PHYSIOLOGICAL, VEGETATIVE, AND PRODUCTION RESPONSE OF PEACH TO WATER RESTRICTION DURING SLOWDOWN PERIODS OF FRUIT GROWTH

The low rainfall and poor rainfall in recent years in Morocco, have led to a situation of water deficit throughout the cropping cycle, including stone fruits. A study was carried out to investigate the behavior of peach trees under regulated deficit irrigation (RDI) in the Sais plain. The aim of this study was to determine the optimal irrigation dose that would guarantee an improvement in productivity and quality of the peach trees. This experimnet used completely randomized design with 3 replications. The study was carried out (in two replications in 2017 and 2018) four water regimes during slowdown periods of fruit growth: T0 (equal to or greater than 100% of the crop's Evapotranspiration (ETc)), T1 (100% ETc), T2 (80% ETc) and T3 (60% ETc). The response of trees is presented for physiological indicators – vegetative development , production and quality parameters for the two years. The effect of RDI on peach trees showed that water restrictions varied according to the water regime. The decrease in irrigation rate negatively affected the main vegetative and production parameters. However, for the 20% decrease in irrigation rate, the effect on yield was not significant. Regarding vegetative growth, the T3 (60%ETc) water regime significantly affected the increase in length and diameter of the current year's shoots, while the T2 (80 % ETc) water regime did not affect leaf area. Trees from treatment T3 (60 % ETc) yielded fruits with the highest sugar content. This increase in sugar content was accompanied by a decrease in the total acidity of the fruit juice.