  Our aim is to show how different hypotheses about Type Ia supernova
progenitors can affect Galactic chemical evolution. We include different Type
Ia SN progenitor models, identified by their distribution of time delays, in a
very detailed chemical evolution model for the Milky Way which follows the
evolution of several chemical species. We test the single degenerate and the
double degenerate models for supernova Ia progenitors, as well as other more
empirical models based on differences in the time delay distributions. We find
that assuming the single degenerate or the double degenerate scenario produces
negligible differences in the predicted [O/Fe] vs. [Fe/H] relation. On the
other hand, assuming a percentage of prompt (exploding in the first 100 Myr)
Type Ia supernovae of 50%, or that the maximum Type Ia rate is reached after
3-4 Gyr from the beginning of star formation, as suggested by several authors,
produces more noticeable effects on the [O/Fe] trend. However, given the spread
still existing in the observational data no model can be firmly excluded on the
basis of only the [O/Fe] ratios. On the other hand, when the predictions of the
different models are compared with the G-dwarf metallicity distribution, the
scenarios with very few prompt Type Ia supernovae can be excluded. Models
including the single degenerate or double degenerate scenario with a percentage
of 10-13% of prompt Type Ia supernovae produce results in very good agreement
with the observations. A fraction of prompt Type Ia supernovae larger than 30%
worsens the agreement with observations and the same occurs if no prompt Type
Ia supernovae are allowed. In particular, two empirical models for the Type Ia
SN progenitors can be excluded: the one without prompt Type Ia supernovae and
the one assuming delay time distribution going like t^{-0.5}.
