Revista de la Facultad de Agronomía de la Universidad del Zulia

Effect of deficit irrigation on Helianthus annuus L. plants in containers

Thu, 06 Apr 2023 00:00:00 +0000

In order to evaluate changes related to plant physiology, infrared thermography has been chosen as a non-invasive complement. The research objective was to analyze the effect of deficit irrigation on Helianthus annuus L. plants in containers by means of IR thermography in a controlled experimental population at the University of Seville. The experiment consisted of three irrigation treatments to sunflower plants; one treatment received full irrigation (C-100) and two treatments received deficit irrigation: 70 % (R-70) and 50 % (R-50). A randomized block design was used. In the initial stage, polystyrene seedling trays of 54 cells (square) were used for the cultivation of sunflowers. The dimension of the trays was 700 x 400 x 70 mm. The cell size was 65 x 70 mm and the capacity was 135 cm³. For the development stage, plastic pots with a capacity of 4 L and a dimension of 21 x 16.4 cm were used. The sunflower plants used in this study did not exhibit significant differences in temperature and physiological analyses as a function of the irrigation treatment applied. However, there was a strong tendency for the plants to better resist water stress under a restrictive irrigation of 70%.

Productivity and nutritional value of common beans with organic fertilization in Durango, Mexico

Fri, 21 Apr 2023 00:00:00 +0000

Biofertilizers help to increase crop yields and nutritional quality, reducing the use of agrochemicals that affect ecosystems and human health. The objective of this study was to evaluate the yield and nutritional value of the Pinto Rarámuri variety bean, under an organic fertilization scheme in rainfed conditions in Durango, Mexico. Sowing was carried out in open fields in Villa Montemorelos, Durango, using a randomized complete block design with six treatments [manure tea (tea), sewage sludge (sludge), super lean (lean), commercial organic fertilizer (foc), chemical fertilizer (fqf) and control] five repetitions, 30 plots and five plants per plot as experimental unit. The variables were: emergence percentage, height and pods per plant, seeds per pod, seed thickness and length, weight of 100 seeds, yield, crude fiber percentage, protein, ash, fat, and nitrogen-free extract. A two-way analysis of variance and Tukey's comparison of means (p ≤ 0.05) were performed. The treatments showed statistical difference, the highest yield and weight of 100 seeds was presented by sludge, fqf and foc; while the highest number of pods and plant height was obtained by sludge and fqf. The lowest yield, pods per plant, seeds per pod and plant height were observed in control. The nutritional value presented statistical equality between treatments. The use of organic fertilization is a sustainable alternative to increase bean productivity in the state of Durango, without disturbing its nutritional quality.

Available phosphorus in soil from three sources and their effect on biomass and corn root development

Ricardo Ramírez, Omaira Sequeraϯ — Fri, 28 Apr 2023 00:00:00 +0000

Phosphorus deficiency in the country is very common, to overcome the problem high soluble phosphates are applied, the use a less soluble acidulated phosphate rock with sulfuric acid (RFA) is one economical alternative. The partial substitution of sulfuric acid by ammonium thiosulfate in the acidulation process (R30T) has proven feasible. The objective of this study was to prove the effect of these P sources on the maize behavior. Two soils were used a neutral and acidic one. Four doses of P treatments were used: 0, 70, 140 and 210 mg.kg^-1, in a glasshouse experiment. 35 days after planting plants were harvest and soil and root samples were taken for phosphorus analysis and determination of dry matter, root length (LR) and root volume (VR). Partial substitution of sulfuric acid by ammonium thiosulfate does not affect the quality of the acidulated rock. A close relationship between biomass and P concentration in the corn tops with residual soil P, LR and VR increased with the first increase of soil P, successive increments of P produced a decrease in roots size. The LR and VR relationship with P uptake and biomass was not the same in the two soils, in the acidic soil there was a higher dependence on P uptake than in the neutral soil.

Evaluation of fungicides used in the management of black Sigatoka in banana cultivation

Tue, 23 May 2023 00:00:00 +0000

The main phytosanitary problem of commercial bananas is black Sigatoka (BS; Mycosphaerella fijiensis), which causes damage to leaf area, loss of exportable quality, and low yields. The management of BS with mixtures of four systemic fungicides in different combinations in the border and central area of three banana plantations, and its effect on the severity of this disease were evaluated. The study was carried out in Ecuador, province of El Oro, Pasaje canton, at the ‘‘El Playón’’, ‘‘Mega Impulso’’ and ‘‘Lolita’’ farms; in an area of 5 hectares of the Williams cultivar with 10 years of production, 50 plants were selected in the vegetative phase in the borders and center of the plantation, four treatments were evaluated: T1 (Triazole+Amine), T2 (Pyrimethanil+Spiroxamine), T3 (Difenoconazole+Amine) and T4 (Amine+Pyrimethanil) and three replicates, with four applications every 14 days. Severity was assessed for 10 weeks using the Stover scale. The experimental design was a randomized block design and the data were analyzed by two-way ANOVA. The greatest fungicidal effect was achieved in ‘‘El Playón’’, the severity for leaf 4 in the border area was 37.5 % and 38 % in the center. On leaf 5, ‘‘El Playón’’ 55 %, ‘‘Mega Impulso’’ 60 %, and ‘‘Lolita’’ 72.5 % reached a severe value. The highest average number of functional leaves was obtained in ‘‘Mega Impulso’’ and the highest average number of old leaves free of streaks in ‘‘Lolita’’. The fungicides applied controlled BS, due to the low percentages of disease severity.

Alternative products with insecticidal effect in the control of Aulacaspis tubercularis; Newstead, 1906 (Hemiptera: Diaspididae) in mango cultivation

Yaneth Ramos , Agustina Valverde-Rodríguez, Antonio Cornejo, Fleli Jara — Tue, 23 May 2023 00:00:00 +0000

The predominant microclimates of the coast and the inter-Andean valleys of Peru have favored the production and export of mango (Mangifera indica L.) to more than 30 countries in the years 2020 - 2021. In this process, phytosanitary support was of vital importance, however, the species Aulacaspis tubercularis Newstead, 1906 (Hemiptera: Diaspididae) is a pest that affects the resulting crop, increasing costs due to cleaning the fruits for marketing. Control with insecticides contaminates the environment; hence the objective of the study was to evaluate alternative products with insecticidal effect and low environmental impact. The use of mineral oil (7.5 mL.L^-1), azadirachtin (3.2 %, 5 mL.L^-1), commercial powder detergent (20 g.L^-1) and potassium soap (10 mL.L^-1) in the field and laboratory. In the field, 9 trees were sprayed per treatment, every seven days at an interval of 15 days and in the laboratory the individuals per bottle. The four evaluated products had a significant impact on the colonies in the field (95.31 %, 88.89 %, 77.38 % and 68.04 %, respectively) in the first three moments of application. In the laboratory, commercial detergent and 3.2 % azadirachtin exerted high mortality (100 %) on the third day post-application, followed by 100 % mineral oil on the fourth day. The four products evaluated are recommended for the management of A. tubercularis.

Lipid Peroxidation, Proline Content and Soluble Sugars as indicators of Oxidative Stress Tolerance in Some Advanced Durum Wheat Lines (Triticum durum Desf.).

Tue, 23 May 2023 00:00:00 +0000

Oxidative stress induced by glyphosate is a complex phenomenon caused by an imbalance between reactive oxygen species (ROS) and antioxidants in plants cells. The present research was carried out at the field crops institute, Agricultural Experimental Station of Setif (ITGC-AES), to assess the response of some durum wheat (Triticum Durum Desf.) lines exposed to oxidative stress induced by glyphosate herbicide. In the heading stage, a solution of 5 Mm of glyphosate was sprayed on flag leaves, and each measurement was taken 48 hours after the glyphosate application. Lipid peroxidation, free proline and soluble sugars were determined. The results indicated that oxidative stress increased the content of lipid peroxidation, proline, and soluble sugars in flag leaves. Analysis of variance revealed significant differences among the genotypes tested, the increase in the level of lipid peroxidation is much higher in advanced lines G5 and G3, in which lipid peroxidation and membrane damage are greater. Oxidative damage also increased the proline content in lines G3 and G4, and soluble sugars in line G5, which were showing a high tolerance to the oxidative stress induced.

Comparative study of biological and metabolic indicators in males and females Pseudocurimata boulengeri of lotic ecosystems

Fri, 17 Mar 2023 00:00:00 +0000

With the objective of evaluating different biological and metabolic indicators in males and females Pseudocurimata boulengeri in three ecosystems of Los Ríos, Ecuador, specimens were captured in the areas of Ventana, Quevedo and Buena Fe (60 per area, 180 total), and proceeded to perform the sexing. The following were determined: size, weight, thickness of the head, trunk and tail, as well as the size-weight relationship. Stomasomatic, gonadal, hepatosomatic, vicerosomatic indices and condition factor. Glucose, total protein, cholesterol and triglyceride were also evaluated. A 3×2 factorial arrangement was used. Regression analysis to establish the functional relationship between length and weight. For the morphometric indicators, differences between interactions were shown, although higher values were observed in females regardless of the locality, with a weight of 185 g, a length of 23.43 cm and head thickness that exceeded 6 cm. The biological indices reflected differences between the interactions, thus the hepatosomatic, gonadal, and vicerosomatic indexes were higher for females in the locality of Ventanas with 0.97, 12.76, and 20.04, respectively. For the metabolic indicators, differences were shown between the interactions with greater variability for sex. It was shown that for the morphometric indicators, sex did not prevail. The biological indices were influenced by sex, with superiority for females except the stomasomatic. While metabolic indicators showed variability with respect to areas and sex.

Surfactant properties and emulsifying activity of the gum exudate of Prosopis juliflora (Sw.) DC.

Tue, 11 Apr 2023 00:00:00 +0000

Gums exudates are macromolecules consisting of carbohydrates (majority fraction), proteins and lipids (minority fraction), with variable concentrations of minerals, polyphenols, flavonoids, tannins and other bioactive phytochemical compounds. These natural products are used as emulsifying agents in multiple industries. The surfactant properties of a new source of gum exudate produced by Prosopis juliflora (Sw.) DC. were evaluated. Additionally, water-oil dispersions prepared with this natural polymer were tested for their emulsifying capacity and stability. A Du Noüy ring tensiometer was used to determine the amphipathic behavior of the investigated gum. The gum exudate of P. juliflora tested at 0.5 % m/v, decreases the values of surface tension (49.35 dyne.cm^-1) and interfacial tension (12.78 dyne.cm^-1), which evidences the potential emulsifying activity (EA) of this polysaccharide. EA values of 95 % and emulsion stability of 95.8 % were obtained, suggesting that P. juliflora gum contributes to improve the capacity and speed of adsorption of molecules between the dispersed phase and continues to form a stable emulsion. The surfactant and emulsifying activity of the investigated gum is associated with the high protein content (16.89 %) and the presence of methyl groups in its structure. Therefore, the gum exudate of P. juliflora constitutes a promising source of hydrocolloids as an emulsifier that could be evaluated in the manufacture of pharmaceuticals, food and even cosmetics. Additionally, it constitutes an unexploited natural resource that would contribute to the development of the South American regional economies where this species grows.