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1 Simposio Intenacional y 2 Nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano.

To increase the availability of nutrients and improve crop productivity, chemical fertilizers are introduced to the soil, although the biological fixation of nitrogen contributes globally with 180 million metric tons of ammonia per year, which is comparable to current contribution of anthropogenic nitrogen. In this way, the present study aimed to evaluate the effect of the interaction of Azospyrillum brasilense and Bradyrhizobium japonicum with different levels of nitrogen on the yield and economic viability of the tomato crop. An experimental design of divided plots was used, with the nitrogen fertilization dose being the largest plot (100% of the dose, 50% of the dose and 0% of the dose) and the minor plot of nitrogen-fixing bacteria (100 cc ha-1, 200 cc ha-1, 300 cc ha-1) with four random internal blocks and five plants as experimental unit. The variables evaluated were: production per plant, yield/ha, number of fruits/plant and average fruit weight. Finally, the economic analysis was performed according to the combination of the treatments. The results obtained showed that the mixture of nitrogen-fixing bacteria (BFN) (Azospyrillum brasilense and Bradyrhizobium japonicum) at a dose of 100 cc ha-1, significantly increased tomato production when nitrogen (urea) was not applied. The application of BFN in combination with adequate levels of nitrogen favors the sustainability of the tomato.

Use of biotechnological potential of native microorganisms as bio-inputs is having a great impact on agricultural systems. Plant Growth Promoting Rhizobacteria (PGPR), in addition to their beneficial effect on plant growth and on the availability of soil elements, also have an antagonistic effect against different pathogens. In this study, growth promotion mechanisms with emphasis on the antagonism of PGPR isolated from sugarcane and tomato crops were evaluated. Antagonism against Fusarium oxysporum f.sp lycopersici (Fol) was determined by dual tests, inhibition of germination and production of chitinases and endoglucanases. 52 isolates were evaluated and according to their results in dual tests 10 were selected for further analysis. Isolate GIBI127 showed the best percentage of Inhibition Germination (IG) of Fol (59.29%). Then, a selection index was calculated using results from gi, dual tests and growth promotion mechanisms to select five best isolates. Finally, these bacteria were evaluated for chitinases and endoglucanases production using Miller´s method. As a result, strain GIBI419 (Burkholderia cepacia) showed a higher production of these enzymes. Selected isolates have antagonistic potential along with plant growth promotion characteristics, which can be used for the development of microbial inoculants which allow the establishment of agricultural systems for tomato cultivation that are sustainable, efficient, and environmentally friendly.

The objective of this study was to document and analyze the effect of climate on the phenological development of ‘Hass’ avocado in two contrasting zones of the Andean tropics of Caldas, located at altitudes of 1,950m and 2,400m a.s.l., respectively. A completely randomized experimental design was carried out using a five to seven year-old ‘Hass’ tree as experimental unit and 15 replicates on each area. Observations were conducted on lateral sylleptic shoots and their corresponding apical buds located on the eastern and western sides of each tree. The destination of the apical bud of lateral shoots was quantified, floral phenology was documented, heat units were calculated from reproductive bud stage 1 to anthesis and to harvest and root growth was followed for each study area. Air temperature, soil temperature, precipitation and photosynthetically active radiation (PAR) values were recorded over time. Differences were found in the number of apical buds of lateral shoots with reproductive and vegetative destination, flowering phenology, heat units, root growth, PAR and precipitation. Differences were found among variables evaluated at the two contrasting altitudes. There is a clear need for further ecophysiological studies on this fruit tree in tropical areas in particular. Resumo Objetivou-se documentar e analisar o efeito do clima no desenvolvimento feno-lógico do abacateiro ‘Hass’ em duas zonas contrastantes dos trópicos andinos de Caldas, localizadas a 1.950m e 2.400m respectivamente. Um delineamento experimental inteiramente casualizado foi implantado usando uma árvore ‘Hass’ de cinco a sete anos como unidade experimental e 15 repetições em cada área. As observações foram realizadas em brotos silépticos laterais e suas gemas apicais correspondentes localizadas no lado leste e oeste de cada árvore. O destino da gema apical das brotações laterais foi quantificado, a fenologia floral foi documentada, as unidades de calor foram calculadas desde o estágio 1 da gema reprodutiva até a antese e até a colheita e o crescimento radicular foi acompanhado para cada área de estudo. Valores de temperatura do ar, temperatura do solo, precipitação e radiação fotossinteticamente ativa (PAR) foram registrados ao longo do tempo. Foram encontradas diferenças no número de gemas apicais de brotações laterais com destino reprodutivo e vegetativo, fenologia de floração, unidades de calor, crescimento radicular, PAR e precipitação. Foram encontradas diferenças entre as variáveis avaliadas nas duas altitudes contrastantes. Há uma clara necessidade de mais estudos ecofisiológicos sobre está frutífera em áreas tropicais em particular.

Background Fusarium oxysporum f. sp. lycopersici (Fol) is a compendium of pathogenic and non-pathogenic fungal strains. Pathogenic strains may cause vascular wilt disease and produce considerable losses in commercial tomato plots. To gain insight into the molecular mechanisms mediating resistance to Fol in tomato, the aim of our study was to characterize the transcriptional response of three cultivars (CT1, CT2 and IAC391) to a pathogenic (Fol-pt) and a non-pathogenic (Fo-npt) strain of Fo. Results All cultivars exhibited differentially expressed genes in response to each strain of the fungus at 36 h post-inoculation. For the pathogenic strain, CT1 deployed an apparent active defense response that included upregulation of WRKY transcription factors, an extracellular chitinase, and terpenoid-related genes, among others. In IAC391, differentially expressed genes included upregulated but mostly downregulated genes. Upregulated genes mapped to ethylene regulation, pathogenesis regulation and transcription regulation, while downregulated genes potentially impacted defense responses, lipid transport and metal ion binding. Finally, CT2 exhibited mostly downregulated genes upon Fol-pt infection. This included genes involved in transcription regulation, defense responses, and metal ion binding. Conclusions Results suggest that CT1 mounts a defense response against Fol-pt. IAC391 exhibits an intermediate phenotype whereby some defense response genes are activated, and others are suppressed. Finally, the transcriptional profile in the CT2 hints towards lower levels of resistance. Fo-npt also induced transcriptional changes in all cultivars, but to a lesser extent. Results of this study will support genetic breeding programs currently underway in the zone.

The interaction between plants and pathogens is a very dynamic and complex relationship that also includes a high degree of specificity, and it is precisely this last characteristic which triggers such important responses in the survival of one or the other. The pathosystem formed by tomato (Solanum lycopersicum L.) and Fusarium oxysporum f. sp. lycopersici (Fol) has been the subject of multiple studies due to the importance of the vegetable worldwide and for the economic and ecological impact of the fungus responsible for the vascular wilt disease in tomato, causing losses that go up to 100%. One way to find alternatives for the management of any pathosystem is to know the actors involved and the mechanisms that govern the interaction through technological and scientific advances that clearly show how the interaction develops on a genetic level. This review collects the information from different scientific sources with focus on the knowledge of the fungus, tomato cultivation and plant defense applied to this pathosystem, as well as the molecular mechanisms.

Colombia is the fourth largest avocado producer globally and the third largest in terms of harvested area, with a 6% share of the world area. The development and promotion of this production line represents an important source of growth in agriculture for Colombia, due to the generation of rural employment, equitable development across the different regions of the country, and due to the diversity of thermal floors and the different varieties planted. Imports of this product have decreased by 96% in the last four years from 3128 tons in 2014 to 133 tons in 2017. In recent years, the projects developed in the Colombian avocado sector have been aimed at the foreign market due to the profitability and demand of the Hass variety of this fruit. In addition, there is a state effort to implement plans for regions free of quarantine pests that allow access to foreign markets. This constitutes a strategic proposal made up of a coherent set of objectives, strategies and programmes which, based on a vision of the future, seek the initial goal of doubling the area of production. That move would ensure the technological and innovative conditions for sustainable and quality production, as well as achieve full links in international markets. This review aimed to know the main developments of avocado production in Colombia, its challenges and opportunities for the next decade. RESUMO: A Colômbia é o quarto produtor e o terceiro em termos de área colhida, com uma participação de 6% da área mundial. O desenvolvimento e a promoção desta linha produtiva representam para a Colômbia uma importante fonte de crescimento na agricultura, para a geração de emprego e desenvolvimento rural com equidade para as diferentes regiões do país, devido à diversidade de pisos térmicos e às diferentes variedades plantadas. As importações deste produto diminuíram 96% nos últimos quatro anos, passando de 3128 toneladas em 2014 para 133 toneladas em 2017. Nos últimos anos, os projetos desenvolvidos no setor de abacate colombiano têm como objetivo o mercado externo devido à lucratividade desta fruta por sua demanda com a variedade Hass. Além disso, há um esforço estatal para implementar planos para regiões livres de pragas de quarentena que permitem o acesso a mercados estrangeiros. Dessa forma, constitui uma proposta estratégica composta por um conjunto coerente de objetivos, estratégias e programas que, com base em uma visão de futuro, buscam o objetivo inicial de duplicar a área de produção, garantindo condições tecnológicas e de inovação com alcance total nos mercados internacionais. Esta revisão tem como objetivo conhecer os principais desenvolvimentos da produção de abacate na Colômbia, seus desafios e oportunidades para a próxima década.

Much of the tomato diversity is found in cherry-type populations. There are promising wild cherry tomato species with good behavior in terms of yield and quality that can be produced with a minimum of agro-inputs. The genetic expression of genotypes is influenced by the optimal environment they can develop in. The genotype-environment interaction must be known to estimate the phenotypic adaptability in different environments. The objective of this research was to evaluate the genotype-environment interaction for 10 cherry tomato introductions in nine environments, four of which were artificial environments (0, 60, 120 and 180 kg ha-1 of potassium) established in natural environments on the Farms Montelindo, Tesorito and CEUNP. The experiment design used randomized complete blocks with four replicates; the experiment unit consisted of five effective plants per introduction. The evaluated variables were production per plant (PFT) (kg/pl), number of fruits per plant (NFT), and average fruit weight (AWF) (g/fruit). The genotype×environment interaction and the stability of the 10 genotypes were estimated with the AMMI multivariate model. The environments for T120K and T180K were optimal for the variables associated with production (PFT, NFT and AWF), with IAC1621, IAC426 and IAC1624 being the most promising genotypes per environment on the Farms Tesorito, Montelindo and CEUNP, respectively. The results are useful for the identification of genotypes in key locations for selection and evaluation in breeding programs. RESUMEN Gran parte de la diversidad del tomate se encuentra en las poblaciones tipo cereza. Se considera que hay especies silvestres de tomate cereza promisorias con buen comportamiento en rendimiento y calidad que pueden ser producidos con un mínimo de agroinsumos. La expresión genética de los genotipos está influenciada por el ambiente óptimo, en el cual puedan desarrollarse, para ello es necesario conocer la interacción genotipo-ambiente que permita estimar la adaptabilidad fenotípica de estos en diferentes ambientes. El objetivo de esta investigación fue evaluar la interacción genotipo-ambiente de 10 introducciones de tomate cereza en nueve ambientes, de los cuales cuatro fueron ambientes artificiales (0, 60, 120 y 180 kg ha-1 de potasio) establecidos en ambientes naturales de las Granjas Montelindo, Tesorito y CEUNP. El diseño experimental fue bloques completos al azar, con cuatro repeticiones, la unidad experimental fue de cinco plantas efectivas por introducción. Las variables evaluadas fueron: producción por planta (PFT) (kg/pl), número de frutos por planta (NFT) y peso promedio de fruto (PPF) (g/fruto). Se estimó la interacción genotipo-ambiente y la estabilidad de los 10 genotipos a través del modelo multivariado AMMI. Los ambientes de T120K y T180K fueron óptimos para las variables asociadas a producción (PFT, NFT y PPF), siendo los genotipos más promisorios por ambiente IAC1621, IAC426 y IAC1624, en las Granjas Tesorito, Montelindo y CEUNP; respectivamente. Los resultados son útiles para la identificación de genotipos en localidades claves de selección y evaluación en programas de mejoramiento.

In this study, 55 tomato genotypes from different geographical regions were evaluated with ISSR markers (Inter Simple Sequence Repeats). The seven ISSR primers originated 63 amplified bands, of which 90.48% were polymorphic. The cluster analysis based on the Nei-Li similarity coefficient using the average genetic clustering method (UPGMA) revealed the conformation of five clusters at a level of similarity of 72%. The ISSR technique did not discriminate tomato genotypes according to the species or region of provenance. The STRUCTURE analysis and the dendrogram did not reveal a genetic structure in the population evaluated. The genotypes of the species of S. pimpinellifolium, S. l. cerasiforme, S. lycopersicum and S. peruvianum were found consistently grouped, showing a close genetic relationship among them. A high genetic variation among the individuals within each of the groups formed was suggested by the AMOVA. The ISSR markers were effective in assessing the genetic diversity and structure of populations of tomato genotypes. The high genetic variability found in this study indicates the valuable genetic potential present in tomato germplasm, especially of wild species, which could be used for future breeding programs of the species.

The aim of this study was to determine the tolerance of water and salt stress in four cultivated species of Passiflora L. Eleven accessions of four species of Passiflora of commercial interest from different plantations were evaluated. The experimental design was in sub-split plots, where the plot was the percentage of water saturation in relation to the requirement of the crop (33% and 100%). The subplot was established by the saturation levels of salt (sodium chloride reactive level - 99.9% purity) (EC: 1.5 and 5.5 dS m-1) with the 11 accessions in a completely randomized array with five replications, where the experimental unit was one plant. Results showed that accessions m11, m13 (P. edulis f. flavicarpa) and m15 (P. tarminiana) were determined as tolerant to salinity and drought; accesses m2 (P. edulis f. edulis), m12 and m14 (P. edulis f. flavicarpa) were moderately tolerant. These observations are the basis for future studies of drought tolerance in Passiflora, which must be followed by field evaluations.

Water-saline stress is one of the factors limiting growth and crop production, with the induction of morphological, structural and metabolic changes in higher plants. This study aimed to evaluate the response of four species with ten accessions of Passiflora to saline stress and drought stress, and the accumulation of proline and content of cationic macronutrients and their relationships with sodium. The plants were grown under controlled conditions for seven months, watered with nutrient solution with additions of NaCl (100 mM) to achieve the desired conductivities (1.5, 2.5, 4.0, and 5.5 dS m-1) and constant substrate humidity of 100%, 66% and 33%. The concentrations of Na+, K+, Ca++, Mg++ and proline in the leaves were determined. Proline accumulation increased in salinized plants, especially in young leaves. Proline increase was evident in accessions tolerant and moderately tolerant to salinity. These results indicate that tolerance to salinity and water stress in Passiflora relates to an improved ability to exclude sodium and greater ability to accumulate proline for osmotic adjustment. The increased salinity of the nutrient solution increased sodium contents, relations Na+/Ca++, Na+/Mg++, Na+/K+, and decreased Ca++, Mg++ and K+ levels, reflecting the nutritional imbalance caused by progressive saline stress.

This study shows the effect of three plant growth-promoting rhizobacteria (PGPR) strains of the genus Bacillus on blackberry (Rubus glaucus Benth.) development under semi cover and field conditions (cropping systems). Endogenous strain Bacillus subtilis GIBI-200, B. pumilus GIBI-206, its mixture (B. subtilis GIBI-200 + B. pumilus GIBI-206), and commercial strain B. subtilis QTS-713 were compared to conventional mineral fertilization (Control) in each cropping system. Field condition system presented higher values (P0.001) than semi cover in: total number of branches (7.32), number of productive branches (7.0), flowers per raceme (26.2), and the lowest percentage of unproductive branches (6.1%). Significant differences (P0.05) were obtained in total number of branches over time by bacterial strains. Nonetheless, last observation of this variable did not present statistical differences among strains and mineral fertilization. No significant differences were evident in terms of number, length, diameter and flowers in the productive branches regarding to bacterial strains and Control. B. subtilis GIBI-200 + B. pumilus GIBI-206 showed a similar statistical behavior compare to mineral fertilization in the number of clusters (8.3) and percentage of unproductive branches (11.1%). In addition, GIBI-200 + GIBI-206, despite statistical equality, exposed greater values than individual strains. Field condition system remains the most promising alternative for the development of blackberry crop and PGPR acts as biofertilizers achieving effects in the long-term growth of blackberry similar to mineral fertilization. Mixtures of PGPR can produce a synergic effect and new combinations should be evaluated in future studies. Este estudio muestra el efecto de tres cepas de rizobacterias promotoras del crecimiento vegetal (PGPR) del género Bacillus sobre el desarrollo de la mora (Rubus glaucus Benth) bajo condiciones de semitecho y libre exposición (sistemas de cultivo). La cepa endógena Bacillus subtilis GIBI-200, B. pumilus GIBI-206, su mezcla (B. subtilis GIBI-200 + B. pumilus GIBI-206) y la cepa comercial B. subtilis QTS-713 se compararon con la fertilización mineral convencional (Control) en cada sistema de cultivo. El sistema a libre exposición presentó valores más altos (P 0.001) que el semitecho en: número total de ramas (7.32), número de ramas productivas (7.0), flores por racimo (26.2) y menor porcentaje de ramas improductivas (6.1%). Se obtuvo diferencias significativas (P 0.05) en el número total de ramas a través del tiempo como efecto las cepas bacterianas. No obstante, la última observación de esta variable no presentó diferencias estadísticas entre cepas y fertilización mineral. No se observaron diferencias significativas en términos de número, longitud, diámetro y flores en las ramas productivas como efecto de las cepas bacterianas y el Control. B. subtilis GIBI-200 + B. pumilus GIBI-206 mostró un comportamiento estadístico similar comparado con la fertilización mineral en el número de racimos (8.3) y porcentaje de ramas improductivas (11.1%). Además, GIBI-200 + GIBI-206, a pesar de la igualdad estadística, expuso mayores valores que las cepas individuales. El sistema a libre exposición sigue siendo la alternativa más prometedora para el desarrollo de cultivos de mora y PGPR actúan como biofertilizantes permitiendo lograr efectos en el crecimiento a largo plazo de mora similar a la fertilización mineral. Las mezclas de PGPR pueden producir un efecto sinérgico y nuevas combinaciones deben ser evaluadas en futuros estudios.

Passiflora tarminiana es una glicofita trepadora, nativa de la región andina que tiene tolerancia a la salinidad y estrés hídrico moderado. El objetivo de este estudio fue evaluar la capacidad para la excreción de sodio como una posible estrategia de esta especie para la tolerancia a la salinidad y a la sequía. La excreción de sal y las concentraciones de iones excretados se examinaron en plantas cultivadas durante siete meses bajo varios niveles de salinidad [(NaCl) 2,5; 4,0 y 5,5 dS m-1 (25, 40 y 55 mM)] y de estrés hídrico moderado (33 y 100% de humedad en el sustrato). El experimento fue llevado a cabo en un diseño completamente al azar con un arreglo de parcelas subdivididas, donde la parcela constituye el porcentaje de saturación de agua (33 y 100%), la subparcela los niveles de saturación de sal (CE: 2,5; 4,0 y 5,5 dS m-1), con cinco repeticiones, y la unidad experimental compuesta por una planta. Se evaluaron los cristales de sal y las estructuras de la epidermis foliar. Las sales fueron excretadas en la superficie adaxial de la hoja, posiblemente debido a las glándulas secretoras de sal especializadas. Se observaron otras estructuras como tricomas y papilas, que se cree que también están implicadas en la tolerancia a la salinidad en P. tarminiana.

Estudios relacionados con la productividad del tomate respecto a la relación entre la eliminación de racimos y su sostenibilidad económica son escasos. El presente estudio se realizó con el fin de evaluar el efecto del número de racimos sobre el rendimiento, calidad y rentabilidad del cultivo de tomate hibrido Torrano® bajo condiciones semicontroladas en dos invernaderos de 12m x 40m (480 m2). Éste se llevó a cabo en la granja Tesorito, propiedad de la Universidad de Caldas, Manizales bajo un diseño de bloques completos al azar con cuatro despuntes: 6; 8 y 10 racimos/planta y sin despunte con crecimiento indeterminado, cada tratamiento contó con seis repeticiones y la unidad experimental fue de cinco plantas. Se evaluó la calidad tamaño del fruto y el rendimiento por planta y por hectárea. Las plantas sin poda con crecimiento indeterminado mostraron los valores más altos en las diferentes calidades de la fruta como primera, segunda, tercera y el rendimiento total con valores de 2236, 1666, 750 y 6883 g/planta respectivamente. Igualmente genero los ingresos netos más altos con USD$27.241 ha/ciclo, sin embargo en términos porcentuales la calidad aumenta a medida que se disminuye el número de racimos por planta. Por tanto, se concluye que no se debe realizar podas de racimos en tomate hibrido Torrano® bajo condiciones semicontroladas en la zona de estudio.

Much of the diversity of tomato is found in wild forms, the most important being the Solanum lycopersicum L. var. cerasiforme and S. pimpinellifolium. The objective of this research was to assess the genetic diversity of 30 introductions of cherry tomato with 36 microsatellite molecular markers. The study was conducted at the Plant Transformation Research Center (PTRC) of the University of California. A dendrogram was built using the Dice-Nei and Li similarity index and the UPGMA clustering method, where introductions were differentiated without preserving a distribution pattern obeying the geographical area of origin. A coefficient of genetic differentiation was found (Fst = 0.3474), showing a high genetic differentiation of the introductions; those from Brazil, Ecuador, and Peru were the most genetically diverse, presenting 100% of polymorphic loci. The molecular variance analysis indicated a variation of 11% between the groups and 89% within the same. The broad genotypic variability of the evaluated introductions favors the possibility of selecting those for genetic improvement and sustainable use of the species.

Currently, tomato is one of the most cultivated crops worldwide, with the highest economic value, increasing its demand and, thus, its expansion, production, and trade. The tomato crop is susceptible to attack of pathogens with devastating consequences on the decline in yields from 50 to 100%. For this reason, new production methods are proposed such as grafting in wild rootstocks, which have high genetic variability and genes responsible for resistance to fungi, bacteria, viruses, and nematodes. The aim of this study was to evaluate the effect of grafting commercial tomato cultivars onto cherry tomato genotypes on yield and fruit quality. The experiment was arranged in a completely randomized design with four replications. The experimental unit consisted of four plants. spaced at 0.9 m between rows (channels), 0.30 m between double rows, and 0.4 m between plants. The treatments consisted of the combination of the following factors: three promising rootstocks (IAC391, IAC426, and LA2076), two commercial scions (Calima and Torrano), two grafting methods (cleft and splice), and two ungrafted commercial controls. Yield components, soluble solids content, percentage of fruit quality, and average fruit weight were evaluated. IAC391 was the most promising rootstock, reaching productions similar to those of the controls. The cleft grafting method, reached a success rate of 98.3%. The commercial scion Torrano stood out for achieving the highest yields.

El presente estudio se realizó con el objetivo de evaluar el efecto del ácido giberélico (AG3) sobre el desarrollo, rendimiento y calidad del tomate bajo condiciones controladas. El estudio se llevó a cabo en la Granja Tesorito propiedad de la Universidad de Caldas ubicada en el municipio de Manizales (Colombia). El diseño experimental fue completo al azar (DCA) con un arreglo factorial 2x4 con dos híbridos (“Alboran” y “Torrano”) y cuatro concentraciones de ácido giberélico (AG3) (0, 50, 100 y 150 ppm), con 4 repeticiones y como unidad experimental se evaluaron 9 plantas por repetición. Las variables evaluadas fueron: altura (cm), la aparición de la última flor (días), número de racimos, longitud de entrenudos (cm), rendimiento, producción de calidades y perdidas en kg ha-1. Los resultados demostraron una relación inversa para el rendimiento y días a última floración para ambos híbridos a las concentraciones evaluadas de AG3, donde el hibrido tipo milano “Alboran” a concentraciones de 0 ppm mostró la producción más alta con 19660,1 Kg ha-1, y el mayor tiempo a última floración con 98 días. Comportamiento similar del híbrido “Torrano” a concentración de 0 ppm, arrojo una producción superior con 16261,8 Kg ha-1 y 98 días a última floración. Las concentraciones de aplicación de la hormona evaluada en el presente estudio mostraron un efecto de detrimento sobre el rendimiento y la calidad del cultivo.

Meloidogyne spp. es un problema de gran importancia económica en el cultivo de tomate tipo cherry, causando pérdidas en rendimiento del 25 al 50%, lo cual conlleva a la búsqueda de materiales silvestres resistentes o promisorios. El objetivo de este trabajo fue contribuir en el conocimiento de la epidemiología del nematodo del Nudo radical, causado por Meloidogyne spp. en quince introducciones de tomate silvestre tipo cereza sembrados a libre exposición y bajo semitecho y, determinar las especies de Meloidogyne presentes en el cultivo. Se utilizó un diseño de parcelas divididas, las parcelas principales fueron asignadas a los dos sistemas de producción (libre exposición y semitecho), mientras que las subparcelas fueron asignadas a las introducciones de tomate, con cuatro repeticiones. El tamaño efectivo de la unidad experimental fue de cuatro plantas por repetición. Se evaluó el daño radical causado por el nematodo y se hizo identificación de especies tanto en hembras como en juveniles (J2). Se realizó un análisis de varianza y pruebas de promedio tipo Duncan. En el sistema productivo a libre exposición la población de nematodos osciló entre 29.472 en IAC1624 y 170.804 en IAC421 con un promedio de 97.677 nematodos y en el sistema bajo semitecho, osciló entre 57.871 en IAC391 y 197.800 en LA2692 con un promedio de 108.572 nematodos, lo que demuestra que este sistema reduce el ciclo del nematodo, y por consiguiente, aumenta la población. Las especies identificadas según el método del patrón perineal sobre las hembras fueron Meloidogyne incognita (80%) y Meloidogyne javanica (20%). Meloidogyne spp. is a problem of great economic importance in tomato Cherry, causing yield losses ranging from 25 to 50%, which conduce to look for wild materials resistant or promising. The objective of this work was to contribute to the knowledge of the epidemiology of the root knob nematode, caused by Meloidogyne spp. in fifteen introductions of wild tomato Cherry planted at free exposition and semi cover, and to determine the species of Meloidogyne present in the crop. The experimental design was a split plots, the main plots were the two production systems, the subplots, the tomato introductions, with four replications and four plants per replication. Was determined the root damage caused by the nematode and the identification of the species in both females and juveniles (J2). It was conducted an analysis of variance and Duncan´s tests. According to the analysis, at free exposition, the population of nematodes ranged between 29.472 in IAC1624 and 170.804 in IAC421 with an average of 97.677 nematodes and under semi cover, ranged between 57.871 in IAC391 and 197.800 in LA2692 with an average of 108.572 nematodes, which demonstrate that under this system the cycle of the nematode is reduced, increasing its population. According to the perineal pattern of the females, were identified two species of the nematode: Meloidogyne incognita with a frequency of 80% and M. javanica with a frequency of 20%.

La mayoría de los genes responsables de la resistencia en tomate a hongos, bacterias, virus y nematodos fitoparásitos han sido derivados de especies silvestres. Es así, como se deben evaluar e identificar genotipos silvestres promisorios, por su respuesta a los principales problemas patológicos de la especie cultivada, para considerarlos en programas de mejoramiento del tomate. Por consiguiente, es necesario evaluar la resistencia de introducciones silvestres del tomate al tizón tardío, causado por Phytophthora infestans, la enfermedad más devastadora en este cultivo. El estudio, se realizó en la granja Montelindo de la Universidad de Caldas, en quince introducciones de tomate silvestre, bajo dos sistemas de producción: libre exposición y semitecho. El diseño experimental fue parcelas divididas; las parcelas principales fueron los dos sistemas de producción; las subparcelas, las introducciones de tomate con cuatro repeticiones. Las variables evaluadas fueron porcentaje de severidad, tasa de desarrollo (r) y área bajo la curva del desarrollo (ABCDE) del tizón tardío; asimismo, se calcularon los coeficientes de regresión de las variables analizadas. Finalmente, se realizó análisis de varianzas y pruebas de promedio tipo Duncan. De acuerdo a los análisis, bajo semitecho, se obtuvieron los valores numéricos más bajos de severidad final, r y ABCDE, con 47%, 0,09 y 1.133, respectivamente, sobresaliendo las introducciones LA1480, IAC1686, LA2076, LA2131 y LA2692; a libre exposición, se obtuvo los más altos valores de severidad final, r y ABCDE, con 77%, 0,15 y 1.573, respectivamente; sin embargo, LA1480 y LA2076 tuvieron los valores más bajos en este sistema de producción. Most of the genes responsible of resistance of tomato to fungi, bacteria, virus and nematodes, has been derivate from wild species of tomato. Hence, it is necessary to evaluate and identify promising wild genotypes to observe their reaction to the main pathological problems of cultivated species, in order to be considered in future programs of tomato production improvement. To reach this purpose, it is necessary to carry out epidemiological studies and evaluate wild introductions against tomato late blight caused by Phytophthora infestans, the most devastating disease worldwide. The study was conducted with fifteen wild tomato introductions at the Montelindo ́s farm of the Universidad de Caldas, in two production systems: free exposition and semi cover. Split plots was the experimental design used, being the main plots the production systems, and the subplots, the tomato introductions, with four replications. The evaluated variables were: severity (%), rate of disease development (r) and area under the disease progress curve (AUDPC) of late blight. In addition, the regression coefficients of the evaluated variables was calculated. Finally, an analysis of variance and Duncan ́s tests was conducted. According to the analysis, under the semi cover system the lowest numerical values for final severity, r and AUDPC, with 47%, 0.09 and 1,133, was obtained, respectively; standing out the introductions LA1480, IAC1686, LA2131 and LA2692. In the free exposition system the highest values of these parameters with 77%, 0.15 and 1,573, respectively, were obtained; however, the introductions LA1480 and LA2075 showed the lowest values under this production system. Incluye referencias bibliográficas

This study was conducted to evaluate the effect of three types of nutrient solutions on the development, performance, quality and cost of chonto tomato (Solanum lycopersicum L.) under semi-controlled conditions. The assessment was conducted in the farm Tesorito, Manizales, Colombia. An experimental design was established in randomized complete blocks (RCB), with 3 treatments, 4 replicates per treatment and 10 effective plants per replicate. The variables were: height of the first cluster, production per plant, yield t ha-1 and qualities of the fruit. The economic variables were production costs, cost-benefit ratio (C/BR), rate of return (IRR) and net present value (NPV). In general, production per plant was greater than 4.7 kg plant-1 and the average yield was 92 t ha-1. The use of conventional fertilization (tt2) generated increased production of premium quality fruit with a value of 37.11 t ha-1, demonstrating that conventional soil fertilization implemented in this culture under semi-controlled conditions in the company of drip irrigation system in the root zone improve outcomes of productive variables, increasing profitability and competitiveness with a net profit of USD$ $ 25203.68 ha-1, with average selling price of USD$ 0.45 per kilogram and a unit production margin of USD$ 0.21 per kilogram, making this technology attractive and economically viable.

El tomate tipo cereza por ser un cultivo de rápido retorno económico, viene despertando el interés de los productores, pero aún hay poca información sobre su estructura de costos de producción y rentabilidad en las condiciones del país, impidiendo la expansión del cultivo. El objetivo del presente estudio fue evaluar técnica y económicamente diez introducciones élites de tomate tipo cereza, bajo condiciones semicontroladas en la región andina colombiana. El ensayo se realizó en la finca Tesorito, Manizales, Colombia. Se estableció un diseño experimental en bloques completos al azar con 10 tratamientos (introducciones elites) y un testigo comercial (Sweet million), con cuatro repeticiones. Las variables fisiológicas evaluadas fueron: rendimiento (g/planta), peso de frutos perdidos, rendimiento neto, rendimiento en kg ha-1, numero de frutos por racimo, numero de racimos por planta, peso promedio de frutos, y como variables económicas se estimaron los costos de producción, el margen unitario de producción, la relación beneficio costo, la tasa de retorno y se realizó un análisis de sensibilidad. Los resultados muestran que las introducciones IAC391, IAC1621 e IAC1688 para las condiciones del estudio superan las perspectivas financieras, convirtiendo estos materiales en opciones para los productores.