Open Access Original Research Article

Different Sources and Concentrations of 6-BA in Chemical Thinning of Post-flowering in Apple Trees

Gentil Carneiro Gabardo, José Luiz Petri, Aike Anneliese Kretzchmar, Mariuccia Schlichting de Martin, André Amarildo Sezerino, Willian Coser

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v32i630121

Aims: Evaluate the efficiency of sources and dosages of 6-benzyladenine in the chemical thinning of the apple tree ‘Fuji Suprema’, as well as possible histological changes in the fruits produced, in the Midwestern region of the state of Santa Catarina.

Study Design: The experiment was arranged in a randomized block design and replicated six replications.

Place and Duration of Study: The experiment was carried out in the municipality of Caçador, Brazil (latitude 26º46 'S, longitude 51º W, altitude 960 meters), during the growing season of 2016/2017.

Methodology: Two commercial products based on 6-BA (Benzyladenine), Exilis® and Maxcel®, both with 2% BA in their composition, were tested and applied individually in post-flowering period (in fruits of 5-10 mm), which were compared with plants with no thinning and manual thinning. Treatments were as follows: Control (no thinning); manual thinning; Exilis® (1.5, 3.0, 4.5 and 6.0 L ha-1) and Maxcel® 4.5 L ha-1), using a spray volume equivalent to 1000 L ha-1. The fruit set and the number of fruit per cm2 branch, was reduced in treated plants, regardless of the concentration of BA or formulation used. The productivity ranged from 38 to 56.5 t ha-1 in the treatments of Exilis®, 60.5 t ha-1 in manual scaling and 24.5 t ha-1 in the Maxcel® 4.5 L ha-1, characterizing excessive thinning. BA is efficient in fruit thinning in 'Fuji Suprema' apple trees, being the reduction of fruiting, and increase of fruit size, proportional to the applied concentration. There may be differentiated efficiency of the product by its formulation, even though they have concentrations of active ingredient equivalent. Exilis® was efficient in thinning of apple "Fuji Supreme", when applied to fruit 5 to 10 mm in diameter reduced the need for manual thinning, without causing toxicity. BA can promote the increase in the cell density of fruits produced in proportion to the applied concentration.

Open Access Original Research Article

Effect of Preharvest Application of Silicon and Saline Water on Postharvest Quality of Beet (Beta vulgaris L.)

José Sebastião de Melo Filho, Toshik Iarley da Silva, Ygor Henrique Leal, Ana Gabriela Sousa Basilio, Mário Leno Martins Véras, Thiago Jardelino Dias

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v32i630122

Beet is one of the vegetables richest in nutrient (bioactive compounds, folic acid and potassium). However, there are few studies on postharvest quality from the crop under irrigation conditions with saline waters, and because of that, the objective of this study was to evaluate effect of saline waters and silicon application in the preharvest on physicochemical quality of the beet. Two experiments were conducted with the objective of evaluating two forms of silicon application: via foliar (experiment 1) and via soil (experiment 2) about its influence in mitigating salt stress. In both experiments was adopted a randomized design with blocks in a 5 x 5 factorial, referring to five levels of electrical conductivity of the irrigation water (ECw): (0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1) five doses of silicon (0.00; 2.64; 9.08; 15.52 and 18.16 mL L-1), they were combined according to the experimental matrix Central composite of Box totaling 10 treatments, with four replicates and three plants per plot. After harvesting, 70 days after transplanting, the following characteristics were evaluated: bulb dry mass, pH, titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio and ash.  There was a significant effect for the salinity x silicon (Si) interaction applied via soil to the dry matter mass and titratable acidity. The electrical conductivities of irrigation water (ECw) and Si doses via leaf and soil influenced significantly for analyzed variables, except pH, total soluble solids, TSS/TA ratio, ash and titratable acidity, which were not influenced by ECw and nor by the doses of Si via soil and foliage. Irrigation with water of 6.0 dS m-1 promotes better quality beet tuber. The fertilization on preharvest with silicon via soil or foliage improved postharvest quality of beet.

Open Access Original Research Article

Evaluation of Mango Peel Extracts on the in vitro Colletotrichum gloeosporioides Development

Luana Sabrine Silva, Edson Hiydu Mizobutsi, Gisele Polete Mizobutsi, Denilson Ferreira de Oliveira, Viviane Aparecida Costa Campos, Flávio Pinto Monção, Regina Cássia Ferreira Ribeiro, Marcos Paz Saraiva Câmara, Maria Luísa Mendes Rodrigues

Journal of Experimental Agriculture International, Page 1-8
DOI: 10.9734/jeai/2019/v32i630123

Aims: To evaluate the in vitro effect of mango peel extracts using different types of solvent and concentrations on the Colletotrichum gloeosporioides development.

Study Design: Activities were aimed at evaluating the in vitro antifungal potential of mango peel extracts.

Study Location and duration: The study was carried out at the Laboratory of Post-Harvest Pathology of Fruits and Vegetables - State University of Montes Claros and Laboratory of Natural Products, Department of Chemistry - Federal University of Lavras during October and December 2018.

Methodology: ‘Palmer’ mango peel (Mangifera indica) was submitted to drying in oven and grinding. Subsequently, extracts were obtained in Soxhlet system, using methanol, ethyl acetate and hexane as solvents. The three extracts were tested in vitro at concentrations of 0.0; 0.25; 0.5; 1.0 and 2.0 mg/mL by adding them in culture medium against C. gloeosporioides, which was isolated from mango fruits with anthracnose symptoms. The effect of extracts and their respective concentrations on the mycelial growth rate and conidia production and germination was evaluated. The design was completely randomized in a 3 x 5 factorial arrangement with 5 replicates.

Results: Increased extract concentrations caused reduction in the mycelial growth rate of the pathogen (R2 = 0.96). Both factors under study acted simultaneously in conidia production (P < 0.05), and the hexane extract presented better results for this analyzed variable. There was total germination inhibition (P < 0.05) when 1 mg/mL ethyl acetate extract and 2 mg/mL methanol and hexane extracts were used.

Conclusion: Methanol, hexane and ethyl acetate mango peel extracts had inhibitory effect on the in vitro C. gloeosporioides development.

Open Access Original Research Article

Chemical Composition and Nutritive Value during Grain Development of Three Varieties of Maize

Ajakaye Adeola Sekunola, Ajewole Tolulope Olumide, Ayesa Abayomi Samuel, Olu Faith Omolade, Oni Ayodeji Christopher

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v32i630124

Two improved varieties of maize (OBA SUPER II and SWAN) and one local variety were grown in the University of Ado Ekiti during the early cropping season of year 2016 to study the changes in their chemical and nutritional quality as the maize kernel develops.

The chemical composition of the three varieties shows a decrease in carbohydrate content and an increase in protein and fat content as the kernel matures while the concentration of Ash and fibre in the three varieties varies and does not follow a consistent pattern as the kernel matures.

The most abundant mineral elements are phosphorus, calcium, magnesium and zinc. Maize grains are low in trace elements.

Open Access Original Research Article

Content of Photosynthetic Pigments and Leaf Gas Exchanges of Young Coffee Plants under Light Restriction and Treated with Paclobutrazol

André Felipe Fialho Ribeiro, Sylvana Naomi Matsumoto, Luanna Fernandes Pereira, Ueliton Soares de Oliveira, Ednilson Carvalho Teixeira, Paula Acácia Silva Ramos

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/jeai/2019/v32i630128

The use of shading and paclobutrazol in coffee plants can be an important cultivation strategy to mitigate the negative effects of high solar radiation and atmospheric temperature. Therefore, the levels of photosynthetic pigments and foliar gas exchanges of young coffee plants submitted to doses of paclobutrazol were evaluated, in environments with artificial light restriction. Five experiments were performed: one in full sunlight and four in artificially shaded environments with black polyethylene meshes at 20%, 40%, 60% and 80% levels of light restriction. In each of these environments, an experiment was carried out, consisting of five treatments, defined by the application of paclobutrazol via substrate, at doses of 0, 10, 20, 30 and 40 mg of active ingredient per plant. Joint analysis of experiments and analysis of variance of the regression were made, for the study of levels of shading and doses of paclobutrazol. The light restriction optimized the photosynthetic apparatus of the plants, mainly at levels close to 60%, and considerably favored leaf gas exchanges of arabica coffee. The application of paclobutrazol in the studied dosages resulted in little or no effect on photosynthetic pigment contents and did not influence leaf gas exchanges of coffee plants.