Effect of deficit irrigation on the postharvest quality of different genotypes of basil including purple and green Iranian cultivars and a Genovese variety

• Moderate deficit irrigation did not strongly impact the postharvest quality of basil.
• Iranian Purple and Green cultivars showed twice the respiration rate of the Genovese basil.
• However, irrigation treatment only influenced significantly the respiration rate of the Genovese genotype.
• Combination of adequate irrigation treatments and suitable cultivars is considered essential.

Fresh basil (Ocimum basilicum L.) has become increasingly popular in recent years because of its superior flavour and good visual quality compared with the dry product. Water resources need to be used efficiently because of the limited water resources for agricultural uses, particularly in arid areas. In this study, the postharvest quality of different genotypes of basil including the purple and green Iranian cultivars and the Genovese variety grown under mild and severe deficit irrigation (25 DI and 50 DI, respectively) compared with a control (100% of the field capacity, FC) were evaluated. As expected, the highest yield was obtained for the control irrigation water while both DI decreased the yield. The respiration rate of the Iranian cultivars was double that of the Genovese variety, increasing with deficit irrigation but only significantly in the Genovese variety. Deficit irrigation did not preserve the sensory quality characteristics such as darkening, dehydration and aroma during storage better than the control irrigation water. Chlorophyll fluorescence did not show significant differences between irrigation water treatments. Antioxidant capacity increased when deficit irrigation was increased. These results show that basil as a fresh herb can be cultivated with less water without decreasing the quality characteristics. Deficit irrigation improves sustainability because of the water scarcity in many Mediterranean areas. However, the combination of adequate amounts of irrigation water applied and suitable cultivars is considered essential.