Abstract
Pollination and thinning are critical processes in the date palm production chain that affect fruit development, quality and yield and regulate tree yearly bearing. Developing a pollination technique that results in an acceptable level of fruit set with a minimum amount of pollen grains and without a further need for thinning is critically required for date palm production, especially under arid conditions. During the 2006 and 2007 seasons, the effect of pollen grains-water suspension application at different concentrations on fruit set, yield and quality were examined on 'Lulu' date palm growing under Al-Ain oasis conditions, UAE. The results showed that the pollen grains-water suspension (PGWS) application at 0.5, 1, 1.5 g/L gave fruit set percentages of 75.6, 86.8 and 87.8%, respectively which was lower than the control (90.0%) (traditionally pollinated). As the mean of both seasons, the GWS application especially at 0.5 and 1.0 g/L significantly decreased both bunch weight (5.52, 6.21, 7.19 and 8.54 kg for 0.5, 1.0, 1.5 g/L and control, respectively) and the total yield per tree (49.71, 55.92, 64.74 and 76.89 kg/tree, for 0.5, 1.0, 1.5 g/L and control, respectively) at the tamer stage. Fruit quality characteristics especially fruit and flesh weight, length and diameter, TSS and dry matter concentration were slightly but significantly increased by the PGWS application treatments during the 2006 season. However, seed weight, acidity and vitamin C concentration were not affected by any of the pollination treatments. It is concluded that this is a pioneer study investigating the possibility to pollinate date palm flowers with pollen grains-water suspension to control fruit set in heavy bearing cultivars such as 'Lulu' to save further thinning cost and pollens of excellent males, and improving fruit quality. However, more research work is required to justify the concentration of grains-water suspension and the response of each date palm cultivar to this pollination technique.