Fig 2. General combining ability estimates of the parents from Groups I and II for net photosynthesis (A, mmol CO₂ m^-2 s^-1), transpiration (E, mmol H₂O m^-2 s^-1), stomatal conductance (gs, mmol m^-2 s^-1), and internal CO₂ concentration (Ci, mmol m^-2 s^-1).