Abadia dos Reis Nascimento

Qualidade de tomates de mesa cultivados em sistema orgânico e convencional no estado de Goiás

Organic agriculture is a cultivation method that looks for the establishment of agricultural systems balanced and ecologically stable, economically productive and highly efficient. The objective of this work was to evaluate the physical, physico-chemical and sensory characteristics of tomato cultivars for fresh consumption grown on organic and conventional systems. Two experiments were carried out; on the first ten cultivars were grown under organic system and fruits at maturity stages 3 (when they presented 60 to 90% of pink-red color or red peel) were evaluated for physical, physicochemical and sensorial characteristics. On the second experiment, cultivar Deborah produced in organic and conventional systems was compared based on the same characteristics. The highest levels of soluble solids (SS) were observed in cultivars Milenium, Andrea and Tathy 1, followed by Giovanna 1, Colibri, Debora, Setcopa and Bonus 1. The cultivars Colibri, Andrea, Thaty 1, Debora and Setcopa had the lowest values for total acidity (AT) and they did not differ (p>0.05), among themselves, neither from cultivars Bonus-1 and Stillus. The cultivars Andrea and Tathy 1 had the highest ratio SS/TA and did not differ (p>0.05) from cultivars Debora, Setcopa and Colibri. Debora, when cultivated in the organic system was more preferred on attribute texture (tenderness), external and internal color, besides presenting a lower acidity, higher SS/TA ratio and density. It is concluded that the most outstanding, in terms of producer (greater mass and density) requirements, were the cultivars Setcopa, Milenium, Giovanna 1, Stillus, Thaty 1 and Colibri, while for the consumer, whose requirements are more focused on sensory and physico-chemical aspects (color, aroma, flavor, texture, soluble solids and acidity), cultivars Deborah, Bonus-1, Andrea, Setcopa, Stillus, Thaty 1 and Colibri stood out. Cultivar Deborah had lower mass, volume and longitudinal diameter when grown in organic system, as well as higher soluble solids and lower acidity, which resulted in greater acceptance for aroma, flavor and texture by consumers.

Intervals and Number of Applications of Acibenzolar-S-Methyl for the Control of Bacterial Spot on Processing Tomato

Acibenzolar-S-methyl (ASM) is a plant activator that triggers systemic acquired resistance that is labeled for use in Brazil for managing tomato bacterial spot. The aim of this study was to define the optimum relationship between interval and number of applications of ASM for the most efficacious control of bacterial spot on processing tomato. Four intervals between applications (4, 7, 10, and 14 days) and four application frequencies (4, 6, 8, and 10 applications) were evaluated in five trials performed between 2010 and 2011 in Brasília, Distrito Federal, and in Morrinhos, in the state of Goiás. Copper hydroxide (CH) was applied after ASM applications to complete 13 applications per growing season. Two check treatments were added: standard CH weekly applications and untreated. The following variables were evaluated: severity of bacterial spot, yield, percentage of ripe and rotten fruit, soluble solids content, and the benefit/cost ratio. Disease severity varied between treatments in three trials and yield varied in two trials. A greater number of applications resulted in a reduction of bacterial spot, and the ideal interval between applications was between 8 to 10 days. However, there was a reduction in yield with 10 ASM applications. The temporal effect of ASM applications on bacterial spot severity was evaluated under greenhouse conditions. Reduction in disease severity was observed up to 6 days following ASM application. Additionally, the weekly treatment of seven applications of ASM followed by six applications of CH was compared with a standard program of CH under commercial production conditions in Itaberaí, Goiás, where bacterial spot occurred naturally. The program with ASM and CH resulted in significantly less foliar disease severity than the standard program, which did not result in yield gains. In addition, no differences were detected between the two programs for soluble solids content, industrial yield, plant height, and percentage of ripe and rotten fruit.

Detecting and grading severity of bacterial spot caused by Xanthomonas spp. in tomato (Solanum lycopersicon) fields using visible spectrum images

A method to detect and grade bacterial spot diseases in visible spectrum images of tomato fields is presented.The method applies segmentation and clustering techniques to CIELab color space channels.An index of the disease is presented.A comparison of the method to experts evaluation, and a correlation to the productivity in the field are presented. We introduce a novel method to detect and classify the severity of bacterial spot (Xanthomonas spp.) in tomato (Solanum lycopersicon) fields. Visual spectrum images were used as inputs and they were taken at 85days of the plantation. Two hybrids, Hypeel 108 and U2006, were planted and then inoculated separately with X. perforans and X. gardneri, respectively at 37 and 57days. Ten (10) different plantation areas were then evaluated taking 18 image samples of each in sub-areas, which were analyzed by 7 experts to grade them and be used as comparison. Productivity was also measured in the areas in order to correlate those to the different severities of the disease in the experiment. Visual spectrum images were preprocessed to area size adjustment and brightness correction and then transformed to a CIELab color space for more stable chroma analysis. A clustering process was applied in the a channel in order to group regions related to healthy leaves, unhealthy ones, bare soil and other artifacts. Post-filtering was applied to channels L and b to evaluate regions with over and underexposition of light and reddish fruits being detected. All of the processed regions were then measured and compared using a novel Severity Index SI, which automatically grades, from 1.0 to 5.0, the presence and the severity of the disease. Sixteen classes of severity SC are also proposed, as equal intervals of SI index. Images were taken in a variety of conditions and results showed besides strong correlation with experts analysis, better explanation and smaller error when analyzing the productivity affected by the disease measurements. Results indicate potential for using this methodology for detecting and grading the severity of bacterial spot in tomato fields, with advantages such as capability of repeatable results with low variance, speed and direct field-based applicability.

Volume de aplicação e eficiência do controle químico da mancha bacteriana em tomateiro industrial

Hortic. bras., Brasília, v.35, n.3, July-September 2017 N Brasil, a cultura do tomate para processamento industrial vem crescendo, resultado do aumento da demanda dos derivados de tomate (Melo & Fonte, 2011). A produção brasileira nesse segmento concentra-se no estado de Goiás, onde as condições de clima, solo e topografia favorecem o cultivo (Silva-Junior et al., 2015). Nessa região, irrigam-se os cultivos de tomate para processamento por aspersão via pivôcentral, o que favorece a ocorrência de doenças que comprometem a produtividade e a qualidade dos frutos, com destaque para a mancha bacteriana (Quezado-Duval et al., 2004). Essa doença está associada a quatro espécies do gênero Xanthomonas: X. euvesicatoria, X. gardneri, X. perforans e X. vesicatoria. Nas principais regiões produtoras do Brasil, os primeiros estudos de epidemias da mancha bacteriana em tomate para processamento indicavam a prevalência da espécie X. gardneri (Quezado-Duval et al., 2004). Entretanto, segundo levantamentos mais recentes, a ocorrência de X. perforans tem aumentado e passou a prevalecer nos campos de tomate para processamento na região central do país (Araújo et al., 2016). Essas bactérias podem sobreviver em restos culturais, sementes, plantas daninhas e plantas voluntárias (Quezado-Duval & Lopes, 2010), o que dificulta a eliminação das fontes de inóculo. Até o momento, não há variedades comerciais desse segmento com níveis efetivos de resistência (Quezado-Duval et al., 2014). Assim, a ferramenta mais utilizada pelos produtores para o manejo da mancha bacteriana tem sido o controle químico. PONTES, NC; NASCIMENTO, AR; GOLYNSKI, A; MOITA, AW; MAFFIA, LA; OLIVEIRA, JR; QUEZADO-DUVAL, AM. 2017. Volume de aplicação e eficiência do controle químico da mancha bacteriana em tomateiro industrial. Horticultura Brasileira 35: 371-376. DOI http://dx.doi.org/10.1590/ S0102-053620170309