Functional response of garlic to optimized regulated deficit irrigation (ORDI) across crop stages and years: Is physiological performance impaired at the most sensitive stages to water deficit?

•Optimized regulated deficit irrigation methodology (ORDI) was evaluated in garlic.•Garlic acclimated its functional response to the irrigation schedule imposed by ORDI.•Functional performance was recovered after the imposed water deficit stages.•ORDI optimized water supply and physiological performance at yield-sensitive stages.•Stomatal conductance monitoring can help improve irrigation management of garlic.