Effects of Regulated Deficit Irrigation on the Vegetative and Generative Properties of the Pear Cultivar ‘Yali’

To investigate the effects of regulated deficit irrigation (RDI) on the growth, yield and quality of ‘Yali’ pears, field experiments for C (fully watered control), EW [early withholding of irrigation, water stress from pullulation to 25 days after flower bloom (DAFB)], MW (mid-growth withholding of irrigation, water stress from 25 DAFB to 80 DAFB), and LW (late withholding of irrigation, water stress from 120 DAFB to 150 DAFB) were conducted in Handan county, North China, during the 2007 and 2008 seasons. The results showed that leaf relative water content (LRWC) was dramatically reduced during water stress. Water stress reduced shoot growth by 9.6%-18.8%, and the need for summer pruning was marginally decreased. No significant difference was seen in mean fresh fruit weight or yield at harvest for the EW, LW and C treatments. Water consumption during RDI was significantly less than the C treatment. Withholding of irrigation at LW not only led to increases in fruit TSS (total soluble solids), soluble sugars and dry matter content but also resulted in an increase in water use efficiency (WUE). Withholding of irrigation at LW and EW can be used in pear production to save irrigation water without adverse effects on the quality of fruits. RDI is a beneficial agricultural practice for the production of pear fruits if it is adopted one month before harvest, and from pullulation to 25 DAFB.