Onion (Allium cepaL.) is one of the main horticultural species in Argentina. The supply of seeds of this species is mainly from national production. Gibberellic acid (AG3) in onion is effective to induce flower buds when applied before or during the period of low temperatures.Throughout three seasons in La Consulta, Mendoza, Argentina, AG3 was tested to determine its effects on the seed production of onion cv Valcatorce INTA using the seed-to-seed method. The treatments were 0-200-400-600 mg.L-1 of AG3 in the first season and 0-300-600-900 mg.L-1 of AG3 in the other two; the plants were sprayed when they had between 5 and 7 leaves.The design was complete blocks with random plots and five replications. The number of umbels per plant, the seed yield per plant and unit area, and the seed quality, were determined. Gibberellic acid increased the number of umbels per plant.In the first two seasons, the highest seed yield per unit area was achieved with the use of the highest dose of AG3. However, in the third season, the best performance was obtained with 300 mg.L-1. The application of AG3 with the highest doses tested decreased the weight of a thousand seeds in two seasons without impairing germination.

Intercropping aims to sustain the yields of the main crop and add additional yield. The objectives of this work have been to compare the productivity, the assimilated biomass partition, the starchy composition of roots and the chemical composition of the different organs of the cassava (Manihot esculentaCrantz) traditionally managed as monoculture versus the consociated cropping in two plantation densities with Tetsukabuto pumpkin (Cucurbita maximaDuchesne x Cucurbita moschata (Duchesne ex Lam.) Duchesne ex Poir.). The Land Use Efficiency (UET) of the different systems have also been evaluated. The experiment was carried out in Corrientes, Argentina. Four treatments (T) were used: the pumpkin monoculture installed within a frame of 3 m x 2 m (T4), pumpkin associated with one (T2) or with two (T3) cassava lines in the interlines spaced 1 m between plants and/or between lines respectively and the cassava monoculture planted in a conventional 1 m x 1 m frame (T1). The results showed that the yield numerical components and the cassava root quality are not affected by the consociations. By the low density cassava consociation with Tetsukabuto pumpkin (T2), the maximum efficiency of the production system with minimum interspecific competition is obtained, and it is also more beneficial in terms of mineral bioconcentrations in the plant tissues of cassava plants.

Aconcagua INTA is an Argentine widespread cucurbit cultivar with high yield and suitability for the dehydration industry, developed from an interspecific cross (Cucurbita maxima x Cucurbita moschata). Its seed production involves the use of etephon in the maternal progenitor to castrate male flower organs, while the other line serves a pollen donor. Because this process is not totally effective, some hermaphrodite flowers remain in the maternal line, leading to self-pollination and –therefore- seeds of non-hybrid origin, which are phenotypically different from the hybrid. Thus, the percentage of non-hybrid seeds needs to be estimated and labelled in commercial seed lots of this cultivar. To this end, the present study analyzed, comparatively, morphological, biochemical and molecular markers that may be used for the early identification of this hybrid and its parental lines. Thus, a morphological marker based on leaf characteristics, protein profiles by UTLIEF, and the microsatellite molecular marker CMBR22, were evaluated in hybrid and parental plants. All three marker systems were able to accurately identify the hybrid and the parental lines, with results revealing 100% correspondence among the three types of markers. The protein and molecular markers developed herein represent a valuable tool for the early identification of hybrids in seed lots of cv. Aconcagua INTA.

The environmental impact indicators (IIA) summarize relevant information, making visible phenomena of interest to quantify, measure and publish them. The AgroEcoIndex®, is a sistem designed at the National Institute of Agricultural Technology for extensive productions in the Pampean region. Currently, this system is being adapted to horticultural productions and is called Periurban AgroEcoIndex (AEIp), which could become a valuable tool for evaluating environmental impact and accompanying improvement processes in horticultural farms. The objectives of the work are to evaluate fifteen commercial horticultural farms near the city of Córdoba, and generate reference values for three production models (conventional in the field, conventional intensive and agroecological), based on the academic contribution of experts from the horticultural sector in the area, in order to compare IIA. Data analysis was performed by Principal Component Analysis (PCA). By estimating the IIA used in this evaluation, it is concluded that no risks of soil contamination by nitrogen and phosphorus were detected, and that the risk of contamination due to pesticide use was low in light vegetable farms (of green leaves) and high in those where they included potato cultivation. In general, the fifteen horticultural farms evaluated in the study area presented similar values compared to the values of the three theoretical models designed, which means an acceptable environmental impact for this type of production.

Environmental impact indicators are tools in process of permanent revision and improvement. Thus, any enriching contribution towards them provides accurate information on the real state of the situation being evaluated. The following research has two objectives: To validate the results of environmental impact indicators obtained through the AgroEcoIndex periurban methodology (AEIp) in horticultural soils; and to arrive to conclusions on the general condition of such soils by comparing them with uncultivated soils as well as soils in the area where other agricultural activities are carried out. A comparison was made between the mean of the results of the horticultural soils and the uncultivated soil, and a Principal Component Analysis (PCA) that also includes the reference values of agricultural soils in the area. A partial coincidence is observed between the data obtained in the soil analyses, and those indicators of the AEIp referring to nitrogen balance and phosphorus balance. In turn, the nitrogen and phosphorus contamination risk indicators reflect the current state of the soils analyzed. In conclusion, there are no signs of degradation or contamination in the soils of the analyzed horticultural establishments according to the methodology used in this study and in comparison, with other agricultural soils in the area.

The cucumber is an economically important crop for the vegetables growers, especially in the Cordillera, Paraguay zone, due to the distance to the market and its appreciated value as food. The research was done in Colonia Curupayty, in the Cordillera department, in the Eusebio Ayala district, (latitude S 25° 22′ 54.34″ meridian W 56° 57′ 38.77″), Paraguay. The aim of this work was to evaluate cucumber crop yield(Cucumis sativusL.) applying different doses of boron (B), and were measured: yield of experimental unit (EU), fruit weigth, plant yield, fruit diameter and length and economic analysis. The experimental design was completely random, composed of four (4) treatments(T1: 0,5 lt/ha T2: 1,0 lt/ha; T3 1,5 lt/ha and T4 ( without boron) and five (5) repetitions.A liquid mineral fertilizer with boron ethanolamine was used, with a concentration of 11% boron.The crop was established in double files. The distance between plants was 1,0 m x 0,70 m. Variance analysis (ANAVA) and Tukey test at 5% demonstrated that boron influences cucumber production. The best results were for treatmentT3 (1,5 lt B/ha), with a yield/m2 of 11,90 kg, a fruit weight of 345 gr, yield per plant of 4,83 kg, fruit diameter with 4,6 cm and length of 26,02 cm.

Nutritional requirements of the‘Margarita’orange cultivar were determined under biophysical conditions of the Momposina Depression region of Colombia. The physical and chemical properties of the soils in the region were characterized. Then 18 experimental plots were chosen, where two tree populations were selected: The first, trees with yield greater than 250 kg of fruit, the second, with yield of less than 250 kg of fruit. The plots were monitored during three years of production (from October 2018 to December 2020). The production cycle was divided into three stages: the first, 35 days after flowering (DAF); the second, 70 DAF and the third, 100 DAF; moment which the fruits are in optimal state for their consumption. At each stage, the concentration of nutrients in leaf tissue and nutrient extraction by the fruit were quantified. Significant differences were found between nutrient extractions among the three stages evaluated (P <0.05). In the first stage, higher N extraction was observed, with 4.78 kg Mg-1 of fruit, followed by K and Ca. In the second and third stages, there was greater extraction of K, with 3.35 and 3.10 kg Mg-1 of fruit, respectively; followed by N and Ca. The highest extraction of microelements in the three stages was B and Fe. Significant correlations were identified between productivity and P, K, Zn, Ca, Fe and B concentrations in leaf tissue, from which general standards were generated to interpret foliar analyses.

Sweet potato is one of the most widespread tuberous root vegetables in regions with a tropical and subtropical climate where it is used in human and animal nutrition. The objective of the work was to evaluate the productivity and quality of roots of five sweet potato genotypes (Morotĩ, IB-023, Morado, Morada INTA and Sa'yju), in two locations (Loma Plata, Department of Boquerón and San Lorenzo, Central Department, Paraguay), using a randomized complete block experimental design with a 2 x 5 factorial arrangement with three repetitions. The harvest was carried out 150 days after planting and the following variables were measured: total and commercial root yield per hectare, total and commercial number of roots per plant, average commercial root mass and fresh mass production of the aerial part. The data collected were subjected to the analysis of variance and comparison of means by the Tukey test at 5% probability. There was significant interaction between genotypes and localities in the total and commercial yield of roots, total and commercial number of roots per plant. In the average mass of commercial roots and production of fresh mass of the aerial part, there were only differences between genotypes. The Morotĩ and IB-023 genotypes stood out in the total and commercial production of roots and average mass of commercial roots, therefore, they are recommended for cultivation in both locations.

Tomato intercropping with antagonistic species is considered a management alternative for Meloidogyne spp. The objective of the work was to evaluate the intercropping of Tagetes erecta, Tagetes minuta and Crotalaria juncea for the management of Meloidogyne spp., in tomato cultivation. The gall index and the number and weight of fruits were determined in tomato plants. Tomato intercropping with T. erecta showed a lower gall index than the rest of evaluated treatments. In addition, a higher weight and number of fruits were observed in this treatment and in the one with T. minuta, respect to the C. juncea treatment and the control without intercropping. Under the conditions of this trial, intercropping of tomato with T. erecta proved to be a good alternative for the management of Meloidoigyne spp. This practice contributes to a lesser use of phytosanitary products, with the positive effect that it has on the environment, and to the obtaining of a more innocuous horticultural product for human consumption.

Measurement of plant physiological response to stress or practices for its alleviation is useful for non-destructive evaluation and early diagnosis. The aim of this work was to study physiological effect of the use of phytohormones on tomato crop in soil infested by Nacobbus aberrans. The essay was carried out under a greenhouse located in EE Julio Hirschhorn (La Plata, Buenos Aires). Tomato Elpida was treated by drench, 24 hours pre-transplanting with 1 ml of: salicilic acid 0.50 x 10-4 M and 1.00 x 10-4 M, ethylen 0.35 x 10-3 M and 0.70 x 10-3 M, jasmonic acid 1.00 x 10-4 M and 1.00 x 10-5 M, using plants without treatment as control. It was recorded gas exchange: CO2 net assimilation rate, stomatal conductance, transpiration and instant water use efficiency, leaf temperature and greenness index. Statistical design was a randomized complete block with 4 replications. Variance analysis and Tukey test were applied. Gas exchange was not modified by treatments. Leaf temperature was significant lesser with salicylic acid 1.00 x 10-4 M, which increased the greenness index; variable that was lower in control plants. Increasing resistance in tomato against N. aberrans by salicylic acid and the measurement of physiological variables to check the response of the plant are promising possibilities.