Open Access Original Research Article

Influence of Post-Flowering Chemical Thinning on Development and Fruit Quality of 'Fuji Suprema' and 'Maxigala' Apple Trees

Gentil Carneiro Gabardo, Aike Anneliese Kretzchmar, José Luiz Petri, Mariuccia Schlichting De Martin, André Amarildo Sezerino, Edson Blattmann

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/jeai/2019/v32i430107

Aims: Evaluate possible alterations in the development, anatomy and quality of fruits from 'Maxi Gala' and 'Fuji Suprema' apple plants treated with Metamitrom (MM) and Benzyladenine (BA) alone or in combination, applied at different stages of fruit development in the Midwestern region of the state of Santa Catarina.

Study Design: The experiment was arranged in a randomized block design with five replicates. Place and duration of Study: The experiment was carried out in the municipality of Caçador-SC, Brazil, during the growing season of 2016/2017.

Methodology: Two products, BA (with hormonal action) and MM (photosynthesis inhibitor) were applied individually or in a tank mix in post-flowering periods (in fruits of 5-10 mm and 15-20 mm in equatorial diameter), which were compared with plants with no thinning and manual thinning of both cultivars. Treatments were as follows: Control (no thinning) MM, BA, MM + BA (in fruits of 5-10 mm in diameter); MM, BA, MM + BA, manual thinning (in fruits of 15-20 mm in diameter). The phenological stage of F2 (Full flowering (FF) was observed on September 28, 2016 for both cultivars. Evaluations of the anatomical characteristics of fruits at the time of harvest did not show any alteration in cell size (mean cell area - μm2) and cell density (number of cells per fruit section area); the mean fruit mass was higher in MM 350 mg L-1 (5-10 mm), MM 350 mg L-1 + BA 40 mg L-1 (5-10 mm), and MM 350 mg L-1 (15-20mm) treatments. In the 'Fuji Suprema' cultivar, except for control treatments, MM 350 mg L-1 (5-10mm) and BA 80 mg L-1 (5-10mm), a significant reduction in production was observed (kg plant-1 and fruit-1). While in 'MaxiGala', all the thinning treatments reduced yield per plant. The cultural thinning practice, fruit load management, adapting the number of fruits according to plant size is the most important factor that producers are able to influence. Thinning reduces fruit load in the plant, which allows remaining fruits the possibility of greater growth and size gain. The combination of MM + BA is efficient in the thinning of apple fruits, especially when applied at the beginning of fruit development (5-10 mm in diameter). The application of chemical thinners, such as MM and BA, may influence the early stages of fruit development.

Open Access Original Research Article

Modified Atmosphere and Refrigeration in Postharvest Conservation of Atemoya cv. Gefner

Maryelle Cristina Souza Aguiar, Gisele Polete Mizobutsi, Raquel Rodrigues Soares Sobral, Juceliandy Mendes da Silva Pinheiro, Joelma Carvalho Martins, Irani Pereira dos Santos, Érika Endo Alves, Edson Hiydu Mizobutsi, Ignacio Aspiazú, Wagner Ferreira da Mota

Journal of Experimental Agriculture International, Page 1-12
DOI: 10.9734/jeai/2019/v32i430108

Aims: The objective of this study was to evaluate the effect of the modified atmosphere under refrigeration for 28 days in the Atemoya Gefner.

Study Design: Experiment 1 and 2 was installed in a completely randomized design, in a factorial 1x4 and 2x8, respectively.

Place and Duration of Study: The experiment was conducted in a cold chamber at the State University of Montes Claros, Brazil, between July and August 2018.

Methodology: In the first, the percentage of fruits that presented cold injury (CI) in unpackaged fruits and stored at 15°C for six days was visually evaluated. In the second experiment two pack were used and stored at 15°C and evaluated the physical and chemical characteristics.

Results: In the first experiment, from the 2nd day 100% of the fruits showed CI that progressed to stage 3 on the 6th day of storage. This result justifies the need to store the atemoya under modified atmosphere under 15°C for 28 days. It was found at the end of 28 days, experiment two, that the packages 1 and 2 showed quality fruits, with characteristics of ripe fruits, with 22 °Brix average values, reduced titrable acidity, light green color peel and good lightness. The pack1 showed better weight maintenance, with 1.54% of fresh weight loss against 2.36% for pack2.

Conclusion: There was a higher solubilization of total sugars and non-reducing sugars in pack1, being this the most indicated for atemoya fruits grown in northern Minas Gerais.

Open Access Original Research Article

Agronomic Performance of New Potato Genotypes Submitted to Increasing Doses of NPK

Keli Cristina dos Santos, Gentil Carneiro Gabardo, Jackson Kawakami, Aline Genú, Sara Passos, Rafael Hermenegildo Contini

Journal of Experimental Agriculture International, Page 1-10
DOI: 10.9734/jeai/2019/v32i430109

Aims: Estimate the morphological characteristics of potato genotypes grown with different doses of NPK fertilizer 4-14-8.

Study Design: The experiment was conducted in randomized blocks with subdivided plots and three replicates.

Place and Duration of Study: The experiment was carried out in the municipality of Guarapuava – PR, Brazil, during the growing seasons of 2013/2014 and 2014/2015.

Methodology: In the main plots the doses of 0, 2, 4 and 6 t ha-1 of NPK fertilizer 4-14-8 were arranged and in the subplots the genotypes (Ágata, BRS Camilla and clone C0205). Were evaluated: The leaf area index (LAI), percentage of light absorption, number of tubers, fresh mass of tubers. In the first agricultural year the evaluations were performed at 25 and 45 days after the emergency (DAE) and in the second seasson at 28 and 48 DAE. Interaction between potato genotypes and fertilizer rates for LAI was observed at 45 DAE in 2013/14 and absorbance at 25 DAE in 2013/14. For the seasson 2013/14, the genotypes showed a significant difference for LAI, absorbance, number of tubers and fresh mass of tubers at 25, LAI and fresh mass of tubers at 45 DAE, clone C0205 presented the largest differences for these characteristics. Fertilizer doses did not influence LAI, absorbance at 25 DAE and 45 DAE in 2013/14 and, at 2014/15 at 28 DAE, there was no response for tuber number and LAI, and at 48 DAE for tuber number, absorbance. There was no significant interaction between fertilizer doses and potato plant genotypes for the data on number of primary stems and number of secondary stems in both seassons The genotypes responded to NPK fertilizer doses 4-14-8 for LAI, and clone C0205 presented the best results. The genotypes responded to the light absorption percentage, with C0205 presenting the best results, so that plants with greater leaf area presented greater light absorption. The genotype C0205 presents greater productive capacity when compared to the Agata and Camila genotypes, being evident the greater number and fresh mass of tubers produced.

Open Access Original Research Article

Development of Pumpkin Young Plants Receiving Dosages of Phosphorus from Different Sources

Tayssa Menezes Franco, Marcos Vinicius Reis de Oliveira Junior, José Darlon Nascimento Alves, Wendel Kaian Oliveira Moreira, Juciley Lima de Souza, Marcus José Alves de Lima, Emerson Carneiro Galvão, Heráclito Eugênio Oliveira da Conceição

Journal of Experimental Agriculture International, Page 1-8
DOI: 10.9734/jeai/2019/v32i430110

Aims: The research aimed to analyze the effect of five different dosages and three sources of phosphorus on the growth and development of young plants of pumpkins (Cucurbita moschata), cultivar Jacarezinho.

Study Design: The experimental design utilized was the completely randomized design with the factorial arrangement 5 x 3 with three repetitions.

Place and Duration of Study: The experiment was performed in a greenhouse of the Federal Rural University of Amazônia in the Capitão Poço City, Pará State. The research was carried out from March to April 2016.

Methodology: The analyzed variables were plant height (PH), stem diameter (SD), number of leaves (NL), fresh root mass (FRM), fresh aerial mass (FAM), dry aerial mass, (DAM) and dry root mass (DRM) at 30 days after sowing. The averages of dosages x sources interactions were submitted to a regression analysis.

Results: There was a significant effect of the interaction dosage x source for the PH, FAM and DAM. However, the dose of fertilizer got an effect on the SD, with linear response. The plots that did not reserve any fertilizers showed the least response for all variables. ARAD was the source that had the least performance in the analyzed variables in comparison to others sources.

Conclusion: The superphosphate and triple superphosphate sources provided better development and accumulation of dry matter.

Open Access Original Research Article

Development and Gas Exchange of Pre-sprouted Sugarcane Seedlings in Three Different Growing Substrate Media

Hanna Ibiapina de Jesus, Maria Luiza de Souza Medeiros, Maria de Fátima de Queiroz Lopes, Bruno de Souza Oliveira, Galileu Medeiros da Silva, Fábio Mielezrski

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/jeai/2019/v32i430114

Objective: Evaluate the development and gas exchange of pre-sprouted sugarcane seedlings in different substrates.

Study Design: A randomized complete block design was used with two genotypes, three types of substrate (2 x 3), four replicates and five plants per replicate, totaling 120 plants.

Location and Duration of Study: Department of Crop Sciences of the Center for Agrarian Sciences, Universidade Federal de Paraíba in the city of Areia, Brazil, between August and October 2018.

Methods: The following were the treatments: T1 – genotype 1 in commercial substrate; T2 – genotype 1 in commercial substrate + bovine manure; T3 – genotype 1 in bovine manure + sand; T4 – genotype 2 in commercial substrate; T5 – genotype 2 in commercial substrate + bovine manure; T6 – genotype 2 in bovine manure + sand. Variables analyzed: height, diameter, dry mass of shoot and root and physiological response of seedlings.

Results: A significant difference at the 1% level was found for the dry matter of the seedling roots among treatments with difference substrates. A significant difference at the 1% level was also found for shoot length and a significant interaction at the 5% level was found between genotype and substrate for this characteristic. Significant effects were found with regard to the rate of photosynthesis, stomatal conductance, transpiration and carboxylation efficiency.

Conclusion: The substrate with manure + sand favored the accumulation of root dry matter and shoot length. Genotype 1 exhibited its best performance with regard to photosynthesis and stomatal conduction in the treatment with the commercial substrate and demonstrated greater carboxylation efficiency than genotype 2, independently of the substrates. The pre-sprouted seedling production system needs to be explored further to obtain greater information regarding the nutritional requirements and characteristics of the genotypes.