DEFICITARY IRRIGATION INCREASES WATER PRODUCTIVITY IN Carica papaya L.

Background. In the face of the imminent global water scarcity, it is necessary to implement alternatives to make its use more efficient and ensure agricultural production with minimal expenditure. Objective. To determine physiological variables of Carica papaya L. under deficit irrigation (DI) which increases water productivity. Methodology. The papaya crop was established in semi-protected conditions in a shade house, in pots with a capacity of 60 kg containing sand as substrate. The treatments consisted of applying different water volumes to the substrate: Control, application of 1678 L of water per pot (maximum water retained in the substrate from 89 to 296 days after transplanting (dat), control), Treatment 1, application of 679.79 L of water per pot (41% of the maximum water retained in the substrate from 89 to 296 dat, DI-59) and Treatment 2, application of 573.6 L of water per pot (34% of the maximum water retained in the substrate from 89 to 296 dat, DI-66). The treatments were distributed in a completely randomized block experimental design with six repetitions. Treatments began at 89 and ended at 296 days after transplant (dat). Results. Stomatal conductance decreased in DI treatments; therefore, CO2 assimilation and transpiration were also negatively affected. The water potential of the leaf (Ya leaf) decreased in DI-66 with respect to the control and DI-59. However, no difference was observed between the treatments in the osmotic potential (Yo leaf) and turgor (Yp leaf) of the leaf. The proline concentration increased similarly throughout the experiment in the control and in the treatments with deficit irrigation. Implications. Water productivity increased by 2 and 2.9 times in the DI treatments compared to the control. Conclusion. The deficit irrigation strategy applied to C. papaya L. is relevant because it allows maximizing the productivity of irrigation water in a semi-protected system in subhumid tropic conditions.