Effect of pollen grain-water suspension spray on fruit set, yield and quality of 'Helali' date palm (Phoenix dactylifera L.)

Abstract: During 2008 and 2009 seasons, the effect of pollen grain-water suspension spray at different concentration on fruit setting, yield and quality of 'Helali' date palm cultivar growing under Hada-Alsham conditions, KSA was examined. The results showed that fruit set, bunch weight and total yield per tree were significantly higher when spray pollinated at 0.5, 1.0 and 1.5 g L^-1 than the traditional pollination. In this respect, there were no significant differences among spray pollination at 0.5, 1.0 and 1.5 g L^-1. However, spray pollination at 2.0 g L^-1 gave fruit set percentage similar to traditional pollination. At harvest, the Rutab percentage in bunches was not affected by the method of pollination. At both the Bisir and Rutab stages, fruit, flesh and seed weight, diameter and length were not significantly affected by any of the pollination treatments. The biochemical characteristics of fruit such as TSS, acidity, vitamin C, total phenols and soluble tannins were not significantly affected by any of the pollination treatments at both stages. The concentrations of TSS and acidity were higher at the Rutab than at the Bisir stage. However, the concentrations of vitamin C, total phenols and soluble tannins were greatly lower at the Rutab than at the Bisir stage. This study showed the possibility to pollinate 'Helali' date trees by pollen grain-water suspension spray with optimum amount of pollen grains with no further need for thinning especially under hot arid conditions. However, more research work is required to standardize the optimum concentration of pollen grain-water suspension and the response of each date palm cultivar to this pollination technique.