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 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 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.

The crop of medicinal cannabis has developed great importance in recent years in Colombia and other Latin American countries. Considering the production characteristics of the crop, which is fundamentally based on organic models, it is important to know the microorganisms that accompany the production system and their possible implications for management. In this research were isolated and characterized the microorganisms in the different phases of production of a high-density cannabis crop: planting, or propagation areas, production areas, and postharvest areas (flower pre-drying). In each area samples of soil, substrates and water were taken and the microorganisms present were identified by direct sowing in culture media, using microscopic identification and molecular characterization. A high diversity was found in all production areas, and it was evidenced that beneficial microorganisms (Trichoderma spp. and Bacillus spp.) applied to the production system regulate the populations of microorganisms in the soil and in the substrates. It was identified that perlite and coconut fiber allow the development of populations of phosphorus solubilizing and nitrogen fixing microorganisms and that the production of compost using crop waste is safe at a sanitary level. No populations of pathogens were identified in any of the samples evaluated at levels that could explain the presence of diseases in the crop.

A greenhouse experiment was carried out to evaluate the mycorrhizal response of seedlings of cocoa (Theobroma cacao variedad FSV-094) to the application of different mycorrhizal inoculum. A complete randomized experimental design was used, with four treatments: three commercial mycorrhizal multispore inoculum, Ab (Glomus spp, Scuttellospora spp y Entrophospora spp), Bs (Glomus spp, Acaulospora spp, Entrophospora spp, y Scutellospora spp) y Bl (Rhizophagus irregularis, R. clarus, R. aggregatus, R. proliferum y Claroideoglomus etunicatum), and the negative control (without inoculation), each treatment was established in the same soil that was adjusted 0.02 mg L-1 of phosphorus (P). Shoot and root dry weight (SDW & RDW), mycorrhizal colonization, leaf P content, and mycorrhizal response were measured. The results indicated that all the inoculum showed colonization, the best treatments were Ab and Bs with values of 27 and 28% respectively. Although there were no significant differences, the Ab and Bs treatments always had higher values in terms of SDW (3,4 y 3,7 g) and leaf P (0,25 y 0,2%). Regarding to mycorrhizal response, it was found that when inoculated with Bs and Ab the response was moderate (25 - 50%), and with Bl marginal (≤ 24%). The use of commercial AMF can lead to a differential response to T. cacao variety FSV-094. Therefore, it is suggested to carry out an evaluation of the mycorrhizal inoculum in relation to the genotype before massively using it to produce cocoa seedlings under greenhouse.

Mango production presents challenges, such as the maturation of the mango branches, which, combined with good nutrition and biochemicals involved in this process, such as carbohydrate and starch favor the development of the plant. Therefore, the use of non-destructive, fast techniques to determine the levels of these components in the plant, such as spectroscopy, can optimize the analysis of these components. Therefore, this work aimed to develop predictive models for determination of starch and carbohydrate contents in “Palmer” mango leaves using vis-nir spectroscopy subjected to different potassium sources. The work was carried out in the region of San Francisco Valley, using the following steps: (1) leaf sampling; (2) spectral analysis; (3) lab determination of carbohydrate and starch contents; and (4) development of predictive regression and classification models. The predictive regression models used were Principal Components Regression (PCR) and Partial Least Squares Regression (PLSR). Supervised discriminant models were also developed to classify mango leaves according to different potassium sources used, using linear discriminant analysis (LDA). Vis-NIR spectroscopy showed low values for the non-destructive evaluation of “Palmer” mango leaves using PCR and PLSR for carbohydrate and starch prediction with R2 of 0.58 lower than the models considered excellent (R2 >0.90); The development of classification models did not allow the discrimination of different sources of potassium in “Palmer” mango leaves with an accuracy of 64.2%.

Grown in different regions of Brazil, mango is of great importance at the national level. However, mango cultivation is directly related to physiological factors such as photosynthesis, stomatal conductance and chlorophyll. Physiological factors are related to the nutritional balance of the plant. Among the nutrients, potassium (K) can be highlighted, which, despite not being a structural element for the plant, stimulates, or is part of several physiological plant processes. Therefore, an experiment was carried out with the purpose of evaluating, in the vegetative period of 'Palmer' mango, the effect of different sources of K to accelerate the maturation stage of mango branches and verify their influence on physiological indexes and chlorophyll. Treatments consisted of three ripeners and a control, which were applied directly to the branches and leaves of “Palmer” mango trees. The variables analyzed were chlorophyll A, B and Total indexes; Internal concentration of CO2; Stomatal conductance; transpiration rate; Net photosynthesis; Instantaneous Carboxylation Efficiency and Water Use Efficiency. After collecting, and analyzing the data, it was concluded that the vegetative period of the “Palmer” mango tree, in relation to the different evaluation dates, was not influenced by potassium sources. The use of T4 treatment (SpeedFol® induction mango) can provide a greater increment of chlorophyll A, B and Total than KCl and K2SO4.

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 objective was to quantify the nutritional contents in seeds of different advanced genotypes of cowpea bean (Vigna unguiculata L. Walp) in the soil of Montería-Córdoba, Colombia. Seeds of 40 lines or genotypes and two commercial varieties Caupicor 50 and ICA Betancí were evaluated as controls. A completely randomized block design was used with three repetitions for a total of 126 experimental units. The seeds were initially subjected to drying in a forced circulation oven at 70 ° C for 72 hours to quantify the nutritional content. The final nitrogen content was evaluated by initially submitting the seeds to digestion in concentrated sulfuric acid for 4 hours. It was subsequently quantified using the Kjeldahl method. Finally, to determine the content of microelements, 1 g of seed was subjected to digestion with nitric, perchloric acid (3:1), and they were quantified in a piece of atomic adsorption equipment. With the information recorded in the laboratory, an analysis of variance, contrasts, and tests of Tukey averages was performed at a 5% probability. The results indicate that it existed genetic variability and genotypes LC-041-016 and LC021016 were identified with 29.2 and 29.1%, with the highest protein content, being superior to Caupicor 50 and ICA Betancí that presented contents of 25, 7 and 25.5%. The genotypes L-047 with 216.3, followed by genotypes LCPM35 and LC027016, with 159.5 and 127.3 mg.kg-1 presented the highest iron content, and the commercial witnesses Caupicor 50 and ICA Betancí, content less than the above, and the content zinc and manganese were similar in all genotypes evaluated.