The purpose of greenhouse crop systems is to generate a high quality product at high production rates, consistently, economically, efficiently and in a sustainable way. To achieve this level of productivity, accurate monitoring and control of some processes of the entire biophysical system must be implemented. In addition, the proper selection of actions at the strategic, tactical and operational management levels must be implemented.Greenhouse management relies largely on human expertise to adjust the appropriate optimum values for each of the production and environmental parameters, and most importantly, to verify by observation the desired crop responses. The subjective nature of observing the plant responses, directly affects the decision-making process (DMP) for selecting these `optimums'. Therefore, in this study several decision support systems (DSS) were developed to enhance the DMP at each of the greenhouse managerial levels.A dynamic greenhouse environment model was implemented in a Web-based interactive application which allowed for the selection of the greenhouse design, weather conditions, and operational strategies. The model produced realistic approximations of the dynamic behavior of greenhouse environments for 28-hour simulation periods and proved to be a valuable tool at the strategic and operational level by evaluating different design configurations and control strategies.A Web-based crop monitoring system was developed for enhancing remote diagnosis. This DSS automatically gathered and presented graphically environmental data and crop-oriented parameters from several research greenhouses. Furthermore, it allowed for real-time visual inspection of the crop.An intelligent DSS (i-DSS) based on crop records and greenhouse environment data from experimental trials and from commercial operations was developed to characterize the growth-mode of tomato plants with fuzzy modeling. This i-DSS allowed the discrimination of "reproductive", "vegetative" and "balanced" growth-modes in the experimental systems, and the seasonal growth-mode variation on the commercial application.An i-DSS based on commercial operation data was developed to predict the weekly fluctuations of harvest rates, fruit size and fruit developing time with dynamic neural networks (NN). The NN models accurately predicted weekly and seasonal fluctuations of each variable, having correlation coefficients (R) of 0.96, 0.87 and 0.94 respectively, when compared with a dataset used for independent validation.

Thesis (Ph. D. Agriculture (Plant Protection)) -- University of Limpopo, 2013 / Global withdrawal of synthetic fumigant and non-fumigant nematicides due to their ecounfriendly impacts and high toxicity to non-target organisms, respectively, increased the research and development of alternatives for managing population densities of plantparasitic nematodes, particularly the root-knot (Meloidogyne species) nematodes. Although Meloidogyne species had been managed using genotypes that are resistant to plant-parasitic nematodes in various crops, various challenges negate the available or introgressed nematode resistance. In tomato (Solanum lycopersicum) production, nematode races and instability of nematode resistant genotypes under certain conditions necessitated the continued research and development of alternatives since most of the existing commercial tomato cultivars are highly susceptible to various biological races of Meloidogyne species. The aim of the study was to research and develop appropriate dosages of two phyto- nematicides which could be applied through drip irrigation system in open field tomato production systems, while the specific objectives were to: (1) determine whether a computer-based model could provide nonphytotoxic concentrations to tomato plants using fresh fruits of wild watermelon (Cucumis africanus) and wild cucumber (C. myriocarpus) under greenhouse conditions, (2) determine whether computer-based concentrations from the two plant species when using dried fruits would be less phytotoxic and more suppressive to nematodes, (3) investigate application time intervals for the two products, (4) determine responses of plant growth in tomato and nematode suppression in respect to the derived dosages, and and (5) validate dosages of fermented crude extracts from the two plant species with respect to plant growth of tomato and suppression of nematode numbers. xxxiii Greenhouse, microplot and field studies were set to test the hypotheses intended to achieve the stated objectives, with reliability of measured variables being ensured by using statistical levels of significance (P ≤ 0.05) and coefficients of determination (R2), while validity was ensured by conducting experiments at the same location over two seasons and/or by setting up factorial treatments. Firstly, fermented plant extracts of fresh fruits from C. africanus and C. myriocarpus consistently reduced population densities of Meloidogyne species by 80-92% and 50-90%, respectively. Tomato plants were highly sensitive to the two products as shown by the total degree of sensitivities (Σk) and biological index of 0 and 3, respectively. Also, the mean concentration stimulation range (MCSR) of 11% and 7% concentrations, respectively, attested to this phytotoxicity. Secondly, fermented crude extracts of dried fruits from C. africanus and C. myriocarpus also reduced population densities of Meloidogyne species by 78-97% and 87-97%, respectively. Tomato plants were highly tolerant to the two products in dried form as shown by the total degree of sensitivities (Σk) and biological index of 4 and 3, respectively. The MCSR values for C. africanus and C. myriocarpus dried fruits on tomato were 2.64% and 2.99%, respectively, which for the purpose of this study were individually adjusted to 3%, which translated to 36 L undiluted material/ha of 4 000 tomato plants. In subsequent studies, 3% concentration was used as the standard, along with double strength concentration, namely, 6% concentration. Thirdly, the MCSR values derived in Objective 4, namely 3% and 6% concentration for both Cucumis species using the CARD model were used in the optimisation of application time interval using the innovative concept of weeks (0, 1, 2, 3 and 4) in a 30-day month period. Application time interval for 3% and 6% concentrations of C. africanus fruits was xxxiv optimised at 2.40 and 2.61 weeks in a 30-day month period, respectively, which translated to 18 days [(2.4 weeks/4 weeks) × 30 days] and 20 days [(2.6 weeks/4 weeks) × 30 days], respectively. In contrast, for both concentrations from fermented crude extracts of C. myriocarpus fruits, application time interval was optimised at 16 days for 2.2 and 2.1 weeks, respectively. During optimisation of application frequencies, fermented crude extracts from C. africanus and C. myriocarpus reduced final population densities of M. incognita race 2 by 70-97% and 76-96%, respectively. Fourthly, optimum application intervals (time), allowed computation of dosage, which is a product of concentration and application frequency (dosage = concentration × application frequency). Fifthly, validation of the dosages under open field conditions suggested that 6% × 16-day dosage under crude extracts from C. myriocarpus fruit significantly (P ≤ 0.05) improved growth of tomato plants when compared with those of either 0% (untreated control) or 3% at 16 days. In contrast, dosages of C. africanus fruit at two application frequency had no effect on growth of tomato plants – suggesting that either of the dosages was suitable for use in tomato production since both reduced nematode numbers. During validation, the materials reduced nematode numbers by margins similar to those observed previously under other environments. In conclusion, crude extracts of the two Cucumis species have stimulatory concentrations which have potential similar reductive effects on population densities of Meloidogyne species and could serve as botanical nematicides. However, since plant responses to the two products differed in terms of their respective dosages and active ingredients, it implied that for further improvement of the two, the overriding focus should be on their interaction with the protected plants and nematode numbers. Ideally, future research xxxv should include environmental impact studies, especially on the influence of the products fruit quality of tomato, earthworms, fish and bees.

Thesis (Ph. D. Agriculture (Plant Protection)) -- University of Limpopo, 2013 / Global withdrawal of synthetic fumigant and non-fumigant nematicides due to their ecounfriendly impacts and high toxicity to non-target organisms, respectively, increased the research and development of alternatives for managing population densities of plantparasitic nematodes, particularly the root-knot (Meloidogyne species) nematodes. Although Meloidogyne species had been managed using genotypes that are resistant to plant-parasitic nematodes in various crops, various challenges negate the available or introgressed nematode resistance. In tomato (Solanum lycopersicum) production, nematode races and instability of nematode resistant genotypes under certain conditions necessitated the continued research and development of alternatives since most of the existing commercial tomato cultivars are highly susceptible to various biological races of Meloidogyne species. The aim of the study was to research and develop appropriate dosages of two phyto- nematicides which could be applied through drip irrigation system in open field tomato production systems, while the specific objectives were to: (1) determine whether a computer-based model could provide nonphytotoxic concentrations to tomato plants using fresh fruits of wild watermelon (Cucumis africanus) and wild cucumber (C. myriocarpus) under greenhouse conditions, (2) determine whether computer-based concentrations from the two plant species when using dried fruits would be less phytotoxic and more suppressive to nematodes, (3) investigate application time intervals for the two products, (4) determine responses of plant growth in tomato and nematode suppression in respect to the derived dosages, and and (5) validate dosages of fermented crude extracts from the two plant species with respect to plant growth of tomato and suppression of nematode numbers. xxxiii Greenhouse, microplot and field studies were set to test the hypotheses intended to achieve the stated objectives, with reliability of measured variables being ensured by using statistical levels of significance (P ≤ 0.05) and coefficients of determination (R2), while validity was ensured by conducting experiments at the same location over two seasons and/or by setting up factorial treatments. Firstly, fermented plant extracts of fresh fruits from C. africanus and C. myriocarpus consistently reduced population densities of Meloidogyne species by 80-92% and 50-90%, respectively. Tomato plants were highly sensitive to the two products as shown by the total degree of sensitivities (Σk) and biological index of 0 and 3, respectively. Also, the mean concentration stimulation range (MCSR) of 11% and 7% concentrations, respectively, attested to this phytotoxicity. Secondly, fermented crude extracts of dried fruits from C. africanus and C. myriocarpus also reduced population densities of Meloidogyne species by 78-97% and 87-97%, respectively. Tomato plants were highly tolerant to the two products in dried form as shown by the total degree of sensitivities (Σk) and biological index of 4 and 3, respectively. The MCSR values for C. africanus and C. myriocarpus dried fruits on tomato were 2.64% and 2.99%, respectively, which for the purpose of this study were individually adjusted to 3%, which translated to 36 L undiluted material/ha of 4 000 tomato plants. In subsequent studies, 3% concentration was used as the standard, along with double strength concentration, namely, 6% concentration. Thirdly, the MCSR values derived in Objective 4, namely 3% and 6% concentration for both Cucumis species using the CARD model were used in the optimisation of application time interval using the innovative concept of weeks (0, 1, 2, 3 and 4) in a 30-day month period. Application time interval for 3% and 6% concentrations of C. africanus fruits was xxxiv optimised at 2.40 and 2.61 weeks in a 30-day month period, respectively, which translated to 18 days [(2.4 weeks/4 weeks) × 30 days] and 20 days [(2.6 weeks/4 weeks) × 30 days], respectively. In contrast, for both concentrations from fermented crude extracts of C. myriocarpus fruits, application time interval was optimised at 16 days for 2.2 and 2.1 weeks, respectively. During optimisation of application frequencies, fermented crude extracts from C. africanus and C. myriocarpus reduced final population densities of M. incognita race 2 by 70-97% and 76-96%, respectively. Fourthly, optimum application intervals (time), allowed computation of dosage, which is a product of concentration and application frequency (dosage = concentration × application frequency). Fifthly, validation of the dosages under open field conditions suggested that 6% × 16-day dosage under crude extracts from C. myriocarpus fruit significantly (P ≤ 0.05) improved growth of tomato plants when compared with those of either 0% (untreated control) or 3% at 16 days. In contrast, dosages of C. africanus fruit at two application frequency had no effect on growth of tomato plants – suggesting that either of the dosages was suitable for use in tomato production since both reduced nematode numbers. During validation, the materials reduced nematode numbers by margins similar to those observed previously under other environments. In conclusion, crude extracts of the two Cucumis species have stimulatory concentrations which have potential similar reductive effects on population densities of Meloidogyne species and could serve as botanical nematicides. However, since plant responses to the two products differed in terms of their respective dosages and active ingredients, it implied that for further improvement of the two, the overriding focus should be on their interaction with the protected plants and nematode numbers. Ideally, future research xxxv should include environmental impact studies, especially on the influence of the products fruit quality of tomato, earthworms, fish and bees.

Due to the recent changes in the economy of Kentucky tobacco production, some producers are seeking an alternative crop that will provide similar economic gains to tobacco without needing more acreage. Tomatoes are an existing crop in Kentucky that have been declining in acreage over the last five years. There is evidence to suggest that, through niche and local marketing, tomatoes may be able to fill the void left by tobacco. However, there is concern among producers that they will lose yield and/or quality if they switch to one of these niche production systems or cultivars. A two year study at Western Kentucky University compared the yield and quality of three tomato cultivars, two heirlooms and one hybrid, under organic and conventional management techniques to see if producers concerns are valid. The heirloom cultivars used were 'Cherokee Purple' (CP) and 'Mr. Stripey', (MS) the hybrid cultivar was 'Crista' (CR). The study was a split block design, with four randomized replications within each block. Plants were grown under black plastic mulch, with drip irrigation under the mulch. Plants were harvested weekly throughout the season and data were collected on individual fruit weight, size, grade and the number of fruit produced per plant. Production and quality were compared between management techniques for each cultivar, and the cultivars were compared to each other under individual management techniques. When comparing organic and conventional management practices, CP produced significantly (p<.05) larger, heavier, and higher quality fruit under organic practices and showed no significant differences in fruit number in 2008. MS and CR showed no significant differences between production systems for fruit weight or size, CR produced significantly higher quality fruit under conventional treatment and MS produced significantly more fruit per plant in 2008. In 2009, CP did not produce enough fruit under organic management to allow statistical comparison between management systems. MS however did not show any significant differences between management systems for any of the traits studied. CR produced significantly larger fruit under organic management, but no other differences were observed. When comparing cultivars in 2008, CP and CR produced fruit of similar weight but significantly heavier than MS under both production systems. CP produced the largest fruit under organic management, with CR following and MS producing the smallest fruit. Under conventional management, CP and CR produced fruit of similar size and both were larger than MS. MS produced the highest quality fruit under organic management, and CR produced the nicest grade under conventional management. No differences were seen for number of fruit per plant between cultivars under organic management, while MS produced the most fruit per plant under conventional management. In 2009 CP did not produce enough fruit to be statistically compared to the other cultivars under organic management. MS and CR produced fruit of similar weight under both organic and conventional management, while CP produced the greatest weight under conventional management. CR produced larger fruit than MS under organic management, while under conventional management CP and CR were of similar size as were CR and MS, but CP was significantly larger than MS. No significant differences were found between cultivars for fruit grade or number of fruit per plant under either management system in 2009.

Made available in DSpace on 2015-03-26T13:23:57Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2434464 bytes, checksum: 80b9d76ccf12598e86e07c096aa00665 (MD5) Previous issue date: 2014-07-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The reason of this experiment was to evaluate the water rates irrigated and the fertilizer rates applied on the tomato plant, under the Viçosa &#769;s staking system, which aimed to obtain the highest yield for the fresh market, maximums on water use efficiency and on the quality of the fruits, and also getting better concentration on nutrients in the tomato leaves. The experiment was installed in two seasons July 2013 and January 2014, both in Viçosa/MG, on the field research center, from the Agronomy Department. The treatments for both experiments were four different water rates irrigated L1, L2, L3 and L4 regarding on 50, 100, 150 and 200% of the real irrigation required by the crop (IRN) and also, four different fertilizer rates D1, D2, D3 and D4 regarding on 50, 100, 150 and 200% from the fertilizer rate recommendation (5a . The variables evaluated were: commercial production (PC), total yield (PT), big fruits (PFG), medium (PFM) and small fruits (PFP); productivity by the plant (PP), water use efficiency (WUE), pH, soluble solids, titratable acidic, flavor, consistence, lycopene and nutrients concentration in the leaves. It was used the average results from the two experiments. It was concluded after getting the final results, that the highest PC, PT, PFG and PP of the tomato, were obtained with 331 mm of water rate irrigated and 150% of the fertilizer rate recommendation. The highest water use efficiency was obtained with 276 mm of water rate irrigated and 150% of the fertilizer rate. The highest lycopene concentration (85,32 &#956;g g-1) was obtained with 331 mm of water rate irrigated and 200% of the fertilizer rate. The macronutrients concentration foliar (N, P, K, Ca, Mg and S) and micronutrients (Mn, Zn, Fe, Cu and B) for the highest crop yield were 58,5; 5,5; 29,5; 60,6; 6,3 e 7,7 g kg-1 for the macronutrients and 481,1; 39,4; 273,1; 784,6 e 61,8 mg kg-1 for the micronutrients. The macronutrients concentration foliar (N, P, K, Ca, Mg and S) and micronutrients (Mn, Zn, Fe, Cu and B) for the maximum water use efficiency were 36,1; 4,9; 24,0; 63,7; 6,8 e 10,0 g kg-1 for the macronutrients and 643,9; 42,3; 312,3; 809,8 e 56,5 mg kg-1 for the micronutrients. / O objetivo do trabalho foi avaliar lâminas de irrigação e doses de adubação para o tomateiro cultivado no sistema Viçosa de tutoramento visando obter a máxima produtividade de frutos comerciais, eficiência no uso de água e qualidade de frutos e a melhor concentração de nutrientes na folha. O experimento foi instalado em duas épocas julho de 2013 e janeiro de 2014 em Viçosa/MG, na área experimental do Departamento de Fitotecnia. Os tratamentos para ambos os experimentos foram quatros lâminas de irrigação L1, L2, L3 e L4 correspondendo a 50, 100, 150 e 200% da irrigação real necessária (IRN) e quatro doses de adubação D1, D2, D3 e D4 correspondendo a 50, 100, 150 e 200% da recomendação (Approach 5th). As variáveis avaliadas foram: produtividade comercial (PC), total (PT), de frutos grandes (PFG), médios (PFM) e pequenos (PFP), produção por planta (PP), eficiência no uso da água (EUA), pH, sólidos solúveis, acidez titulável, sabor, firmeza, licopeno e concentração de nutrientes na folha. Trabalhou-se com os resultados médios dos dois experimentos. Com os resultados obtidos conclui-se que: As maiores PC, PT, PFG e PP de tomate foram obtidas com lâmina de irrigação de 331 mm e adubação de 150%. A maior eficiência no uso da água foi obtida com lâmina de irrigação de 276 mm e dose de adubação de 150%. O máximo teor de licopeno (85,32 &#956;g g-1) foi obtido com a lâmina de 331 mm e dose de adubação de 200%. A concentração foliar de macronutrientes (N, P, K, Ca, Mg e S) e micronutrientes (Mn, Zn, Fe, Cu e B) para a máxima produtividade foram de 58,5; 5,5; 29,5; 60,6; 6,3 e 7,7 g kg-1 dos macronutrientes e 481,1; 39,4; 273,1; 784,6 e 61,8 mg kg-1 dos micronutrientes. A concentração foliar de macronutrientes (N, P, K, Ca, Mg e S) e micronutrientes (Mn, Zn, Fe, Cu e B) para a máxima eficiência no uso da água foram de 36,1; 4,9; 24,0; 63,7; 6,8 e 10,0 g kg-1 dos macronutrientes e 643,9; 42,3; 312,3; 809,8 e 56,5 mg kg-1 dos micronutrientes.

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