ABSTRACT. The use of dwarf lines to obtain mini-tomato hybrid plants has led to agronomic and economic advantages. However, the benefits provided by dwarf parents in tomato hybrids of the Santa Cruz type remain unexplored. The aims of this study were to determine the agronomic enhancement in BC1F2 dwarf populations bearing characteristic fruit of the Santa Cruz type after the first backcross and to select populations with high agronomic potential and fruit quality. The experiment was conducted in a greenhouse using a randomized block design with 15 treatments and 4 replicates. Evaluated genetic materials included 11 BC1F2 dwarf tomato populations, both parents (recurrent and donor), and the cultivars (Santa Cruz Kada and Santa Clara). Traits evaluated included: mean weight, soluble solid concentration, number of locules, shape, pulp thickness, fruit longitudinal and transversal diameters, internode length, and plant height. Univariate, multivariate, correlation, and selection index analyses showed that mean fruit weight, transverse diameter, and pulp thickness increased significantly in dwarf populations after a single backcross, most of them exhibiting a fruit shape similar to that of the Santa Cruz type. The dwarf BC1F2 populations UFU-Sci#11 and UFU-Sci#12 showed high potential for obtaining lines and, subsequently, Santa Cruz type hybrids.

ABSTRACT Lettuce bacterial leaf spot caused by Xanthomonas campestris pv. vitians is an aggressive disease that is difficult to control. So far there are no reports of the reaction of biofortified lettuce genotypes to different isolates of the bacteria. Thus, the objective was to evaluate the aggressiveness of X. campestris pv. vitians, as well as the reaction of biofortified lettuce genotypes to bacterial spot. Two experiments were performed in two distinct seasons (winter and summer), in greenhouse at the Vegetable Experimental Station of the Federal University of Uberlândia (UFU). The experimental design in both experiments was a randomized block design, in a factor scheme of 5 × 4 (five genotypes and four strains), with four repetitions. Were evaluated the severity and the area under the disease progress curve. In general, the biofortified lettuce ‘Uberlândia 10000’ was more resistant to most bacterial strains in the summer cultivation, and in the winter period UFU ‘Crespa 206’. The commercial cultivar Robusta was the most susceptible to the strains during both seasons. The UFU E125 strain was the most aggressive for most genotypes in both seasons.

ABSTRACT The aim of this study was to estimate genetic divergence and select BC1F3 populations of dwarf tomato plant within the Santa Cruz segment by computational intelligence techniques. The experiment was conducted in a greenhouse in the Vegetable Crop Experimental Station of the Universidade Federal de Uberlândia (UFU), Monte Carmelo, MG, Brazil. A randomized block experimental design was used with 17 treatments and four replications. The genetic material evaluated comprised thirteen dwarf tomato plant populations obtained by a backcross and two self-fertilizations, plus both parents (recurrent and donor), and two commercial check varieties. The traits evaluated were mean fruit weight (MFW), soluble solids content (SSC), fruit diameter (FD), fruit length (FL), fruit shape (FS), pulp thickness (PT), number of locules (NL), distance between internodes, and acylsugar, β-carotene, and lycopene content. The data were analyzed by means testing, and genetic divergence was measured using Mahalanobis generalized distance by the unweighted pair group method with arithmetic mean (UPGMA) and through computational intelligence using Kohonen self-organizing maps (SOM). Genetic dissimilarity in relation to the donor parent could be confirmed through both methodologies. However, the SOM was able to detect differences and organize the similarities among the populations in a more consistent manner, resulting in a larger number of groups. In addition, the computational intelligence techniques allow the weight of each variable in formation of the groups to be ascertained. Among the BC1F3 populations, UFU-SC#3 and UFU-SC#5 stood out for agronomic traits, and UFU-SC#10 and UFU-SC#11 stood out for quality parameters.

Resumo: O objetivo deste trabalho foi determinar os parâmetros genéticos e a eficiência de diferentes índices de seleção para linhagens de alface de folhas vermelhas (Lactuca sativa var. crispa) biofortificada e com potencial agronômico e nutricional. O experimento foi conduzido em delineamento de blocos ao acaso, com três repetições e 31 genótipos de alface do tipo crespa e com pigmentação roxa: a cultivar Belíssima, com baixa quantidade de carotenoides e rica em antocianina; e 30 linhagens provenientes do cruzamento entre as cultivares Belíssima e Uberlândia 10000, rica em carotenoides e com baixo teor de antocianina. As características avaliadas foram: massa verde total (g), diâmetro do caule (cm), número de folhas, diâmetro da planta (cm), temperatura foliar (°C), índice de desenvolvimento de análise de planta de solo (SPAD), teor de antocianina (mg por 100 g de amostra) e pendoamento (dias após a semeadura). Para as estimativas dos ganhos de seleção, foram selecionados 12 genótipos por meio de índices de seleção. O índice clássico proposto por Smith & Hazel e o índice da soma de “ranks” de Mulamba & Mock proporcionaram os maiores ganhos de seleção na alface biofortificada. O coeficiente de determinação genotípica para número de folhas, teor de antocianina, pendoamento e índice SPAD é de alta magnitude.

Abstract: The objective of this work was to determine the genetic parameters and the efficiency of different selection indices for biofortified red leaf lettuce (Lactuca sativa var. crispa) lines with agronomic and nutritional potential. The experiment was carried out in a randomized complete block design with three replicates and 31 crisp-textured and red-tinted leaf lettuce genotypes: the Belíssima cultivar, with a low carotenoid content and rich in anthocyanins; and 30 lines from the cross between the Belíssima and Uberlândia 10000 cultivars, rich in carotenoids and with a low anthocyanin content. The assessed traits were: total green mass (g), stem diameter (cm), leaf count, plant diameter (cm), foliar temperature (°C), soil plant analysis development (SPAD) index, anthocyanin content (mg 100 g-1 sample), and bolting (days after sowing). To estimate selection gains, 12 genotypes were selected through selection indices. The traditional index proposed by Smith & Hazel and the sum of ranks index by Mulamba & Mock provided the highest selection gains in the biofortified lettuce. The coefficient of genotypic determination for leaf count, anthocyanin content, bolting, and SPAD index is of high magnitude.

RESUMO Vantagens agronômicas e econômicas tem sido observadas com o uso de linhagens anãs para obtenção de híbridos em minitomate. No Brasil, predomina-se o cultivo de tomate do tipo salada. A exploração dos beneficios proporcionados pelo uso do parental anão em híbridos de tomateiro do tipo salada ainda não é uma realidade. A avaliação e seleção de populações de porte anão pode aumentar a eficiência do desenvolvimento de tais linhagens. Sendo assim, torna-se necessário o desenvolvimento de linhagens anãs do tipo salada. O retrocruzamento é o método mais adequado para se desenvolver tais linhagens. Portanto, o objetivo deste trabalho foi selecionar populações F2RC1 de tomateiro anão com potencial agronômico e qualidade de fruto.O experimento foi conduzido na Estação Experimental de Hortaliças da Universidade Federal de Uberlândia (UFU). Utilizou-se o delineamento de blocos casualizados com 15 tratamentos e três repetições. O material genético avaliado consistiu de 12 populações F2RC1 de tomateiro anão, mais ambos os genitores (recorrente e doador) e um híbrido comercial. As características avaliadas foram: massa média (g), teor de sólidos solúveis (ºBrix), número de lóculos (lóculos fruto-1), formato, espessura da polpa (cm), diâmetro longitudinal (cm) e transversal do fruto (cm); comprimento dos internódios (cm) e altura das plantas (cm). Os dados foram analisados por meio de teste de médias, análises multivariadas e índice de seleção. De maneira geral, a massa média dos frutos das populações anãs aumentou significativamente após o primeiro retrocruzamento e algumas destas apresentaram o formato de fruto próximo ao do segmento salada. Ao selecionaras populações UFU-DTOM7, UFU-DTOM10, UFU-DTOM5, UFU-DTOM9 e UFU-DTOM3 foi estimado um incremento de até 6% no número de lóculos, diâmetro transversal, relação DT/DL e peso médio do fruto. As populações anãs F2RC1 UFU-DTOM7 e UFU-DTOM10 se destacaram sendo promissoras para obtenção de linhagens. Apesar do avanço considerável obtido na presente pesquisa, sugere-se a realização do segundo retrocruzamento e posterior obtenção de linhagens para formar híbridos.

ABSTRACT The use of dwarf lines to obtain mini-tomato hybrids has provided agronomic and economic benefits. In Brazil, round tomatoes predominate over other varieties. The benefits of using a dwarf parent in round tomato hybrids has yet to be explored, making it important to develop dwarf round tomato lines. Backcrossing is the most suitable method to develop these lines. Evaluation and selection of the dwarf populations can improve the development of such lines. Thus, the aim of this study was to select BC1F2 populations of dwarf round tomatoes with agronomic potential and high-quality fruit. The study was conducted at the Vegetable Experimental Station of the Federal University of Uberlândia (UFU). A randomized block design was used, with 15 treatments and three replicates. The genetic material analyzed consisted of 12 BC1F2 dwarf tomato populations, plus both parents (recurrent and donor) and a commercial hybrid. The characteristics assessed were: average fruit weight (g), total soluble solids (ºBrix), number of locules (locules per fruit-1), fruit shape, pulp thickness (cm), longitudinal (cm) and transverse fruit diameter (cm), internode length (cm) and plant height (cm). The data were submitted to mean testing, multivariate analyses and a selection index. In general, average fruit weight in the dwarf populations increased significantly after the first backcross, with some fruits exhibiting a similar shape to round tomatoes. Selection of the populations UFU-DTOM7, UFU-DTOM10, UFU-DTOM5, UFU-DTOM9, and UFU-DTOM3 resulted in an estimated 6% increase in the number of locules, transverse diameter, TD/LD ratio and average fruit weight. The BC1F2 dwarf populations UFU-DTOM7 and UFU-DTOM10 were the most promising for develop inbred lines with round fruits. Despite the considerable progress achieved in this study, we suggest a second backcross, in order to obtain lines and, posteriorly, hybrids with round fruits and compact plants.

RESUMO Pouco se sabe a respeito do potencial comercial de híbridos de minitomate obtidos a partir de um genitor anão. Assim, o objetivo deste trabalho foi avaliar o desempenho agronômico de híbridos de minitomate obtidos pelo cruzamento entre linhagens anãs (A) versus linhagens normais de crescimento indeterminado (I), determinado (D) e semideterminado (SD). O experimento foi conduzido em casa de vegetação, na Estação Experimental de Hortaliças da Universidade Federal de Uberlândia (UFU), Monte Carmelo. Utilizou-se o delineamento inteiramente casualizado com 17 tratamentos e quatro repetições. O material genético consistiu de 16 híbridos experimentais de minitomate pertencentes ao Banco de germoplasma de tomateiro da UFU, e um híbrido comercial Mascot (testemunha). As variáveis utilizadas para analisar o desempenho agronômico foram: peso do fruto (g); número de frutos planta-1; produtividade (kg planta-1); número de pencas planta-1; número de frutos penca-1; diâmetro do caule (mm); distância do primeiro cacho ao solo (cm); comprimento de internódios (cm) e sólidos solúveis totais (ºBrix). O hábito de crescimento dos genitores influenciou o desempenho dos híbridos provenientes de linhagens anãs. De maneira geral, os híbridos de minitomate provenientes de linhagens anãs e a testemunha se diferenciaram em todas as variáveis, exceto no número de frutos planta-1, número de frutos penca-1 e no diâmetro do caule. Em média, os híbridos provenientes de linhagens anãs apresentaram maior produtividade (20%), internódios mais curtos (11%) e menor distância da primeira penca ao solo (30%) em relação à testemunha. A exploração de linhagens anãs demonstra ser viável na obtenção de híbridos de minitomate, uma vez que estes apresentam potencial comercial.

ABSTRACT Little is known about the commercial potential of mini-tomato hybrids obtained from one dwarf parent. Thus, our objective was to evaluate the agronomic performance of mini-tomato hybrids obtained by crossing a dwarf line (A) with normal lines with indeterminate (I), determinate (D) and semi-determinate (SD) growth habits. The experiment was conducted in a greenhouse at the Estação Experimental de Hortaliças at the Universidade Federal de Uberlândia-UFU in Monte Carmelo, Brazil. The experiment was completely randomized with 17 treatments and four repetitions. The genetic material consisted of 16 experimental mini-tomato hybrids from the tomato germplasm bank at UFU, and a commercial hybrid (Mascot) as a control. The following variables were used to evaluate agronomic performance: fruit weight (g); number of fruits plant-1; productivity (kg plant-1); number of bunches plant-1; number of fruits bunch-1; stem diameter (mm); distance between first bunch and soil (cm); internode length (cm) and total soluble solids (°Brix). The growth habit of the parents influenced the performance of the hybrids. In general, the mini-tomato hybrids from dwarf lines differed from the control with respect to all variables except number of fruits plant-1, number of fruits bunch-1 and stem diameter. On average, hybrids from dwarf lines showed higher productivity (20%), shorter internodes (11%) and a shorter distance between the first bunch and the ground (30%), relative to the control. Using dwarf lines to obtain mini-tomato hybrids was shown to be viable since the hybrids demonstrated better agronomic performance.

A radiação solar é um dos elementos responsáveis pela manutenção da vida no planeta. Apesar da sua importância, o registro da radiação solar não é feito na maioria das estações meteorológicas convencionais, uma vez que nem todas dispõem de equipamentos para medi-la, tendo que recorrer a métodos de estimação empíricos. Com o intuito de testar e calibrar equações para estimar a radiação solar, foram coletados dados de quatro estações meteorológicas pertencentes ao Instituto Nacional de Meteorologia (INMET) para representar a região climática noroeste de Minas Gerais, no período de 2008 a 2010. Com base nesses dados, foram testados e calibrados nove modelos para estimar a radiação solar global. Todos os modelos utilizam temperatura máxima e mínima do ar como preditores e dois deles utilizam também a precipitação pluviométrica. Os modelos mais precisos foram de De Jong e Stewart, Bristow e Campbell, Donatelli e Campbell e o modelo dois de Hunt, com raiz quadrada do quadrado médio do erro em torno de 3,1MJ m-2 d-1 e coeficiente de determinação em torno de 62%. No entanto, todos esses modelos apresentaram tendência de superestimação para valores de radiação inferiores à média e subestimação para valores superiores. Portanto, há necessidade de propor novos modelos que minimizem essa tendência.

Solar radiation is a component responsible for maintaining the life on the planet. Despite its importance, solar radiation is not recorded in most conventional meteorological station since not all have equipments to measure it, and then, it is usual to use empirical solar radiation estimation methods. In order to test and calibrate models for estimating solar radiation data were collected from four meteorological stations belonging to the National Institute of Meteorology (INMET) to represent the climatic region northwest of Minas Gerais for the period from 2008 to 2010. Based on these data, nine models to estimate global solar radiation were tested and calibrated. All the models use maximum and minimum air temperature as predictor and two of them also use rainfall. The most accurate models were De Jong and Stewart, Bristow and Campbell, Donatelli and Campbell and model of two Hunt, with root mean square error about 3.1MJ m-2 d-1 and determination coefficient around of 62%. However, all these models tended to have an overestimation for values of radiation below the average and an underestimation for values higher than the average. Therefore there is need to propose new models that minimize this trend.