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Determinación de componentes de la varianza y heredabilidad en cebadilla criolla (Bromus catharticus Vahl.)
Abbott,L.; Pistorale,S.;
Agriscientia , 2010,
Abstract: over a three-year period, 13 genotypes of bromus catharticus vahl. (prairie grass) were evaluated in a completely randomized design with six replications to estimate statistical and genetic parameters. individual plants were analyzed in relation to the following characters: number of tillers, number of panicles, number of spikelets per spike, total number of seeds and number of full seeds, weight of 1000 seeds, length of panicle, flag leaf length and flag leaf width. multivariate tests were conducted which showed significant differences for all characters. the genetic variance was higher than the environmental variance in the three years for all characters. broad-sense heritability ranged from 0.48 to 0.90. the relationship between the coefficient of genetic and environmental variation ranged from 1.14 to 3.21 for all traits, indicating that the selection has the best conditions in terms of immediate genetic gain. the high variability detected in all genotypes, the high heritability and the relationship of coefficient of genetic and environmental variation greater than one, are promising for the implementation of selection programs aimed at genetic improvement of prairie grass.
Análisis de la estabilidad y adaptabilidad de caracteres de interés agronómico en genotipos selectos de cebadilla criolla (Bromus catharticus) Stability and adaptability analysis of characters of agronomical interest in selected genotypes of prairie grass (Bromus catharticus)
L. Abbott,S. Pistorale
Agriscientia , 2011,
Abstract: Trece genotipos de Bromus catharticus se evaluaron, durante 3 a os, utilizando un dise o experimental completamente aleatorizado con seis repeticiones. Por planta individual se analizaron el número de panojas, el número de semillas y el peso de 1000 semillas. La interacción genotipo x ambiente fue estadísticamente significativa e indica un comportamiento diferencial de los genotipos evaluados a través de los a os. Una vez comprobada la interacción, se aplicaron tres metodologías para evaluar la estabilidad y adaptabilidad de los genotipos: la ecovalencia de Wricke, el índice de Lin & Binns y el modelo de Eberhart & Russell. Estas dos últimas metodologías coinciden en identificar como estables y adaptables a los mismos genotipos para los caracteres estudiados, mientras que la coincidencia con Wricke fue parcial. Considerando las tres metodologías usadas, la de Lin & Binns es fácil de aplicar e interpretar, ya que siempre asocia mayor productividad con mayor estabilidad, y no presenta las restricciones de uso de la regresión. Sin embargo, es necesario acumular más resultados antes de proceder a la generalización de su uso. Thirteen genotypes of Bromus catharticus were evaluated over a three year period, using a completely randomized experimental design with six replications. Individual plants were analyzed for the number of panicles, number of seeds and weight of 1000 seeds. The genotype x environment interaction was statistically significant and it indicates a different performance of genotypes throughout the years. After verifying the interaction, three methodologies were applied in order to assess the stability and adaptability of the genotypes. These were: the Wricke's ecovalence, the Lin & Binns index and the model by Eberhart & Russell. These last two methods agree in identifyinthe same genotypes for the traits studied as stable and adaptable, while the coincidence with Wricke's method was partial. Considering the three methodologies used, the index of Lin & Binns is easy to apply and to interpret because it is always related to higher yield, greater stability, and it does not present any of the restrictions of using regressions. However, it is necessary to gather more information before this method can be widely used.
Determinación de componentes de la varianza y heredabilidad en cebadilla criolla (Bromus catharticus Vahl.) Determination of variance components and heritability in prairie grass (Bromus catharticus Vahl.)
L. Abbott,S. Pistorale
Agriscientia , 2010,
Abstract: Trece genotipos de Bromus catharticus Vahl. (cebadilla criolla) se evaluaron, durante 3 a os, utilizando un dise o experimental completamente aleatorizado con seis repeticiones para estimar parámetros estadísticos y genéticos. Por planta individual se analizaron los siguientes caracteres: número de macollos, número de panojas, número de espiguillas por espiga, número de semillas llenas, número de semillas totales, peso de 1000 semillas, largo de la panoja, ancho de hoja bandera y largo de hoja bandera. Las pruebas multivariadas mostraron diferencias significativas para todos los caracteres en estudio. La varianza genética fue superior a la ambiental en los tres a os para todos los caracteres. La heredabilidad en sentido amplio varió de 0,48 a 0,90. La relación entre el coeficiente de variación genética y ambiental varió de 1,14 a 3,21 para todos los caracteres, lo que indica que la selección tiene las mejores condiciones en términos de ganancia genética inmediata. La alta variabilidad detectada en todos los genotipos, la alta heredabilidad y la relación coeficiente de variación genética y ambiental mayor a uno, resultan promisorios para la realización de programas de selección orientados a la mejora genética de cebadilla criolla. Over a three-year period, 13 genotypes of Bromus catharticus Vahl. (prairie grass) were evaluated in a completely randomized design with six replications to estimate statistical and genetic parameters. Individual plants were analyzed in relation to the following characters: number of tillers, number of panicles, number of spikelets per spike, total number of seeds and number of full seeds, weight of 1000 seeds, length of panicle, flag leaf length and flag leaf width. Multivariate tests were conducted which showed significant differences for all characters. The genetic variance was higher than the environmental variance in the three years for all characters. Broad-sense heritability ranged from 0.48 to 0.90. The relationship between the coefficient of genetic and environmental variation ranged from 1.14 to 3.21 for all traits, indicating that the selection has the best conditions in terms of immediate genetic gain. The high variability detected in all genotypes, the high heritability and the relationship of coefficient of genetic and environmental variation greater than one, are promising for the implementation of selection programs aimed at genetic improvement of prairie grass.
Evaluación de los componentes del rendimiento en semilla mediante coeficientes de sendero en poblaciones de agropiro alargado
Abbott,L.; Pistorale,S.; Andrés,A.;
Agriscientia , 2009,
Abstract: ten populations of thinopyrum ponticum (tall wheatgrass) were evaluated to determine the relationship between seed yield and its components using the method of path coefficients. the total yield of seeds per plant was the dependent variable and independent variables (components) were: number of spikes per plant, number of spikelets per spike, spike length and weight of 1000 seeds. the direct effect of number of spikes was high in all populations with values between 0.82 and 0.55. the indirect effect of number of spikelets via number of spikes and length of spikes via number of spikes had values from 0.11 to 0.29 and 0.17 to 0.33 respectively for nine of the populations, except one whose values were very low. the coefficient of total determination of the system (r2) values ranged between 70% and 53% and the component that contributed the most was the number of spikes per plant. only one population showed an r2 of 33% apparently due to very low correlation values between the component variables. this methodology should provide information to facilitate selection in a breeding program, oriented toward the obtainment of high performance cultivars in seed production.
Evaluación de los componentes del rendimiento en semilla mediante coeficientes de sendero en poblaciones de agropiro alargado Seed yield components evaluation using path coefficients in tall wheatgrass populations
L. Abbott,S. Pistorale,A. Andrés
Agriscientia , 2009,
Abstract: Diez poblaciones de Thinopyrum ponticum (agropiro alargado) se estudiaron para determinar la relación existente entre el rendimiento en semilla y sus componentes mediante el método de coeficientes de sendero. El rendimiento total de semillas por planta fue la variable dependiente, y las variables independientes (componentes) fueron: número de espigas por planta, número de espiguillas por espiga, largo de espiga y peso de 1000 semillas. El efecto directo de número de espigas fue alto en todas las poblaciones, con valores entre 0,82 y 0,55. El efecto indirecto del número de espiguillas vía número de espigas y del largo de espiga vía número de espigas varió de 0,11 a 0,29 y de 0,17 a 0,33 respectivamente para nueve de las poblaciones, excepto una cuyos valores fueron muy bajos. Los coeficientes de determinación del sistema (R2) variaron entre 70 y 53% y el componente que más contribuyó fue el número de espigas por planta. Sólo una población mostró un R2 de 33%, aparentemente debido a los muy bajos valores de correlación entre las variables componentes. Esta metodología brinda información que facilita la selección en un programa de mejoramiento genético orientado hacia la obtención de cultivares de alto rendimiento en semillas. Ten populations of Thinopyrum ponticum (tall wheatgrass) were evaluated to determine the relationship between seed yield and its components using the method of path coefficients. The total yield of seeds per plant was the dependent variable and independent variables (components) were: number of spikes per plant, number of spikelets per spike, spike length and weight of 1000 seeds. The direct effect of number of spikes was high in all populations with values between 0.82 and 0.55. The indirect effect of number of spikelets via number of spikes and length of spikes via number of spikes had values from 0.11 to 0.29 and 0.17 to 0.33 respectively for nine of the populations, except one whose values were very low. The coefficient of total determination of the system (R2) values ranged between 70% and 53% and the component that contributed the most was the number of spikes per plant. Only one population showed an R2 of 33% apparently due to very low correlation values between the component variables. This methodology should provide information to facilitate selection in a breeding program, oriented toward the obtainment of high performance cultivars in seed production.
Análisis de coeficientes de sendero para el rendimiento de semillas en Bromus catharticus
Abbott,Liliana A; Pistorale,Susana M; Filippini,Olga S;
Ciencia e investigación agraria , 2007, DOI: 10.4067/S0718-16202007000200007
Abstract: over a two-year period, 13 genotypes of rescue grass were evaluated in a completely randomized design with six replications. the correlation coefficients and the path coefficient were analysed over nine characters related to seed production. genotypic variability was significant for total seeds per panicle in the second year (p = 0.019), flag leaf length was significant in both years (p = 0.039 and 0.045, respectively), and the number of tillers per plant was significant in the first year (p = 0.003). for the rest of the characters, variability was highly significant (p ≤ 0.001). the relationship between genotype and the environment interaction was significant for the following characteristics: the number of tillers per plant (p = 0.003), the number of panicles per plant (p = 0.010), the width of the flag leaf (p = 0.010) and the 1000 seeds weight (p = 0.047). for the remaining characters, the interaction was not significant. path coefficient analyses demonstrated that the total number of seeds per panicle and the number of spikelets per panicle were the main components that determined seed yield. the contribution of these components was influenced by other characters, such as panicle and flag leaf lengths. therefore, these can be considered to be secondary yield components. the following four components: the number of total seeds per panicle, the number of spikelets per panicle, the panicle length and the flag leaf length rendered a total determination for this system that explained 83.36 % and 81.61 % of the phenotypic variation for the number of fully developed seeds per panicle each year
Diversidad genética y heredabilidad en sentido amplio en agropiro alargado, Thinopyrum ponticum
Pistorale,Susana M; Abbott,Liliana A; Andrés,Adriana;
Ciencia e investigación agraria , 2008, DOI: 10.4067/S0718-16202008000300003
Abstract: ten naturalized populations of tall wheatgrass (thinopyrum ponticum) were evaluated in a completely randomized block design with three replicates. each plant was analyzed for morphological and reproductive characters, and statistical and genetic characters were estimated. significant differences (p < 0.001) were obtained for the means of all ten populations, indicating great variability between tall wheatgrass populations. the results show that the environmental coefficients of variation were high for total seed production (69.24%), number of tillers (54.93%), number of spikes (48.50%), and dry matter production (49.01%). coefficients of variation were rather low for spike length (19.11%) and the 1000-seed weight (18.44%). heritability was high for seed weight (0.86), dry matter production (0.55), and the number of tillers (0.55). intermedíate heritability was found for total seed production (0.30), and low heritability for the number (0.19) and length (0.09) of spikes. even though the number of spikes showed an intermedíate heritability, it was highly and positively correlated with seed production (r=0.603), and a little less so with seed weight (r=0.177). seed weight showed a high heritability and was positively correlated with seed production (r=0.285). the wide variability observed between populations for almost all the studied characters will allow them to be integrated into a single germoplasm or into a genetic pool that could be used in programs aimed at the genetic improvement of tall wheatgrass.
Tolerancia a la salinidad durante la germinación de semillas provenientes de poblaciones naturalizadas de agropiro alargado (Thinopyrum ponticum)
Bazzigalupi,Omar; Pistorale,Susana M; Andrés,Adriana N;
Ciencia e investigación agraria , 2008, DOI: 10.4067/S0718-16202008000300005
Abstract: the phenotypic variability among ten adapted populations of tall wheatgrass (thinopyrum ponticum) germinating under saline stress conditions was evaluated as part of a breeding program. the aim of the breeding program was to provide new cultivars of tall wheatgrass adapted to saline soil conditions. saline soils represent 8% of the total agricultural soil surface in argentina. seeds were sown on towel paper (30 gm2) and germinated with alternating light and darkness (16 and 8 h, respectively) and temperature (20-30°c), under 0, 60, 135 y 220 ram nacl treatments, equivalent to electric conductivity of 0, 6, 12 y 18 dsm-1. treatments were distributed in a randomized complete block design, with a factorial arrangement of 4 x 11, four salinity treatments x eleven tall wheatgrass populations; four replications were carried out, consisting of 25 seeds per experiment. the germination percentage and germination índex were calculated. the results indicated large differences between populations and between treatments for both attributes. the mean germination percentage decreased 4.2, 18.6 and 61.0%, as compared to the control, as electric conductivity increased to 6, 12 and 18 dsm-1, respectively. differences between populations were significant only in 18 dsm-1. the germination índex had a similar performance with the increase in electric conductivity (y = 28.827x-35.091, r2 = 0.9692). population number 3 had the best germination and index performance. at 18 dsm-1, all populations had a variable number of seeds with germination capadty. therefore, this electric conductivity could be adequate for a salt tolerance breeding and selection program.
Study of the Structural and Electrical Properties of Cr-Doped BiFeO3 Ceramic  [PDF]
S. S. Arafat, S. Ibrahim
Materials Sciences and Applications (MSA) , 2017, DOI: 10.4236/msa.2017.810051
Abstract: Multiferroic BiFe1-xCrxO3 (x = 0.2 and 0.4) ceramics were synthesized in a single phase. The effects of Cr3+ substitution on the crystal structure, dielectric permittivity and leakage current were investigated. Preliminary X-ray structural studies revealed that the samples had a rhombohedral perovskite crystal structure. The dielectric constant ε' significantly increased while the dielectric loss tanδ was substantially decreased with the increase in Cr3+ substitution. The temperature effect on the dielectric properties exhibited an anomaly corresponding to magneto-electric coupling in the samples and was shifted to lower temperatures with the increase in Cr3+ substitution. The leakage current density also reduced in magnitude with the increase in the Cr3+ substitution.
Degree Splitting of Root Square Mean Graphs  [PDF]
S. S. Sandhya, S. Somasundaram, S. Anusa
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.66086
Abstract: Let \"\" be an injective function. For a vertex labeling f, the induced edge labeling \"\" is defined by, \"\" or \"\"; then, the edge labels are distinct and are from \"\". Then f is called a root square mean labeling of G. In this paper, we prove root square mean labeling of some degree splitting graphs.
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