Tolerância de genótipos de manjericão ao estresse salino em sistema hidropônico DFT

Abstract

Many studies about effect of salinity on growth and plant metabolism have been conducted. However, there are still incipient studies that relate the salinity tolerance of medicinal species cultivated in a hydroponic system. The objective of this work was to evaluate the tolerance of three basil genotypes to salinity in a Deep Flow Technique (DFT) hydroponic system. The experiment was carried out at the Federal University of Recôncavo da Bahia - UFRB. A splitplot design (salinity in the main blocks, genotype in the elemental plots) was used in a 6x3 factorial scheme, with three replications totaling 54 plots. Six salinity levels of water in nutrient solution (0, 2.2, 4.2, 6.2, 8.2 and 10.2 dS m-1 NaCl) were applied to three basil genotypes: Ocimum basilicum L. var. Genovese (‘Alfavaca Basilicão’), Ocimum basilicum minimum (‘Grecco a Palla’) e Ocimum basilicum L. var. Crispum (‘Toscano Folha de Alface’). Biometric variables (plant height and stem diameter), yield variables (shoot fresh weight, shoot and root dry weight, absolute and relative growth rates), water consumption and water use efficiency, essential oil content and yield and salinity tolerance based on the relative reduction of the production were evaluated. Salt stress decreases biometric and yield variables. Stem diameter is a good indicator of salinity tolerance. Essential oil content increased with salinity stress, however, there was reduction in yield of essential oil content. Salinity tolerance evaluations indicated the genotypes ‘Grecco à Palla' stand out as more tolerant to salt stress and 'Toscano Folha de Alface’ as the most sensitive. Assuming loss of production of up to 50%, basil cultivation under salinity in hydroponic DFT system can be done with the nutrient solution conductivity up to 8.15 dS m-1.