ABSTRACT Aluminum is a heavy metal toxic to living organisms and is released into soils with a strong acidic composition. The floating aquatic weed Eichhornia crassipes (Mart.) Solms is reported as the most widespread invasive vascular plant in the world and is distributed all over Colombia ranging from sea level to the cold Andean highlands. As a consequence of the solubility of Al3+ in soils, it flows into fresh water sources where E. crassipes grows as an invasive plant. A greenhouse study was conducted in Tunja, Colombia, with the objective of evaluating the growth of aquatic weed in an aqueous substrate with Al3+ content similar to those recorded in lakes (0.0, 0.2, 0.4, 0.6, and 0.8 mg L-1 Al3+). Biomass production, leaf area, evapotranspiration, water use efficiency, and other allometric variables were evaluated. An increase of 18.2% in the transpiration rate and a reduction between 9.7%-41.8% in the leaf area were found. The latter reduced the value of variables such as the specific leaf area between 9.9%-34.6% and leaf area ratio between 16.7%-40.4%. However, the total dry weight, DM partitioning, root to shoot ratio, leaf weight ratio, and the absolute and relative growth rates did not show significantly different values between treatments. Therefore, Al content found in water sources in Colombia, despite being in the ranges reported as toxic for some aquatic plants, did not significantly affect the growth of E. crassipes due to its phenotypic plasticity and anthropic alteration of water sources but rather favor its growth.

ABSTRACT Leaf area loss is a frequent problem in crops, and it can be caused by biotic or abiotic factors. Reduced leaf area can produce alterations in plants, affecting their metabolism, growth, and yield. The leaf area in lettuce plants (Lactuca sativa L.) is often affected by herbivores such as slugs. The effects of partial defoliation on the growth of lettuce plants were evaluated under greenhouse conditions in Tunja, Colombia. Some plants had half of their leaves removed, while others were left intact as a control. The variables normally used in the basic analysis of plant growth were evaluated. There was nonsignificant difference between the two treatments; however, lettuce plants showed a remarkable ability to reduce the negative effect caused by partial defoliation, and they managed to maintain a balance in the root to shoot ratio, leaf area ratio, specific leaf area, leaf weight ratio, DM partitioning, and harvestable DM. Partial defoliation decreased the absolute growth rate by 17.8% and the relative growth rate by 13.8%. Additionally, the chlorophyll content index and the number of leaves increased by 16.0% and 15.4%, respectively, in plants subjected to partial defoliation compared with the control plants. These results indicate the regeneration capacity of the plants after partial defoliation.

Resumo A Colômbia conta com recursos genéticos de amora que apresentam ampla diversidade morfológica. Entre os caracteres mais relevantes relacionados com sua diversidade, encontram-se a presença de aguilhões, a forma das folhas, o número e a cor dos frutos, e seu enorme potencial agroindustrial devido a seu dulçor e a seus compostos bioativos, como os polifenóis. Estas plantas podem crescer entre 1.700 e 3.400 metros acima do nível do mar. No presente estudo, avaliaram-se 13 materiais silvestres e cultivados do gênero Rubus. Realizou-se sua caracterização molecular mediante 16 marcadores microssatélites SSR, dos quais, todos produziram amplificação positiva, gerando 23 lócus e 26 alelos. A AMOVA indicou uma diferenciação genética molecular de 23% entre os grupos, os quais correspondem à localização geográfica da amostra, e o maior aporte à variância está no interior dos grupos (76%), possivelmente devido a que cada um deles está composto por diferentes espécies cultivadas e parentes silvestres do gênero . RubusIsto sugere que a agrupação dos genótipos estudados não necessariamente corresponde à origem geográfica. Não obstante, as descobertas evidenciam alta variação genética, com o valor Fst de 0.27, a qual pode ser útil em futuros programas de fitomelhoramento, nos quais se tenham em conta a diversidade genética, as características morfológicas dos frutos e a identificação molecular das cultivares.

Abstract Colombia is home to blackberry genetic resources which present a morphological diversity. The relevant characteristics related to its diversity are the presence of prickles, the shape of its leaves, the number and color of its fruits, and its enormous agro-industrial potential due bioactive compounds such as polyphenols. These plants can grow between 1,700 and 3,400 m asl and are cultivated in the central region of the country. The study evaluated 13 wild and cultivated plants from the genus Rubus. A molecular characterization was carried out using 16 SSR microsatellite markers, all of which produced positive amplification generating 23 loci and 26 alleles. The AMOVA indicated a molecular genetic differentiation of 23% between the groups which corresponded to the geographic location of the sample. The greatest contribution to variance is found within the groups (76%), possibly because each of them is composed of different cultivated species and wild relatives of the genus Rubus. This suggests that the grouping of the genotypes studied doesn’t necessarily correspond to geographical origin. However, the findings show high genetic variation, with an Fst value of 0.27. This may be useful in breeding programs where genetic diversity, morphological characteristics of the fruits, and the molecular identification of the fruits are taken into account.

Resumo No município de Gachantivá, Colômbia, Rubus alutaceus é usada com fins comerciais, ha mais de uma década, sem que até o momento se conheça a sua identidade taxonômica. Com o propósito de identifica-la, estudaram–se as características anatômicas e morfológicas das suas flores, frutos, folhas, caules, sementes; características físico-químicas dos frutos, sua cor, segundo a escala CIELAB, o diâmetro equatorial e polar, peso fresco, pH e sólidos solúveis totais (SST). Avaliaram-se as variáveis morfológicas qualitativas e quantitativas, e realizaram-se cortes longitudinais e transversais com o objetivo de fazer estudos histológicos. Encontraram-se plantas que apresentam folhas trifoliadas e pentafoliadas; polidrupas subglobosas de cor amarela–esbranquiçada, SST de 8,8 °Brix em frutos completamente maduros; sementes elípticas, subglobosas com endocarpo ruminado; anatomicamente apresentam-se cristais de oxalato cálcico em forma de drusas e ráfides nas folhas e ramos e abundantes pelos simples e coléteres, além do tecido vascular de aspecto mais ou menos contínuo. O alto teor em TSS influencia positivamente o agronegócio dos frutos e a presença de estruturas secretoras incluindo tricomas e coléteres simples podem reduzir o ataque de pragas; essas variáveis caracterizam a nova espécie e conferem potencial agronômico para fortalecer seu cultivo e sua comercialização.

Abstract In Gachantivá, Colombia, Rubus alutaceus has been used for commercial purposes for more than one decade but so far with unknown taxonomic identity. For its identification, the anatomical and morphological characteristics of its flowers, fruits, leaves, stems, and seeds, as well as the physicochemical characteristics of its fruits such as color, equatorial and polar diameter, fresh weight, pH and total soluble solids (TSS), were studied. Qualitative and quantitative morphological parameters were evaluated, and longitudinal and transverse cuts were made for histological studies. The plants were found to have trifoliate and pentafoliate leaves; whitish–yellow subglobose polydrupes, fully mature fruits with 8.8°Brix TSS; elliptical, subglobose seeds with ruminated endocarps; anatomical calcium oxalate crystals in the form of druses and raphides in the leaves and branches; and abundant hairs, simple and glandular (colleters) addition to vascular tissue with a more or less continuous appearance. High value in TSS, positively influences fruit agribusiness and the presence of simple hair and colleters can reduce the attack of pests, these variables identify the new species and give it agronomic potential to strengthen its cultivation and marketing.

RESUMEN Los virus representan una amenaza para las plantas cultivadas en Colombia, y algunos estudios indican que las pérdidas económicas causadas por estos problemas fitosanitarios podrían evitarse mediante procedimientos preventivos estándar. Como objeto de estudio, se seleccionaron tres importantes productos de Colombia, como lo son: rosa ornamental (Rosa sp.), uchuva (Physalisperuviana L.) y gulupa (Passiflora edulis Sims). En el presente artículo, se muestran los primeros desarrollos resultantes del monitoreo de virus en estas plantas, para determinar el estado de las virosis en fincas colombianas. Se realizaron análisis serológicos de 21 fincas en Cundinamarca y Boyacá, Colombia, en 2016-18. El objetivo de esta investigación fue el desarrollo de un protocolo piloto para el diagnóstico rutinario, que se pueda aplicar en un programa de certificación de material vegetal para la determinación de la presencia de virus, en varios productos hortícolas colombianos. Con base en este protocolo, se pueden determinar los riesgos que representan ciertos virus y se puede considerar la necesidad de certificar el material de siembra evaluado según la presencia de virus. Se están desarrollando herramientas de diagnóstico confiables y prácticas, para la detección de los virus más relevantes, en un proyecto conjunto entre universidades alemanas y colombianas, el Instituto Colombiano de Agropecuario (ICA), la Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA) y el Centro Internacional de Agricultura Tropical (CIAT).

ABSTRACT Plant viruses may pose a threat to crops in Colombia. To evaluate the potential risk of yield losses due to plant virus infection, a literature analysis followed by a first field study was carried out focusing on purple passion fruit (Passiflora edulis Sims), cape gooseberry (Physalis peruviana L.), and ornamental rose (Rosa sp.), which are important Colombian exports. Over the past three years, plant material was collected from 21 farms in Cundinamarca and Boyacá, Colombia, two regions that are in close proximity to El Dorado International Airport, the country's largest air freight terminal. Plants were visually inspected and subsequently tested by bioassay and serological methods. Overall, in the samples investigated by the two diagnostic methods, plant viruses were detected. Detected viruses belong to the genus Poty-, Tobamo-, Nepo-, llar-, and Tospovirus. The extent of the distribution and occurrence of these viruses in each crop has to be determined in a representative field study. Such a monitoring program could be supported by a standardized farmer interview. The development of suitable plant virus diagnostic and managements tools is the focus of a cooperation project between German and Colombian universities, the Colombian Agricultural Institute (ICA), the Colombian Corporation of Agricultural Investigation (AGROSAVIA) and the International Center for Tropical Agriculture (CIAT).

Resumo O objetivo da pesquisa foi caracterizar a qualidade do fruto de pessegueiro cv. Jarillo, produzido sob as condições de tropical de altitude em três locais: Pamplona, Chitagá e Pamplonita, no Norte de Santander, Colômbia. Dez árvores foram amostradas pela técnica hipercúbica condicional latina e oito frutos em crescimento e estado fisiológico de maturidade foram selecionados em cada um. Por meio de uma análise de perfil, foram testadas as hipóteses de paralelismo, coincidência e horizontalidade das variáveis de qualidade no intervalo completo de medição e em alguns segmentos do intervalo, alguns padrões foram encontrados do ponto de vista gráfico. Um diagrama radial foi feito para estudar o desenvolvimento da cor dos frutos em cada nível térmico. Quando o quociente entre o diâmetro longitudinal e o diâmetro equatorial tende para 1 pela esquerda, os maiores valores de peso são alcançados, destacando-se o menor nível de elevação, com pesos em torno de 150 g. A análise do perfil mostrou, nas variáveis de qualidade, que houve interação significativa entre o tempo de avaliação e o nível de altitude. Os resultados mostram que as condições climáticas predominantes afetam suas características físico-químicas durante o processo de crescimento até a maturação.

Abstract The aim of this study was to characterize the quality of peach fruits Jarillo cv., produced under the conditions of altitude tropical climate in three locations: Pamplona, Chitagá and Pamplonita, in Northern Santander, Colombia. Ten trees were sampled by the conditioned latin hypercube method and eight growing fruits with physiological state of maturity were selected. By means of a profile analysis, the hypotheses of parallelism, coincidence and horizontality of quality variables in the complete measurement interval were tested, and in some segments of the interval, some patterns from the graphic point of view were found. A radial diagram was made to study the development of fruit color at each thermal level. When the quotient between longitudinal diameter and equatorial diameter tends to 1 to the left, the highest weight values are reached, highlighting the lowest elevation level, with weights around 150 g. The profile analysis showed, regarding quality variables, that there was a significant interaction between evaluation time and altitude level. The results show that the prevailing climatic conditions affect the physicochemical characteristics of fruits during the growth process until maturation.

El estrés por encharcamiento es un factor limitante en la producción de algunos cultivos que se desarrollan en localidades, con alta frecuencia de lluvias. El encharcamiento causa disminución en la disponibilidad de O2 en las raíces, lo cual, afecta sustancialmente la anatomía, la morfología y el metabolismo de las plantas. El déficit de oxígeno inhibe la respiración mitocondrial, la oxidación y los procesos de oxigenación, con lo cual, el metabolismo de la planta resulta severamente afectado. Se desarrolló en Tunja, Colombia, un ensayo en condiciones de invernadero, con el propósito de evaluar el efecto del encharcamiento sobre el crecimiento de plantas de repollo (Brassica oleracea var. capitata). Algunas plantas fueron encharcadas durante 25 días y su respuesta fisiológica se comparó con la de plantas mantenidas a capacidad de campo. Como consecuencia del encharcamiento, se redujo el área foliar, el peso seco total, el contenido de clorofila y los valores de la relación de área foliar, de la tasa absoluta de crecimiento y de la tasa relativa de crecimiento. Adicionalmente, solo en las plantas expuestas al encharcamiento, se presentó necrosis en las hojas, en un alto porcentaje. En cuanto a las variables relacionadas con la fluorescencia de la clorofila, se registró una disminución de 17,9; 50,0 y 36,0%, en los valores de Fv/Fm, ΦPSII and qP, respectivamente. El conjunto de estos resultados indica baja tolerancia de las plantas de repollo al encharcamiento.

Waterlogging stress is a limiting factor in the production of crops grown in localities with high rainfall frequency. Waterlogging causes a decrease in the availability of O2 in roots, which substantially affects the anatomy, morphology and metabolism of plants. Oxygen deficiency inhibits mitochondrial respiration, oxidation, and oxygenation processes, causing severe affection of plant metabolism. A test in greenhouse conditions was carried out in Tunja, Colombia, in order to evaluate the effect of waterlogging on the growth of cabbage plants (Brassica oleracea var. capitata). Some plants were waterlogged for 25 days and their physiological response was compared with plants maintained at field capacity. As consequence of waterlogging, leaf area, total dry weight, chlorophyll content, leaf area ratio, absolute growth rate and relative growth rate were reduced. In addition, necrotic plants exhibited a high percentage of necrosis in the leaves. As for the variables related to chlorophyll fluorescence, there was a decrease of 17,9, 50,0 and 36,0% in the Fv/Fm values, ΦPSII and qP, respectively. All of these results indicate low tolerance of cabbage plants to waterlogging.

RESUMEN El crecimiento es un aumento irreversible en el tamaño de los órganos de las plantas que puede implicar cambios en su forma, y está acompañado de procesos como la morfogénesis y la diferenciación celular. La expresión matemática del crecimiento del fruto en plantas cultivadas es una herramienta que permite estimar aspectos relacionados con la producción, y además contribuye a definir protocolos aplicables al manejo agronómico del cultivo. Se desarrolló en el municipio de Caldas (Boyacá, Colombia), un ensayo en condiciones de campo, con el objetivo de describir la dinámica de diferentes variables implicadas en el crecimiento y caída de frutos de curuba (Passiflora tripartita var. mollissima). Se calcularon modelos matemáticos para la estimación de algunas variables, usadas comúnmente para describir el crecimiento de frutos. Las variables evaluadas presentaron valores de R 2 superiores a 0,98 con excepción de la tasa de crecimiento absoluto de la longitud del fruto y la caída instantánea de frutos, cuyos valores de R 2 fueron de 0,82 y 0,76, respectivamente. Los resultados mostraron que la tasa de crecimiento relativo presentó los valores máximos hasta 22 días después de la apertura floral, mientras que la tasa de crecimiento absoluto presentó el mayor valor entre 15-22 días después de la apertura floral. La longitud y el ancho de los frutos mostraron una curva de forma sigmoide, típica de otras Passifloraceae reportadas previamente. La máxima caída de frutos de presentó a los 15 días después de la apertura floral y se encontró que sólo el 38,9% de las flores desarrollan frutos que alcanzan el momento de la cosecha. Esta información es de gran importancia cuando se pretende efectuar un manejo tecnificado del cultivo, con el propósito de optimizar la producción de curuba.

ABSTRACT Growth is an irreversible increase in the size of plant organs that may involve changes in their form, and is accompanied by processes such as morphogenesis and cell differentiation. The mathematical expression of fruit growth in cultivated plants allows one to estimate aspects related to production, and contributes to defining protocols applicable to the agronomic management of the crop. A field trial was carried out in Caldas (Boyaca, Colombia), to describe the dynamics of different variables involved in the growth and fall of fruits in Banana passion fruit plants (Passiflora tripartita var. mollissima). Mathematical models were developed for variables commonly used to describe fruit growth. The evaluated variables presented values of R 2 higher than 0.98, except for the absolute growth rate of fruit length and at the time of fruit drop, whose R 2 values were 0.82 and 0.76, respectively. The results showed that the relative growth rate presented maximum values up to 22 days after floral opening, whereas the absolute growth rate presented the highest value between 15-22 days after floral opening. The length and width of the fruits showed a sigmoid-shaped curve, typical of other previously reported Passifloraceae. The maximum fruit fall occurred at 15 days after the floral opening and it was found that only 38.9% of the flowers develop fruits that reach the time of harvest. This information contributes to the technical management and optimal production of banana passion fruit.

RESUMEN Las plantas tienen la capacidad de responder de diferentes formas a la calidad de la luz, a su intensidad, y a la combinación de ambas. Adicionalmente, las clorofilas absorben la luz en las franjas azul y roja del espectro, pero la luz verde e infrarroja se absorben poco o no se absorben, no obstante, afectan la morfogénesis en plantas. Se desarrolló en Tunja, Colombia, un experimento en el que se evaluó la influencia del sombreado sobre plantas de fique (Furcraea hexapetala). Se colocaron las plantas bajo filtros de polipropileno de color verde que indujeron 55,4; 85,8 y 90,1% de reducción de la luz y se compararon con plantas a libre exposición dentro de un invernadero. Como consecuencia del sombreado, en relación con las plantas control, se redujeron los valores de las siguientes variables: el índice de contenido de clorofila entre 52,2 y 55,0%, el contenido de masa seca entre 80,8 y 94,0%, la toma de agua entre 40,9 y 44,9%, la eficiencia en el uso del agua entre 23,0 y 53,7%, la tasa de crecimiento relativo entre 35,1 y 58,4%, mientras que los valores de la relación raíz/parte aérea, el área foliar específica y la relación de área foliar se aumentaron en rangos de 24,2 a 73,5%; 107,5 a 132,4% y 116,6 a 174,9%, respectivamente. El sombreado mediante los filtros de color verde indujo una reducción en la relación rojo/rojo lejano de la luz. Con base en estos resultados se pudo inferir que las plantas de fique presentan poca plasticidad para tolerar el estrés abiótico inducido por el sombreado a través de los filtros de color verde.

ABSTRACT Plants have the ability to respond in different ways to the quality of light, its intensity, and the combination of both. In addition, chlorophyll absorbs light in the blue and red bands of the spectrum, but green and infrared light are poorly absorbed or not absorbed, yet they affect plant morphogenesis. An experiment was carried out in Tunja, Colombia, in which the influence of shading on sisal plants (Furcraea hexapetala) was evaluated. The plants were placed under green polypropylene filters that induced 55.4, 85.8 and 90.1% light reduction and were compared with open exposure plants in a greenhouse. As a consequence of shading, the values of the following variables were reduced: chlorophyll content index by between 52.2 and 55.0%, dry mass by between 80.8 and 94.0%, water uptake by between 40.9 and 44.9%, water use efficiency by between 23.0 and 53.7% and relative growth rate by between 35.1 and 58.4%, as compared to the control, while the values for the root to shoot ratio, specific leaf area and leaf area ratio were increased by ranges of 24.2 to 73.5%, 107.5 to 132.4% and 116.6 to 174.9%, respectively. The shading with green filters induced a reduction in the red/far red ratio of light. Based on these results, it was possible to infer that the sisal plants presented low plasticity for tolerating the abiotic stress induced by green-filter shading.

RESUMEN El área foliar es un parámetro ampliamente usado en estudios de ecofisiología de cultivos, debido a que la relación existente entre el área foliar y la producción de fruta es bastante estrecha. Para su determinación se utilizan diferentes métodos ya sean destructivos, no destructivos o indirectos. La estimación del área foliar es una importante observación biométrica que debe hacerse con el propósito de comparar el comportamiento de los vegetales en función de diferentes tratamientos. El objetivo del estudio fue la determinación y validación de las funciones de regresión más acertadas para la estimación no destructiva del área foliar en algunos cultivares de duraznero y ciruelo. En este trabajo se calcularon funciones matemáticas para estimar el área foliar en los cultivares Gold Fruly, Ecuatoriano, Methley y Horvin, de ciruelo, y en los cultivares Dorado, Rubidoux, Diamante y Rey Negro, de duraznero. Las hojas se colectaron de árboles cultivados en Paipa, Colombia. Se seleccionó una función de regresión para cada cultivar y se realizó su validación comparando datos de área foliar estimados con las funciones matemáticas y datos medidos con el medidor de área foliar. Se tomó como variable independiente (X) de la función, el producto del largo por el ancho de la hoja. En todos los casos el coeficiente de correlación de Pearson presentó valores superiores a 0,9, señalando la estrecha relación entre los datos estimados y los observados. Con el uso de estas funciones, es posible estimar de manera no destructiva, el área foliar en los cultivares de duraznero y ciruelo involucrados en el estudio.

SUMMARY Leaf area is a widely used parameter in the study of crop ecophysiology because of its direct implications on fruit production. Different destructive, non-destructive or indirect methods are used for its determination. The estimation of the leaf area is an important biometric observation that must be made when comparing the behavior of plants in response to different agricultural treatments. The objective of the study was to determine and validate the most accurate regression functions for non-destructive estimation of leaf area in some cultivars of peach and plum. In this work, mathematical functions were applied to estimate leaf area in the plum cultivars Gold Fruly, Ecuatoriano, Methley and Horvin, and in the peach cultivars Dorado, Rubidoux, Diamante and Rey Negro. The leaves were collected from trees grown in Paipa, Colombia. A regression function was selected for each cultivar and the estimated leaf area data was compared with the functions and data measured with a leaf area integrated analyzer. The product for the length by the width of the leaf was used as independent variable (X) of the function. In all cases, the Pearson correlation coefficient presented values higher than 0.9, indicating the close relationship between the estimated and observed data. With the use of these functions, it is possible to non-destructively estimate the leaf area in the peach and plum cultivars involved in the study.

La elevada concentración de dióxido de carbono (CO2) y otros gases de efecto invernadero ha resultado en un calentamiento global, mayores niveles de radiación ultravioleta (UV) y cambios en el ciclo hidrológico afectando el crecimiento, desarrollo, producción y calidad de los cultivos frutales, que sin duda, serán difíciles de predecir y generalizar debido a que los procesos fisiológicos de las plantas son multidimensionales. Se reseña, cómo los efectos de una alta y baja radiación solar y temperatura, estrés hídrico por sequía e inundación y el aumento del nivel de CO2 en la atmósfera inciden sobre los cultivos y afectan su crecimiento y fisiología.

The increased concentration of carbon dioxide (CO2) and other greenhouse effect gases has led to global warming, which has resulted in climate change, increased levels of ultraviolet (UV) radiation and changes in the hydrological cycle, affecting the growth, development, production and quality of fruit crops, which undoubtedly will be difficult to predict and generalize because the physiological processes of plants are multidimensional. This review outlines how the effects of high/low solar radiation, temperature, water stress from droughts, flooding and rising levels of CO2 in the atmosphere affect fruit crops and their growth and physiology.

Los virus fitopatógenos afectan en gran medida la producción agrícola colombiana. Diferentes estudios indican que las pérdidas económicas causadas por estos problemas fitosanitarios podrían evitarse teniendo un mejor conocimiento de estos patógenos y empleando un procedimiento estándar de manejo preventivo como guía. Los productores, viveros, comercializadores y consumidores, se beneficiarían con productos de calidad, al controlarse las fuentes de transmisión de virus. Los acuerdos de libre comercio han dado lugar a una expansión de la producción agrícola y a la proliferación de cientos de viveros que no pudieron ser objeto de inspección minuciosa por parte del Estado. Este artículo presenta los principales virus que afectan dos importantes frutales exóticos de exportación para Colombia, la uchuva (Physalis peruviana) y las pasifloras (Passiflora sp.). A su vez, esquematiza un programa de certificación de material vegetal sano para viveros y la creación de un programa nacional de certificación agrícola, dirigido por el Ministerio de Agricultura y Desarrollo Rural y el Instituto Colombiano Agropecuario (ICA); apoyado por universidades con programas en agricultura, centros de investigación y laboratorios de diagnóstico fitosanitario que proporcionarían un sistema de supervisión y control adecuados, para el material vegetal. Adicionalmente, serían un soporte para las unidades municipales de asistencia técnica agropecuaria. Esta iniciativa interinstitucional también apoyaría la implementación y ajuste de las resoluciones fitosanitarias del ICA en semillas (R.2046/2003), material de propagación en frutales (R.3180/2009) y transporte interno de material vegetal (R.3973/2016). La competitividad de la agricultura colombiana en los mercados internacionales depende del uso de material vegetal sano.

Phytopathogenic viruses greatly affect Colombian agricultural production. Several studies indicate that economic losses caused by these phytosanitary problems could be avoided by having a better understanding of these pathogens and using a standard procedure for preventive management as a guide. Producers, nurseries, distributors and consumers would benefit from quality products by controlling the sources of virus transmission. Free trade agreements have resulted in an expansion of agricultural production and the proliferation of hundreds of nurseries that could not have undergone thorough inspection by the state. This article presents the main viruses that affect two important exotic fruits exported from Colombia, cape gooseberry (Physalis peruviana) and Passiflora (Passiflora sp.). The article then outlines a certification program for healthy plant material for nurseries and the establishment of a national agricultural certification program, addressed by the Ministry of Agriculture and Rural Development and the Colombian Agricultural Institute (ICA). This program would be also assisted by agricultural universities, research centers and phytosanitary laboratories that would provide monitoring and control systems for the plant material. In addition, it would be a support for municipal agricultural technical assistance units. This inter-agency initiative would also support the implementation and adjustment of phytosanitary ICA resolutions for seeds (R.2046/2003), propagation material in fruit (R.3180/2009) and internal transport of plant material (R.3973/2016). The competitiveness of Colombian agriculture in international markets depends on the use of healthy plant material.

El cultivo de mora en Colombia es un renglón importante para el desarrollo económico de medianos y pequeños productores. Las actividades de poda son labores indispensables en este cultivo y tienen el propósito de renovar las ramas productivas y mejorar la relación entre la oferta y demanda de fotoasimilados. En el presente ensayo se utilizaron plantas de dos años de edad, tutoradas en T; se marcaron 48 tallos bajo diferentes sistemas de poda (testigo: sin podar; poda corta: tallo a 1,6 m de longitud; poda larga: tallo a 2,6 m de longitud), se midió la longitud de los tallos, y se registró el número de hojas y de panículas aparecidas a lo largo del tiempo, se graficó el comportamiento de las variables respecto a los días después de brotación (ddb). Se establecieron las curvas y las tasas de crecimiento mediante análisis funcional. Como resultado se obtuvo que los modelos logísticos fueron de mejor ajuste para la descripción del crecimiento de esta especie, la máxima longitud del tallo se presentó a los 231 ddb con 535 cm, la tasa relativa de crecimiento (TRC) del tallo disminuyó gradualmente, la tasa absoluta de crecimiento (TAC) del tallo así como el número de hojas y panículas disminuyeron con el tiempo. El número máximo de hojas fue de 55 a los 231 ddb; la floración en todos los sistemas de poda inició a los 126 ddb aproximadamente; el número de inflorescencias en promedio fue de 18 en plantas sin poda, mientras que con poda corta tuvo un valor de 10, y de 21 con poda larga. Los resultados mostraron que la poda es un factor determinante en el desarrollo fisiológico y productivo en esta especie de mora.

In Colombia, the blackberry is an important perennial crop for the economic sustainable development of medium and smallholder farmers. Pruning is essential for this crop and aims to renew the productive, fruit bearing branches and normalize the sink-source relationships of photoassimilates. The establishment of physiological indices and growth curves for blackberry crops with different pruning practices will develop proposals for the agricultural handling of this species. In this study, two-year-old blackberry crops were used with a T-trellis; 48 canes were grouped into three pruning treatments; a) control: without pruning; b) short pruning: canes with a 1.6 m length; and c) long pruning; canes with a 2.6 m length. The length of the canes, and the number of leaves and panicles were registered over time, in terms of days after sprouting. The curves and rates of growth were established with a functional analysis. The logistic model was ideal for expressing the growth of the plants. The maximum length of the canes was seen at 231 days after sprouting: 535 cm. The relative growth rate of the canes decreased gradually over time. The values of the absolute growth rate of the canes as well as the number of leaves and panicles decreased over time too. The maximum number of leaves was seen from 55 to 231 days after sprouting; the flowering in the plants in the pruned treatments started at 126 days after sprouting. The average number of inflorescences was 18 in the shrubs without pruning, 10 with the short pruning and 21 with the long pruning. The results showed that pruning is a determinant factor in the physiological and productive development of blackberry shrubs and that the long pruning, with a 2.6 m length, was the best pruning alternative.

Utilizando un diseño completamente aleatorizado, con dos tratamientos (defoliación al 50% y control sin defoliación) y seis repeticiones por tratamiento, se determinó la producción y la calidad del fruto en plantas de uva sometidas a defoliación parcial temprana en Villa de Leyva - Colombia. Como material vegetal se utilizaron plantas de Vitis vinifera L. 'Chardonnay' de cinco años de edad, sembradas en un sistema de espalderas a una distancia de 2,1 x 1 m. Quincenalmente, se realizó la defoliación parcial a las plantas, retirando una de cada dos hojas recién emergidas en cada una de las plantas sometidas al tratamiento de defoliación. 130 días después de la poda de inducción, se determinó el número de racimos cosechados en cada planta evaluada, el número de bayas por racimo, el peso fresco de los racimos y el peso promedio de la baya, el pH del fruto, su diámetro, el porcentaje de sólidos solubles total (SST), la acidez titulable total (ATT) y el índice de madurez del fruto (IM). El peso promedio del racimo y el peso promedio de la baya, fueron significativamente mayores en las plantas sometidas a la reducción del área foliar. El valor de todos los parámetros de calidad del fruto aumentó con la defoliación, excepto la ATT, la cual fue mayor en las plantas control. Con lo anterior, se pudo concluir que la defoliación parcial tuvo una marcada influencia sobre la producción y la calidad del fruto de uva 'Chardonnay'.

Using a completely randomized design with two treatments (50% defoliation and a control without defoliation) and six replications per treatment, the fruit quality and production of grape plants subjected to early partial-defoliation in Villa de Leyva - Colombia were determined. Five-year-old Vitis vinifera L. 'Chardonnay' plants were used as the plant material, planted in a trellis system with distances of 2.1 x 1 m. The plants were partially defoliated biweekly, removing every other recently emerged leaf in each of the plants subjected to the defoliation treatment. 130 days after the start of the pruning, the number of harvested clusters was determined for each of the evaluated plants along with the number of berries per cluster, the fresh weight of the clusters, the average berry weight, the fruit pH and diameter, the total soluble solids (TSS), the total titratable acidity (TTA) and the fruit maturity index (MI). The average weights of the clusters and the berries were significantly higher in the plants subjected to a reduced foliar area. All of the fruit quality parameter values increased with defoliation with the exception of TTA, which was higher in the control plants. Therefore, it was concluded that partial-defoliation had a pronounced influence on the fruit quality and production of the 'Chardonnay' grapes.

La caléndula (Calendula officinalis L.) es la segunda planta medicinal más comercializada en Colombia. El estudio, se realizó en Tunja, Colombia, en el que se evaluaron los conte- nidos de clorofila y de carotenoides en plantas de caléndula, expuestas a condiciones de plena iluminación solar y som- bra, bajo una malla de fibra sintética, que reduce la luz en un 35%. También se evaluaron los parámetros de fluorescencia de la clorofila y la tasa de transporte de electrones. En com- paración con las plantas a pleno sol, las plantas sombrea- das presentaron una mayor proporción de clorofila a/b y una proporción inferior de carotenoides/clorofila. Los valores de fluorescencia máxima (Fm), la fluorescencia variable (Fv) y la eficiencia cuántica máxima del fotosistema II (la relación Fv/ Fm) aumentaron en las plantas bajo sombra, mientras que la tasa de transporte de electrones, se redujo. Estos resultados sugieren que las plantas de caléndula son muy sensibles a las condiciones de poca luz.

Pot marigold (Calendula officinalis L.) is the second most commonly-sold medicinal herb in Colombia. The study was performed in Tunja, Colombia, in which chlorophyll and carotenoid content were evaluated in pot marigold grown under low and high light conditions (35% and 100% of full daylight). Chlorophyll fluorescence parameters and electron transport rate were also evaluated. Compared to full sun plants, shaded plants had a higher ratio of chlorophyll a to chlorophyll b, and a lower ratio of carotenoids to chlorophyll. Values for maximum fluorescence (Fm), variable fluorescence (Fv), and maximum quantum efficiency of photosystem II (the ratio Fv/Fm) increased in shaded plants, while electron transport rate was reduced. These results suggest that pot marigold plants are very sensitive to low-light conditions.