The correlation of the pear (Pyrus communis L.) cv. 'Williams' yield quality to the foliar nutrition and water regime

Abstract

The influence of the foliar nutrition and the water regime on the pear fruits quality (Pyrus communis L.) cv. ‘Williams’ was studied in 1998. We determined the contents of individual sugars (glucose, fructose, sucrose and sorbitol) and organic acids (malic, citric, fumaric and shikimic) by HPLC (High Performance Liquid Chromatography). The sizes of the fruits (diameter, length, weight) were measured as well as the amounts of soluble solids and titrable acids. The experiment comprised three treatments: the foliar nutrition, the irrigation and the control. In the treatment of the foliar nutrition the trees were sprayed for five times (from May 22 to July 7) with a foliar fertilizer, which contained 15% of P2O5, 20% of K2O, 0.1% of Mn, 0.1% of B and 0.1% of Mo. In the treatment of irrigation the trees were watered during the growth period with 4 l/tree/day. The foliar nutrition influenced bigger sizes of fruits, increased contents of glucose, sorbitol, soluble solids, malic, citric and fumaric acids, titrable acids and higher pH of juice. The irrigation had influence on the decrease in the contents of individual sugars (glucose, fructose, sucrose, sorbitol), soluble solids, organic acids (malic, citric, fumaric and shikimic) and pH of juice as well as on the bigger sizes of fruits (length, diameter, weight).