ABSTRACT Cobalt (Co) and molybdenum (Mo) are essential elements with a fundamental role in biological nitrogen fixation in legumes. Vitamins such as thiamine, despite being required in small quantities, influence plant growth. This study aimed to assess the efficiency of different doses of thiamine applied as seed treatment, combined or not with Co and Mo, in enhancing the development of soybean crops. The experiment was conducted in a greenhouse according to a randomized block design with a 6 × 2 factorial arrangement, comprising six thiamine doses (0, 10, 25, 50, 100, and 200 mg kg-1) in the presence or absence of Co and Mo at the recommended rate of 100 mL ha-1. At 40 days after sowing, plants were analyzed for root length, root dry weight, shoot length, shoot dry weight, nodule number, and nodule dry weight. Principal component analysis showed that combined application of Co and Mo with thiamine was negatively associated with all variables and that the thiamine doses most positively associated with the analyzed variables were 50 and 200 mg kg-1. In treatments containing thiamine alone, there was a linear direct relationship between thiamine dose and nodule dry weight. Root and shoot lengths and dry weights were highest in plants treated with thiamine only at a dose of 122 mg kg-1. Application of Co and Mo combined with thiamine via seed treatment does not promote the development of soybean crops. Thiamine application is a promising treatment to increase shoot length, root dry weight, and nodule dry weight in soybean. (Co (Mo legumes quantities growth crops arrangement 0, 0 (0 10 25 20 kg1 kg 1 kg-1 ha1. ha1 ha 1. ha-1 4 sowing length number 5 kg1. alone 12 ( kg- ha-

ABSTRACT The sorghum crop is considered one of the most important worldwide due to its versatility. However, water stress can be considered a significant threat to its yield. The search for products that mitigate water stress is a crucial area of research in agriculture and water resources management. Thus, the objective in this study was to evaluate the feasibility of using salicylic acid as a water stress attenuator in sorghum. The experiment was conducted in a screened environment in a randomized block design with a 4 × 2 factorial scheme, with four replicates. Four levels of water (40, 60, 80, and 100% of evapotranspiration) and two concentrations of salicylic acid (0 and 2.76 g L-1) were evaluated. Plant height, stem diameter, number of leaves, gas exchange, photosynthetic pigments, and chlorophyll a fluorescence were analyzed. Application of deficit irrigation depths reduced plant height, stem diameter, number of leaves, and total chlorophyll in sorghum. However, when these depths were associated with salicylic acid, it was observed that the damage was attenuated, especially in chlorophyll a and b. Furthermore, salicylic acid reduced leaf temperature and increased water use efficiency when applied alone. Thus, salicylic acid can be used to mitigate the effects of salt stress on sorghum plants. versatility However yield management Thus scheme replicates 40, 40 (40 60 80 100 evapotranspiration 0 ( 276 76 2.7 L1 L 1 L-1 evaluated height diameter leaves exchange pigments analyzed attenuated b Furthermore alone plants (4 6 8 10 27 7 2. L-

RESUMO A cultura do sorgo é considerada uma das mais importantes do mundo devido a sua versatilidade de utilização. No entanto, o estresse hídrico pode ser considerado uma ameaça significativa para sua produtividade. A busca por produtos mitigadores do estresse hídrico é uma área de pesquisa crucial na agricultura e na gestão de recursos hídricos. Assim, o objetivo deste trabalho foi avaliar a viabilidade do uso do ácido salicílico como atenuante de estresse hídrico na cultura do sorgo. O experimento foi conduzido em ambiente telado, em delineamento em blocos ao acaso com esquema fatorial 4 × 2, com quatro repetições. Foram avaliados quatro níveis hídricos (40, 60, 80 e 100% da evapotranspiração) e duas concentrações de ácido salicílico (0 e 2,76 g L-1). Foram analisados a altura das plantas, diâmetro do caule, número de folhas, trocas gasosas, pigmentos fotossintéticos e fluorescência da clorofila a. A aplicação de lâminas de irrigação deficitárias reduziu a altura da planta, diâmetro do colmo, número de folhas e clorofila total no sorgo. No entanto, quando essas lâminas foram associadas ao ácido salicílico, foi observado que houve atenuação dos danos, especialmente em relação a clorofila a e b. Além disso, o ácido salicílico quando aplicado isoladamente, contribuiu para redução da temperatura da folha e aumento da eficiência de uso da água. Assim, o ácido salicílico pode ser usado para mitigar os efeitos do estresse salino em plantas de sorgo. utilização entanto produtividade Assim telado 2 repetições 40, 40 (40 60 8 100 evapotranspiração 0 ( 276 76 2,7 L1. L1 L 1 . L-1) caule gasosas planta colmo danos b disso isoladamente água (4 6 10 27 7 L-1 L-

ABSTRACT: One of the causes of productivity loss in sugarcane cultivation has been associated with the species Diatraea saccharalis, also known as the sugarcane borer. Therefore, this study evaluated the feasibility of using hyperspectral sensors to obtain the leaf spectral response of sugarcane in different periods of infestation at leaf and canopy levels to diagnose D. saccharalis damage in advance. The study included three varieties of sugarcane: CTC9003BT, CTC4, and RB966928. The insecticide Altacor® was used to control pestsin half of the plots. Data collection occurred at the following stages: sprouting, tillering, stalke longation, and early maturation. Data regarding relative water content (RWC), leaf spectral signature in the laboratory and canopy, vegetation indices (NDVI and MCARI), productivity, purity, and total recoverable sugar (TRS) were collected to evaluate the borer effects on the sugarcane crop. The highest RWC was observed for CTC9003BT (60.15%) without insecticide and 59.0% with insecticide. The visible (400-680 nm) and near-infrared (750-1300 nm) spectral bands identified spectral variations in plants with and without sugarcane borer. The percentage of sugarcane borer showed high and negative correlations between productivity, NDVI, and TRS, with coefficients of -0.68, -0.76, and -0.76, respectively. The NDVI and MCARI indices effectively detect plants under stress, but their variation is influenced by multiple factors, making it difficult to associate them with a single problem (sugarcane borer). ABSTRACT Therefore D advance CTCBT CTC BT CTC4 RB966928 RB Altacor plots stages sprouting tillering longation maturation RWC, , (RWC) MCARI, MCARI) purity TRS (TRS crop 60.15% 6015 60 15 (60.15% 590 59 0 59.0 400680 400 680 (400-68 nm nearinfrared near infrared 7501300 750 1300 (750-130 0.68, 068 68 -0.68 0.76, 076 76 -0.76 respectively stress factors . borer) RB96692 (RWC 60.15 601 6 1 (60.15 5 59. 40068 40 (400-6 750130 75 130 (750-13 0.68 06 -0.6 0.76 07 7 -0.7 RB9669 60.1 (60.1 4006 4 (400- 75013 13 (750-1 0.6 -0. 0.7 RB966 60. (60. (400 7501 (750- 0. -0 RB96 (60 (40 (750 - RB9 (6 (4 (75 ( (7

RESUMO: Uma das causas de perda de produtividade em lavouras de cana está associada à espécie Diatraea saccharalis, também conhecida por broca da cana. Portanto, este estudo avaliou a viabilidade do uso de sensores hiperespectrais para obter a resposta espectral foliar da cana-de-açúcar em diferentes períodos de infestações, tanto a nível foliar quanto dossel, a fim de diagnosticar antecipadamente os danos da Diatraea saccharalis. O estudo contou com três variedades de cana-de-açúcar: CTC9003BT, CTC4 e RB966928. Em metade das parcelas foi utilizado o inseticida Altacor® para o controle de pragas. As coletas de dados ocorreram nas fases: brotação, perfilhamento, crescimento de colmos e início da maturação. Para avaliar os efeitos da broca na cana foi coletado os dados referentes ao conteúdo relativo de água (CRA), assinatura espectral foliar em laboratório e dossel, índices de vegetação (NDVI e MCARI), produtividade, pureza e ATR (Açúcar Total Recuperável). O maior CRA encontrado foi para a CTC9003BT (60,15%) sem inseticida e 59,0% com inseticida. As faixas espectrais do visível (400-680 nm) e infravermelho próximo (750-1300 nm) identificaram variações espectrais nas plantas com e sem broca. O percentual de broca apresentou correlações altas e negativas entre a produtividade, NDVI e ATR, com coeficientes de -0,68, -0,76 e -0,76, respectivamente. Os índices NDVI e MCARI foram eficazes na detecção de plantas sob estresse, contudo, sua variação é influenciada por múltiplos fatores, sendo difícil associá-los a um único problema (broca). RESUMO saccharalis Portanto canadeaçúcar açúcar infestações dossel CTCBT CTC BT RB966928 RB Altacor pragas fases brotação perfilhamento maturação CRA, , (CRA) MCARI, MCARI) Açúcar Recuperável. Recuperável . Recuperável) 60,15% 6015 60 15 (60,15% 590 59 0 59,0 400680 400 680 (400-68 nm 7501300 750 1300 (750-130 0,68, 068 68 -0,68 0,76 076 76 -0,7 0,76, respectivamente estresse contudo fatores associálos associá los (broca) RB96692 (CRA 60,15 601 6 1 (60,15 5 59, 40068 40 (400-6 750130 75 130 (750-13 0,68 06 -0,6 0,7 07 7 -0, (broca RB9669 60,1 (60,1 4006 4 (400- 75013 13 (750-1 0,6 0, -0 RB966 60, (60, (400 7501 (750- - RB96 (60 (40 (750 RB9 (6 (4 (75 ( (7

ABSTRACT Traditional agroecosystems (TA) are considered more resilient to climatic extremes due to higher crop diversity and agroecological approach. The TA of Tének were studied to evaluate their drought tolerance. Open-ended questionnaire surveys, field visits, and botanical collections, with the participation of local farmers, were considered. Cultivated plant diversity was analyzed using the Shannon-Wiener diversity index (H’), and the Morisita-Horn index (CMH) in ten different agroecosystems in April and August. Remote sensing methods included the triangular greenness index (TGI). Additionally, normalized difference vegetation index (NDVI) and standardized precipitation index (SPI) were determined, covering the period from 2013 to 2022. The cultivated plant richness (P > 0.5382) and their abundance (P > 0.3622) did not change from April to August considering the total analyzed parcels. However, differences between types of agroecosystems were observed because higher diversity corresponded to managed jungle (teʼlom) (Hʼ = 1.5-1.7), and some parcels cultivated with maize (milpa) (Hʼ = 1.02-1.54). Nevertheless, in August, lower similarity was observed in milpa (CMH = 0.23-0.87) due to the absence of maize (Zea mays L.) and other herbaceous annual crops. Landscape interconnection can be affirmed with TGI correlations obtained by comparison of different TA. The negative SPI values were associated with a decrease of NDVI, but Tének polyculture agroecosystems maintained higher NDVI values compared to rainfed monocropping during the analyzed period. Tének polyculture agroecosystems exhibited higher drought tolerance, although maize and other herbaceous plants are susceptible to disappearing during prolonged drought events, thereby increasing food insecurity.

Abstract Introduction. Endophytic fungi (EF) in grapevines (Vitis vinifera) have great potential for agricultural applications and may represent possible biological control agents for vineyards. Objective. To isolate and identify endophytic fungi (EF) from grapevine plants with antibiosis capacity against Botrytis cinerea. Materials and methods. Young and mature branches from forty healthy grapevine plants were collected from seven production lots in the Cañete province, Lima, Peru, during March to May 2022. EF isolation was performed on 702 sections of disinfected tissues using potato dextrose agar (PDA) culture medium, and identification was carried out at the genus level. Secondary metabolites were extracted from twenty-eight EF strains to determine the mycelial inhibition of the pathogen. An analysis of variance (ANOVA) was conducted on the evaluated parameters using the Minitab statistical program. Results. A total of 129 EF strains were isolated from leaves and stems of young and mature grapevine branches, encompassing seven genera (Trichoderma, Aspergillus, Alternaria, Cladosporium, Fusarium, Nigrospora, and Stemphylium). The highest frequency was found in leaves and mature branches. Trichoderma and Alternaria were the most frecuent genera in grapevine plants, with 22.48 % and 21.71%, respectively. Metabolites obtained from the EFVH-01 strain of the genus Cladosporium, and EF-99 and EF-70 strains of the genus Alternaria, had the greatest effect on mycelial inhibition of the pathogen. Conclusions. Strains of endophytic fungi from the genera Cladosporium and Alternaria showed antibiosis capacity against Botrytis cinerea at the laboratory scale, which could potential biocontrol agents of pathogens in grapevine cultivation.

Resumen Introducción. Los hongos endófitos (HE) de la vid (Vitis vinifera) tienen un gran potencial de aplicación en la agricultura y pueden representar posibles agentes de control biológico de los viñedos. Objetivo. Aislar e identificar los hongos endófitos (HE) de plantas de vid con capacidad de antibiosis hacia Botrytis cinerea. Materiales y métodos. Se colectaron ramas jóvenes y maduras de cuarenta plantas sanas de vid de siete lotes de producción en la provincia de Cañete, Lima, Perú, durante los meses de marzo a mayo 2022. El aislamiento de HE se realizó de 702 secciones de tejidos desinfectados en medio de cultivo papa dextrosa agar (PDA) y la identificación fue a nivel de género. Se extrajeron metabolitos secundarios de veintiocho cepas de HE para determinar la inhibición micelial del patógeno. Se llevó a cabo un análisis de varianza (ANDEVA) de los parámetros evaluados con el programa estadístico Minitab. Resultados. Se aislaron un total de 129 cepas de HE de hojas y tallos de ramas jóvenes y maduras de vid, que correspondieron a siete géneros (Trichoderma, Aspergillus, Alternaria, Cladosporium, Fusarium, Nigrospora y Stemphylium). La mayor frecuencia se presentó en las hojas y rama madura. Trichoderma y Alternaria fueron los géneros más frecuentes en las plantas de vid con 22,48 % y 21,71 %, respectivamente. Los metabolitos obtenidos de las cepas HEVH-01 del género Cladosporium, HEV-99 y HEV-70 del género Alternaria, tuvieron mayor efecto en la inhibición micelial del patógeno. Conclusiones. Cepas de hongos endofitos del género Cladosporium y Alternaria mostraron capacidad de antibiosis hacia Botrytis cinerea a escala de laboratorio, los cuales podrían ser potenciales biocontroladores de patógenos en el cultivo de vid.

Abstract Introduction. Quinoa downy mildew is a disease that causes economic losses and has been poorly studied.Therefore, researching quinoa’s response to the disease and treatment methods is a topic that requires further investigation. Objective. To describe how downy mildew infection affects quinoa plants and the non-traditional methods used to control this disease. Development. A systematic search was conducted to compile the results associated with P. variabilis in quinoa (Chenopodium quinoa Wild.) under various conditions. The analysis determined that factors such as incidence, severity, and disease tolerance depended largely on the quinoa grain variety and altitude (along with its climatic conditions). Plant height and yield per hectare were influenced by soil conditions, pest and disease treatment, and the planting day. Conclusions. The incidence and severity of downy mildew depended on the quinoa variety used. Other factors such as altitude or humidity also influenced disease progression, with infection rates close to 90 % in high humidity environments. Non-conventional methods for treating downy mildew included plant infusions such as chamomile and garlic, showing positive short-term results; however, they did not surpass conventional treatments with chemical fungicides.

Resumen Introducción. El mildiu de la quinua es una enfermedad que ocasiona pérdidas económicas y que ha sido poco estudiada, por lo que la investigación de la respuesta de la quinua a la enfermedad y las formas de tratamiento es un tema que debe investigarse con mayor profundidad. Objetivo. Describir cómo afecta la infección del mildiu velloso en la planta de la quinua y los métodos no tradicionales empleados en el control de esta enfermedad. Desarrollo. Se realizó una búsqueda sistemática a fin de realizar una recopilación de los resultados asociados al P. variabilis en la quinua (Chenopodium quinoa Wild.) en diversas condiciones. El análisis determinó que factores como la incidencia, la severidad y la tolerancia a la enfermedad del mildiu, dependieron en gran medida de la variedad de grano de quinua y la altitud (con sus condiciones climáticas). La altura de la planta y el rendimiento por hectárea estuvieron influenciados por las condiciones del suelo, el tratamiento empleado contra plagas y patógenos, y el día de siembra. Conclusiones. La incidencia y la severidad del mildiu velloso dependió de la variedad de la quinua con la que se trabajó. Otros factores como la altitud o la humedad también influyeron en el progreso de la enfermedad, con una infección cercana al 90 % en ambientes con alta humedad. Los métodos no convencionales para tratar el mildiu fueron infusiones de plantas como la manzanilla y el ajo, con resultados positivos a corto plazo; no obstante, no superaron a los tratamientos convencionales con fungicidas químicos.

Resumen (Objetivo) El objetivo fue analizar la composición de aves asociadas a cultivos orgánicos de cacao (Theobroma cacao) manejado debajo de 3 diferentes tipos de cobertura arbórea. (Metodología) Distribuimos 3 puntos de conteo en cada finca, para registrar todas las aves observadas y escuchadas, en muestreos de 5 minutos. Los conteos fueron realizados por triplicado, tanto en las primeras horas de la mañana como al atardecer. La diferencia en la composición de la avifauna entre las fincas fue analizada con la prueba ANOSIM. Las abundancias se transformaron por medio de la función decostand y el método Hellinger del paquete estadístico R-Vegan. La agrupación de las especies entre las plantaciones se efectuó mediante el escalamiento multidimensional no métrico (nMDS) y el índice de Bray-Curtis. La contribución de las especies a la disimilitud entre grupos fue analizada con el módulo SIMPER. Consideramos diferencias estadísticamente significativas cuando P ≤ 0,05. (Resultados) Observamos 428 individuos, clasificados en 49 especies y 23 familias. La finca donde las plantas de cacao crecen en condiciones más sombreadas, debido al desarrollo del dosel, mostró mayor cantidad de especies (34) y de individuos (146). La composición de aves varió significativamente entre las fincas (F(1,8) = 3,22; P < 0,02). La abundancia media de 19 especies (39,6 %) hizo notar diferencias significativas (P < 0,05), al comparar la finca con mayor sombra y menor sombra. (Conclusión) La composición de aves es más compleja en aquellas fincas de cacao orgánico que conservan un mayor desarrollo estructural de los árboles de dosel y que están cerca de bosque en regeneración.

Resumo (Objetivo) O objetivo foi analisar a composição das aves associadas às plantações de cacau orgânico (Theobroma cacao) manejadas sob três tipos diferentes de cobertura arbórea. (Metodologia) Distribuímos 3 pontos de contagem em cada fazenda, para registrar todas as aves observadas e ouvidas, em amostragens de 5 minutos. As contagens foram realizadas em triplicata, tanto nas primeiras horas da manhã quanto no final da tarde. A diferença na composição da avifauna entre as fazendas foi analisada com o teste ANOSIM. As abundâncias foram transformadas usando a função de costande o método Hellinger do pacote estatístico R-Vegan. O agrupamento de espécies entre as plantações foi feito usando o escalonamento multidimensional não métrico (nMDS) e o índice de Bray-Curtis. A contribuição das espécies para a dissimilaridade entre os grupos foi analisada com o módulo SIMPER. Consideramos as diferenças estatisticamente significativas quando P ≤ 0,05. (Resultados) Observamos 428 indivíduos, classificados em 49 espécies e 23 famílias. A fazenda onde as plantas de cacau crescem em condições mais sombreadas, devido ao desenvolvimento do dossel, apresentou um número maior de espécies (34) e indivíduos (146). A composição das aves variou significativamente entre as fazendas (F(1,8) = 3,2 apresentou diferenças significativas (P < 0,05) n; Paco< 0, mpa 02). A abundância média de 19 espécies (39,6%) ração entre a fazenda mais sombreada e a menos sombreada. (Conclusão) A composição das avesé mais complexa nas fazendas de cacau orgânico que mantêm árvores de dossel mais desenvolvidas estruturalmente e estão próximas à floresta em regeneração.

Abstract (Objective) The objective of this investigation was to analyze the composition of birds associated with organic cocoa (Theobroma cacao) crops managed under 3 different types of tree cover. (Methodology) Three census points were established in each farm to record all birds observed and heard in 5-minute sample periods. Counts were conducted in triplicate, both in the early morning and at dusk. Differences in avifauna composition between farms were analyzed using the ANOSIM test. Abundances were transformed using the Decostand function and the Hellinger method in the R-Vegan statistical package. Analysis of clustering of species among plantations was performed using non-metric multidimensional scaling (nMDS) and the Bray-Curtis index. Contribution of species to the dissimilarity between groups was analyzed with the SIMPER module. Statistically significant differences were considered when P ≤ 0.05. (Results) Four hundred and twenty-eight individuals were observed, and classified into 49 species and 23 families. The farms where cocoa plants grow in shadier conditions due to canopy development showed a higher number of species (34) and individuals (146). Bird comp P < 0.02). The mean abundance of 19 species osit (39.ion 6%) varied significantly between farms (F (1,8) = 3.22; showed significant differences (P < 0.05) when comparing the farms with the most and least shade. (Conclusion) Bird composition is more complex on organic cocoa farms, which have more developed canopies and are near regenerating forests.

Abstract The association between cacti and nurse plants has been reviewed by different authors. These reviews however were qualitative because only evaluated aspects such as species identity of cacti and nurse plants, probable explanatory causes of their association, and location of study sites. To our knowledge, there are no quantitative reviews that have evaluated the association between cacti and nurse plants for different subfamilies, tribes, and growth forms of cacti and nurse plants, and different plant communities and soil properties. To address these issues, we performed a quantitative review of the studies on the association between cacti and nurse plants. The studies were searched in the ISI Web of Knowledge from 1986 to 2021. Data obtained from studies were analyzed with the relative risk ratio and ratio of medians. Most studies on the association between cacti and nurse plants were performed mainly in Mexico and the USA. Globose, cylindrical, and columnar cacti of the subfamily Cactoideae, and tribes Cacteae, Cereeae, and Echinocereeae were associated to nurse plants of Asteraceae, Euphorbiaceae, and Fabaceae. However, other subfamilies (Opuntioideae) and tribes (Notocacteae) of cacti, and families (Asparagaceae) of nurse plants were not associated. Nurse plants ameliorated temperature, moisture, and nitrogen of soil. The association between cacti and nurse plants occurred in desert shrubland and tropical dry forest. Further studies are needed on the association between cacti and nurse plants that consider more cactus subfamilies and tribes in countries with high cactus diversity in Central and South America.

Resumen La asociación entre cactáceas y plantas nodriza ha sido revisada por diferentes autores. Sin embargo, estas revisiones fueron cualitativas porque solo evaluaron las especies de cactáceas y plantas nodriza, las probables causas de su asociación y los sitios de estudio. Hasta donde sabemos, no existen revisiones cuantitativas que hayan evaluado la asociación entre cactáceas y plantas nodriza para distintas subfamilias, tribus y formas de crecimiento de cactáceas y plantas nodriza, y distintas comunidades de plantas y propiedades del suelo. Para abordar estos aspectos, realizamos una revisión cuantitativa de los estudios sobre la asociación entre cactáceas y plantas nodriza. Los estudios fueron buscados en el ISI Web of Knowledge de 1986 a 2021. Los datos fueron analizados con la razón de riesgo relativo y la razón de medianas. Los estudios sobre la asociación entre cactáceas y plantas nodriza fueron realizados en México y EUA. Las cactáceas globosas, cilíndricas y columnares de la subfamilia Cactoideae y las tribus Cacteae, Cereeae y Echinocereeae estuvieron asociadas a plantas nodriza de Asteraceae, Euphorbiaceae y Fabaceae. Sin embargo, otras subfamilias (Opuntioideae) y tribus (Notocacteae) de cactáceas, y familias (Asparagaceae) de plantas nodriza no estuvieron asociadas. Las plantas nodriza mejoraron la temperatura, humedad y nitrógeno del suelo. La asociación entre cactáceas y plantas nodriza ocurrió en matorral desértico y selva baja caducifolia. Es necesario realizar estudios adicionales sobre la asociación entre cactáceas y plantas nodriza que consideren otras subfamilias y tribus de cactáceas, en países con alta diversidad de cactáceas en Centro y Sudamérica.

Resumen Antecedentes: Las especies de la familia Podostemaceae poseen rasgos inusuales en angiospermas. Crecen sumergidas en ríos de corriente fuerte y su ciclo de vida está ligado a la estacionalidad. Debido a su estructura floral reducida, el análisis de las etapas de desarrollo y eventos como la antesis o la receptividad del estigma ha sido complicado. Pregunta: ¿Cuál es la relación entre la morfología, el desarrollo y la receptividad del estigma en diferentes etapas del desarrollo de la flor de Marathrum rubrum? Especie de estudio: Marathrum rubrum Novelo & C. T. Philbrick. Sitio y años de estudio: Río Horcones, Jalisco, México. Enero 2014 y 2015. Métodos: Se realizó un análisis in situ y en laboratorio de la morfología floral de M. rubrum para evaluar la relación entre la morfología y desarrollo floral, y la receptividad del estigma en distintas etapas. Resultados: Cuando las flores emergen de la espatela, los óvulos y el polen están completamente desarrollados, por ello, la esporogénesis y la gametogénesis ocurren dentro del tallo, estando las plantas aún sumergidas. Conclusiones: Los cambios morfológicos observados en las flores de M. rubrum durante las etapas analizadas se relacionan únicamente con eventos asociados con la fecundación y el desarrollo del fruto. Las observaciones detalladas de la biología reproductiva de M. rubrum en el ambiente aéreo tienen importantes implicaciones para el conocimiento básico de la biología de las plantas de esta familia, la estructura genética de las poblaciones, el éxito reproductivo y la biología de la conservación en ambientes amenazados.

Abstract Background: Podostemaceae is the largest family of strictly aquatic angiosperms. Species of this family possess unusual morphological and reproductive characters, grow attached to rocks in rivers with strong currents, and have a life cycle tightly linked to seasonality. Due to its reduced floral structures, which characterizes most species, the analysis of developmental stages and events such as anthesis or stigma receptivity has proven difficult. Question: How floral morphology, floral development and stigma receptivity of different stages of flower development of Marathrum rubrum Novelo & C. T. Philbrick are related among them? Studied species: Marathrum rubrum Novelo & C. T. Philbrick. Study site and dates: Horcones River, Jalisco, Mexico. January, 2014 and 2015. Methods: We made an in situ and lab analyses of flower morphology to assess the relationships between flower morphology, stages of development, reproductive structures, and stigma receptivity, during different stages of flower development. Results: When flowers emerge from the spathella, both the ovules and pollen grains are fully developed, implying that sporogenesis and gametogenesis take place within the stem while the plant is still submerged. Conclusions: The morphological changes observed in the flowers of M. rubrum during the analyzed stages are related only to events associated with fertilization and fruit development. The time-course of morphological changes in the flowers, from anthesis to fruit formation, lasts 20 to 30 days. The detailed observation of the aerial reproductive biology of M. rubrum bears important implications to the genetic structure of populations, plant fitness and conservation biology in threatened environments.

Resumen Antecedentes: Los sistemas agroforestales tradicionales (SAF) son capaces de mantener la diversidad vegetal nativa mediante diferentes prácticas campesinas. Preguntas: ¿En qué medida los SAF mantienen la composición, diversidad y abundancia de plantas perennes? ¿Qué variaciones hay entre distintos tipos de vegetación? Especies de estudio: Plantas perennes presentes en SAF asociados a bosques de cactáceas columnares, bosques templados, bosques espinosos, matorrales rosetófilos y selvas bajas caducifolias. Sitio y años de estudio: 13 comunidades del Valle de Tehuacán-Cuicatlán, en Oaxaca y Puebla, México. Revisión de trabajos y datos propios publicados entre 2010 y 2020. Métodos: Evaluamos la composición florística, capacidad de conservación de diversidad y abundancia de individuos mediante un análisis de redundancia, la estimación de números efectivos de especies y modelos lineales generalizados en 30 SAF y 30 muestreos de la vegetación silvestre de la que derivan. Resultados: Los SAF analizados son capaces de mantener 68 % de la riqueza de especies y 34 % de los individuos de plantas perennes presentes en la vegetación silvestre circundante. Los SAF y la vegetación silvestre son semejantes en términos de composición y diversidad de especies, aunque en el caso del bosque espinoso hay una clara reducción del número de especies y un cambio en la composición. La abundancia de individuos es notoriamente menor en los SAF. Conclusiones: Los SAF son una alternativa capaz de resguardar una parte significativa de la diversidad vegetal nativa. La justa valoración y la promoción del manejo campesino agroecológico mediante SAF debe ser considerado en las políticas de conservación.

Abstract Background: Traditional agroforestry systems (AFS) can maintain native plant diversity through different peasant practices. Questions: How much AFS maintain the composition, diversity and abundance of perennial plants? What variations are there among different types of vegetation? Studied species: Perennial plant species occurring in AFS associated with columnar cacti forests, temperate forests, thorn forests, rosetophyllous forests and tropical deciduous forests. Study site and dates: 13 communities of the Tehuacán-Cuicatlán Valley, in Oaxaca and Puebla, Mexico. Revision of works and own data published between 2010 and 2020. Methods: We evaluated the floristic composition, diversity conservation capacity and abundance of individuals by means of a redundancy analysis, the estimation of effective numbers of species and generalized linear models in 30 AFS and 30 samples of the wild vegetation from which they derive. Results: The AFS analyzed can maintain 68 % of the species richness and 34 % of the individuals of perennial plants present in the surrounding wild vegetation. The AFS and wild vegetation are similar in terms of species composition and diversity, although in the case of the thorn forest there is a clear reduction in the number of species and a change in the composition. The abundance of individuals is notoriously lower in the AFS. Conclusions: The AFS are an alternative capable of safeguarding a significant part of the native plant diversity of the Tehuacán-Cuicatlán Valley. The fair valuation and promotion of agroecological peasant management through AFS should be considered in the policies of biodiversity conservation.

Resumen El fréjol es un cultivo importante debido a su alto valor nutritivo. En los últimos años la producción en Ecuador de este cultivo ha disminuido drásticamente debido entre otros factores a ineficientes procesos y falta de tecnificación en la producción. Entender cómo se generan y determinan los componentes del rendimiento del grano es primordial para diseñar estrategias que permitan aumentar el rendimiento del cultivo. En este estudio, se modificó la densidad de plantas con el objetivo de evaluar su impacto sobre el número de granos, peso de granos y rendimiento, bajo condiciones de campo en una región andina de Ecuador. Se realizaron dos experimentos sembrados en fechas distintas, donde se evaluaron densidades de plantas contrastantes 4 y 11 plantas m−2. El efecto de los tratamientos se estudió sobre la duración del periodo emergencia - antesis, el número de vainas llenas y vanas, el número de granos, el peso seco de 100 granos y el rendimiento de grano. Los resultados indican que la densidad de plantas tiene un efecto significativo (p<0,05) sobre el rendimiento, alcanzando un promedio de 257,15 g m−2 en alta densidad y 151,45 g m−2 en baja densidad. Los componentes principales del rendimiento mostraron una respuesta distinta a la modificación de la densidad de plantas; el número de granos presentó una fuerte variabilidad y fue positivamente asociado con el rendimiento final del grano (p<0,05), mientras que el peso del grano no fue afectado.

Abstract Common bean is an important crop due to its high nutritional value. However, its production in Ecuador has decreased due to biotic and abiotic factors. Understanding the mechanisms that determine the yield components of this crop is essential to establish strategies that allow increasing the yield. In this study, the plant density was modified to evaluate its impact on yield and its two main components, the grain number and grain weight under field conditions in an Andean region of Ecuador. Two experiments planted on different dates were performed, where two planting densities 4 and 11 plants m−2 were evaluated. The effect of the treatments was studied on the length of the period, from emergence to anthesis, the number of full and empty pods, grain number, 100 grain weight and grain yield. The results indicate that the plant density has a significant effect (p<0.05) on the yield, reaching an average of 257.15 g m−2 in high density, and 151.45 g m−2 in low density. The yield main components showed a different response to plant density modification; the grain number exhibited a strong variability and was positively associated with final grain yield (p<0.05) while the grain weight was not affected.

Resumen Ecuador es un pequeño país andino ubicado en el hemisferio occidental de América del Sur. El país cuenta con 361.747 hm 3 anuales de recursos hídricos superficiales. Como resultado, Ecuador, en los últimos quince años (2005 a 2020), ha estado desarrollando proyectos hidroeléctricos para triplicar la producción en esta fuente renovable. Hubo ocho nuevas centrales hidroeléctricas construidas en Ecuador entre 2007 y 2015, en donde se invirtieron cerca de USD 6 mil millones en los proyectos, lo que incrementó la respuesta energética con renovables; por ejemplo, en 1985 el país produjo 4 TWh, en 2005 registró 7 TWh y hasta 2020, 24 TWh. Según la Corporación de Electricidad del Ecuador en 2020 informó que generó alrededor del 80% de toda la electricidad a través de hidroelectricidad. Así, el artículo tiene como objetivo analizar críticamente el desarrollo de la energía hidroeléctrica en Ecuador en los últimos años y establecer proyecciones energéticas generales al 2030 para ampliar los campos de conocimiento y perspectivas. La metodología del trabajo es cuantitativa, de acuerdo con fuentes editoriales científicas, artículos, documentos de investigación, y recolecta datos de agencias gubernamentales que regulan el desarrollo energético en Ecuador. Se concluye que, mediante un cálculo de proyecciones, Ecuador necesitará para el año 2030 alrededor de 43 TWh, 47 TWh o 52 TWh para abastecer la red energética, según los escenarios propuestos (bajo, medio, alto). Si bien la energía hidroeléctrica será fundamental para contribuir a este requerimiento, el país tiene una barrera porque la energía hidroeléctrica es muy sensible a factores externos de diversa índole, generando un futuro incierto directamente asociado a los efectos climáticos.

Abstract Ecuador is a small Andean country located in the western hemisphere of South America. The country has 361,747hm 3 annual superficial water resources; As a result, Ecuador, in the last fifteen years (2005 to 2020), has been rapidly developing hydropower projects to triple the production in this renewable source. There were eight new hydroelectric plants constructed in Ecuador among 2007 and 2015 invested close to USD 6 billion the projects. Increased the energy response with renewables; for example, in 1985, the country produced 4 TWh, in 2005-registered 7 TWh, and to 2020, 24 TWh. According to the Electricity Corporation of Ecuador in 2020 reported that generated around 80% of all electricity through hydropower; thus, the article aims to critically analyze the development of hydropower in Ecuador in recent years and establish general energy projections to 2030 to expand the fields of knowledge and perspectives. The paper methodology is quantitative, according to scientific editorial sources, articles, investigative documents, and collects data from government agencies that regulate energy development in Ecuador. It is conclusive between a projection’s calculation, Ecuador will need for the year 2030 around 43 TWh, 47 TWh, or 52 TWh to supply the energy grid, according to the scenarios proposed (low, medium, high). Although hydropower will be essential to contribute to this requirement, the country has a barrier because hydropower is very sensitive to external factors of diverse nature, generating an uncertainly future directly associated with climatic effects.

ABSTRACT Lemon verbena, Aloysia citriodora (Palau) has been widely used in traditional medicine, cosmetics, and the food industry. In Colombia the foliage is marketed fresh but there is no information regarding the plant phenology, nor on the insects associated, therefore the management practices are still empirical, and sometimes does not comply with the national regulations for the commercialization of medicinal plants. In this study it was determined that it takes 32 weeks from planting to flower senescence completing its phenological cycle; likewise, an associated arthropofauna of 50 families with different feeding habits were found, suggesting that the species offers different ecosystem services. The information obtained could contribute to establish more effective management plans for arthropods, and to improve quality of materials with medicinal purposes.

RESUMEN El cidrón, Aloysia citriodora (Palau) ha sido ampliamente utilizada en la medicina tradicional, la cosmética y la industria alimentaria. En Colombia el follaje se comercializa fresco, pero no se cuenta con información sobre la fenología de la planta, ni sobre los insectos asociados, por lo que las prácticas de manejo son aún empíricas, y en ocasiones no cumplen con las normas nacionales para la comercialización de plantas medicinales. En este estudio se determinó que la planta tarda 32 semanas desde la siembra hasta la senescencia de la flor completando su ciclo fenológico; así mismo, se encontró una artrofauna asociada de 50 familias con diferentes hábitos alimentarios, lo que sugiere que la especie ofrece diferentes servicios ecosistémicos. La información obtenida podría contribuir a establecer planes de manejo más efectivos para los artrópodos y a mejorar la calidad de los materiales con fines medicinales.

ABSTRACT Hop stunt viroid (HSVd) is the causal agent of citrus cachexia, which can lead to significant crop losses. As part of a preventive management strategy, it is essential to use healthy plants from a certification program. This study aimed to evaluate the healthiness of 17 citrus cultivars against HSVd using both biological and molecular diagnostics. For biological diagnosis, Etrog citron (Citrus medica L.) clone Arizona 861 S1 was used as an indicator plant, incorporating negative and positive controls for HSVd infection. For molecular diagnosis, reverse transcription polymerase chain reaction (RT-PCR) technique was employed with specific primers for viroid detection. Results indicated that six months after inoculation, the positive control exhibited symptoms associated with viroid infection, such as necrosis in the petiole and stem, leaf epinasty, and necrosis in the midvein. In contrast, both the negative control and evaluated citrus cultivars showed no symptoms. These findings were supported by molecular analysis, which allowed the amplification of a viroid genome region only in the positive control. Both biological and molecular diagnosis confirmed the absence of HSVd in the citrus varieties assessed. This study will allow the evaluation of the citrus plant collections used in the foundation category as a source of buds for plant multiplication of registered and certified seeds for citrus propagation nurseries in Colombia.

RESUMEN El viroide del enanismo del lúpulo (HSVd) es el agente causal de la cachexia de los cítricos, que puede provocar pérdidas significativas en el cultivo. Como parte de una estrategia de manejo preventivo, es indispensable utilizar plantas sanas provenientes de un programa de certificación. Este estudio tuvo como objetivo evaluar la sanidad de 17 cultivares de cítricos frente a HSVd, utilizando diagnósticos biológico y molecular. Para el diagnóstico biológico, se empleó como planta indicadora cidro Etrog (Citrus medica L.) clon Arizona 861 S1, incluyendo controles negativos y positivos para la infección por HSVd. Para el diagnóstico molecular se utilizó la técnica de Reacción en Cadena de la Polimerasa con Transcriptasa Inversa (RT-PCR) con cebadores específicos para la detección del viroide. Los resultados indicaron que seis meses después de la inoculación, el control positivo mostró síntomas asociados con la infección por el viroide, como necrosis en el peciolo y tallo, epinastia foliar y necrosis en vena media. Por el contrario, tanto el control negativo como los cultivares de cítricos evaluados no presentaron síntomas. Estos resultados fueron corroborados por el análisis molecular, que permitieron amplificar una región del genoma del viroide, únicamente en el control positivo. Ambos diagnósticos biológico y molecular confirmaron la ausencia de HSVd en las variedades de cítricos evaluadas. Este estudio permitirá la evaluación de las colecciones de plantas de cítricos utilizadas en la categoría fundación como fuente de yemas para la multiplicación de semilla registrada y certificadapara los viveros productores de material de propagación de cítricos en Colombia.

Abstract The use of biostimulants is an alternative in plant production that allows increasing growth and vigor. The objective of this work was to evaluate the application of nanochitosan-iodine complexes (NPsCs-I) in the growth and development of tomato plants. The application of the treatments was foliar every 15 days. Plant growth, vigor and yield variables were evaluated. In the results, only in the stem diameter variable, there were significant differences with respect to the absolute control (T0). The treatment of NPsCs-KIO3 25 mg L-1 increased 29% at 20 dat, NPsCs-KIO3 5 mg L-1 increased 19% at 60 dat and NPsCs increased 27% at 120 dat compared to T0. The increase in stem diameter is associated with greater plant vigor, which translates into a biostimulant effect on tomato plants.

Resumen El uso de bioestimulantes es una alternativa en la producción de plantas que permite aumentar el crecimiento y vigor. El objetivo del trabajo fue evaluar la aplicación de complejos de nanoquitosán-yodo (NPsCs-I) en el crecimiento y desarrollo de plantas de tomate. La aplicación de los tratamientos fue de forma foliar cada 15 días. Se evaluaron variables de crecimiento, vigor y rendimiento en las plantas. Los resultados muestran que solamente para el diámetro de tallo se presentaron diferencias significativas con respecto al testigo absoluto (T0); aumentando al aplicar NPsCs-KIO3 25 mg L-1 un 29% a los 20 ddt, NPsCs-KIO3 5 mg L-1 en 19% a los 60 ddt y con NPsCs en 27% a los 120 ddt con respecto al T0. El aumento del diámetro de tallo está asociado a un mayor vigor en las plantas, lo que se traduce a un efecto bioestimulante en las plantas de tomate.