Predicting responses to stressful conditions is very important. Chlorophyll a fluorescence (ChlF) can be used to assess effects of various stresses on photosynthetic performance. We tested the responses of five 10-d old maize hybrids to salinity stress by measuring ChlF parameters, fresh (FM) and dry mass (DM). ChlF data were incorporated into a penalized regression model to predict biomass traits. The values of FM and DM significantly decreased under salt stress by 42 and 25%, respectively. Strong responses in ChlF parameters assessing the absorption dissipation and trapping fluxes to NaCl treatment were detected. In penalized regression models, 118 transients showed greater (R2 = 0.663 for FM and R2 = 0.678 for DM), although comparable, predictive abilities as 18 selected JIP-test parameters (R2 = 0.597 for FM and R2 = 0.636 for DM). Genetic assessment of developed models is needed, as they efficiently predict biomass traits and provide physiological context to the obtained predictions.