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.

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.

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.