The University of Córdoba, the Faculty of Agricultural Sciences and IBAC have once again fulfilled their mission of disseminating scientific knowledge and contributing to the development of the agricultural sector. The proceedings of these papers will be published in volume 27 of the journal Temas Agrarios, the natural organ of dissemination of the Symposium. Likewise, participation in the III International Symposium and IV National Symposium on Agronomic Sciences, to be held Agronomic Sciences, which will be held in 2023. | La Universidad de Córdoba, la Facultad de Ciencias Agrícolas y el IBAC, han cumplido nuevamente con su misión de difundir el conocimiento científico y contribuir con el desarrollo del sector agrícola. Las memorias de estos trabajos se publicarán en el volumen 27 de la revista Temas Agrarios, órgano natural de difusión del Simposio. Así mismo, se invita a la participación del III Simposio Internacional y IV Simposio Nacional de Ciencias Agronómicas, que realizaremos en el 2023.

The University of Córdoba, the Faculty of Agricultural Sciences and IBAC have once again fulfilled their mission of disseminating scientific knowledge and contributing to the development of the agricultural sector. The proceedings of these papers will be published in volume 27 of the journal Temas Agrarios, the natural organ of dissemination of the Symposium. Likewise, participation in the III International Symposium and IV National Symposium on Agronomic Sciences, to be held Agronomic Sciences, which will be held in 2023. | La Universidad de Córdoba, la Facultad de Ciencias Agrícolas y el IBAC, han cumplido nuevamente con su misión de difundir el conocimiento científico y contribuir con el desarrollo del sector agrícola. Las memorias de estos trabajos se publicarán en el volumen 27 de la revista Temas Agrarios, órgano natural de difusión del Simposio. Así mismo, se invita a la participación del III Simposio Internacional y IV Simposio Nacional de Ciencias Agronómicas, que realizaremos en el 2023.

El departamento de La Guajira (Colombia) presenta gran diversidad de especies vegetales, entre éstas, especies halófilas y psamófilas como Ipomoea pes-caprae (L.) R.Br., la cual se distribuye en la zona costera del departamento. Se desconocía si I. pes-caprae produce fenoles en concentraciones lo suficientemente altas, bajo las condiciones ambientales de La Guajira, como para considerar su aprovechamiento; por ende, el objetivo de esta investigación fue establecer la influencia de los periodos climáticos sobre la producción de fenoles totales y el potencial antioxidante de los extractos foliares de esta especie. Se tomaron muestras de tejido foliar durante un año y se sometieron a extracción con metanol. Para establecer la concentración de fenoles totales se utilizó el método de Folin-Ciocalteau y se correlacionó con la precipitación y temperatura mensual. También se estimó el porcentaje de inhibición de los extractos sobre el radical DPPH. Los resultados obtenidos evidenciaron que el contenido de fenoles varió durante todo el año, siendo febrero de 2019 donde se presentó la mayor concentración de estas sustancias (18,41%), coincidiendo con un periodo de bajas precipitaciones y menor temperatura. Por otra parte, la actividad antioxidante de los extractos fue de 83,79%. Se concluyó que la temperatura afecta parcialmente la concentración de fenoles totales, mientras que la precipitación no tuvo efectos significativos; además, este estudio comprueba la posibilidad de utilizar I. pes-caprae como fuente de sustancias con actividad antioxidante de bajo costo y se constituye como base para proyectar futuras investigaciones dirigidas a la evaluación y aprovechamiento de otras convolvuláceas presentes en La Guajira. |  The department of La Guajira (Colombia) presents a great diversity of plant species, among these, halophilic and psamophilic species such as Ipomoea pes-caprae (L.) R.Br., which is distributed in the department coastal area. It was unknown whether I. pes-caprae produces phenols in concentrations high, enough under La Guajira’s environmental conditions, to consider its use; therefore, the aim of this research was to establish the climatic periods influence on total phenols production and antioxidant potential of foliar extracts of this species. Leaf tissue samples were taken for one year and subjected to methanol extraction. To establish total phenols concentration, Folin-Ciocalteau method was used and correlated with precipitation and monthly temperature. Extracts percentage of inhibition on DPPH radical was also estimated. Results obtained showed that phenols content varied throughout one year, with February 2019 showing the highest concentration of these substances (18.41%), coinciding with a low rainfall and lower temperatura period. On the other hand, antioxidant activity of extracts was 83.79%. It was concluded that temperature partially affects the total phenols concentration, while precipitation did not have significant effects; in addition, this study verifies the possibility of using I. pes-caprae as a low-cost source of substances with antioxidant activity and constitutes a basis for future research aimed at the evaluation and use of other Convolvulaceae present in La Guajira

Rice cultivation is part of the economy of the Mojana subregion, the seed is a basic input, produced by farmers who have conserved the genetic material year after year. The literature does not report a production characterization study, for this reason this research aimed to characterize the seed production of regional rice materials in this region. With data from a formal structured survey applied to 95 farmers selected by simple random sampling. Techniques such as frequencies, contingency tables, and basic statistics were used. In addition, the formulation of an econometric model to estimate the seed supply and demand functions. The results show that these are small producers who, on average, sow 1 hectare, with a low level of education, 71% of the surveyed sample has attended elementary school. The average age of the farmers is 52 years. 57% of the surveyed farmers obtain the seed of the previous harvest. It was found that more than 90% of those surveyed are likely to increase the cultivated area and it is estimated that this could grow by 60 hectares. It is concluded that the demand for seed may increase because 66% of the sample sows twice a year, which allows us to infer that seed is required throughout the year and the months where it is most sown are December, January, February. and March took advantage of the dry season with the so-called serene crops.

The department of La Guajira (Colombia) presents a great diversity of plant species, among these, halophilic and psamophilic species such as Ipomoea pes-caprae (L.) R.Br., which is distributed in the department coastal area. It was unknown whether I. pes-caprae produces phenols in concentrations high, enough under La Guajira’s environmental conditions, to consider its use; therefore, the aim of this research was to establish the influence of weather on total phenols production and antioxidant potential of foliar extracts. Leaf tissue samples were taken during one year and subjected to methanol extraction. To establish total phenols concentration, Folin-Ciocalteau method was used and correlated with rains and monthly temperature. Extracts percentage of inhibition on DPPH radical was also estimated. Results showed that phenols content varied throughout one year, with February 2019 showing the highest concentration (18.41%), coinciding with a low rainfall and lower temperature period. On the other hand, antioxidant activity of extracts was 83.79%. It was concluded that temperature partially affects the total phenols concentration, while rains did not have significant effects; in addition, this study verifies the possibility of using I. pes-caprae as a low-cost source of substances with antioxidant activity and constitutes a basis for future research aimed at the evaluation and use of other Convolvulaceae species present in La Guajira.

The medicinal Cannabis crop is one of the main growing agricultural activities in Colombia. However, the increase in production areas and the intensification of crops brings a greater predisposition to pests and diseases incidence. The objective of this research was to identify the main diseases associated with a high-density commercial Cannabis crop in a greenhouse. Samples of disease symptoms present in the crop during a round year of production were characterized. Samples were taken in different phenological phases and areas of the farm such as: propagation areas, field production and post-harvest. A total of 43 samples were collected among diseased tissue, soil, compost, substrates, and water. "Damping off" was present in the highest percentage of samples collected from cuttings (28%), followed by samples affected with leaf spot chlorotic halo symptoms (19%). 26 pure isolates of phytopathogenic fungi were obtained, and morphologically and molecularly characterized causing diseases in the crop. They were consistent with Botrytis cinerea (8%), Sclerotinia sclerotiorum (15%), Fusarium sp. (46%), Bipolaris sp. (12%), Rhizoctonia solani (8%) and Corynespora casiicola (8%). Symptoms associated with "Damping off" or wilt tissues revealed the presence of Rhizoctonia solani causing strangulation and cutting rot at the base. Three species of Fusarium were reported: Fusarium fujikuroi, Fusarium oxysporum and Fusarium graminearum, the latter associated with stem end rot. Leaf spot associated with Bipolaris sp. and Corynespora casiicola was present at a high incidence.

To identify symbiosis between roots and arbuscular mycorrhizal fungi (HMA), methodologies have been reported with variations in concentrations of reagents, temperature, and time of exposure for staining, which does not always adjust to the need for specific cultures due to variation in root structures. The objective of this research was to standardize a methodology to identify mycorrhizal colonization in banana crops in an efficient way. The research was carried out during the second semester of 2022 in the municipality of Apartadó-Antioquia. Four treatments were established that consisted of the evaluation with and without mycorrhizal inoculation with two bleaching techniques each (with and without subjection to Bain Marie). A total of 108 plates (54/technique) were evaluated, where percentage of colonization, visibility, vesicles and arbuscules were identified. There was a complete randomized design. Data were analyzed with R Studio 2022.02 software. An ANAVA and means separations were obtained with a post-hoc analysis of Tukey and Kruskal-Wallis with a confidence level of 95%. Symbiosis was found in all cases, statistical differences were identified in percentage of colonization with 46.8% to 90.2%; arbuscules from 12.1 to 338.0 units and a visibility percentage of 100% in treatments subjected to a Bain Marie, highlighting the need for subjecting banana roots to heat to favor discoloration, staining and visibility due to their architecture.

Ragweed (Ambrosia artemisiifolia L.) is an invasive plant species from the American continent, which has actively penetrated plant communities, displacing local species of cultivated and weed vegetation. The uncontrolled development and widespread distribution of ragweed in the South of Russia are associated with the absence of natural enemies of this weed. Ragweed is not only a competitor of cultivated and weed plants but also causes allergic diseases. The ragweed moth (Tarachidia candefacta Hbn.) was imported from Canada as a biological agent to control ragweed's development and distribution. We used the mass release of herbiphage into agrocenoses during the emergence of ragweed, which implies an artificial shift in the phenophase of the bioagent, which was achieved by early mass dilution on an artificial nutrient medium (ANM) under laboratory conditions. To cultivate the ragweed moth, the ANM was improved by adding powdered milk as a source of protein and vitamins to the composition, which made it possible to improve the quality of the environment and improve the biological indicators of the development of the bioagent. Replacement of wheat germ with soybean meal in ANM made it possible to obtain a feed balanced in protein and amino acid composition for growing herbiphage. As a result of the research, a method of colonization of the ragweed moth was developed, based on the early mass cultivation of herbiphage on an improved formulation of ANM and the release of T. candefacta at the beginning of the growing season of the weed, which allowed to suppress its growth by half.

The reproduction process of Apis mellifera L. (Hymenoptera: Apidae) occurs in defined congregation areas where natural mating occurs and males and unfertilized queen bees from different colonies converge. This work focused on the identification and characterization of a congregation drone zone in a biogeographic region of the low montane dry forest corridor, in the upper Andean valley of Sugamuxi-Tundama, for the density of bee colonies established there, considering the climatic factors of the environment and the description of biometric characters of bees and drones collected, and which constitutes the first report of a congregation zone for Colombia. In the study area, dry summer periods predominate alternating with short winter, cloudy days, and intense cold, with thermal sensations between 8 to 19°C. The drone movement route was established with an unmanned flight vehicle, through the interaction between the vehicle and bee specimens. The path of movement of drones was established operated between 10 and 60 m in North-South direction. Specimens of worker bees were collected identifying African, European, or Eastern European lines and drones of two types, yellow and black, evaluating biometric parameters and estimating the discriminant factor. The activity of the drones, occurs in two periods of 10:00 to 12:00 hours and 15:00 to 17:00 hours, flying regularly between round trips up to a 1 km radius. This work describes a methodology for monitoring congregation areas and consolidates itself as a tool for beekeepers for the conservation of regional ecotypes through bee reproductive planning.

The goldenberry, Physalis peruviana L., is an important fruit in Colombia due to its export value and nutritional quality. However, commercial crops face challenges of fruit heterogeneity and the presence of diseases that reduce fruit yield and quality. These drawbacks could be handled through different breeding methods to develop uniform cultivars, for example, through anther culture, which is used to rapidly produce homozygous lines. However, the ploidy level may change when using this technique. Therefore, in this study, the level of ploidy of parental and the plants obtained by anther culture was determined by cytogenetics, flow cytometry, and single-simple repeat or microsatellites (SSR).Additionally, the homozygous condition of obtained plants and the degree of heterozygosity of parental plants were evaluated using SSR. Cytogenetic analysis showed parental plants with 48 chromosomes and anther culture generated plants with 24, 32 and 48 chromosomes, and mixoploids and average nuclear DNA content between 5.04 and 20.08 pg. Diploid, tetraploid, hexaploidy, and octoploid plants were identified by flow cytometry; the highest levels of ploidy (6x and 8x) correspond to mixoploid plants found by cytogenetics. The SSRs did not allow identifying ploidy due to the lack of a particular band pattern, however, they showed heterozygosity in most of the plants obtained by anther culture. It was concluded that the anther culture modified the ploidy level with respect to the parental plants, and that flow cytometry is efficient, precise, and less laborious, compared to cytogenetics, to determine the ploidy level of goldenberry in the laboratory.