ABSTRACT Climatic factors can decisively influence the growth and productivity of agricultural crops. For unconventional vegetables, such as the Amazon chicory, the influence of sunlight on growing cycle is unknown. The aim of this study was to evaluate the influence of shading levels on the productive performance of Amazon chicory. The authors used a randomized block design, with four treatments and five replicates. The treatments were black polypropylene screens, 30, 50 and 70% shading, and cultivation at full sunlight. Vegetative development and production traits were evaluated. Correlation and principal components analysis (PCA) were performed with the aid of the computer program R. No significant difference between the shading levels for the evaluated traits was noticed. Nevertheless, the cultivation at full sunlight allowed an increase in production, compared to the 70% shading screen. A strong positive correlation between productivity, leaf fresh mass and amount of water in the shoot area was verified, with a coefficient equal to 1. Only the leaf area characteristic was poorly correlated with other traits (angle >90º). Therefore, we suggest growing the Amazon chicory both at full sunlight and under 70% shading.

RESUMO Fatores climáticos podem influenciar de modo decisivo no crescimento e produtividade de culturas agrícolas. Para hortaliças não convencionais, como a chicória da Amazônia, é desconhecido a influência da luz solar em seu ciclo de cultivo. O objetivo deste trabalho foi avaliar a influência de níveis de sombreamento no desempenho produtivo de chicória da Amazônia. Para isso, adotou-se o delineamento em blocos ao acaso, com quatro tratamentos e cinco repetições. Os tratamentos foram telas de polipropileno preta, com 30, 50 e 70% de sombreamento e cultivo a pleno sol. Avaliou-se características de desenvolvimento vegetativo e de produção. Realizou-se a análise de correlação e de componentes principais (PCA), no programa computacional R. Não houve diferença significativa entre os níveis de sombreamento para as características avaliadas. Apesar disso, o cultivo a pleno sol possibilitou incremento na produção, em comparação à tela de 70% de sombreamento. Houve forte correlação positiva entre a produtividade, massa fresca das folhas e quantidade de água da parte aérea, com coeficiente igual a 1. Apenas as características de área foliar foram pouco correlacionadas com as demais (ângulo >90º). Logo, pode ser indicado que a chicória da Amazônia seja cultivada tanto a pleno sol como em 70% de sombreamento.

RESUMO Conhecer a variabilidade genética de genótipos crioulos, por meio do uso de descritores morfológicos em espécies como a chicória da Amazônia, é uma ferramenta imprescindível no processo de quantificação da diversidade de variedades locais e na proteção de cultivares melhoradas. Diante disso, objetivou-se propor descritores morfológicos multicategóricos foliares para a chicória da Amazônia. Para isso, foi realizado um experimento, utilizando o delineamento experimental em blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos de oito genótipos crioulos de chicória da Amazônia, obtidos de coletas junto aos produtores. Os descritores multicategóricos propostos foram formato do limbo, formato do ápice foliar, formato da base foliar, tipo de margem foliar, consistência das brácteas e tipo de margem das brácteas. Após a obtenção dos dados multicategóricos em classes, os mesmos foram transformados em matriz de dissimilaridade. Observou-se que o formato do limbo apresentou variação, podendo ser do tipo lanceolado ou espatulado, assim como o tipo de margem foliar, que pode ser do tipo dentado ou serreado. Sendo assim, as características de formato do limbo e margens foliares se mostraram descritores qualitativos importantes na quantificação da diversidade genética, conservação e uso nos programas de melhoramento da chicória da Amazônia.

ABSTRACT The knowledge concerning genetic variability of creole genotypes by using morphological descriptors in species such as Amazon chicory is crucial to quantify local diversity and protect improved cultivars. Accordingly, this study aimed to propose multicategory leaf morphological descriptors for Amazon chicory species. To achieve that, an experiment was arranged in randomized block design with four repetitions. The treatments comprised eight creole genotypes of Amazon chicory, which were obtained from local producers’ collection. The proposed multi-categorical descriptors are based on limb shape, leaf apex shape, leaf base shape, leaf margin, bract consistency, and bract margin traits. Once the multicategorical clustered data were obtained, they were transformed into a dissimilarity matrix. The limb shape presents dissimilarity, being either lanceolate or spatulate; as well as for leaf margin, which can be dentate or serrate. Thus, both limb shape and leaf margin constitute important qualitative descriptors for genetic diversity assessment and conservation for Amazon chicory, besides a recommended tool to be exploited in breeding programs.

ABSTRACT The cultivation of melon (Cucumis melo L.) in greenhouses has contributed to the increased incidence of fungal diseases, particularly gummy stem blight caused by Didymella bryoniae (Fuckel) Rehm. This disease is currently considered the main disease affecting this crop, causing conditions such as water soaked seedlings, and stem and fruit cankers, reducing productivity and fruit quality. Considering the importance of this disease, the aim of this study was to evaluate the reaction of different C. melo genotypes to D. bryoniae. Sixty-eight different melon genotypes were investigated. Two phenotyping assays were performed to investigate the resistance to the disease, following a randomized block design with four replicates. Subsequently, a new assay was conducted to validate the resistance of the genotypes selected in the previous step, using a randomized block design with three replicates. The plants were inoculated using the toothpick method, and resistance was evaluated according to a grading scale. Also, reaction classes and assay groups were used for classifying the resistance level of the genotype. The JAB-11 and JAB-20 strains were susceptible to the pathogen, as well as the commercial hybrids Louis F1 and Fantasy Fi. The hits AC-29, C160, Charentais Fom 1, PI 420145, PI 482398 and PI 532830 were resistant to D. bryoniae, and could become an important gene source for the development of resistant cultivars.