Abstract: The thermoinhibition of lettuce seed germination causes important losses for producers, who do not have thermotolerant commercial cultivars. One of the obstacles has been the scarcity of optimizing techniques capable of efficiently discriminating thermotolerant and thermosensitive cultivars. The aim of this work was to evaluate the use of neural networks to discriminate different levels of thermoinhibition in lettuce seeds. Seeds of 18 cultivars were evaluated for thermoinhibition considering the characteristics of the first and last germination count and germination speed index, in seeds subjected to temperatures of 20, 25, 30 and 35 °C. The remaining seeds, which did not germinate, were subjected to the tetrazolium test. Analyses were performed immediately after seed harvesting and repeated after six months of storage. Discriminant analysis was performed and the Kohonen’s Self-Organizing Map (SOM) was created using Artificial Neural Networks (ANNs). Neural networks discriminate lettuce cultivars and organizes them in terms of seed thermoinhibition tolerance through Kohonen’s Self-Organizing Map. Discriminant analysis consistently identifies the Everglades and Luiza genotypes as tolerant to thermoinhibition.

Resumo: A termoinibição causa perdas importantes para os produtores, os quais não dispõem de cultivares comerciais com sementes termotolerantes. Há escassez de técnicas otimizadoras capazes de discriminar cultivares termotolerantes e termosensíveis com eficiência. Objetivou-se avaliar o uso de redes neurais para discriminar diferentes níveis de termoinibição em sementes de alface. Foram avaliadas sementes de 18 cultivares quanto à termoinibição considerando às características de primeira e última contagem de germinação e índice de velocidade de germinação, em sementes submetidas às temperaturas de 20, 25, 30 e 35 °C. As sementes remanescentes, que não germinaram, foram submetidas ao teste de tetrazólio. As análises foram realizadas imediatamente após a colheita das sementes e repetidas após seis meses de armazenamento. Uma análise discriminante e o Mapa Auto-Organizável de Kohonen (SOM) por Redes Neurais Artificiais (RNA’s) foram realizados. As redes neurais discriminam as cultivares de alface e as organiza quanto a tolerância a termoinibição das sementes por meio do Mapa Auto-Organizável de Kohonen. A análise discriminante indentifica de maneira coerente o genótipo Everglades e Luiza como tolerantes a termoinibição.

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. Brazilian consumers are increasingly seeking unique vegetable products, such as mini lettuces. However, their production is hampered by a wide variety of pathogens, including Pectobacterium carotovorum subsp. carotovorum, which causes soft rot in lettuce. In this study, we aimed to select biofortified mini lettuce genotypes with good agronomic traits and resistance to P. carotovorum. A randomized block design consisting of 12 treatments, conducted in a field and greenhouse (Federal University of Uberlândia [UFU]), was used to select biofortified mini lettuce with good agronomic traits: SPAD index, stem and plant diameter, stem length, plant height, number of leaves, fresh weight, and bolt resistance. A completely randomized design consisting of 13 treatments was used for resistance or susceptibility testing. The bacterial suspension was inoculated and the following were assessed: disease severity, 16 days after inoculation; area under the disease progress curve, calculated separately at 4, 8, 12, and 16 days after inoculation as well as the sum of data calculated on all the assessment days; and the disease resistance class. The genotypes UFU 215#1 and UFU 215#2 had significantly high carotenoid concentrations. The genotypes UFU 66#4, UFU 215#1, and UFU 215#7 showed high bolt resistance. All genotypes were classified as resistant or moderately resistant to the P. carotovorum isolate, UFU A7.

ABSTRACT. Removal of lettuce basal leaves is a technique used by the seed industry; however, the effects on seed production and physiological potential are unknown. Genetic dissimilarity is fundamental in the identification of individuals in terms of traits of interest, although it is rarely considered in relation to seeds that are tolerant to thermoinhibition. The aim of this study was to ascertain the relationship between defoliation of lettuce plants and seed yield/physiological quality, as well as the genetic dissimilarity among genotypes with regard to seed thermoinhibition. We used 35 lines of biofortified lettuce, the cultivars Uberlândia 10000, Belíssima, UFU MC BIOFORT1, and Everglades (tolerant to thermoinhibition), and Grand Rapids and Verônica (susceptible to thermoinhibition). The seed yield and physiological quality of the genotypes with and without defoliation were evaluated, artificially aged, and germinated at four temperatures in a factorial arrangement. The genetic dissimilarity was estimated by Tocher graphing and the UPGMA clustering method, based on the Mahalanobis generalized distance (D2 ii). Four UFU genotypes and Grand Rapids had high seed yields. With removal of basal leaves, there was higher seed yield per plant and there was an effect on their physiological quality. The genotypes exhibited genetic variability for thermoinhibition, with UFU-86#2#1#1 and Everglades showing similar performance.

RESUMO O uso de cultivares de alface resistentes é uma das formas de controle do míldio. Objetivou-se avaliar as resistências vertical e horizontal de progênies F5:6 de alface biofortificada com carotenoides aos fenótipos de virulência de Bremia lactucae: 63/63/51/00, 63/31/19/00 e 63/63/19/00. O delineamento experimental utilizado foi inteiramente casualizado, em parcelas subdivididas no tempo. Nas parcelas utilizaram-se os 12 genótipos de alface e nas subparcelas utilizou-se o tempo, sendo este de 7 a 18 dias após a inoculação. Para cada fenótipo de virulência de Bremia lactucae fez-se um experimento separado, com três repetições. Para selecionar genótipos resistentes procedeu-se a inoculação, com mistura de água destilada, esporângios retirados de tecidos infectados do hospedeiro e Tween 20. A avaliação dos genótipos iniciou-se quando houve o aparecimento da esporulação nas folhas cotiledonares da cultivar suscetível Solaris, verificando-se a proporção de plantas necrosadas e com esporulação. Houve interação entre genótipos e tempos para todos os fenótipos de virulência avaliados. Os genótipos de alface biofortificada UFU-189#2, UFU-206#1, UFU-215#3 e UFU-215#14 apresentam resistência vertical aos fenótipos de virulência 63/63/51/00, 63/31/19/00 e 63/63/19/00 de B. lactucae. Níveis de resistência horizontal foram observadas no genótipo UFU- 206#1 para os fenótipos de virulência 63/63/51/00 e 63/31/19/00; no genótipo UFU-66#7 para o fenótipo de virulência 63/31/19/00 e no genótipo UFU-215#10 para o fenótipo de virulência 63/63/19/00 de Bremia lactucae.

ABSTRACT The use of resistant cultivars is one of the strategies for downy mildew management. The objective of this study was to evaluate the vertical and horizontal resistance of F5:6 progenies of carotenoidbiofortified lettuce to virulence phenotypes of Bremia lactucae 63/63/51/00, 63/31/19/00 and 63/63/19/00. The experimental design was completely randomized and subdivided into plots that were evaluated over time. In the plots, 12 genotypes of lettuce were used, and the subplots were monitored over time (7th to the 18th day after inoculation). For each virulence phenotypes of Bremia lactucae, a separate experiment was performed with three replicates. To select resistant genotypes, plants were inoculated with distilled water, sporangia removed from infected tissues and Tween 20. The genotypes were evaluated when sporulation appeared on cotyledonary leaves of the susceptible cultivar Solaris, verifying the proportion of necrotic and sporulated plants. There was a correlation between genotypes and times for all virulence phenotypes evaluated. Genotypes UFU-189#2, UFU-206#1, UFU-215#3 and UFU-215#14 showed vertical resistance to virulence phenotypes 63/63/51/00, 63/31/19/00, and 63/63/19/00 of B. lactucae. Horizontal resistance levels were observed in genotype UFU 206#1 for virulence phenotypes 63/63/51/00 and 63/31/19/00; in genotype UFU-66#7 for virulent phenotype 63/31/19/00; and in genotype UFU-215#10 for virulence phenotype 63/63/19/00.

RESUMO Informações da variação de importantes características morfológicas e fisiológicas do quiabo são limitadas. A análise molecular é uma ferramenta adicional importante nos estudos de caracterização de germoplasma. O estudo teve como objetivo avaliar o desempenho do crescimento e da produção de 20 acessos pré-comerciais de quiabo para identificar a associação de marcadores moleculares com características morfológicas. Dezenove caracteres morfológicos foram medidos com cinco descritores qualitativos e 14 quantitativos. Para a análise dos padrões genéticos, foram utilizados marcadores RAPD com nove primers e 24 bandas utilizáveis. A dissimilaridade genética foi avaliada com base em matrizes morfológicas e genéticas. Além disso, a representação gráfica das distâncias genéticas foi realizada pelo método UPGMA e otimização de Tocher. A caracterização morfológica dos acessos detectou polimorfismo para todas as características avaliadas. Os marcadores RAPD foram eficientes na detecção da variabilidade genética entre os acessos de quiabo. Para os primers usados no experimento, apenas OPE10 não amplificou a fita de DNA. Os outros oito primers produziram um total de 35 bandas, sendo 25 polimórficas e dez monomórficas. Os caracteres morfológicos e marcadores moleculares identificaram ampla variabilidade genética entre os 20 acessos de quiabo, indicando a possibilidade de cruzamentos bem-sucedidos em programas de melhoramento e o isolando genótipos interessantes. As análises morfológica e molecular foram complementares e auxiliaram na seleção dos genótipos. A análise molecular indicou alguns acessos divergentes que não foram encontrados na análise morfológica, o que poderia destacar alguns materiais que apresentam uma característica desejável, sendo interessantes para detectar características de dificil mensuração em campo.

ABSTRACT Information of the variation for important morphological and physiological traits of okra is still limited. Molecular analysis is an important additional tool in germplasm characterization studies. The study aimed to evaluate the performance of the growth and yield of 20 pre-commercial okra accessions to identify molecular markers’ association with morphological traits. Nineteen morphological traits were measured with five qualitative and 14 quantitative descriptors. For analysis of genetic patterns Random Amplified Polymorphic DNA (RAPD) markers were used with nine primers and 24 usable bands. The genetic dissimilarity was evaluated based in morphological and genetic matrices. Also, graphical representation of genetic distances was obtained by UPGMA and Tocher’s optimization method. The morphological characterization of the accessions detected polymorphism for all evaluated traits. RAPD markers were efficient in detecting genetic variability among okra accessions. For the primers used in the experiment, only OPE10 did not amplify the DNA strand. The other eight primers produced a total of 35 bands, in which 25 were polymorphic and ten were monomorphic. The morphological traits and molecular markers identified wide genetic variability among the 20 okra accessions, indicating successful crosses in breeding programs and isolating some interesting materials. Morphological and molecular cluster analyses were complementary and helped in the genotype selection. Molecular analysis indicated some divergent accessions that were not found in morphological analysis, which could highlight some materials that have a desirable trait, that is difficult and highly costly to access in field experiments.

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.

RESUMO O desconhecimento dos parâmetros genéticos e o tipo de ação gênica resultam em dificuldades na obtenção de variedades que combinam características agronômicas e funcionais. O objetivo deste estudo foi determinar o tipo de ação gênica envolvida com o conteúdo de clorofila e características agronômicas em populações de alface. A pesquisa foi realizada na Estação Experimental de Hortaliças, Monte Carmelo, Brasil. Para realizar os cruzamentos e obter as gerações P1, P2, F1, F2, Bc1 e Bc2, os genótipos UFU-Albina#2, UFUAlbina#3, UFU-Lisa124#2#1, UFU-Crespa199#1 e UFU-Lisa217#5#2 foram usados como parentais. As gerações foram avaliadas para três características (número de folhas, diâmetro das plantas e teor de clorofila) e analisados os seguintes parâmetros: variância genética, ambiental, fenotípica, aditiva, dominância em F2, herdabilidade no sentido amplo, herdabilidade no sentido restrito, grau médio de dominância baseado em médias, número de genes, medida dos desvios da dominância, medida dos efeitos aditivos, medida de todas interações do tipo aditiva x aditiva, aditiva x dominante e dominante x dominante. O teor de clorofila foi a característica mais influenciada pelo ambiente. O diâmetro de planta apresentou a maior herdabilidade no sentido restrito para o cruzamento UFU-Lisa-124#2#1 x UFU-Albina#3 (82,1%). O número de genes para a característica de número de folhas oscilou desde valores inconclusivos até um máximo de 9 genes. As interações gênicas para número de folhas demonstraram ser do tipo sobredominância enquanto que para diâmetro de plantas e teor de clorofila do tipo dominância parcial. Sugere-se que as características avaliadas são de natureza poligênica ou oligogênica.

ABSTRACT The lack of knowledge of the genetic parameters and the type of gene action results in difficulties to obtain varieties that combine agronomic and functional characteristics. The objective of this study was to determine the type of gene action associated with the contents of chlorophyll and agronomic characteristics in lettuce populations. The research was conducted at the Experimental Station of Vegetables, Monte Carmelo, Brazil. To perform the crosses and obtain the generations P1, P2, F1, F2, Bc1 and Bc2 the genotypes UFU-Albina#2, UFU-Albina#3, UFU-Lisa124#2#1, UFU-Crespa199#1#1 and UFU-Lisa217#5#2 were used as parents. The generations were evaluated for three characteristics: number of leaves, plant diameter and chlorophyll content. The parameters: genetic, phenotypic, environmental and additive variance, the dominance in F2, heritability in the broad and narrow-sense, the average degree of dominance based on averages, number of genes, the measure of the dominance deviations, additive effects and all interactions of ‘additive x additive’, ‘additive x dominant’ and ‘dominant x dominant’ type, were evaluated. Chlorophyll content was the most influenced by the environment. Plant diameter had the highest narrow-sense heritability for the cross UFU-Lisa-124#2#1 x UFU-Albina#3 (82.1%). The number of genes for the number of leaves varied from inconclusive to a minimum of 9 genes. The gene interactions for number of leaves were of overdominance type, while for plant diameter and for chlorophyll content the gene interactions were of partial dominance. The characteristics are suggested as being of polygenic or oligogenic nature.

ABSTRACT Zucchini (Cucurbita pepo L.) is a horticultural plant species of great socioeconomic value in tropical countries such as Colombia and Brazil. The production of zucchini is qualitatively and quantitatively affected by many diseases, especially viruses belonging to the Potyvirus (Zucchini yellow mosaic virus - ZYMV) and Comovirus (Squash mosaic virus - SqMV) groups. The primary strategy to reduce the spread of potentially damaging plant viruses is the development of genotypes with genetic tolerance; however, there are not many zucchini genotypes with multiple tolerance. Therefore, this study evaluated 66 zucchini genotypes to find sources of tolerance to the ZYMV and SqMV viruses. This experiment was conducted in a completely randomized design using genotypes from the germplasm bank of the Federal University of Uberlândia, including the genotypes: Emanuela (common commercial genotype) ‘Tronco Caserta’ (susceptible genotype) and PX 13067051 (resistant genotype). Leaf extracts containing viral particles were used as inoculant, and the distribution of grades of tolerance was recorded at the seedling stage. The lineages UFU-C×UFU-A#18#3;1, UFU-C×UFU-F#19#11;3, UFU-F#4#9;1, and UFU-D×UFU-F#7#21;1 and the Emanuela cultivar are alternatives for the production of new zucchini genotypes or hybrids with tolerance to the viruses ZYMV and SqMV. More severe symptoms were observed, as well as a larger number of susceptible genotypes for the ZYMV virus, indicating that this virus has great potential for causing damage and losses to zucchini crops.

RESUMEN El calabacín (Cucurbita pepo L.) es una especie de planta hortícola de gran valor socioeconómico en países tropicales como Colombia y Brasil. Su producción se ve afectada tanto cualitativa como cuantitativamente por muchas enfermedades en especial por los virus pertenecientes a los grupos Potyvirus (Virus de mosaico amarillo de Zucchini - ZYMV) y Comovirus (Virus de mosaico de calabaza - SqMV). La estrategia principal para reducir la propagación de virus vegetales potencialmente dañinos es el desarrollo de genotipos con tolerancia genética; sin embargo, no hay muchos genotipos de calabacín con tolerancia múltiple. Por lo tanto, este estudio evaluó 66 genotipos de calabacín para encontrar fuentes de tolerancia a los virus ZYMV y SqMV. El experimento se llevó a cabo en un diseño completamente aleatorio utilizando genotipos del banco de germoplasma de la Universidad Federal de Uberlândia, incluyendo los genotipos: 'Emanuela' (genotipo comercial común), 'Caserta' (genotipo susceptible) y 'PX 13067051' (genotipo resistente). Los extractos de hojas que contienen partículas virales se utilizaron como inoculantes y la distribución de los grados de tolerancia se registró en la etapa de plántula. Los linajes UFU-C×UFU-A#18#3;1, UFU-C×UFU-F#19#11;3, UFU-F#4#9;1, UFU-D×UFU-F#7#21;1, y el cultivar Emanuela son alternativas para la producción de nuevos genotipos de calabacín o híbridos tolerancia a los virus ZYMV y SqMV. Se observaron síntomas más graves, así como un mayor número de genotipos susceptibles para el virus ZYMV, lo que indica que este virus tiene un gran potencial para causar daños y pérdidas al cultivo de calabacín.

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 A avaliação de acessos em um banco de germoplasma é essencial para determinar os potenciais genitores em programas de conservação, especialmente para árvores nativas. O objetivo do trabalho foi verificar a diversidade genética entre 68 genótipos de Amburana cearensis situados em diferentes localidades no estado de Pernambuco, Brasil. Os padrões genéticos foram avaliados por marcadores moleculares Inter Simple Sequence Repeats (ISSR) e a divergência genética por meio de análises multivariadas empregando-se diferentes métodos de agrupamento. O método de otimização empregado (Tocher) foi concordante com todos os modelos hierárquicos utilizados, onde o agrupamento dos genótipos ocorreu de forma semelhante, especificamente para o acesso BB116, sendo este um importante material genético a ser preservado e estudado. Dentre os vários métodos hierárquicos aplicados, o de Ligação Média apresentou maior poder de discriminação, permitindo a identificação de maior quantidade de grupos divergentes, inferindo assim grande diversidade genética entre os acessos de A. cearensis.

ABSTRACT The evaluation of accessions in a germplasm bank is essential for determining the potential parents in conservation programs, especially for native trees. This study aimed to determine the genetic diversity among 68 Amburana cearensis genotypes from different locations in the state of Pernambuco, Brazil. Their genetic patterns were evaluated by Inter Simple Sequence Repeat (ISSR) molecular markers and genetic divergence was evaluated through multivariate analyses using different clustering methods. The optimization method used (Tocher) was in agreement with all the hierarchical models used, in which clustering of the genotypes occurred similarly, specifically for the accession BB116, which is an important genetic material to be preserved and studied. Among the various hierarchical methods applied, the Average Linkage method exhibited higher discrimination power, allowing identification of a larger number of divergent groups, thus implying wide genetic diversity among A. cearensis accessions.

RESUMO O uso comercial de híbridos de cebola é preferido pelos produtores. Em contrapartida, a produção de sementes híbridas de cebola é extremamente ineficiente. Isso se deve ao fato do uso de linhagens obtidas por sucessivas autofecundações assumindo o efeito de depressão por endogamia per se. Diante disso, faz-se necessário buscar novas alternativas capazes de reduzir o efeito de depressão por endogamia nas linhagens. Objetivou-se neste trabalho avaliar possíveis diferenças de polimorfismo e níveis de heterozigosidade de linhagens obtidas de plantas intercruzadas e autofecundadas. Foram utilizadas 12 populações de cebola pertencentes ao programa de melhoramento da Bayer (Granex, IPA-1, IPA-2 e IPA-3), obtidas por autofecundação de uma planta, entrecruzamento de duas plantas ou intercruzamento de três plantas. Três indivíduos de cada linhagem foram utilizados nas análises. As amplificações foram realizadas a partir do uso de 8 microsatélite primers com maior polimorfismo, de acordo com estudos de caracterização de germoplasma realizados pela CITA-Espanhola. A heterozigosidade geralmente diminui com a autofertilização e aumenta à medida que mais plantas são usadas no cruzamento. Os marcadores SSRs usados no presente estudo foram eficientes para detectar variabilidade nos diferentes backgrounds genéticos. Com os resultados obtidos, sugere-se realizar a obtenção de híbridos entre as diferentes combinações e analisar o desempenho per se das diferentes modalidades de obtenção de linhagens propostas na presente pesquisa.

ABSTRACT The commercial use of onion hybrids is preferred by producers. In contrast, the production of hybrid onion seeds is extremely inefficient. This is due to the use of lineages obtained by successive self-fertilizations assuming the effect of inbreeding depression per se. Therefore, it is necessary to understand new alternatives to reduce the effect of inbreeding depression in the strains. The objective of this study was to evaluate possible differences in polymorphism and levels of heterozygosity of strains obtained from intercrossed and self-fertilized plants. Twelve onion populations belonging to Bayer’s breeding program (Granex, IPA-1, IPA-2 and IPA-3) were used, obtained by self-fertilization of one plant, intercrossing of two plants or intercrossing of three plants. Three individuals from each strain were used in the analyzes. The amplifications were performed using 8 microsatellite primers with greater polymorphism, according to germplasm characterization studies carried out by CITA. Heterozygosity generally decreases with self-fertilization and increases as more plants are used in the cross. The SSR markers used in the present study were efficient in detecting variability in different genetic backgrounds. With the results obtained, it is suggested to carry out the obtaining of hybrids between the different combinations and to analyze the performance per se of the different modalities of obtaining strains proposed in the present research.

ABSTRACT Developing biofortified foods such as lettuce is a frequent goal of breeding programs. One obstacle to the success of these efforts is the high temporal and financial cost of determining leaf constituents. Image phenotyping has been increasingly used in crop breeding, but not in lettuce breeding. Until now, the use of image phenotyping to indirectly select carotenoid-rich lettuce inbred lines has not been reported. Therefore, the goal of this study was to use image phenotyping to select lettuce inbred lines with different carotenoid levels. Twenty-two inbred lettuce lines, resulting from the hybridization of the cultivars Pira 72 and Uberlândia 10000 and six successive selfings were evaluated. ‘Grand Rapids’, ‘UFU-Biofort’ and ‘Uberlândia 10000’ were used as controls. The following variables were evaluated: agronomic potential, apparent genetic diversity and image phenotyping. The data were submitted to the ANOVA F test (p ≤ 0.05) and means compared by the Scott–Knott test (p ≤ 0.05). Genetic divergence was represented by dendrograms constructed by UPGMA and the Tocher optimization method. The relative contribution of characters was assessed to identify the most relevant response variable. The genetic diversity of the evaluated germplasm bank was the greatest regarding soil plant analysis development (SPAD)/carotenoid values. Image phenotyping was successfully used to detect different levels of SPAD/carotenoid levels and could be a useful tool for plant breeding. The results of this study can be used to predict the nutritional values of the carotenoid content in lettuce leaves before commercialization.

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.