional de Agricultura Tropical, 2017Co-Authors: José Augusto Imaz, Víctor Merani, M A Benvenutti, O. Hernandez, Daniel Dos Santos, Daniel O. Giménez, Jose Ignacio ArroquyAbstract:En La Plata, Buenos Aires, Argentina, en un experimento en macetas a aire libre (condiciones de luz y temperatura naturales) se evaluó el efecto del forraje diferido como cobertura invernal en 2 gramíneas tropicales C4 (Chloris gayana y Panicum coloratum). Plantas adultas fueron extraídas de un establecimiento ganadero, trasplantadas a macetas en un jardín experimental y después de crecer durante 111 días (2 de Febrero al 23 de Mayo) sometidas a los tratamientos: (1) control [sin remoción del forraje diferido de otoño (DF)]; y (2) remoción del forraje diferido de otoño (DFR) a 15 cm del suelo. Se utilizaron 10 repeticiones por tratamiento y una planta por maceta (unidad experimental). Las plantas fueron cosechadas el 27 de Septiembre (después del invierno) y nuevamente en Noviembre para medir la biomasa del rebrote primaveral en los estratos superior (>15 cm) e inferior (<15 cm sobre el suelo), láminas, vainas y estolones. Se realizó un análisis alométrico para dilucidar la incidencia del estrés por frio y se registraron la temperatura del aire, la humedad relativa y la ocurrencia de heladas. Las plantas con forraje diferido alcanzaron una mayor biomasa (55‒80%) que aquellas con remoción del forraje. Panicum coloratum mostró un ajuste significativo entre la biomasa total y la biomasa de los diferentes estratos para ambos tratamientos, mostrando buena tolerancia al estrés por frio. Por otro lado, C. gayana mostró falta de ajuste de la biomasa y un mayor estrés por la remoción del forraje, mientras que las plantas sin remoción presentaron menor daño por frío y un mayor ajuste. La cobertura invernal del forraje diferido podría mejorar la productividad y supervivencia de estas especies forrajeras cuando son utilizadas en sistemas pastoriles templados. Estos resultados preliminares deben ser evaluados en condiciones de campo durante un mayor número de años, considerando diferentes estrategias de pastoreo. Palabras clave: Cobertura invernal, daño por frío, manejo de pasturas, protección de heladas
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effects of deferred forage as winter cover on spring growth of the tropical grasses chloris gayana and Panicum coloratum
Tropical Grasslands - Forrajes Tropicales, 2016Co-Authors: José Augusto Imaz, Víctor Merani, D. O. Giménez, Daniel Dos A Santos, M A Benvenutti, O. Hernandez, Jose Ignacio ArroquyAbstract:En La Plata, Buenos Aires, Argentina, en un experimento en macetas a aire libre (condiciones de luz y temperatura naturales) se evaluo el efecto del forraje diferido como cobertura invernal en 2 gramineas tropicales C4 ( Chloris gayana y Panicum coloratum ). Plantas adultas fueron extraidas de un establecimiento ganadero, trasplantadas a macetas en un jardin experimental y despues de crecer durante 111 dias (2 de Febrero al 23 de Mayo) sometidas a los tratamientos: (1) control [sin remocion del forraje diferido de otono (DF)]; y (2) remocion del forraje diferido de otono (DFR) a 15 cm del suelo. Se utilizaron 10 repeticiones por tratamiento y una planta por maceta (unidad experimental). Las plantas fueron cosechadas el 27 de Septiembre (despues del invierno) y nuevamente en Noviembre para medir la biomasa del rebrote primaveral en los estratos superior (>15 cm) e inferior (<15 cm sobre el suelo), laminas, vainas y estolones. Se realizo un analisis alometrico para dilucidar la incidencia del estres por frio y se registraron la temperatura del aire, la humedad relativa y la ocurrencia de heladas. Las plantas con forraje diferido alcanzaron una mayor biomasa (55‒80%) que aquellas con remocion del forraje. Panicum coloratum mostro un ajuste significativo entre la biomasa total y la biomasa de los diferentes estratos para ambos tratamientos, mostrando buena tolerancia al estres por frio. Por otro lado, C. gayana mostro falta de ajuste de la biomasa y un mayor estres por la remocion del forraje, mientras que las plantas sin remocion presentaron menor dano por frio y un mayor ajuste. La cobertura invernal del forraje diferido podria mejorar la productividad y supervivencia de estas especies forrajeras cuando son utilizadas en sistemas pastoriles templados. Estos resultados preliminares deben ser evaluados en condiciones de campo durante un mayor numero de anos, considerando diferentes estrategias de pastoreo. Palabras clave : Cobertura invernal, dano por frio, manejo de pasturas, proteccion de heladas.
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Effects of deferred forage as winter cover on spring growth of the tropical grasses Chloris gayana and Panicum coloratum
Tropical Grasslands-Forrajes Tropicales, 2016Co-Authors: José Augusto Imaz, Víctor Merani, D. O. Giménez, M A Benvenutti, O. Hernandez, Daniel Andrés Dos Santos, Jose Ignacio ArroquyAbstract:This pot study assessed the effects of deferring forage during autumn and leaving as winter cover on reducing cold damage to plants of 2 tropical (C4) grasses ( Chloris gayana and Panicum coloratum ) in a temperate environment in La Plata, Buenos Aires, Argentina. Mature plants were subjected to the following treatments: (i) autumn-deferred forage retained (DF) as control; and (ii) autumn-deferred forage removed (DFR) cutting at 15 cm from soil level at beginning of winter. This experiment had 10 replicates per treatment and 1 plant per pot (experimental unit). Plants of both species were extracted from a commercial beef farm and transplanted into an experimental garden in pots where they grew outdoors from 2 February to 23 May (111 days) when treatments were applied. After winter, both grasses were cut to 15 cm in early spring (27 September) and spring growth was measured in November. Shoot biomass was harvested at ground level and separated into lower and upper layers (above and below 15 cm), leaf blades, sheaths and stolons. Daily air temperature, relative humidity and frost events were registered. Allometric analysis of shoot biomass was performed to determine the stress incidence by cold. DF plants achieved 55‒80% higher shoot biomass than DFR plants during spring in both species. The allometric analysis revealed for P. coloratum significant relationships between shoot biomass from plant compartments (lower and upper layers, leaf blade and sheath) and total shoot biomass in both treatments, indicating good cold tolerance. However, for C. gayana, unlike DF plants, DFR plants were strongly stressed, showing a lack of shoot biomass fit. These results suggest that deferring autumn forage growth and retaining as winter cover may improve survival during winter and productivity during spring of these two tropical grasses in temperate pastoral systems. However, the study needs to be repeated under field conditions and under grazing or cutting over a number of years in different situations to verify these preliminary results. Keywords : Winter cover, cold damage, frost protection, pasture management.
Jann P. Conroy - One of the best experts on this subject based on the ideXlab platform.
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Root and shoot factors contribute to the effect of drought on photosynthesis and growth of the C4 grass Panicum coloratum at elevated CO2 partial pressures
Functional Plant Biology, 2001Co-Authors: Saman Seneweera, Oula Ghannoum, Jann P. ConroyAbstract:We examined the hypothesis that root and shoot factors influence growth responses to elevated CO2 of the C4 grass Panicum coloratum var. makarikiense cv. Bambatsi (NAD-ME malic enzyme subtype) when well watered and droughted. Plants were grown at CO2 partial pressures (pCO2) of 36 (ambient) and 100 Pa (elevated) in pot ed soil in growth chambers for 3 weeks with adequate water (day 0) before being subjected to 15 d of drought. At day 15, enhancement of shoot growth by elevated pCO2 was 70% under drought, and 44% when well watered. During the drought period, leaf CO2 assimilation rates (A) and stomatal conductance (g) (measured at 36 Pa CO2) declined after day 2, but the decline was faster at 36 Pa CO2, and by day 9, A was negligible and intercellular pCO2 had sharply increased compared with 100 Pa CO2. Changes in carbon metabolism and water relations occurred during drought and elevated CO2 generally delayed these changes. Leaf growth rates were higher at elevated CO2 at day 0 and during drought. Importantly, the decline in soil water content was slower at elevated pCO2 due to lower transpiration rates. This explained the slower decline in A, gand shoot water relations at elevated CO2 and indicates that root factors were responsible for their decline. In contrast, leaf growth rates were higher at elevated CO2, irrespective of soil water content. We conclude that both soil and leaf factors contribute to the greater growth response of P. coloratum to high CO2 under drought, and that reduced transpiration rates explains their enhanced growth.
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Influence of High CO2Partial Pressure on Nitrogen Use Efficiency of the C4Grasses Panicum coloratum and Cenchrus ciliaris
Annals of Botany, 2001Co-Authors: Silvia G. Rudmann, Paul J. Milham, Jann P. ConroyAbstract:Australia's tropical grasslands are dominated by C4grasses, characterized by their unique biochemistry and anatomy. Two naturalized C4grasses (Panicum coloratum and Cenchrus ciliaris) were used to investigate whether high CO2partial pressure [ p(CO2)] influences photosynthetic nitrogen use efficiency and plant nitrogen use efficiency (PNUE and NUE respectively). Plants were grown for 30 d with four levels of N at p(CO2) of 38 or 86 Pa. PNUE was calculated from leaf CO2assimilation rates (A) and leaf N concentrations, and NUE from total leaf N content and plant dry mass. At each p(CO2), PNUE and NUE were greater for C. ciliaris than for P. coloratum due to higher A and dry mass combined with lower leaf N concentrations. Elevatedp (CO2) increased PNUE of C. ciliaris only. This effect was due to lower leaf N concentrations (area basis). At high p(CO2), NUE of C. ciliaris was also greater. This resulted from a 1.6-fold stimulation of dry mass by high p(CO2). Although dry mass of P. coloratum was increased 1.2-fold by elevated p(CO2), its NUE was unaffected. Leaf transpiration rates were halved at elevated p(CO2), and we suggest that this factor plays a major role in the growth response of C4grasses to high p(CO2).
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High vapour pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment
Functional Plant Biology, 1998Co-Authors: Saman Seneweera, Oula Ghannoum, Jann P. ConroyAbstract:The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.
Arroquy, Jose Ignacio - One of the best experts on this subject based on the ideXlab platform.
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Effects of deferred forage as winter cover on spring growth of the tropical grasses Chloris gayana and Panicum coloratum = Efectos del forraje diferido como cobertura de invierno en el crecimiento primaveral de las gramíneas tropicales Chloris gayana
'Centro Internacional de Agricultura Tropical', 2017Co-Authors: Imaz, José Augusto, Gimenez, Daniel Oscar, Merani Víctor, Dos Santos, Daniel Andrés, Benvenutti, Marcelo A., Hernandez Olegario, Arroquy, Jose IgnacioAbstract:This pot study assessed the effects of deferring forage during autumn and leaving as winter cover on reducing cold damage to plants of 2 tropical (C4) grasses (Chloris gayana and Panicum coloratum) in a temperate environment in La Plata, Buenos Aires, Argentina. Mature plants were subjected to the following treatments: (i) autumn-deferred forage retained (DF) as control; and (ii) autumn-deferred forage removed (DFR) cutting at 15 cm from soil level at beginning of winter. This experiment had 10 replicates per treatment and 1 plant per pot (experimental unit). Plants of both species were extracted from a commercial beef farm and transplanted into an experimental garden in pots where they grew outdoors from 2 February to 23 May (111 days) when treatments were applied. After winter, both grasses were cut to 15 cm in early spring (27 September) and spring growth was measured in November. Shoot biomass was harvested at ground level and separated into lower and upper layers (above and below 15 cm), leaf blades, sheaths and stolons. Daily air temperature, relative humidity and frost events were registered. Allometric analysis of shoot biomass was performed to determine the stress incidence by cold. DF plants achieved 55‒80% higher shoot biomass than DFR plants during spring in both species. The allometric analysis revealed for P. coloratum significant relationships between shoot biomass from plant compartments (lower and upper layers, leaf blade and sheath) and total shoot biomass in both treatments, indicating good cold tolerance. However, for C. gayana, unlike DF plants, DFR plants were strongly stressed, showing a lack of shoot biomass fit. These results suggest that deferring autumn forage growth and retaining as winter cover may improve survival during winter and productivity during spring of these two tropical grasses in temperate pastoral systems. However, the study needs to be repeated under field conditions and under grazing or cutting over a number of years in different situations to verify these preliminary results.En La Plata, Buenos Aires, Argentina, en un experimento en macetas a aire libre (condiciones de luz y temperatura naturales) se evaluó el efecto del forraje diferido como cobertura invernal en 2 gramíneas tropicales C4 (Chloris gayana y Panicum coloratum). Plantas adultas fueron extraídas de un establecimiento ganadero, trasplantadas a macetas en un jardín experimental y, después de crecer durante 111 días, sometidas el 23 de Mayo a los tratamientos: (1) control [sin remoción del forraje diferido de otoño (DF)]; y (2) remoción del forraje diferido de otoño (DFR) después de un corte a 15 cm del suelo. Se utilizaron 10 repeticiones por tratamiento y una planta por maceta (unidad experimental). Las plantas fueron cosechadas el 27 de Septiembre (después del invierno) y nuevamente en Noviembre, mediante corte a ras del suelo, para medir la biomasa del rebrote primaveral en los estratos superior (>15 cm) e inferior (
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Efectos del forraje diferido como cobertura de invierno en el crecimiento primaveral de las gramíneas tropicales Chloris gayana y Panicum coloratum
'Centro Internacional de Agricultura Tropical', 2017Co-Authors: Imaz, José Augusto, Gimenez, Daniel Oscar, Merani Víctor, Dos Santos, Daniel Andrés, Hernandez Olegario, Benvenutti Marcelo, Arroquy, Jose IgnacioAbstract:This pot study assessed the effects of deferring forage during autumn and leaving as winter cover on reducing cold damage to plants of 2 tropical (C4) grasses (Chloris gayana and Panicum coloratum) in a temperate environment in La Plata, Buenos Aires, Argentina. Mature plants were subjected to the following treatments: (i) autumn-deferred forage retained (DF) as control; and (ii) autumn-deferred forage removed (DFR) cutting at 15 cm from soil level at beginning of winter. This experiment had 10 replicates per treatment and 1 plant per pot (experimental unit). Plants of both species were extracted from a commercial beef farm and transplanted into an experimental garden in pots where they grew outdoors from 2 February to 23 May (111 days) when treatments were applied. After winter, both grasses were cut to 15 cm in early spring (27 September) and spring growth was measured in November. Shoot biomass was harvested at ground level and separated into lower and upper layers (above and below 15 cm), leaf blades, sheaths and stolons. Daily air temperature, relative humidity and frost events were registered. Allometric analysis of shoot biomass was performed to determine the stress incidence by cold. DF plants achieved 55-80% higher shoot biomass than DFR plants during spring in both species. The allometric analysis revealed for P. coloratum significant relationships between shoot biomass from plant compartments (lower and upper layers, leaf blade and sheath) and total shoot biomass in both treatments, indicating good cold tolerance. However, for C. gayana, unlike DF plants, DFR plants were strongly stressed, showing a lack of shoot biomass fit. These results suggest that deferring autumn forage growth and retaining as winter cover may improve survival during winter and productivity during spring of these two tropical grasses in temperate pastoral systems. However, the study needs to be repeated under field conditions and under grazing or cutting over a number of years in different situations to verify these preliminary results.Fil: Imaz, José Augusto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Investigación Animal del Chaco Semiárido; Argentina. The University of Sydney. Faculty of Agriculture and Enviroment. Centre of Carbon, Water & Food; AustraliaFil: Merani, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Dos Santos, Daniel Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucuman. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Benvenutti, Marcelo. The University Of Queensland; AustraliaFil: Gimenez, Daniel Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Hernandez, Olegario. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Investigación Animal del Chaco Semiárido; ArgentinaFil: Arroquy, Jose Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero. Estación Experimental Agropecuaria Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
