Upper panel: absolute r-band magnitude M_r vs. redshift of the whole CALIFA mother sample (gray dots) compared with the SN host galaxy sample used in this work from different sources (larger dots in different colors). Note that PINGS galaxies are more nearby than CALIFA galaxies. Lower panel: g − r color vs. M_r diagram of the CALIFA mother sample and the galaxies studied in this work. The dotted line shows the separation between blue from red galaxies proposed by Masters et al. (2010). The open blue circles show the passive SN Ia hosts (see Sect. 4). The points encircled with cyan open circles are the eight least massive galaxies in our sample (see Sect. 5.2), which are all blue.