  The scaling of the rate of type Ia Supernovae (SNIa) with the parent
galaxies' color provides information on the distribution of the delay times
(DTD) of the SNIa progenitors. We show that this information appears to depend
on the photometric bands used to trace the stellar age distribution and
mass-to-light ratio in the parent galaxies. Using both (U-V) and (B-K) colors
to constrain the star formation history, we model the SNIa rate as a function
of morphological galaxy type for different DTDs. The comparison with the
observed rate per unit B and K band luminosity yields consistent results,
although the large error bars allow us to exclude only very flat and very
narrow DTDs. The number of SNIa from one stellar generation results of ~ 2, 3
events every 1000 Mo of stars formed.
