Towards the Improvement of Fruit-Quality Parameters in Citrus under Deficit Irrigation Strategies

Abstract

Water shortage is becoming a severe problem in arid and semiarid regions worldwide, reducing the availability of agricultural land and water resources. In Spain, citrus is one of the most economically important crops, with 74,000 ha devoted to its cultivation. Since water resources are increasingly more insufficient, the efficient use of water is becoming more essential. Deficit irrigation in many agricultural crops has frequently proved to be an efficient tool for improving water-use efficiency. This paper examines the effects a deficit irrigation during the ripening period on yield and the most representative fruit quality properties. The study was conducted during two consecutive years (2009-2010) in a commercial 12-year-old orange orchard (Citrus sinensis L. Osb. cv. Navelina) grafted onto Carrizo citrange (Citrus sinensis L. Osb. × Poncirus Trifoliata L. Osb.). A regulated deficit irrigation (DI) was applied, which was fully irrigated during the flowering and fruit-growth stage, and during the ripening period it was subjected to a water-stress ratio of 0.75. A control treatment was established, this being irrigated at 100% of crop evapotranspiration. Along the water stress period, it was tested the temporal evolution of the main organoleptic and nutraceutical fruit properties (color index, the total soluble solids, titrable acidity, maturity index, rind weight, juice weight, the ratio of juice weight versus fruit weight, and the total C vitamin and flavonoids). It was not observed a descend in juice content, or fruit weight, or in the final yield. In terms of fruit organoleptic and nutraceutical properties, there were not detected negative effects in the studied properties. Furthermore, DI treatment showed higher values of maturity index than control treatment, which can be considered as a positive aspect in the fruit quality. Considering these results, we can affirm that a moderate water stress applied during the maturity period is a sustainable strategy for saving water, increasing the irrigation productivity and obtaining fruits with similar properties to those without deficit irrigation.