Arizona is currently experiencing an explosion in the commercial cultivation and production of table grapes. Decreasing water supplies, increasing water cost, and recent groundwater legislation are forcing Arizona growers to be more water efficient if they are to remain competitive with other markets. Research was conducted to determine the effect of water stress on vine growth and berry ripening. “Flame Seedless” table grapes (4th leaf) were subjected to increasing water stress levels based upon infrared canopy temperatures and the crop water stress index (CWSI). A lower water stress level (CWSI = 0.18 units at irrigation) promoted earlier berry sizing, increased berry weight, and increased cluster weight over drier treatments. Significantly higher growth (P= 0.01), based on pruning weights, also was attained at the lower water stress level. However, highest production (grade 1 and 2 packed boxes) was attained when irrigations were scheduled at 0.30 CWSI units. Total applied water to maintain the wet, medium, and dry treatments was 1136 mm (CWSI = 0.18), 775 mm (CWSI = 0.30), and 669 mm (CWSI = 0.33), respectively.
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