Effects of boron on the growth and fruit quality of Dangshansu pear

In order to increase the nutrition levels and fruit quality of pear, Dangshansu pear (Pyrus bretshneideri cv. Dangshansu pear) was selected to be the experimental material in this research. The effects of different boron levels on the dynamic change of the boron contents of leaves, the vegetative growth and fruit quality of Dangshan pear were studied by spraying boron to the foliage four times in different levels (0.2%, 0.3% and 0.4%) at Dangshan pear shoot growth stage (May to July). The results show that the boron contents are increased with shoot growth, reach to its highest level at stage of shoot cease growth, and then start to decline. After foliage spraying with different levels of boron, the boron contents of leaves are increased in the treatments of 0.2% to 0.3%. Appropriate boron application would promote the shoot growth, enlarge the single-leaf area, the weight per 100 leaves and the content of chlorophyll, and increase the soluble sugar, the soluble solids content and pulp hardness, while the fruit acidity is decreased significantly. As the tree is deficient in boron, the foliage fertilization by spraying 0.3% boron two or three times at shoot growth stage (April to July) is the best treatment refering to the tree vigour, fruit quality and production costs.