In arid and semi arid areas water resources management of orchards is critical. Therefore knowledge of tree responses and tree sensitivity determination in water stress conditions is very important. The effects of five water stress (stress in the1St, 2nd and 3rd fruit growth stages respectively SW1, SW2 and SW3, stress in 1st and 2nd stage of fruit growth=SW4 and control plants=SW5) on vegetative and fruiting tree as well as different fruit Characteristics of four peach cvs. (With Mashhad, Red & Wight Mashhad, Red haven and G.H. Hale) Were studied. The results indicated that water stress (in SW1, SW2, and SW4) severely decreased shoot length growth and leaf area in comparison to SW3 and SW5 treatments. Water stress in 1st stage decreased the fruit density. SW4 treatment had the highest yield and a significant difference of %1 probability with water stress treatments in the 2nd and 3rd stages. No significant differences were found diameter growth, leaf water potential, and flowering density. Result also indicated that stress in SW4 stage significantly decreased the mean fruit weight. Fruit size and fruit water content, while total soluble solid (T.S.S) as well as fruit acidity were increased. Water stress at stage 2nd of fruit growth (Pit hardening) increased fruit weight significantly (at %1 level) as compared with other treatments. In conclusion reduced water supply in some fruit growth stages resulted in control of vegetative growth and to retrench of peach tree water consumption and eventually suitable yield and high quality fruits.
