ABSTRACT The jambu (Acmella oleracea) production can be influenced by the growing season and light available for metabolic processes. This study aimed to assess the agronomic and physiological performance of two jambu varieties, under different shading levels, during the winter and summer of the Brazilian Amazon. Two random block experiments were conducted, in a 2 x 4 factorial scheme, consisting of two jambu varieties (yellow and purple flower) and four shading levels (0, 30, 50 and 70 %), with four replications. Physiological, growth and yield traits were assessed. There was no significant interaction between treatments and growing seasons (Amazon winter and summer) for growth or yield traits, nor between treatments for the physiological characteristics. The cultivation without shading screen can increase the shoot dry weight of both varieties; the yellow flower variety exhibited early-onset flowering regardless of the shading screen used; the “Amazon summer” growing season increased the jambu yield by 33 %, while the 70 % shading reduced the net photosynthetic rate, consequently not favoring the vegetative development of the jambu plants. As such, it is recommended that the yellow and purple flower jambu varieties be grown without shading screen in the Amazon summer.

RESUMO A produção de jambu pode ser influenciada pela época de cultivo e luminosidade disponível para processos metabólicos. Objetivou-se avaliar o desempenho agronômico e fisiológico de variedades de jambu, em diferentes níveis de sombreamento, no inverno e verão amazônicos. Foram realizados dois ensaios no delineamento de blocos ao acaso, em esquema fatorial 2 x 4, sendo duas variedades de jambu (flor amarela e roxa) e quatro níveis de sombreamento (0, 30, 50 e 70 %), com quatro repetições. Foram avaliadas características de crescimento, produção e fisiológicas. Não houve interação significativa entre os tratamentos e as épocas de cultivo (inverno e verão amazônicos) para as características de crescimento e produção. Para as fisiológicas, também não houve interação entre os tratamentos. O cultivo sem tela pode aumentar a massa seca da parte aérea em ambas as variedades; a variedade flor amarela apresentou precocidade para o início do florescimento, independentemente da tela utilizada; e a época do ano “verão amazônico” proporcionou aumento de 33 % para a produção de plantas de jambu, enquanto o nível de 70 % de sombreamento diminuiu a taxa fotossintética líquida, não favorecendo o desenvolvimento vegetativo do jambu. Assim, recomenda-se o cultivo das variedades de jambu flor roxa e amarela em ambiente sem tela no verão amazônico.

RESUMO A chicória da Amazônia é uma hortaliça ainda pouco conhecida, mas com grande potencial agronômico. A caracterização dos genótipos de chicória quanto a divergência genética é um importante passo para programas de melhoramento genético, pois permite selecionar indivíduos superiores e explorar a variabilidade e a complementariedade de características, a partir dos novos genótipos gerados. Nesse contexto, o objetivo deste estudo foi avaliar a divergência genética de genótipos crioulos de chicória da Amazônia dos estados do Pará e Rondônia, com base em caracteres morfoagronômicos. Realizou-se um experimento em delineamento de blocos ao acaso, com oito genótipos de chicória (tratamentos) e quatro repetições. Foram avaliadas características quantitativas e qualitativas. A divergência genética foi estimada a partir da distância quadrada generalizada de Mahalanobis (D2), levando em consideração apenas os caracteres quantitativos, e os genótipos foram agrupados pelo método UPGMA. A análise de variância evidenciou diferença significativa entre os genótipos para todas as características, exceto massa fresca. O UPGMA agrupou os genótipos em três grupos, sendo os genótipos de Colares e Santarém Novo (Pará) (Chic-02 e Chic-04) os mais divergentes em comparação com os genótipos da região de Castanhal e Santa Isabel do Pará (Pará). As características qualitativas apresentaram padrão monomórfico, não sendo, portanto, utilizadas para avaliar a divergência. Para obter populações segregantes com complementariedade de características, recomenda-se o cruzamento entre os dois grupos mais divergentes.

ABSTRACT Amazon chicory is still a little-known vegetable despite its great agronomic potential. The characterization of chicory genotypes concerning genetic divergence is a key step for breeding programs, as it allows the selection of superior individuals and to explore the variability and complementarity of characteristics via interbreeding between newly generated genotypes. In this context, this study aimed to evaluate the genetic divergence among Amazon chicory creole genotypes from the northern Brazilian states of Pará and Rondônia based on morpho-agronomic traits. We conducted an experiment in a randomized block design with eight chicory genotypes (treatments) and four replications. Both quantitative and qualitative characteristics were evaluated. Genetic divergence was estimated via squared generalized Mahalanobis distance (D2), considering only quantitative characters, and the genotypes were subsequently clustered via the UPGMA method. Analysis of variance showed significant differences among genotypes for all studied characteristics, except shoot fresh weight. The UPGMA grouped the genotypes into three clusters, which demonstrated that the genotypes from Colares and Santarém Novo (Pará) (Chic-02 and Chic-04) were the most divergent as compared to the genotypes from Castanhal and Santa Isabel do Pará (Pará). Qualitative characteristics showed a monomorphic behavior and, therefore, were not used to assess genetic divergences. To obtain segregating populations with complementary characteristics, crossbreeding between the two most divergent clusters is recommended.

RESUMO Há poucas fontes de resistência genética a nematoides-de-galha relatadas em algodoeiro, e não há cultivares no Brasil que combinem simultaneamente resistência e bons atributos agronômicos. Técnicas que possibilitem selecionar eficientemente fontes de resistência genética promissoras são necessárias. Objetivou-se identificar genótipos de algodoeiro resistentes a Meloidogyne incognita raça 3, por meio de REML/Blup. O experimento foi inteiramente casualizado, com 32 genótipos e sete repetições, em ambiente protegido. Foi utilizado o modelo estatístico 83. Foram estimados a massa de raízes, população final, fator de reprodução e índice de reprodução. A população final e o índice de reprodução apresentaram os maiores valores de variância genotípica e coeficientes de variação genética, sinalizando situação favorável à seleção de genótipos de algodão resistentes ao nematoide. A herdabilidade média do genótipo (h2mg) foi superior a 85 % para população final, fator de reprodução e índice de reprodução, abrindo a possibilidade de sucesso de seleção com base nas médias dos genótipos. Os genótipos CS8601, SA2572, Coodetec 404 e BJ 3128 são promissores para cruzamentos visando à seleção de genótipos resistentes ao nematoide.

ABSTRACT Few genetic resistance sources to root-knot nematodes are known for cotton, and there are no cultivars combining both resistance and good agronomic attributes in Brazil. Techniques that allow an efficient selection of promising sources of genetic resistance are needed. This study aimed to identify cotton genotypes resistant to Meloidogyne incognita race 3 via REML/Blup. The experiment was completely randomized, with 32 genotypes and seven replicates, in a protected environment. The statistical model 83 was used. The root weight, final population, reproduction factor and reproduction index were estimated. The final population and reproduction index presented the highest values for genotypic variance and genetic variation coefficients, indicating a favorable situation for the selection of cotton genotypes resistant to the nematode. The mean heritability (h2mg) of the genotype was higher than 85 % for the final population, reproduction factor and reproduction index, opening a possibility of selection success based on genotype means. The genotypes CS8601, SA2572, Coodetec 404 and BJ 3128 are promising for crosses aiming the selection of genotypes resistant to the nematode.

ABSTRACT Shading screens have been extensively used in leafy-vegetables production system. Nevertheless, there is still a substantial lack of knowledge regarding the effects of this technology on the performance of non-conventional vegetables such as jambu, a typical staple food with social and economic importance for the Amazon region. This study thus aimed to evaluate the effects of shading screens on the agronomic performance of two jambu varieties. The experiment was performed in a randomized block design, in a 4 x 2 factorial scheme (shading screens and varieties), with four replications. Plants were then evaluated for morphophysiological and yield parameters. As an outcome, there was no significant interaction between shading screens and varieties for assessed variables. On the other hand, the shading screen itself affected significantly jambu varieties yield. The 50%-shading screen for instance provided both higher fresh weight accumulation and higher shoot water content. Moreover, 50%-shading screen led to an increase in both productivity (Kg m-2) and yield (bunch m-2) by 46%, respectively. The use of 50%-shading screen improves the agronomic performance of jambu, hence being a suitable technological alternative available for the farmers.

ABSTRACT This study aimed to estimate the production of seeds per umbel and to assess both the effect of gibberellic acid (GA3) and umbel order on seed germination in Amazon chicory species. The experiment was conducted in two steps. Firstly, traits related to seed production were evaluated. Afterward, a germination test was carried out, and the following parameters were assessed: germination speed index (GSI), average germination time (AGT), germination percentage (%G), percentage of abnormal seedlings (%AS), and percentage of non-germinated seeds (%NGS). Remarkably, there was strong interaction between the analysed factors. The highest production of seeds per plant was observed in the treatment containing the blend of seeds from different umbels (1.41 g·plant-1), in which the number of umbels by order and the total number of seeds per plant were the major traits related to the improved yield. The application of GA3 at 200 mg·dm-3 increased %G in second-order seeds. Regardless of GA3 application, seeds from secondary umbels showed shorter AGT by up to two days, while no difference in GSI was observed. Collectively, these results offer novel and timely information on the seed germination behavior in Amazon chicory, revealing practical advice of utmost importance for local producers.

RESUMO O uso pouco difundido da enxertia em quiabeiro, principalmente para incorporar resistência a nematoides, requer avaliação de compatibilidades interespecíficas. Objetivou-se determinar a compatibilidade do quiabeiro ‘Santa Cruz 47’ em diferentes porta-enxertos da família Malvaceae. A pesquisa foi dividida em duas etapas experimentais, sendo os tratamentos constituídos por plantas de quiabeiro pé-franco, autoenxertadas ou enxertadas sobre porta-enxertos de malva, vinagreira e algodoeiro arbóreo. Para a primeira etapa, adotou-se o delineamento inteiramente casualizado, com quatro repetições e mudas conduzidas em câmara úmida. Na segunda etapa, as mudas foram transplantadas para casa-de-vegetação, empregando-se o delineamento em blocos ao acaso, com cinco repetições. Os resultados da primeira etapa mostraram que a autoenxertia proporcionou melhor desempenho nas características de crescimento avaliadas, exceto para o diâmetro da região enxertada. Não houve diferença entre os tratamentos para a porcentagem de enxertos vivos. Na segunda etapa, o uso da vinagreira como porta-enxerto possibilitou adequado desenvolvimento vegetativo, mas não diferiu dos tratamentos autoenxertia e porta-enxerto de malva para a porcentagem de enxertos vivos. Os tratamentos não diferiram em diâmetro, comprimento e massa média de frutos. As enxertias em vinagreira foram as mais precoces, com médias estimadas de produção por planta (478,75 g), produtividade comercial (10,07 t ha-1) e produtividade total (10,64 t ha-1) similares às obtidas para autoenxertia e pé-franco. Logo, entre os porta-enxertos avaliados, a vinagreira foi identificada como o mais promissor para enxertia com quiabeiro.

ABSTRACT The little-known use of okra grafting, mainly to incorporate nematode resistance, requires evaluation of interspecific compatibilities. This study aimed to determine the compatibility of the okra ‘Santa Cruz 47’ cultivar grafted onto different rootstocks of the Malvaceae family. The research was divided into two experimental stages, with the treatments consisting of non-grafted, self-grafted or grafted okra plants onto rootstocks of mallow, roselle and pima cotton. In the first stage, a completely randomized design was used, with four replications and seedlings grown in a humidity chamber. In the second stage, the seedlings were transplanted to a greenhouse and a randomized block design was used, with five replications. The results of the first stage demonstrated that the self-grafting provided the best results for the growth characteristics assessed, except for the diameter of the grafted region. There was no difference among the treatments for the graft survival rate. In the second stage, the use of roselle as a rootstock enabled an adequate vegetative development, but did not differ from the treatments of self-grafting and mallow rootstock for the graft survival rate. The treatments did not differ for fruit diameter, length and average mass. Grafts onto roselle were the most precocious ones, with estimated means for production per plant (478.75 g), commercial yield (10.07 t ha-1) and total yield (10.64 t ha-1) similar to those observed for self-grafted and non-grafted plants. Hence, among the assessed rootstocks, roselle was identified as the most promising one for grafting with okra.

SUMMARY: The consumption of industrialized foods and beverages contributes to the increase in body weight and manifestation of diverse illnesses. Among these industrialized products, soft drinks can be mentioned, which when consumed in large quantities can contribute to weight gain and the emergence of chronic non-communicable diseases such as hypertension, diabetes, and obesity. In terms of performance, several training protocols have been used, among which concurrent training is presented as a tool that can aid in the control of body weight and muscle development. Thus, the identification of dietary factors, as well as the use of appropriate training methods, can be essential factors in the increase in physical performance. To study the effects of concurrent training on the skeletal muscles of animals submitted to soft drink consumption. In the present study, 32 male rats were used, of the Wistar breed, in the post-weaning biological phase (30 days). The animals performed a concurrent training protocol. Forty-eight hours after the final training session, the animals were submitted to a surgical procedure to remove samples of gastrocnemius muscle. After preparation of the histological slides, the muscle fibers of the different groups of animals were measured. The median values for the minimum diameter of muscle fibers presented the following values: Control (C): 35.78, Control Soft Drinks (CSD): 36.93, Training (T): 39.12, and Training Soft Drinks (TSD): 37.82. The CSD and TSD groups demonstrated the greatest increase in body mass in relation to the C and T groups. In addition, the groups that performed the concurrent training presented a higher mean of the smallest fiber diameter. It was concluded that the ingestion of soft drinks had a negative effect on the muscular hypertrophy of animals submitted to a concurrent training protocol.

RESUMEN: El consumo de alimentos y bebidas industrializadas contribuyen al aumento de peso corporal y manifestación de diversas enfermedades. Entre estos alimentos, se encuentran las bebidas refrescantes, que al ser consumidas en grandes proporciones, pueden contribuir al aumento de peso y a la aparición de enfermedades crónicas, tales como la hipertensión, diabetes y obesidad. En cuanto al desempeño, diversos protocolos han sido utilizados, entre estos, el entrenamiento concurrente que puede ser una forma de ayuda en el control de peso corporal y el desarrollo muscular. Siendo así, la identificación de los factores alimentarios, como también la utilización de los métodos correctos de entrenamiento, pueden ser esenciales en el aumento del desempeño físico. El objetivo del estudio fue investigar los efectos del entrenamiento concurrente en la musculatura esquelética de animales sometidos al consumo de bebidas refrescantes. En la presente investigación fueran utilizadas 32 ratas Wistar. Los animales fueran sometidos a un protocolo de entrenamiento concurrente. Después de 48 horas de la última sesión de entrenamiento, los animales fueran sometidos a un proceso quirúrgico para la remoción de muestras de tejido muscular. Los valores de la media del diámetro de las fibras musculares fueron: Control (C): 35,78; Control y Bebida Refrescante (CBR): 36,93; Entrenamiento (ET): 39,12; y Entrenamiento y Bebida Refrescante (EBR): 37,82. Se observó que los grupos CBR y EBR presentaron mayor aumento de masa corporal en comparación con C y T. Además, los grupos que realizaran el entrenamiento concurrente obtuvieron una mayor media en el diámetro de las fibras. Es posible concluir que el consumo de bebidas refrescantes tiene una influencia negativa en la hipertrofia muscular de animales sometidos a un protocolo de entrenamiento concurrente.

ABSTRACT. The development of melon lines resistant to gummy stem blight (GSB) is an important strategy for decreasing losses caused by this disease. Thus, selecting the best parents for such a goal is essential. We evaluated the general (GCA) and specific (SCA) combining abilities of lines and accessions to guide the selection of the most promising parents to develop GSB-resistant lines. Six genotypes representing two groups (group I - susceptible: group II - resistant) were crossed in a partial diallel mating design. The genotypes were evaluated for disease expression using a rating scale from 0 (resistant) to 4 (susceptible). Estimates of GCA were negative and significant for the accessions PI 420145 and PI 482398, which can be suggested for crosses aimed at obtaining melon lines resistant to GSB. There is a reciprocal effect for the resistance of melon genotypes to Didymella bryoniae, especially when PI 482398, PI 420145, and PI 140471 are crossed with JAB-20. Such results indicate that maternal effects may be involved in the resistance to gummy stem blight.

RESUMO A cultura da melancia apresenta grande importância econômica e social. Paralelamente, novos nichos de mercado são requeridos pelos consumidores, a fim de fornecer produtos diferenciados, dentre os quais destaca-se a minimelancia. Objetivou-se avaliar o desempenho agronômico e a qualidade de frutos de minimelancia cultivados em fibra de casca de coco, em função do número de hastes e densidade de planta. Utilizaram-se o híbrido Smile e delineamento experimental em blocos casualizados, em esquema fatorial 2 x 2, com oito repetições, sendo o primeiro fator constituído pelo número de hastes por planta (1 ou 2) e o segundo pelo número de plantas por vaso (1 ou 2). Foram avaliadas características relacionadas à produção, parâmetros fisiológicos da planta e qualidade de frutos. Houve interação entre o número de hastes e a densidade de plantas apenas para as características de área foliar, massa fresca média de frutos, produtividade total e percentual de frutos grandes, sendo que, para as demais características, os fatores foram avaliados separadamente. As plantas conduzidas com duas hastes, na densidade de uma planta por vaso, proporcionam maior produtividade, sem prejudicar a qualidade dos frutos, sendo, nessas condições, o método mais indicado para os produtores.

ABSTRACT Watermelon farming has a high economic and social importance. In parallel, the consumers’ demand for distinctive products has led to niche markets, where mini watermelons stand out. This study aimed to assess the agronomic performance and fruit quality of mini watermelon grown in coconut husk fiber, as a function of number of stems per plant and plant density. The Smile hybrid was used, as well as a randomized block design, in a 2 x 2 factorial scheme, with eight repetitions, being the first factor the number of stems per plant (1 or 2) and the second the number of plants per pot (1 or 2). Characteristics related to yield, physiological parameters and fruit quality were assessed. Interaction between number of stems and plant density was only observed for leaf area, average fruit fresh weight, total yield and percentage of large fruits. The factors were evaluated separately for the remaining traits. Two-stemmed training systems, at a density of one plant per pot, produce the highest yield, without compromising the quality of the fruits, being, in these conditions, the most suitable method for farmers.

RESUMO O uso de resistência genética é um dos métodos mais adequados para o controle de oídio das cucurbitáceas em melão, causado por Podosphaera xanthii ou Golovinomyces orontii. Contudo, muitas raças desses patógenos têm sido descobertas, o que pode comprometer a eficácia desse método. Fazem-se, então, necessários o constante monitoramento de raças de oídio e a busca por novas fontes de resistência. Objetivou-se identificar em nível de raça uma população natural de oídio das cucurbitáceas em casa-de-vegetação, bem como avaliar a reação de genótipos locais e exóticos de meloeiro à raça identificada. A identificação da raça foi baseada na reação de oito linhagens diferenciadoras (PI 414723, PMR 45, PMR 5, WMR 29, Edisto 47, Nantais Oblong, PI 124111 e Védrantais). Foram avaliados 59 genótipos de meloeiro, sendo 53 destes acessos de germoplasma e seis linhagens de melão rendilhado, além de duas cultivares (Louis e Fantasy). As plantas foram avaliadas com base em escala visual para lesões nas folhas. A espécie P. xanthii foi confirmada como o agente causal, pela visualização de corpos de fibrosina nos conídios e pela resistência da abóbora d’água (Benincasa hispida). A raça 4 foi identificada pela primeira vez no estado de São Paulo. Os genótipos A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 e Solarking mostraram-se resistentes à raça 4.

ABSTRACT Genetic resistance is one of the most suitable strategies to control cucurbit powdery mildew (CPM) on melon, incited by Podosphaera xanthii or Golovinomyces orontii. However, many races of these pathogens have been reported worldwide in recent years, what may compromise the effectiveness of this method. Thus, annual surveys of CPM races and the screening of germplasm for new sources of genetic resistance provide a vital support to melon breeding programs. This study aimed at identifying a natural population of CPM race under greenhouse conditions, as well as evaluating the reaction of local and exotic melon germplasm for CPM-resistance. CPM race identity was based on the reaction of eight race differentials: Védrantais, Nantais Oblong, PMR 45, PMR 5, WMR 29, Edisto 47, PI 414723 and PI 124111. Fifty-nine melon genotypes were evaluated, 53 of them being germplasm accessions, and six net melon elite-inbred lines, besides two net melon-type cultivars (Louis and Fantasy). Plants were evaluated using a visual scale for leaf lesions. The causal pathogen was confirmed to be P. xanthii, based on the presence of fibrosin bodies in conidia and the complete resistance response of winter melon (Benincasa hispida). Race 4 was identified for the first time in the São Paulo state, Brazil. Genotypes A19, A30, A32, C67, C384, JAB-3, JAB-7, JAB-9, JAB-11, JAB-18, JAB-20 and Solarking showed to be resistant to the race 4.

RESUMO: Com o objetivo de avaliar o controle genético da resistência do melão ‘Gaúcho Redondo’ ao nematoide de galha Meloidogyne incognita, foi conduzido um experimento em blocos casualizados com três blocos e seis tratamentos, os quais envolveram as linhas parentais ‘Gaúcho Redondo’ (P1, resistente) e JAB 20 (P2, suscetível), assim como as gerações F1, F2, e retrocruzamentos (RC1P1 e RC1P2). Avaliaram-se plantas individuais após 70 dias da inoculação com o patógeno, por meio do fator de reprodução do nematoide (FR). A hipótese de herança monogênica foi rejeitada pelo teste do qui-quadrado (χ2), indicando que a resistência está sob controle de mais de um loci gênico, sendo confirmado pela análise quantitativa, que evidenciou a presença de seis genes.

ABSTRACT: In order to assess the genetic control of resistance in the melon ‘Gaúcho Redondo’ to the root-knot nematode Meloidogyne incognita, an experiment was conducted in a randomized complete block design with three blocks and six treatments using the parental lines ‘Gaúcho Redondo’ (P1 resistant) and JAB 20 (P2 susceptible), as well as F1, F2, and backcross generations (RC1P1 and RC1P2). Seventy days after inoculation, individual plants were evaluated for resistance using the nematode reproduction factor (RF). The hypothesis of monogenic inheritance was rejected by the chi-square test (χ2), and results indicated that resistance is controlled by more than one gene locus, as confirmed by the quantitative analysis that revealed the presence of six genes.

RESUMO O melão é uma das culturas de grande importância econômica no Brasil, especialmente para o Nordeste. Contudo, à medida que seu cultivo é intensificado, surgem problemas fitossanitários, dentre eles os causados por nematoides, cujo controle tem como medida mais efetiva o uso de cultivares resistentes. Objetivou-se avaliar a reação de genótipos de meloeiro quanto à hospedabilidade de Meloidogyne incognita e M. javanica. O ensaio foi conduzido em condições de casa-de-vegetação, utilizando-se delineamento inteiramente casualizado, em esquema fatorial 2 x 15, com seis repetições. Foram avaliados 15 genótipos de meloeiro, e o tomateiro 'Santa Cruz Kada' foi utilizado como padrão de suscetibilidade. Para avaliação da reação dos genótipos, utilizadram-se o número total de ovos e juvenis nas raízes e o fator de reprodução. Nenhum dos genótipos foi resistente a M. incognita. Oito genótipos foram classificados como resistentes a M. javanica e promissores para emprego em programas de melhoramento genético do meloeiro.

ABSTRACT Melon is one of the most economically important crops cultivated in Brazil, especially in the Northeast region. However, as its cultivation increases, phytosanitary problems arise, including those caused by nematodes, which are most effectively controlled using resistant cultivars. This study aimed at assessing the reaction of muskmelon genotypes, in terms of resistance to Meloidogyne incognita and M. javanica infestation. The experiment was conducted under greenhouse conditions using a completely randomized design, in a 2 x 15 factorial scheme, with six replications. A total of 15 muskmelon genotypes were evaluated and the 'Santa Cruz Kada' tomato was used as a susceptible control. The total number of eggs and juvenile nematodes in the roots and the reproduction factor were used to assess the genotype reaction. None of the genotypes was resistant to M. incognita. Eight genotypes were classified as resistant to M. javanica and promising for use in melon breeding programs.