PRODUCTIVIDAD DE Cynodon plectostachyus K. (Schum) Pilger y Dolichos lablab L. SOLOS Y ASOCIADOS BAJO DIFERENTES FRECUENCIAS DE CORTE

The production of biomass from Cynodon plectostachyus K. (Schum) Pilger and Dolichos lablab L., was evaluated as single crop and in association, at different frequencies of cutting, with the aim of presenting schemes for fodder and protein for livestock in the dry tropics. The treatments were the species alone and associated in combination with three frequencies of cutting, distributed as nine treatments in a design of plots divided into random blocks with four repetitions. Morphological and physiological variables of the yield were recorded in order to measure their productivity and response to the association. The data were analyzed statistically with SAS and a means comparison (Tukey p?0.05). The single-crop and associated plants modify their yield components in interaction with the cutting frequencies. The cutting intervals of the species alone or associated induced a higher production of aerial dry matter, as the evaluation period increased. As single crops, C. plectostachyus and D. lablab present low modification in the leaf/stem index as compared to the cutting intervals, except the legume which increased this relation when the cutting interval is more frequent. In association the pulse increased its leaf/stem relation by increasing the cutting time, and it decreased in the legume. The aerial biomass production increased with the association of C. plectostachyus plus D. lablab, and in this way both species expressed their ease in association. It is concluded that the association of both species is positive, although the different morphological and physiological attributes of the species and their contrasting effect in the study with cutting frequencies suggest a differential management that could lead to the persistence of the association.Se evaluó la producción de biomasa de Cynodon plectostachyus K. (Schum) Pilger and Dolichos lablab L., a diferentes frecuencias de corte como monocultivo y en asociación con el fin de presentar fuente de forraje y proteínas a la ganadería del trópico. Los tratamientos fueron las especies solas y asociadas en combinación con tres frecuencias de corte distribuidas como nueve tratamientos en un diseño de parcelas divididas en bloques al azar con cuatro repeticiones. Se registraron variables morfológicas y fisiológicas del rendimiento para medir su productividad y respuesta a la asociación. Las plantas en monocultivo y asociadas modificaron sus componentes del rendimiento en interacción con las frecuencias de corte. Los intervalos de corte en las especies solas o asociadas, indujeron mayor producción de biomasa seca aérea conforme se incrementó el tiempo de evaluación. C. plectostachyus y D. lablab en monocultivo presentaron poca modificación en el índice hoja/tallo con relación a los intervalos de corte, a excepción de la leguminosa, que incrementó dicho índice cuando el intervalo de corte fue más frecuente. En la asociación, la gramínea incrementó su relación hoja/tallo al aumentar el tiempo de corte y se disminuyó en la leguminosa. La producción de biomasa aérea aumentó con la asociación C. plectostachyus más D. lablab y de esta forma, ambas especies expresaron su facilidad de asociación, sin embargo, los diferentes atributos morfológicos y fisiológicos de ambas especies y su efecto contrastante en el estudio con las frecuencias de corte, sugieren un manejo diferencial en la parcela que favorezcan su persistencia

BIOFERTILIZANTE MICORRÍZICO Y FERTILIZANTE MINERAL EN EL CRECIMIENTO DE Elaeis guineensis Jacq. EN VIVERO

The influence of Rhizophagus intraradices in interaction with mineral fertilization on the growth of two oil palm hybrids, Deli X Ghana and Deli X Nigeria, was evaluated in Huehuetán, Chiapas. To develop the research, the experiment was established in a random block design with eight treatments and 16 repetitions. The treatments used with both hybrids were: 1) Rhizophagus intraradices, 2) 80N-60P-80K-10Ca-10Mg+B, 3) R. intraradices + 80N-60P-80K-10Ca-10Mg + B, and 4) Regional control 18N-46P-00K and 17N-17P-17K. The study variables were: length of stem, diameter of stem, number of leaves, aerial and root biomass, and foliage health. The data were analyzed statistically by applying the STATGRAPHICSCenturion XVI package, and the multiple-range Tukey test (P?0.05) was used to compare means. Results indicate that the Deli x Ghana hybrid presents greater plant development in comparison to Deli x Nigeria. The treatment with R. intraradices plus mineral fertilization was better for the growth variables and aerial biomass, and decrease of root biomass, and it presented less damage from pests and disease.Se evaluó la influencia de Rhizophagus intraradices en interacción con la fertilización mineral en el crecimiento de dos híbridos de palma de aceite Deli´+Ghana y Deli+Nigeria en Huehuetán, Chiapas. Para el desarrollo de la investigación se estableció el experimento en un diseño bloques al azar con ocho tratamientos y 16 repeticiones. Los tratamientos en ambos híbridos fueron, 1) Rhizophagus intraradices, 2) 80N-60P-80K-10Ca-10Mg+B, 3) R. intraradices + 80N-60P-80K-10Ca-10Mg+B, y 4) Testigo regional 18N-46P-00K y 17N-17P-17K. Las variables de estudio fueron: longitud de tallo, diámetro de tallo, númerode hojas, biomasa aérea y radical, y sanidad de follaje. Los datos fueron analizados estadísticamente aplicando el paquete estadístico STATGRAPHICS Centurión XVI y se utilizó la prueba de rango múltiple de Tukey (P?0.05) para la comparación de medias. Los resultados indican que el híbrido Deli+Ghana presenta mayor desarrollo vegetal en comparación a Deli+Nigeria. El tratamiento R. intraradices más fertilización mineral fue superior en las variables de crecimiento y biomasa aérea y disminución de biomasa radical, así mismo presentó menor daño por plagas y enfermedades

PRODUCTIVIDAD DE Brachiaria brizantha (Hochst. ex A. Rich) y Clitoria ternatea L. CON BIOFERTILIZANTES

Se evaluaron los microorganismos Azospirillum brasilense y Rhizophagus intraradices en un suelo cambisol de la región del Itsmo de Tehuantepec, Oaxaca, inoculados a Brachiaria brizantha y Clitoria ternatea con el fin de contar con alternativas de forrajes para la ganadería tropical. Se registró la efectividad de R. intraradices y Azospirillum brasilense con la promoción del desarrollo vegetal y el aumento en las cantidades de nitrógeno y fósforo en Brachiaria brizantha y Clitoria ternatea en condiciones de alta población de otros hongos micorrízicos

RELACIONES HÍDRICAS EN EXPLANTES FOLIARES DE Coffea canephora (Pierre) ex Froehner

The demand for Robusta coffee (Coffea canephora) has increased, for the elaboration of soluble coffee, because it contains 2-3 % more caffeine. Genotypes with higher yield have been identified and their massive reproduction is sought through somatic embryogenesis and by identifying their physiological response to different disinfectants through the determination of the capacity for osmotic adjustment. A study was developed to determine the degree of osmotic adjustment of foliar explants of Robusta coffee in the aseptic in vitro establishment. Foliar explants were used of the following genotypes of C. canephora: INIFAP 95-8, 95-9, 97-10, 97-15, 97-18 and 97-20, disinfected with NaClO (0.1, 0.5,1.0, 1.5, 2.0, 2.5, 3.0 and 4.0 %), and Ca(ClO)2 (3, 4, 5, 6, 7, 8, 9 and 10 %), as well as the combination of both. The hydric, osmotic potential, turgidity, and concentration of Cl-, Na+ and Ca++ ions was determined. The results indicated that the genotypes present different capacity of tolerance to disinfectants alone or combined, and in their response to the accumulation of osmotically active substances, with INIFAP 95-9 and 97-20 standing out, with an osmotic adjustment from accumulation of Cl-, Na+ and Ca++ , while when combining NaClO and Ca(ClO)2, the INIFAP 95-8 genotype showed the osmotic adjustment.El café robusta (Coffea canephora) ha incrementado su demanda para elaboración de café soluble por contener entre 2-3% más de cafeína. Se han identificado genotipos con mayor rendimiento y se busca su reproducción masiva por medio de embriogénesis somática e identificar su respuesta fisiológica a diferentes desinfectantes mediante la determinación de la capacidad de ajuste osmótico. Se desarrolló un estudio para determinar el grado de ajuste osmótico de explantes foliares de café robusta en el establecimiento aséptico in vitro. Se utilizaron explantes foliares de los genotipos de C. canephora: INIFAP 95-8, 95-9, 97-10, 97-15, 97-18 y 97-20, desinfectados con NaClO (0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 y 4.0 %), y Ca(ClO)2 (3, 4, 5, 6, 7, 8, 9 y 10%), así como, la combinación de ambos. Se determinó el potencial hídrico, osmótico, turgencia, y concentración de iones Cl-, Na+ y Ca++. Los resultados indicaron que los genotipos presentan diferente capacidad de tolerancia a los desinfectantes solos o combinados y en su respuesta a la acumulación de sustancias osmóticamente activas, sobresaliendo INIFAP 95-9 y 97-20 con ajuste osmótico por acumulación de Cl-, Na+ y Ca++ mientras que al combinar NaClO y Ca(ClO)2, el genotipo INIFAP 95-8, disminuyó el ajuste osmótico al incrementar la concentración de los desinfectante

EVALUACIÓN DE DIFERENTES CONCENTRACIONES DE AUXINAS EN EL ENRAIZAMIENTO DE ESTACAS DE Jatropha curcas L.

The influence of three auxins with different concentrations in the rooting of Jatropha curcas L. pine nut cuttings was evaluated. Cuttings were collected with a length of 30±3 cm and a diameter of 20±3 mm. After the cut, they were placed in containers with the cut facing down, and they remained there for three days. Before planting, they were immersed in auxins for 1 h and planted in polyethylene bags of 5 kg capacity, and later 66 ml of each treatment were applied to each pot. The substrate was a mixture of soil and sand. There were 13 resulting treatments with four concentrations (10, 250, 500 and 1000 mg kg-1) of indole-acetic acid (IAA), indole-butyric acid (IBA), naphthalene-acetic acid (NAA) and a control, distributed in a completely random design with eight repetitions. The number of roots, dry weight of radical and aerial biomass was recorded, and analyzed statistically considering differences between treatments (Tukey 5 %). The results indicated that auxins promoted the root and plant development of J. curcas in a differential manner, depending on the concentration applied. The NAA promoted the highest response, while IBA showed an intermediate response, and IAA was the lowest. The greatest aerial and radical biomass was quantified with the application of naphthalene-acetic acid (NAA), and in terms of greater increase in structures and biomass, it was seen with indole-butyric acid (IBA) and indoleacetic acid (IAA) with the lowest dose applied, respectively.Se evaluó la influencia de tres auxinas con diferentes concentraciones en el enraizamiento de estacas de piñón Jatropha curcas L. Se colectaron estacas con una longitud de 30±3 cm y un diámetro de 20±3 mm. Después de cortadas, se depositaron en recipientes con el corte hacia abajo donde permanecieron tres días. Antes de la siembra, se sumergieron en las auxinas durante 1 h y se sembraron en bolsas de polietileno de 5 kg de capacidad y posteriormente se aplicaron 66 ml de cada tratamiento por maceta. El sustrato fue mezcla de suelo y arena. Se tuvieron 13 tratamientos resultantes de cuatro concentraciones (10, 250, 500 y 1000 mg kg-1) de ácido indolacético (AIA), ácido indolbutírico (AIB), ácido naftalenacético (ANA) y un testigo, distribuidos en un diseño completamente al azar con ocho repeticiones. Se registró el número de raíces, peso seco de raíces y biomasa aérea, analizados estadísticamente considerando diferencias entre tratamientos (Tukey 5%). Los resultados indicaron que las auxinas promovieron el desarrollo radical y vegetal de J. curcas de forma diferencial de acuerdo a la concentración aplicada. El ANA promovió la mayor respuesta, mientras que AIB registró una intermedia y AIA fue la menor. La mayor biomasa aérea y radical se cuantificó con aplicación de ácido naftalenacético (ANA), y en cuanto a mayor incremento en estructuras y biomasa se registró con el ácido indolbutírico (AIB) y ácido indolacético (AIA) con la menor dosis aplicada respectivamente

EFECTO DE REGULADORES DE CRECIMIENTO EN LA REPRODUCCIÓN in vitro DE Musa sp. CV GRAN ENANO

The study was carried out in the Biotechnology Laboratory of the Agricultural Sciences School Campus IV (UNACH) with the objective of determining the effect of two traditional growth regulators and one homobrassinolide (brassinosteroid) added in two concentrations to the MS medium for the in vitro growth of Gran Enano banana (Musa sp.). It was established on two growth media based on modified Murashige and Skoog (MS) (1962), and three growth regulators, BAP, AIA and Br in two concentrations of 2 mg L-1 and 4 mg L-1, at pH of 5.6. The explants were incubated at 26±1 °C, 60% H.R., I.L: 45 mE.m-2 s-1 and a light period of 16 hours light and 8 darkness; in total, 14 treatments with 10 repetitions in a completely random design. The number of buds, leaves, roots and height were measured. The results indicated differential effect between growth media and concentrations of growth regulators. In the radical induction, the MS medium at 50 % in interaction with AIA and brassinosteroid increased the number of roots in the explants, while the number of leaves increased with BAP and brassinosteroid and decreased with AIA.La investigación se realizó en el Laboratorio de Biotecnología de la Facultad de Ciencias Agrícolas Campus IV (UNACH) con el objetivo de determinar el efecto de dos reguladores del crecimiento tradicionales y un homobrasinólido (brasinoesteroide) adicionados en dos concentraciones al medio MS en el crecimiento in vitro del clon de banano gran enano (Musa sp.). Se estableció en dos medios de cultivo con base a Murashige y Skoog (MS) (1962) modificado, y tres reguladores del crecimiento BAP, AIA y Br en dos concentraciones de 2 mg L-1 y 4 mg L-1, a pH de 5.6. Los explantes se incubaron a 26±1°C, 60% H.R., I.L: 45 mE.m-2 s-1 y un fotoperiodo de 16 horas luz y 8 de oscuridad. En total 14 tratamientos con 10 repeticiones en un diseño completamente al azar. Se midieron, número de brotes, hojas, raíces y altura. Los resultados indicaron efecto diferencial entre medios de cultivo y concentraciones de reguladores del crecimiento. En la inducción radical el medio MS al 50% en interacción con AIA y Brasinoesteroide aumentaron el número de raíces en los explantes, mientras que el número de hojas lo aumentó BAP y Brasinoesteroide y disminuyó con AIA

CCD measurements of visual double stars at Calar Alto.

342 CCD measurements of relative positions and magnitude differences for 145 visual double stars are presented. Observations were carried out at the 1.23m telescope of the German-Spanish Astronomical Center at Calar Alto (Spain), all of them in V and R photometric bands

Deep sequencing of virus derived small interfering RNAs and RNA from viral particles shows highly similar mutational landscape of a plant virus population.

RNA viruses exist within a host as a population of mutant sequences, often referred to as quasispecies. Within a host, sequences of RNA viruses constitute several distinct but interconnected pools, such as RNA packed in viral particles, double-stranded RNA, and virus-derived small interfering RNAs. We aimed to test if the same representation of within-host viral population structure could be obtained by sequencing different viral sequence pools. Using ultradeep Illumina sequencing, the diversity of two coexisting Potato virus Y sequence pools present within a plant was investigated: RNA isolated from viral particles and virus-derived small interfering RNAs (the derivatives of a plant RNA silencing mechanism). The mutational landscape of the within-host virus population was highly similar between both pools, with no notable hotspots across the viral genome. Notably, all of the single-nucleotide polymorphisms with a frequency of higher than 1.6% were found in both pools. Some unique single-nucleotide polymorphisms (SNPs) with very low frequencies were found in each of the pools, with more of them occurring in the small RNA (sRNA) pool, possibly arising through genetic drift in localized virus populations within a plant and the errors introduced during the amplification of silencing signal. Sequencing of the viral particle pool enhanced the efficiency of consensus viral genome sequence reconstruction. Nonhomologous recombinations were commonly detected in the viral particle pool, with a hot spot in the 3′ untranslated and coat protein regions of the genome. We stress that they present an important but often overlooked aspect of virus population diversity. IMPORTANCE This study is the most comprehensive whole-genome characterization of a within-plant virus population to date and the first study comparing diversity of different pools of viral sequences within a host. We show that both virus-derived small RNAs and RNA from viral particles could be used for diversity assessment of within-plant virus population, since they show a highly congruent portrayal of the virus mutational landscape within a plant. The study is an important baseline for future studies of virus population dynamics, for example, during the adaptation to a new host. The comparison of the two virus sequence enrichment techniques, sequencing of virus-derived small interfering RNAs and RNA from purified viral particles, shows the strength of the latter for the detection of recombinant viral genomes and reconstruction of complete consensus viral genome sequence

Conservation threats and future prospects for the freshwater fishes of Ecuador: A hotspot of Neotropical fish diversity

Freshwater fish communities in Ecuador exhibit some of the highest levels of diversity and endemism in the Neotropics. Unfortunately, aquatic ecosystems in the country are under serious threat and conditions are deteriorating. In 2018–19, the government of Ecuador sponsored a series of workshops to examine the conservation status of Ecuador''s freshwater fishes. Concerns were identified for 35 species, most of which are native to the Amazon region, and overfishing of Amazonian pimelodid catfishes emerged as a major issue. However, much of the information needed to make decisions across fish groups and regions was not available, hindering the process and highlighting the need for a review of the conservation threats to Ecuador''s freshwater fishes. Here, we review how the physical alteration of rivers, deforestation, wetland and floodplain degradation, agricultural and urban water pollution, mining, oil extraction, dams, overfishing, introduced species and climate change are affecting freshwater fishes in Ecuador. Although many of these factors affect fishes throughout the Neotropics, the lack of data on Ecuadorian fish communities is staggering and highlights the urgent need for more research. We also make recommendations, including the need for proper enforcement of existing environmental laws, restoration of degraded aquatic ecosystems, establishment of a national monitoring system for freshwater ecosystems, investment in research to fill gaps in knowledge, and encouragement of public engagement in citizen science and conservation efforts. Freshwater fishes are an important component of the cultural and biological legacy of the Ecuadorian people. Conserving them for future generations is critical. © 2021 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles

Study of the effects of thermal regime and alternative hormonal treatments on the reproductive performance of European eel males (Anguilla anguilla) during induced sexual maturation

[EN] Since 1960, the European eel (Anguilla anguilla) has suffered a dramatic reduction in natural stocks. Breeding in captivity is considered an alternative, but obtaining high quality sperm seems basic on this regard. The main objective of this study was to assess the effects of three thermal regimes (two of them variable: T10 and T15; and one of them constant: T20) and three hormonal treatments with different hormones (hCG, hCGrec and PSMG) on the induction of maturation in European eel males. In the case of the thermal regimes, our results demonstrated that the onset and progression of spermiation are strongly influenced, and perhaps closely regulated, by water temperature. T20 demonstrated the best results in all the sperm parameters (volume, density, motility, kinetic features, etc.) throughout most weeks of treatment, becoming a reliable and productive method for inducing spermiation in this species. In the case of hormonal treatments, the onset and progression of spermiation in European eel males were influenced by the hormone used. In this respect, hCGrec produced the best results in all the sperm parameters including volume, density, motility, kinetic features, etc., throughout most weeks of treatment, thus becoming an effective alternative treatment to the standard hCG treatment used to induce spermiation in eel species. Moreover, hCGrec gave rise to the best economical profitability, making it possible to obtain good quality sperm samples at a lower price than by using the other two hormonal treatments. © 2012 Elsevier B.V. All rights reserved Guardar / Salir Siguiente >Funded by the European Community's 7th Framework Programme under the Theme 2 "Food, Agriculture and Fisheries, and Biotechnology", grant agreement no. 245257 (PRO-EEL) and Generalitat Valenciana (ACOMP/2012/086). Victor Gallego, Ilaria Mazzeo and M. Carmen Vilchez have predoctoral grants from the Spanish Ministry of Science and Innovation (MICINN), Generalitat Valenciana, and UPV PAID Programme (2011-S2-02-6521), respectively. Paulo C.F. Carneiro had post-doc grants from PAC-EMBRAPA and UPV PAID Programme (PAID-02-11). David S. Penaranda was supported by a contract co-financed by MICINN and UPV (PTA2011-4948-I).Gallego Albiach, V.; Mazzeo, I.; Vilchez Olivencia, MC.; Peñaranda, D.; Carneiro, PCF.; Pérez Igualada, LM.; Asturiano Nemesio, JF. (2012). Study of the effects of thermal regime and alternative hormonal treatments on the reproductive performance of European eel males (Anguilla anguilla) during induced sexual maturation. Aquaculture. 354:7-16. https://doi.org/10.1016/j.aquaculture.2012.04.041S71635