⁵⁶Ni mass synthesized during the SN Ia explosion as a function of the progenitor metallicity (Z_progenitor). Our sample of the 34 normal SNe Ia is indicated with orange stars. The analytical TBT03 (solid curved black line) and B10 linear and non-linear (solid and dashed blue lines, respectively) models are overplotted with various SN Ia models we investigated: 3 LN18 near-M_ch models (circles with solid lines), 3 LN20 sub-M_ch models (squares with dashed lines), and 11 G21 sub-M_ch models (diamonds with dash-dotted lines).