The Brazilian semiarid is historically characterized by the water scarcity of good-quality. In this region there is great availability of groundwater reserves, however, these waters has high concentrations of dissolved salts, that makes them inappropriate to be used in the irrigation of most crops. The objective of this study was to evaluate the growth, production and salinity tolerance of three cauliflower cultivars in hydroponics NFT (Nutrient Film Technique), subjected to different electrical conductivities of the nutrient solution (ECsol) prepared with saline water. The experiment was carried out in a randomized blocks design in split-plot, with six replications. The plants were subjected to six levels of ECsol (1.94 - control, 3.24, 4.10, 5.04, 5.92 and 7.01 dS m-1) in the main plots, with three cauliflower cultivars (‘Piracicaba de Verão’, ‘Sabrina’ and ‘SF1758’) in the subplots, which were grown in the same hydroponic channel. Vegetative growth, inflorescence production and salinity tolerance of cultivars were evaluated. In general, except for the number of leaves, leaf width and fresh matters of leaves and shoot, the different ECsol levels negatively influenced the vegetative growth and inflorescences yield of cultivars cauliflower. The cultivars ‘Piracicaba de Verão’ and ‘Sabrina’ were considered moderately sensitive to salinity, while cultivar ‘SF1758’ was moderately tolerant to salinity.

Historically, and in the aggravating climate change scenario, droughts are increasingly severe in arid and semi-arid regions, limiting the use of irrigation. As an alternative for these regions, brackish waters have been used, despite the severe risks of soil salinization, as well as losses in crop production and quality. Thus, the adoption of adequate technologies should mitigate or control the impacts caused by salt stress. Therefore, in the present study two experiments were conducted to evaluate the cultivation of cauliflower with brackish waters using a nutrient film technique (NFT) hydroponic system from July to October 2019 (winter-spring) and from October 2019 to January 2020 (spring-summer). Cauliflower plants were subjected to six values of ECw: 0.3 - control (without NaCl), 1.5, 2.5, 3.5, 4.5, and 5.5 dS m^-1 (with NaCl), in a randomized block design with six replicates. For the leaf blade area at inflorescence harvest, reductions per dS m^-1 increment in ECw of 7.22 and 6.41% were found in the winter-spring and spring-summer experiments, respectively. The quality losses of cauliflower inflorescences were more pronounced in the spring-summer experiment, varying according to the ECw used. Therefore, it is possible to grow cauliflower hydroponically under ECw of up to 5.5 dS m^-1; however, in the hottest seasons these waters should be reserved and used only for the preparation of nutrient solutions or replacement of water consumed by plants.

CRESCIMENTO, PRODUÇÃO E TOLERÂNCIA DO BROCÓLIS EM HIDROPONIA COM O USO DE ÁGUAS SALOBRAS PAULO VITOR SANTA ROSA SILVA1; TALES MILER SOARES2; LIZANDRA REIS BOMFIM2; MAIRTON GOMES DA SILVA1 E LEANDRO FERREIRA DA COSTA1 1 Programa de Pós-Graduação em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, 710 – Campus Universitário, CEP: 44380-000, Cruz das Almas, Bahia, Brasil. E-mail: paulovitor.srs@hotmail.com, mairtong@hotmail, leandroifbaianobonfim@gmail.com 2 Centro de Ciências Agrárias, Ambientais e Biológicas, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, 710 – Campus Universitário, CEP: 44.380-000, Cruz das Almas, Bahia, Brasil. E-mail: talesmiler@gmail.com, lizandrareis6@hotmail.com 1 RESUMO O presente estudo foi realizado visando avaliar o cultivo de brócolis (Brassica oleracea var. itálica, cv. ‘Imperial’) empregando águas salobras em sistema hidropônico. Dois experimentos foram realizados simultaneamente em casa de vegetação sob hidroponia NFT, entre março e junho de 2022 (outono-inverno): um com reposição com água doce e outro com águas salobras. As plantas foram submetidas a quatro níveis de condutividade elétrica (CE) da água: 0,3 dS m-1 (controle, sem adição de NaCl), 1,75, 3,50 e 5,25 dS m-1 (com adição de NaCl), no delineamento em blocos casualizados com seis repetições. Ao longo dos experimentos, foram realizadas medições biométricas e, no ponto de colheita, avaliou-se o crescimento vegetativo, a biometria e produção das inflorescências, além de sua qualidade. Também foi calculado o teor de água nas folhas e inflorescências. Os resultados indicam que é viável cultivar o brócolis com CE da solução nutritiva de até 4,46 dS m-1 no outono-inverno. Contudo, no experimento com águas salobras, foram observadas perdas na qualidade comercial no nível salino mais alto. Portanto, recomenda-se evitar o uso exclusivo de águas salobras com CE de 5,25 dS m-1, reservando-as apenas para o preparo das soluções nutritivas. Palavras-chave: Brassica oleracea, água de baixa qualidade, inflorescência, hidroponia NFT, estresse salino. SILVA, P. V. S. R.; SOARES, T. M.; BOMFIM, L. R.; SILVA, M. G.; COSTA, L. F. GROWTH, PRODUCTION AND TOLERANCE OF BROCCOLI IN HYDROPONICS USING BRACKISH WATERS 2 ABSTRACT The present study aimed to evaluate the cultivation of broccoli (Brassica oleracea var. itálica, cv. 'Imperial') using brackish water in a hydroponic system. Two experiments were simultaneously conducted in a greenhouse under NFT hydroponics between March and June 2022 (autumn-winter): one with replenishment using fresh water and the other with brackish water. The plants were subjected to four levels of electrical conductivity (EC) of the water: 0.3 dS m⁻¹ (control, no NaCl added), 1.75, 3.50, and 5.25 dS m⁻¹ (with NaCl addition), in a randomized block design with six replications. Throughout the experiments, biometric measurements were taken, and at harvest time, vegetative growth, biometric parameters, inflorescence production, and quality were evaluated. The water content of the leaves and inflorescences was also calculated. The results indicate that broccoli can be cultivated with an EC of up to 4.46 dS m⁻¹ in nutrient solution during autumn‒winter. However, in the experiment with brackish water, losses in commercial quality were observed at the highest salinity level. Therefore, it is recommended to avoid the exclusive use of brackish water with an EC of 5.25 dS m⁻¹, which should be reserved only for nutrient solution preparation. Keywords: Brassica oleracea, poor water quality, inflorescence, NFT hydroponics, salt stress.