Artificial neural networks (ANN) are computational models inspired by the neural systems of living beings capable of learning from examples and using them to solve problems such as non-linear prediction, and pattern recognition, in addition to several other applications.In this study, ANN were used to predict the value of the area under the disease progress curve (AUDPC) for the tomato late blight pathosystem. The AUDPC is widely used by epidemiologic studies of polycyclic diseases, especially those regarding quantitative resistance of genotypes.However, a series of six evaluations over time is necessary to obtain the final area value for this pathosystem. This study aimed to investigate the utilization of ANN to construct an AUDPC in the tomato late blight pathosystem, using a reduced number of severity evaluations. For this, four independent experiments were performed giving a total of 1836 plants infected with Phytophthora infestans pathogen. They were assessed every three days, comprised six opportunities and AUDPC calculations were performed by the conventional method. After the ANN were created it was possible to predict the AUDPC with correlations of 0.97 and 0.84 when compared to conventional methods, using 50 % and 67 % of the genotype evaluations, respectively. When using the ANN created in an experiment to predict the AUDPC of the other experiments the average correlation was 0.94, with two evaluations, 0.96, with three evaluations, between the predicted values of the ANN and they were observed in six evaluations. We present in this study a new paradigm for the use of AUDPC information in tomato experiments faced with P. infestans. This new proposed paradigm might be adapted to different pathosystems.

RESUMO O objetivo deste estudo foi caracterizar e avaliar populações híbridas e segregantes, provenientes de cruzamentos entre acessos de Cucurbita moschata, com potencial oleaginoso, e cultivares que apresentam o gene para crescimento do tipo moita (Bush), visando à obtenção de genótipos com elevado teor de óleo nas sementes e com crescimento da planta do tipo moita. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições. Cada repetição foi constituída por cinco plantas dos acessos BGH-7319 e BGH-7765, dos cultivares Piramoita e Tronco Verde e dos híbridos F1 (BGH-7319 x Piramoita, BGH-7319 x Tronco Verde, BGH-7765 x Tronco Verde), sendo consideradas as três plantas centrais das parcelas como úteis. Para cada uma das três populações F2 (‘População 1 F2’, ‘População 2 F2’, ‘População 3 F2’), 30 plantas foram avaliadas. Foram utilizados 28 descritores fenotípicos, sendo nove relativos à fase vegetativa das plantas, 12 referentes aos frutos e sete às sementes. Os dados foram submetidos à análise de variância e as médias dos tratamentos contrastadas com as médias das testemunhas, a 5% de probabilidade, pelo teste Dunnett. Na predição do potencial das populações para obtenção de linhagens superiores, foi utilizada a metodologia de Jinks & Pooni (1976). O híbrido BGH-7319 x Tronco Verde destaca-se para os caracteres massa de sementes por fruto, massa de cem sementes, comprimento, largura e espessura da semente, sendo considerada promissora quanto ao teor de óleo nas sementes. A ‘População 2 F2’ derivada do cruzamento entre os genitores BGH-7319 e Tronco Verde foi considerada a mais promissora para planta com crescimento do tipo moita.

Late blight is one of the most destructive diseases of the tomato, resulting in substantial economic losses. There is difficulty in controlling this disease, so the molecular characterization of tomato genotypes may help in the selection of higher resistance tomato plants against Phytophthora infestans, late blight's pathogen. The objective was to analyze the differences with regard to the constitutive proteome between the access Vegetable Germplasm Bank (BGH)-2127, resistant genotype, and Santa Clara-susceptible genotype to late blight. Proteomic analysis of leaf samples by two-dimensional electrophoresis (2-DE) followed by identification by mass spectrometry (MALDI TOF/TOF) was performed. Nineteen proteins were identified, which were then related to metabolism and energy, photosynthesis, transcription, stress, and defenses. Approximately 90% of these proteins were more abundant in Santa Clara, a susceptible cultivar. Acidic 26 kDa endochitinase and ribonuclease T2 proteins were more abundant in BGH-2127 access. The enzymatic activity confirmed a greater abundance of chitinase in the BGH-2127 access as compared to the cultivar Santa Clara. Gene expression analyses by real-time PCR demonstrated that the mRNA levels were not correlated with the respective protein levels. Abundance of the acidic 26 kDa endochitinase and ribonuclease T2 proteins in the constitutive proteomes of BGH-2127 may be associated with the answer to the resistance of this access.

Resumo -O objetivo deste trabalho foi selecionar acessos resistentes à pinta-preta (Alternaria tomatophila) por meio da análise de agrupamento das curvas de progresso da doença em tomateiro (Solanum lycopersicum). Foram avaliados 134 acessos de tomateiro do Banco de Germoplasma de Hortaliças da Universidade Federal de Viçosa (BGH-UFV), no delineamento de blocos ao acaso, além das testemunhas suscetíveis 'Débora' e 'Santa Clara'. As plantas foram inoculadas com uma mistura de conídios de diferentes isolados de Alternaria spp. e avaliadas regularmente quanto à severidade da doença a cada três dias após a inoculação, no total de seis avaliações. Ajustou-se o modelo logístico aos dados de severidade da pinta-preta, e as estimativas obtidas para a incidência final da doença (B 1 ) e a taxa de progresso da doença (B 3 ) foram submetidas à análise de variância multivariada (Manova). As médias dessas estimativas, para cada acesso, foram submetidas à análise de agrupamento. Foram formados 24 grupos distintos com base no agrupamento das curvas de progresso da doença, o que possibilitou identificar os acessos BGH-2143, BGH-2235, BGH-2270 e BGH-2118 de tomateiro como potenciais fontes de resistência à pinta-preta.Termos para indexação: Alternaria tomatophila, Solanum lycopersicum, banco de germoplasma, estatística multivariada, modelos não lineares, recursos genéticos. Selection of tomato accessions resistant to early blight by cluster analysis of disease progress curvesAbstract -The objective of this work was to select accessions resistant to early blight (Alternaria tomatophila) through cluster analysis of the disease progress curves in tomato (Solanum lycopersicum). One hundred and thirty-four tomato accessions from the Banco de Germoplasma de Hortaliças of Universidade Federal de Viçosa (BGH-UFV) were evaluated in a randomized complete block design, as well as the susceptible controls 'Débora' and 'Santa Clara'. The plants were inoculated with a mixture of spores from different Alternaria spp. isolates and evaluated regularly regarding disease severity every three days after inoculation, totalizing six evaluations. The logistic model was adjusted to data on early blight severity, and the estimates obtained for final disease incidence (B 1 ) and rate of disease progression (B 3 ) were subjected to multivariate analysis of variance (Manova). The means of these estimates, for each access, were subjected to cluster analysis. Twenty-four distinct groups were formed based on disease-progress curve clusters, which allowed the identification of the BGH-2143, BGH-2235, BGH-2270, and BGH-2118 accessions as potential sources of resistance to early blight.

Resumo -O objetivo deste trabalho foi avaliar genitores com potencial de hibridação para o pré-melhoramento do tomateiro (Solanum lycopersicum) quanto à resistência à requeima. Foram utilizados seis acessos de tomateiro (BGH-2102, BGH-2117, BGH-2127, BGH-2130, BGH-2332 e BGH-2343 como genitores resistentes e 15 híbridos F 1 originários destes genitores. Utilizou-se o delineamento de blocos ao acaso, com três repetições. As plantas foram inoculadas com uma mistura de esporângios de Phytophthora infestans, agente etiológico da requeima, na concentração de 5x10 3 esporângios mL -1 . A área abaixo da curva de progresso da doença foi utilizada para avaliar a resistência. Realizou-se a análise dialélica, tendo-se considerado o efeito de genótipos como fixo. Estimou-se a capacidade geral e específica de combinação dos acessos. O padrão de resistência dos genitores e da maioria dos F 1 foi o mesmo que o das testemunhas resistentes. Foram observados: variabilidade genética aditiva entre os genitores, predominância de efeitos gênicos não aditivos e desvios de dominância bidirecional no controle do caráter. A frequência de alelos favoráveis e divergentes para resistência à requeima é maior nos acessos BGH-2117, BGH-2127 e BGH-2343.Termos para indexação: Phytophthora infestans, Solanum lycopersicum, capacidade combinatória, fonte de resistência. Hybridization potential among tomato accessions for pre-breeding for resistance to late blightAbstract -The objective of this work was to evaluate parents with hybridization potential for pre-breeding of tomato (Solanum lycopersicum) for resistance to late blight. Six tomato accessions (BGH-2102, BGH-2117, BGH-2127, BGH-2130, BGH-2332, and BGH-2343) were used as resistant parents and 15 F 1 hybrids originated from these parents. The design was a randomized complete block with three replicates. The plants were inoculated with a mixture of Phytophthora infestans sporangia, the etiological agent of late blight, at a concentration of 5x10 3 sporangia mL -1 . The area under the disease progress curve was used to evaluate resistance. Diallelic analysis was performed, considering the effect of genotypes as fixed. The general and specific combining ability of the accessions was estimated. The resistance pattern of the parents and of most of the F 1 was the same as that of the resistant controls. The following were observed: additive genetic variability among the parents, predominance of nonadditive gene effects, and bidirectional dominance deviations in the control of the trait. The frequency of favorable and divergent alleles for late blight resistance is higher in the BGH-2117, BGH-2127, and BGH-2343 accessions.