Enhancing the productivity and fruit quality of Le conte pear trees via growth regulators, nutrients and amino acids

This study was carried out during two successive seasons 2008 and 2009 on mature Le Conte pear trees. Selected trees were sprayed Stimulate at 0.5%, Stimulate at 0.5 + X-Cyte at 1%, Stimulate at 0.5%. + Sett at 1.5%, Antistress at 0.3%, Potassium Phosphite at 2.5%, Pepton at 1000ppm, Berelex 15ppm a.i. and control. Treatments were sprayed with the specified solutions till run off at full bloom stage (70% of flower buds reached the stage of full open) except for Berelex which was applied three times at 30%, 60% and 100% open flower stages at 15ppm every time. Then selected trees were sprayed Pepton at 1000 ppm, Antistress at 0.3%, Potassium Phosphite at 2.5%, and Nitrite balancer. Treatments were sprayed with the specified solutions till run off at three times after fruit set stage (mid May, mid June and mid July) on pear trees. The basic productivity, fruit quality, vegetative growth parameters were assessed. All the applied treatments significantly increased initial fruit set, decreased fruit abscission, increased yield and enhanced fruit quality compared with the control trees. Immunity isozymes showed clear enhancements in activity due to treatments and this might be the indirect reason for the better productivity in addition to the direct effect of treatments. Highest significant effects were due to Stimulate + X-Cyte treatment which in a way led to better fruit quality in terms of both TSS% and firmness. This treatment also induced highest P and Ca leaf contents. Reasons for this effect might be directly due to the effects of these growth regulators in increasing the parthenocarpic setting, cell division and elongation or indirectly as a result of the increased calcium and phosphorus in the leaves which have positive effects on productivity and quality. Potassium Phosphite followed in its effect might be attributed directly to its nutritive effect in increasing the potassium content or in directly due to enhancing trees immunity towards bacterial and fungal diseases that destroy, abscise or abort the blossoms. Antistress treatment was sprayed at three times after fruit set stage (mid May, mid June and mid July) on pear trees induced significantly the highest average fruit weight,volume,length and diameter