scholarly journals Evaluation of Maize Germ Plasm for Resistance to Maize Rayado Fino Virus

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Pedro I. Bustamante ◽  
Rosemarie Hammond ◽  
Pilar Ramirez
Keyword(s):  
Zea Mays ◽  
Latin America ◽  
Costa Rica ◽  
Symptom Severity ◽  
Germ Plasm ◽  
Enzyme Linked Immunosorbent Assay ◽  
Yield Losses ◽  
Maize Genotypes ◽  
Maize Rayado Fino Virus ◽  
New Cultivars

Maize rayado fino virus (MRFV) causes severe yield losses in maize (Zea mays) in Latin America with reductions of 40–50% on indigenous genotypes and 100% in some new cultivars. A collection of 20 different maize genotypes were obtained from the Center for the Improvement of Maize and Wheat (CIMMYT, México), Estación Experimental Fabio Baudrit (EEFB-Alajuela), and the Consejo Nacional de la Producción (CNP-Costa Rica). Enzyme-linked immunosorbent assay (ELISA) and symptom severity were used to evaluate the responses of the maize genotypes to MRFV infection under screenhouse conditions. Two genotypes from the CIMMYT germ plasm collection (accession nos. 2980-93 and 3974) showed mild and delayed symptoms and low MRFV concentrations as determined by ELISA.

Identification of Maize Rayado Fino Virus by Immunoelectron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 636-637
Author(s):  
O. E. Bradfute
Keyword(s):  
Electron Microscopy ◽  
Zea Mays ◽  
Costa Rica ◽  
Severe Disease ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Virus Particles ◽  
Far North ◽  
Maize Rayado Fino Virus ◽  
Antibody Coating

Maize rayado fino virus (MRFV) causes a severe disease of corn (Zea mays) in many locations throughout the neotropics and as far north as southern U.S. MRFV particles detected by direct electron microscopy of negatively stained sap from infected leaves are not necessarily distinguishable from many other small isometric viruses infecting plants (Fig. 1).Immunosorbent trapping of virus particles on antibody-coated grids and the antibody coating or decoration of trapped virus particles, was used to confirm the identification of MRFV. Antiserum to MRFV was supplied by R. Gamez (Centro de Investigacion en Biologia Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica).Virus particles, appearing as a continuous lawn, were trapped on grids coated with MRFV antiserum (Fig. 2-4). In contrast, virus particles were infrequently found on grids not exposed to antiserum or grids coated with normal rabbit serum (similar to Fig. 1). In Fig. 3, the appearance of the virus particles (isometric morphology, 30 nm diameter, stain penetration of some particles, and morphological subunits in other particles) is characteristic of negatively stained MRFV particles. Decoration or coating of these particles with MRFV antiserum confirms their identification as MRFV (Fig. 4).

Evaluation of germ plasm for resistant to Soybean mosaic virus (SMV)

2020 ◽  
Vol 21 (1) ◽  
pp. 6-9
Author(s):  
Wuye Ria Andayanie
Keyword(s):  
Abiotic Stress ◽  
Environmental Factors ◽  
Mosaic Virus ◽  
Polyclonal Antibody ◽  
Symptom Severity ◽  
Germ Plasm ◽  
Polyclonal Antibodies ◽  
Soybean Mosaic Virus ◽  
High Yield ◽  
High Yields

Soybean superior varieties with high yields and are resistant to abiotic stress have been largely released, although some varieties grown in the field are not resistant to SMV. In addition, the opportunity to obtain lines of hope as prospective varieties with high yield and resistance to SMV is very small. The method for evaluating soybean germplasm is based on serological observations of 98 accessions of leaf samples from SMV inoculation with T isolate. The evaluation results of 98 accessions based on visual observations showed 31 genotypes reacting very resistant or healthy to mild resistant category to SMV T isolate  with a percentage of symptom severity of 0 −30 %. Among 31 genotypes there are 2 genotypes (PI 200485; M8Grb 44; Mlg 3288) with the category of visually very resistant and resistant, respectively and  Mlg 3288  with the category of mild resistant.  They have a good agronomic appearance with a weight of 100 seeds (˃10 g) and react negatively with polyclonal antibodies to SMV, except Mlg 3288 reaction is not consistent, despite the weight of 100 seeds (˃ 10 g). Leaf samples from 98 accessions revealed various symptoms of SMV infection in the field. This diversity of symptoms is caused by susceptibility to accession, when infection occurs, and environmental factors. Keywords—: soybean; genotipe; Soybean mosaic virus (SMV); disease severity; polyclonal  antibody

Costa Rica in 1948: Cold War or Local War?

1996 ◽  
Vol 52 (4) ◽  
pp. 465-493 ◽  
Author(s):  
Marcia Olander
Keyword(s):  
Latin America ◽  
Cold War ◽  
Costa Rica ◽  
Critical Role ◽  
Costa Rican ◽  
Panama Canal Zone ◽  
First Case ◽  
The Government ◽  
The Cold War ◽  
The U.S

The years following World War Two produced a strong resurgence of U.S. intervention in Central America and the Caribbean couched in Cold War terms. Although the U.S. intervention in Guatemala to overthrow the government of Jacobo Arbenz in 1954 has generally been seen as the first case of Cold War covert anti-Communist intervention in Latin America, several scholars have raised questions about U.S. involvement in a 1948 Costa Rican civil war in which Communism played a critical role. In a 1993 article in The Americas, Kyle Longley argued that “the U.S. response to the Costa Rican Revolution of 1948, not the Guatemalan affair, marked the origins of the Cold War in Latin America.” The U.S. “actively interfered,” and achieved “comparable results in Costa Rica as in Guatemala: the removal of a perceived Communist threat.” Other authors have argued, even, that the U.S. had prepared an invasion force in the Panama Canal Zone to pacify the country. The fifty years of Cold War anti-Communism entitles one to be skeptical of U.S. non-intervention in a Central American conflict involving Communism. Costa Ricans, aware of a long tradition of U.S. intervention in the region, also assumed that the U.S. would intervene. Most, if not all, were expecting intervention and one key government figure described U.S. pressure as like “the air, which is felt, even if it cannot be seen.” Yet, historians must do more than just “feel” intervention. Subsequent Cold War intervention may make it difficult to appraise the 1948 events in Costa Rica objectively. Statements like Longley's that “it is hard to believe that in early 1948 … Washington would not favor policies that ensured the removal of the [Communist Party] Vanguard,” although logical, do not coincide with the facts of the U.S. role in the conflict.

scholarly journals New distribution records for Muscidae (Insecta: Diptera) in Latin America

Check List ◽  
2015 ◽  
Vol 11 (6) ◽  
pp. 1810
Author(s):  
Kirstern Lica Follmann Haseyama ◽  
Alessandre Pereira-Colavite ◽  
Claudio José Barros De Carvalho
Keyword(s):  
Latin America ◽  
Costa Rica ◽  
Geographical Distribution ◽  
New Records ◽  
New Distribution

The geographical distribution of Muscidae from Latin America has been extended. The following eight genera, including 28 species, were collected: Cyrtoneurina (2 spp.), Cyrtoneuropsis (8 spp.), Dolichophaonia (1 sp.), Neomuscina (7 spp.), Ophyra (1 sp.), Phaonia (2 spp.), Philornis (5 spp.), and Polietina (2 spp.). New records and additional collecting data have been provided for Brazil, Colombia, and Costa Rica, including reference maps for the species listed.

scholarly journals Caracterización florística de un paisaje antrópico con árboles remanentes en el Valle Central Occidental de Costa Rica

2020 ◽  
Vol 22 (1) ◽  
pp. 17-28
Author(s):  
Verónica Bonilla-Villalobos
Keyword(s):  
Zea Mays ◽  
Costa Rica ◽  
Phaseolus Vulgaris ◽  
Cedrela Odorata ◽  
Enterolobium Cyclocarpum ◽  
Tabebuia Rosea ◽  
Samanea Saman

Con la finalidad de describir la composición florística de la finca Los Llanos, (renombrada por la UNED, Estación Experimental Los Llanos, según acuerdo Rectoría CR 2019-914), se realizó una caracterización florística del bosque húmedo premontano transición a basal en un paisaje degradado ubicado en la comunidad de Los Llanos, Alajuela. El trabajo se realizó entre los años 2016 y 2017, por un periodo aproximado de siete meses. Se establecieron aleatoriamente 20 parcelas circulares donde se contabilizaron e identificaron todas las especies de plantas con un diámetro (DAP) mayor o igual a 10 cm. Se obtuvo información sobre: a) el estado actual del ecosistema, b) muestreo rápido de especies forestales, c) identidad taxonómica de las especies, d) gremios ecológicos de las especies, e) área basal, f) análisis de diversidad alfa y g) caracterización del suelo y h) recurso hídrico. Se encontró que el sitio es atravesado por la quebrada ojo de agua y cuenta con un bosque ribereño alterado, el cuál colinda con dos nacientes de agua registradas. Gran parte del territorio es dominado por plantas herbáceas, mayoritariamente de las familias Asteraceae, Poaceae, Verbenaceae, así como de cultivos mixtos como Phaseolus vulgaris y Zea mays. El sitio se caracteriza por tener suelos muy pedregosos y arcillosos (vertisoles), una cobertura forestal dispersa, con presencia de algunos árboles con alto valor comercial especialmente cedro (Cedrela), cenízaro (Samanea saman) y guanacaste (Enterolobium cyclocarpum) y el bosque ribereño está compuesto principalmente de especies como roble sabana (Tabebuia rosea), yos (Sapium glandulosum), cedro (Cedrela odorata) y guarumo (Cecropia). Además, la cobertura forestal riparia es discontinua y las áreas de cultivos dentro de la finca. Este estudio encontró una composición florística del bosque transicional muy alterada, pero con algunas especies representativas del Valle Central que pueden colaborar como remanentes para iniciar un proceso de restauración ecológica en la comunidad de Los Llanos.

scholarly journals Genetic Variability of Maize (Zea mays L.) Genotypes on Some Yield and Yield Components at Haramaya, Eastern Ethiopia

2020 ◽  
Vol 8 (9) ◽  
pp. 1840-1845
Author(s):  
Mekuannet Belay Kebede ◽  
Degefa Gebissa
Keyword(s):  
Zea Mays ◽  
Genetic Variability ◽  
Zea Mays L ◽  
Genotype 1 ◽  
Eastern Ethiopia ◽  
Maize Production ◽  
Maize Genotypes ◽  
Coefficients Of Variation ◽  
Study Results ◽  
Almost All

Genetic improvement in components of economic importance along with maintaining a sufficient amount of variability is always the desired objective in the any maize (Zea mays L.) breeding program which will be handled under the conditions of Haramaya, Eastern Ethiopia. Therefore, an experiment was conducted using (27) and (3) check/control varieties to determine the genetic variability of maize genotypes at Haramaya, eastern Ethiopia. The study results revealed that significantly the tallest plant heights for (PH) were recorded from (3) (170 cm) and (18) (167.5 cm) genotypes whereas the shortest PH were recorded from (13) (117.5 cm) and (23) genotypes (120 cm). Good plant aspects (PA) were obtained from genotype 12, 22 and 26 (PA-1.5) and poor PA were attained from genotype 1 (PA-2.5). Besides, genetic and phenotypic variances were estimated for seven components. The highest genotypic coefficients variation (GCV) and phenotypic coefficients of variation (PCV) were calculated from grain yield (GY – 23.39%). Comparatively the higher GY were attained from the genotypes of 3, 9 and 12. It can be concluded that almost all components of the PCV are greater than the GCV. Superior selected genotypes are recommended to the researchers /breeders to develop disease resistant and high yielder varieties to increase maize production by farmers under Haramaya and other similar agroecologies.

scholarly journals Efecto de las densidades de siembra y un fungicida en el rendimiento del frijol.

2016 ◽  
Vol 9 (2) ◽  
pp. 09
Author(s):  
Bernardo Mora ◽  
Santiago Fernández ◽  
Guillermo Flores ◽  
Arturo Solórzano
Keyword(s):  
Costa Rica ◽  
Economic Analysis ◽  
Yield Losses ◽  
Marginal Return ◽  
Plant Populations ◽  
Low Incidence ◽  
Pathogenic Agents

Varieties of Guaymí bean and the MUS 181 line were evaluated in five locations in Costa Rica, in five plant populations (140.000; 170.000; 200.000; 230.000 and 260.000 plants per hectare). Some plants were sprayed with benomyl 50PM fungicide at 0.35 kg per hectare, while others did not receive such treatment. Yield losses caused by pathogenic agents were determined, and an economic analysis of the treatment was performed. A low incidence of Mustia Hilachosa/bean diseases was reported on treated plants. Plant populations of 140.000 and 170.000 plants per hectare produced the greatest profit and the highest marginal return rateo

Physopella zeae. [Distribution map].

1970 ◽  
Author(s):  
Keyword(s):  
Zea Mays ◽  
Puerto Rico ◽  
Costa Rica ◽  
South America ◽  
Dominican Republic ◽  
Central America ◽  
Geographical Distribution ◽  
West Indies ◽  
Distribution Map ◽  
New Distribution

Abstract A new distribution map is provided for Physopella zeae (Mains) Cummins & Ramachar. Hosts: Maize (Zea mays). Information is given on the geographical distribution in CENTRAL AMERICA & WEST INDIES, Central America (general), Costa Rica, Cuba, Dominican Republic, Grenada, Guatemala, Honduras, Jamaica, Mexico, Nicaragua, Panama, Puerto Rico, Salvador, St. Vincent, Trinidad, SOUTH AMERICA, Colombia,? Ecuador, Peru, Venezuela.

Maize rayado fino marafivirus. [Distribution map].

1997 ◽  
Author(s):  
Keyword(s):  
Zea Mays ◽  
Costa Rica ◽  
North America ◽  
South America ◽  
El Salvador ◽  
Central America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
New Distribution

Abstract A new distribution map is provided for Maize rayado fino marafivirus Viruses: Marafivirus Hosts: Maize (Zea mays). Information is given on the geographical distribution in NORTH AMERICA, Mexico, USA, Florida, Texas, CENTRAL AMERICA & CARIBBEAN, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama, SOUTH AMERICA, Argentina, Brazil, Parana, Colombia, Peru, Uruguay, Venezuela.

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