European peach production accounts for 27.1% of the world's output. Spain is the second highest European producer after Italy, with a production characterized by its precocity and high quality.Generally, the cultivation of peach is based on water inputs amounting to 7000 m3/ha/year. Nowadays, the agriculture of arid and semi-arid areas face the pressure of the limited water resources, thus it became necessary the adoption of watering strategies such as regulated deficit irrigation (RDI). This consists of providing water below the characteristic crop evapotranspiration (ETc) during certain growth stages, obtaining a sustainable system with high water efficiency and with little or no impact on the quality of the fruit or crop yield.
Spanish scientists from Universidad Politécnica de Cartagena evaluated the effect of water stress on enzyme activity and its relationship with the synthesis of healthy compounds under different RDI strategies in Flordastar early peaches.
For the study, the irrigation strategies were:
- Control
- RDI1 (=severe) treatment had a reduction of 82% as compared to the estimated crop water requirements as found in the FAO56 protocol
- RDI2 (=moderate) treatment had a reduction of 69% as compared to the estimated crop water requirements as found in the FAO56 protocol
Both RDI caused stress to the plant. This resulted in higher antioxidant concentration [averaging 1.30±0.27 g ascorbic acid equivalents (AAE) kg−1 fresh weight (FW) for control and 1.77±0.35 and 1.50±0.30 g AAE kg−1 FW for RDI1 and RDI2, respectively]. Antioxidant levels decreased with storage by polyphenoloxydase action, which increased (from 0.04±0.01 U mg−1 protein to 0.32±0.08 U mg−1 protein). Vitamin C was initially higher in RDI samples (44.22±0.05 g total vitamin C kg−1 FW for control vs. 46.77±0.02 and 46.27±0.03 g total vitamin C kg−1 FW for RDI1 and RDI2, respectively).
Scientists concluded that the intensity and timing of RDI had a clear effect on antioxidant compounds found in fruit tissues. In this case, RDI1 achieved a higher concentration of bioactive compounds due to a higher specific enzyme activity. It is important to highlight that peel contained a significantly higher antioxidant compound content, which can be relevant to the consumers. Catalase and dehydroascorbic acid are good indicators of how water stress affects the plant.
Finally, both RDI strategies contributed to reduce water demand, saving 5223 and 4395 m3/ha/year for RDI1 and RDI2, respectively, as well as the increase of healthy compounds of ‘Flordastar’ peaches.
Source: Falagán N., Artés F., Gómez P.A., Artés-Hernández F., Conejeroc W., Aguayo E., ‘Deficit irrigation strategies enhance health-promoting compounds through the intensification of specific enzymes in early peaches’, 2015, Journal of Science and Food Agriculture. doi: 10.1002/jsfa.7290.
Contacts:
Encarna Aguayo,
Postharvest and Refrigeration Group, Regional Campus of International Excellence ‘Campus Mare Nostrum’ - Universidad Politécnica de Cartagena (UPCT)
Paseo Alfonso XIII, 48,
30203 Cartagena,
Murcia, Spain
Email: encarna.aguayo@upct.es