ABSTRACT No study has investigated the fertilization of beet with manganese (Mn) in the Brazilian semi-arid region. In this study, we evaluated the agronomic performance of manganese fertigated beet in Mossoró, Rio Grande do Norte. The experiments were conducted at Fazenda Experimental Rafael Fernandes in 2019 and 2021, and the study had a complete randomized block design with five treatments (0, 3, 6, 9, and 12 kg ha-1 Mn) and four replications. The Mn content increased in foliar diagnosis with fertilization. The accumulation of dry mass and the number of leaves did not differ significantly as a function of the dose. The highest total (21.59 t ha-1) and commercial (20.55 t ha-1) yields of tuberous roots were obtained with 6 kg ha-1 Mn. The adverse effects of excess Mn were expressed in the lower total and commercial productivity of beet fertilized with more than 6 kg ha-1 Mn. The accumulation of Mn in the tuberous roots was not affected by fertilization. In the leaves and the whole plant, the maximum accumulation occurred when 12 kg ha-1 Mn was applied. Although Mn did not influence the content of soluble solids, the pH of the tuberous roots of plants fertilized with 6 kg ha-1 Mn decreased, and the dose with the highest total and commercial productivity had a lower content of soluble sugars. Our findings suggest that treatment with 6 kg ha-1 Mn is optimum for the beet crop.

RESUMO Não há na literatura recomendações de adubação com manganês (Mn) para beterraba estabelecidas no semiárido brasileiro. Objetivou-se avaliar o desempenho agronômico de beterraba fertirrigada manganês em Mossoró, RN. Foram desenvolvidos experimentos na Fazenda Experimental Rafael Fernandes nos anos de 2019 e 2021, delineados em blocos casualizados completos com cinco tratamentos (0, 3,0, 6,0, 9,0 e 12,0 kg ha-1 de Mn) e quatro repetições. Houve aumento no teor de Mn na diagnose foliar com a adubação. O acúmulo de massa seca e o número de folhas não diferiram estatisticamente em função das doses. A maior produtividade total (21,59 t ha-1) e comercial (20,55 t ha-1) de raiz tuberosa foi obtida com 6,0 kg ha-1 de Mn. O efeito deletério do excesso de Mn foi expresso na menor produtividade total e comercial de beterraba adubada com mais que 6,0 kg ha-1 de Mn. O Mn acumulado na raiz tuberosa não foi influenciado pela adubação. Nas folhas e na planta inteira, o acúmulo máximo ocorreu na dose 12,0 kg ha-1 de Mn. O Mn não influenciou no conteúdo de sólidos solúveis, mas reduziu o pH e, a raiz tuberosa das plantas adubadas com 6,0 kg ha-1 de Mn, dose com maior produtividade total e comercial, tiveram menor teor de açúcares solúveis. Recomenda-se adubação com 6,0 kg ha-1 de Mn para a cultura da beterraba.

ABSTRACT Melon cultivation under saline conditions is a challenge, as the plants can suffer a reduction in fruit production and quality. The aim of this study was to evaluate the production and quality of noble melon fruit fertigated with different saline solutions and K/Ca ratios. The experimental design was of randomised blocks, with treatments arranged in a 3 x 6 factorial scheme, using three melon cultivars (Bazuca, McLaren, County) fertigated with six nutrient solutions [S1 - standard nutrient solution (SNS); S2 - SNS + NaCl (5.0 dS m-1); S3 - S2 enriched with K (50%); S4 - S2 enriched with K (100%); S5 - S2 enriched with Ca (50%); S6 - S2 enriched with Ca (100%)]. At the end of each cultivar cycle, the fruit was harvested and assessed for the following parameters: fresh fruit weight, fruit diameter, internal cavity, pulp thickness, pulp firmness, soluble solids content, titratable acidity, soluble solids/titratable acidity ratio, and vitamin C. Salt stress impaired the physical characteristics of the fruit of the three noble melon cultivars. The nutrient solution enriched with 50% K (S3) did not reduce the effect of salt stress on fresh weight or fruit size in the melon, but afforded an increase in fruit quality.

RESUMO O teste de tetrazólio é um método rápido e eficaz para avaliar a viabilidade das sementes. Este trabalho teve como objetivo determinar a metodologia de execução do teste de tetrazólio e a sua eficiência para verificar a viabilidade em sementes de maxixe (Cucumis anguria L.). Para isso, cinco lotes de sementes de maxixe foram inicialmente avaliados pelo teste de germinação, primeira contagem e velocidade de germinação. Posteriormente os lotes foram submetidos aos tratamentos para adequação da metodologia do teste de tetrazólio, sendo avaliadas três concentrações da solução de tetrazólio (0,100; 0,075 e 0,050%), mantidas no escuro, por duas, quatro e seis horas, sob temperaturas de 35 e 40 °C, com quatro repetições de 25 sementes para cada tratamento. Decorridos os períodos de coloração, as sementes foram lavadas em água corrente, seccionadas longitudinalmente entre os cotilédones e classificados em viáveis e não viáveis. A avaliação da viabilidade de sementes de maxixe pelo teste de tetrazólio é eficiente quando realizada sob concentração de 0,050% por seis horas a 35 °C ou quatro horas a 40 °C.

ABSTRACT The tetrazolium test is a quick and effective method for evaluating viability in seeds. The aim of this study was to determine a methodology for using the tetrazolium test, and its efficiency in verifying viability in seeds of the gherkin (Cucumis anguria L.). Consequently, five batches of gherkin seed were initially evaluated by the tests for germination, first count and speed of germination. The batches were then subjected to treatments in order to adjust the methodology for the tetrazolium test, evaluating three concentrations of tetrazolium solution (0.100, 0.075 and 0.050%), kept in the dark for two, four and six hours, under temperatures of 35 °C and 40 °C, with four replications of 25 seeds per treatment. At the end of the staining period, the seeds were washed in running water, split lengthways between the cotyledons, and classified as viable and non-viable. Evaluation of viability in seeds of the gherkin by tetrazolium test is efficient when carried out at a concentration of 0.050%, either for six hours at 35 °C or four hours at 40 °C.