Radial metallicity gradient: in red the results of Gaia-ESO iDR5 from Magrini et al. (2018), in green the results of APOGEE DR16 (clusters with at least three member stars and high-quality flag), and in blue our SPA clusters. The blue square is the mean [Fe/H] of Ruprecht 171 obtained with only the hottest stars analysed by ROTFIT (ID from 3 to 8). The clusters in common between APOGEE and Gaia-ESO are linked by a black line. The magenta and black circles are the SPA clusters ASCC 123 and Praesepe studied by Frasca et al. (2019) and D’Orazi et al. (2020), respectively. The light green diamonds are the young Gaia-ESO open clusters by Baratella et al. (2020).