LONG-TERM EFFECT OF WATER DEFICIT IRRIGATION ON CHERRY VIGOR AND PRECOCITY

Different post-harvest regulated deficit irrigation treatments were established in a young and vigorous commercial ‘Bing’ cherry (Prunus avium L.) orchard planted in dry shallow soil with drip irrigation. The treatments given over a three-year period were as follows: T1= 100%, T2= 75% and T3= 50% of full ETc. The available water remaining percentage (%AWr) and midday stem water potential (SWP) were measured during the water-deficit period. During the three-year period average SWP was -0.68, -0.83 and -1.04 MPa while %AWr was 89.9, 71.7 and 41.4 for T1, T2 and T3 respectively. SWP was highly correlated with %AWr (r2= 0.89). After three years trunk growth decreased by 6% (T2) and 10% (T3). Shoot length for T3 was 27% lower, flower bud density and yield efficiency were 85% and 57% higher when compared to T1. Seasonal shoot length was highly correlated with flower bud density on productive branches (r2= -0.76). Average fruit weight was not affected while double fruits were not substantially affected by treatments. An accurately adjusted post-harvest water deficit can be used to control vigor and promote early production of cherries, while saving significant amounts of water.