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Search Results: 1 - 10 of 22432 matches for " Alejandro Del Pozo "
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Productivity and Persistence of Yellow Serradela (Ornithopus compressus L.) and Biserrula (Biserrula pelecinus L.) in the Mediterranean Climate Region of Central Chile
del Pozo,Alejandro; Ovalle,Carlos;
Chilean journal of agricultural research , 2009, DOI: 10.4067/S0718-58392009000300006
Abstract: the production and sustainability of non-irrigated pastures in the mediterranean climate region of central chile is currently limited by the low diversity of valuable species and cultivars of annual forage legumes, able to persist in zones with highly variable annual rainfall, and low fertility or poorly drained soils. in this work, dm production, seed yield, hardseededness and pasture persistence were evaluated for cultivars of yellow serradella (ornithopus compressus l.) and biserrula (biserrula pelecinus l.), in field experiments conducted in the subhumid portion of the mediterranean climate region of chile. burr medic (medicago polymorpha l.) and sub clover (trifolium subterraneum l.) were used as a reference plants. a remarkable dm production and seed yield were observed in biserrula (cvs. mor96 and casbah), and in some cultivars of yellow serradella (e.g. madeira, santorini); biserrula produced by far the largest number of seeds per m2. as was expected for species that produce very high levels of hard-seeds, the regeneration of biserrula and serradella was low in second growing season, but plant density and productivity were high in the third growing season. the use of biserrula and serradela in monoculture or in mixture with other annual legumes, either in pasture-crop rotation or permanent pasture, would contribute to the improvement of the prevailing productive systems in the mediterranean climate region of central chile.
Productivity and Persistence of Yellow Serradela (Ornithopus compressus L.) and Biserrula (Biserrula pelecinus L.) in the Mediterranean Climate Region of Central Chile Productividad y Persistencia de Serradela Amarilla (Ornithopus compressus L.) y Biserrula (Biserrula pelecinus L.) en la Región Climática Mediterránea de Chile Central
Alejandro del Pozo,Carlos Ovalle
Chilean Journal of Agricultural Research , 2009,
Abstract: The production and sustainability of non-irrigated pastures in the Mediterranean climate region of central Chile is currently limited by the low diversity of valuable species and cultivars of annual forage legumes, able to persist in zones with highly variable annual rainfall, and low fertility or poorly drained soils. In this work, DM production, seed yield, hardseededness and pasture persistence were evaluated for cultivars of yellow serradella (Ornithopus compressus L.) and biserrula (Biserrula pelecinus L.), in field experiments conducted in the subhumid portion of the Mediterranean climate region of Chile. Burr medic (Medicago polymorpha L.) and sub clover (Trifolium subterraneum L.) were used as a reference plants. A remarkable DM production and seed yield were observed in biserrula (cvs. Mor96 and Casbah), and in some cultivars of yellow serradella (e.g. Madeira, Santorini); biserrula produced by far the largest number of seeds per m2. As was expected for species that produce very high levels of hard-seeds, the regeneration of biserrula and serradella was low in second growing season, but plant density and productivity were high in the third growing season. The use of biserrula and serradela in monoculture or in mixture with other annual legumes, either in pasture-crop rotation or permanent pasture, would contribute to the improvement of the prevailing productive systems in the Mediterranean climate region of central Chile. La producción y la sostenibilidad de las praderas de secano en la región de clima mediterráneo de Chile central están actualmente limitadas por la baja diversidad de especies valiosas y cultivares de leguminosas forrajeras anuales, capaces de persistir en zonas con precipitaciones anuales sumamente variables, y suelos de baja fertilidad o de mal drenaje. En este trabajo se evaluó la producción de fitomasa, producción de semilla, dureza seminal y la persistencia de cultivares de serradela amarilla (Ornithopus compressus L.) y biserrula (Biserrula pelecinus L.), en experimentos de campo conducidos en la región mediterránea subhúmeda de Chile. La hualputra (Medicago polymorpha L.) y el trébol subterráneo (Trifolium subterraneum L.) fueron utilizados como especies de referencia. La producción de fitomasa y de semillas fue considerablemente más alta en biserrula (cvs. Mor96 y Casbah), y en algunos cultivares de serradella amarilla (e.g. Madeira y Santorini); biserrula produjo el mayor número de semillas por m2. Como era esperable en especies que presentan niveles muy altos de semillas duras, la recuperación de la pradera en el segu
EFECTO DE LA TEMPERATURA Y LA SUPLEMENTACIóN ENERGéTICA SOBRE LA PRODUCCIóN DE LECHE EN VACAS LECHERAS A PASTOREO
Jahn,Ernesto; Arredondo,Susana; Bonilla,Walter; Del Pozo,Alejandro;
Agricultura Técnica , 2002, DOI: 10.4067/S0365-28072002000200007
Abstract: a study was carried out to evaluate the effect of supplementation in the shade in summer months for cows grazing on a perennial pasture of clover-ryegrass (trifolium repens l. - lolium multiflorum l.). four treatments were compared: i. day and night grazing without supplementation; ii. day and night grazing plus supplementation; iii. day and night grazing plus supplementation in the shade between 11:30 and 17:00 h; and iv. day and night grazing plus supplementation in the sun between 11:30 and 17:00 h. thirty-two holstein cows with an average production of 20.5 l d-1 were used, and assigned to the four treatments in a completely randomized block design. there were no significant (p 3 0.05) treatment effects on milk production; highest production was observed on treatment iii (19.5 l d-1). highest ambient temperatures during january and february where 33.5 and 34.5oc, respectively. rectal temperature was significantly higher (p < 0.05) in the treatments where the animals were in the sun, reaching 39.55, 39.00 and 39.43oc for treatments ii, iii and iv, respectively. a slight increase in corn silage consumption during supplementation was observed for cows in the shade. the lower silage consumption of animals remaining in the sun was apparently compensated by higher pasture intake during the night. measurements of animal behavior were made by periodic observation 24 hours a day.
Cubiertas Vegetales en Vi?edos: Comportamiento de mezclas de Leguminosas Forrajeras Anuales y Efectos sobre la Fertilidad del Suelo
Ovalle,Carlos; del Pozo,Alejandro; Lavín,Arturo; Hirzel,Juan;
Agricultura Técnica , 2007, DOI: 10.4067/S0365-28072007000400006
Abstract: with the objective of evaluating and selecting cover crops to improve soil management in vineyards (vitis vinifera l.) cv. cabernet sauvignon, five cover pastures were evaluated: a) control without vegetation; b) control with spontaneous vegetation; c) legume mixture of early maturing cultivars of subterranean clover (trifolium subterraneum l.) and burr medic (medicago polymorpha l.); d) legumes mixture of late maturing cultivars of subterranean clover and balansa clover (t. michelianumsavi); and e) legumes mixture of late maturing cultivars and annual ryegrass (lolium rigidum gaud.). the study was conducted at cauquenes experimental center, agriculture research institute (inia), over two seasons, 2005-2006 and 2006-2007. the experimental design was randomized blocks with four replicates. the three pasture mixtures had a good establishment and achieved high populations. biomass production was significantly higher (p ≤ 0.05) in the mixtures with late maturing cultivars of subterranean clover and balansa clover, compared to the mixture of early maturing cultivars of subterranean clover and burr medic (2.3 to 4 t dm ha-1 yr -1 and 5.3 to 6.2 t dm ha-1 yr -1 in the first and second year, respectively). the contents of n, p and k in the biomass of the cover crops were higher (p ≤ 0.05) than those covers with spontaneous species, which allowed for increasing the content of available n in the soil. as well, higher contents of k and p were detected in the soil. the over crops exercised an important detrimental effect on the population of the spontaneous species that grow in the inter-rows of the vineyard.
EFECTOS DE LA PROFUNDIDAD DE PLANTACIóN Y POBLACIóN DE PLANTAS EN LA CALIDAD Y RENDIMIENTO DE ESPáRRAGO VERDE
González A.,María Inés; del Pozo L.,Alejandro;
Agricultura Técnica , 2003, DOI: 10.4067/S0365-28072003000300001
Abstract: the effect on asparagus (asparagus officinalis l.) yield and quality of three planting depths (10, 20 and 30 cm) and two plant densities (22 222 and 33 333 plants ha-1) was assessed in the sub-humid mediterranean climatic zone of chile. crowns of the cv. uc-157 f1 were transplanted to a volcanic soil in september 1995. the experimental design was a randomized complete block in a factorial arrangement, with four replications. the plots were harvested on a daily basis during five seasons (1997-2001), and the number, weight and diameter of spears were determined after trimming at 18 cm. no interaction was detected between the studied factors on yield and its components. high plant density only increased the yield in the first harvest season (1997), whereas planting depth had an effect during the first four harvest seasons (1997-2000), but this effect disappeared in the fifth harvest season (2001). the maximum commercial yield was obtained during the third harvest season (1999) at the most superficial planting depth (10 cm) with production of 10.2 t ha-1. the number of harvested spears per m2 and the proportion of thin spears (7-17 mm) decreased on increasing planting depth from 10 to 30 cm. the number of utilized buds per plant was greater (p £ 0,05) at the lowest plant density (22,222 plants ha-1) and decreased as planting depth increased from 10 to 30 cm. finally, seven years after planting, the asparagus crown depth was shallower in the three planting depths but continued being different (p £ 0,05).
Drought Tolerance in Recombinant Chromosome Substitution Lines (RCSLs) Derived from the Cross Hordeum vulgare subsp. spontaneum (Caesarea 26-24) × Hordeum. vulgare subsp. vulgare cv. Harrington
Inostroza,Luis; del Pozo,Alejandro; Matus,Iván; Hayes,Patrick;
Agricultura Técnica , 2007, DOI: 10.4067/S0365-28072007000300004
Abstract: grain yield (gy) and drought tolerance of recombinant chromosome substitution lines (rcsls) derived from the cross between hordeum vulgarel.subsp. spontaneum (k. koch) thell. and h. vulgare l. subsp. vulgare cv. harrington, were studied in two contrasting environments, one with water stress (wws) and the other with no water stress (nws), during three growing seasons, 2004-2005, 2005-2006 and 2006-2007. in the first season 80 rcsls were sowed and in the following a selection of 13 rcsls. an a-lattice design was used in all the experiments. with the data of gy obtained in sites wws and nws it was calculated the drought sensitivity index (dsi). during 2004-2005 growing season gy varied greatly among locations, reflecting differences in water availability. the average gy of the 80 rcsls was 4.4 and 8.0 mg ha-1 in sites wws and nws, respectively. the dsi varied between genotypes from 0.24 to 1.53. furthermore, the dsi was negative and significantly correlated with the grain yield obtained in the wws site and allowed to select a group of genotypes tolerant and other sensitive to drought. the group of drought tolerant genotypes yielded in wws 18, 12 and 17% more than the sensitive ones, in 2004-2005, 2005-2006 and 2006-2007 seasons, respectively
Developmental Responses of Garlic to Temperature and Photoperiod
del Pozo L.,Alejandro; González A.,María Inés;
Agricultura Técnica , 2005, DOI: 10.4067/S0365-28072005000200001
Abstract: bulb initiation and maturity of four chilean clones of garlic (allium sativum l.) were studied in controlled and field conditions in order to assess temperature and photoperiod requirements of selected clones. the effect of cold storage temperature prior to planting and photoperiod on bulb initiation was assessed in two clones of garlic. in one experiment bulbs were stored at 4, 7, 10, 13 and 16°c for 20, 40 or 60 days, and planted in pots in a heated greenhouse with a 14 h photoperiod. in a second experiment bulbs of the same clones were stored at 4 and 10°c, and room temperature (> 13°c) for 30 days, and later grown in a heated greenhouse with 8, 10, 12, 14 or 16 h of photoperiod. in the field, days from emergence to bulb initiation and to maturity were evaluated in 13 clones planted on six sequential planting dates. percentage of bulbing increased and the number of days from emergence to bulb initiation decreased, as storage temperature decreased and duration of storage increased. plants of studied clones did not form bulbs with photoperiods of 8, 10 or 12 h with any storage temperature. all plants of both clones formed bulbs when photoperiod was over 14 h and storage temperature was 4 or 7oc. a reduction on the period emergence-bulb initiation was observed as planting date was delayed from april to september.
Diversidad isoenzimática en accesiones de Medicago polymorpha colectadas a lo largo del gradiente climático en Chile, y su relación con otras especies de Medicago
PAREDES,MARIO; BECERRA,VIVIANA; CORREA,PILAR; DEL POZO,ALEJANDRO;
Revista chilena de historia natural , 2000, DOI: 10.4067/S0716-078X2000000300011
Abstract: medicago polymorpha is a naturalized species in chile which presents great variability in agronomic traits such as flowering and reproductive phenology, seed production, seed hardness, and dry matter production, associated to a climatic gradient. the objectives of this work were to assess the isozymatic diversity in accessions of m. polymorpha and its relation with the phenotypic variability, and to establish possible genetic links with other species of medicago. forty one accessions of m. polymorpha obtained from a wide range of climatic and edaphic conditions, and 16 accessions of m. arabica, m. rotata, m. rigidula, m. tornata, m. littoralis and m. truncatula, were evaluated for 12 isozyme systems. the results showed a low isozymatic diversity within accessions of m. polymorpha, and a lack of association between geographical distribution and isozyme diversity. multivariate analysis allowed to cluster the species separately. m. arabica, another naturalized species in chile, was the closest species to m. polymorpha, whereas m. littoralis, m. rigidula and m. rotata presented a higher genetic distance from m. polymorpha.
Tratamiento del síndrome nefrótico con corticoesteroides
HUMBERTO DEL POZO P,ALEJANDRO KUZMANI,SILVIA VILLANUEVA
Revista chilena de pediatría , 1959,
Abstract:
Diversidad isoenzimática en accesiones de Medicago polymorpha colectadas a lo largo del gradiente climático en Chile, y su relación con otras especies de Medicago Isozymatic diversity in accesions of Medicago polymorpha collected along an environmental gradient in Chile, and its relationship with other species of Medicago
MARIO PAREDES,VIVIANA BECERRA,PILAR CORREA,ALEJANDRO DEL POZO
Revista chilena de historia natural , 2000,
Abstract: Medicago polymorpha es una especie naturalizada en Chile que presenta una gran varaibilidad en características agronómicas, tales como precocidad, producción de semilla, y producción de materia seca, asociada de un gradiente climático. Los objetivos de este trabajo fueron evaluar la diversidad isoenzimática en accesiones de M. polymorpha y su relación con la variabilidad fenotípica, y establecer posibles relaciones genéticas con otras especies de Medicago. Para esto se analizaron 12 sistemas isoenzimáticos en 41 accesiones de M. polymorpha, provenientes de un amplio rango de condiciones edafoclimáticas, y de 16 accesiones de M. arabica, M rotata, M. rigidula, M. tornata, M. littoralis y M. truncatula. Los resultados indicaron una escasa diversidad isoenzimática dentro de M. polymorpha, y una falta de correspondencia con la variabilidad fenotípica y distribución geográfica de las accesiones. El análisis multivariado permitió agrupar las especies en forma separada. M. arabica, que también está naturalizada en Chile, fue la especie mas cercana a M. polymorpha, en cambio, M. littoralis, M. rigidula y M. rotata fueron las especies que presentaron una mayor distancia genética con M. polymorpha. Medicago polymorpha is a naturalized species in Chile which presents great variability in agronomic traits such as flowering and reproductive phenology, seed production, seed hardness, and dry matter production, associated to a climatic gradient. The objectives of this work were to assess the isozymatic diversity in accessions of M. polymorpha and its relation with the phenotypic variability, and to establish possible genetic links with other species of Medicago. Forty one accessions of M. polymorpha obtained from a wide range of climatic and edaphic conditions, and 16 accessions of M. arabica, M. rotata, M. rigidula, M. tornata, M. littoralis and M. truncatula, were evaluated for 12 isozyme systems. The results showed a low isozymatic diversity within accessions of M. polymorpha, and a lack of association between geographical distribution and isozyme diversity. Multivariate analysis allowed to cluster the species separately. M. arabica, another naturalized species in Chile, was the closest species to M. polymorpha, whereas M. littoralis, M. rigidula and M. rotata presented a higher genetic distance from M. polymorpha.
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