Abstract:In order to understand the effects of irrigation amount on fruit quality and yield and to investigate the efficient mode of water supply of peach tree in semi-arid area field, two-year experiments were conducted to study the response of water demand signal (sap flow velocity, net photosynthetic rate Pn, transpiration rate Tr, stomatal conductance Gs), yield and fruit quality of four years peach tree to the different irrigation amount treatments (I1:100%ETc, I2:75%ETc, I3:50%ETc, I4:25%ETc, ETc is crop evapotranspiration) under mobile rain shelter in two consecutive seasons (2010—2011). The two-year results showed that the number of fruit per hectare were both performance for I1＞I2＞I3＞I4 and the yield per hectare are both characterized by I1≈I2＞I3＞I4. Compared with I1, I2 didn’t have lower sap flow velocity and had higher water use efficiency (WUE) which was improved by 6.2% and 7.7% without reduction on the Pn and yield significantly, while I3 and I4 reduced yield by 9.2%, 21.4% and 16.9%, 42.5% respectively in 2010 and 2011, even if it had the low transpiration rate and high WUE. Meanwhile, irrigation had extremely significant effects (P＜0.01) on peach mouthfeel, vitamin C, sugar/acid, single fruit weight and yield so that I2 was improved by 2.2%, 4.5%, 24.4%, 28.8%, -2.3% and 5.9%, 3.2%, 26.5%, 9.3%, 0.4% respectively compared with I1, and significant effects (P＜0,05) on fruit number, color, firmness and titratable acid so that I2 was improved by -24,1%,85.7%, 22.1%, 12.1% and -8.1%, 40%, 28.8%, -2.7% respectively compared with I1. It had little impact on fruit moisture content and deficit irrigation (I2, I3 and I4) all improved the fruit quality of peach. The research also showed that there were high correlative relationships between peach yield, net photosynthetic rate and soil water content in two-year experiments. Under the condition of experiment, the highest yield, higher water benefit and better fruit quality of peach tree can be obtained with irrigation of 75% ETc.
