Morphophysiology of tomato crop under saline stress in different environments

The use of brackish water can cause severe effects and irreversible damage to the growth and physiological indices of agricultural crops. Thus, the agricultural environment emerges as an alternative to mitigate saline stress in tomato hybrids (Solanum lycopersicum L.). This study evaluated the gas exchange and growth of tomato hybrids irrigated with brackish water in different environments. The study was carried out in Aratuba, Ceará, Brazil. The experimental design was a randomized block design with split-split plots. The main plots consisted of two environments (protected environment and full sun); the subplots consisted of five levels of irrigation water electrical conductivity (ECw) (1.0, 1.7, 2.4, 3.1, and 3.8 dS m-1) and the sub-subplots consisted of two tomato hybrids (Itaipava and BS DI0014), with five replicates. Salt stress reduced CO2 assimilation rate and instantaneous carboxylation efficiency rates more intensely in the full sun environment, while the use of low electrical conductivity in the protected environment promoted greater stomatal conductance in tomato hybrids. The BS DI0014 hybrid was more tolerant to salt stress in terms of transpiration in the protected environment and in full sun than the Itaipava F1 hybrid. The Itaipava F1 and BS DI0014 hybrids grown in a protected environment had higher internal CO2 concentrations. Keywords: protected cultivation, salinity, Solanum lycopersicum L.