ISHS Acta Horticulturae 557: VII International Symposium on Orchard and Plantation Systems
INFLUENCE OF BLACK AND WHITE NETS ON PHOTOSYNTHESIS, YIELD AND FRUIT QUALITY OF APPLE (MALUS DOMESTICA BORKH.) |
| Authors: | F. Stampar, M. Hudina, V. Usenik, K. Sturm, P. Zadravec |
| Keywords: | cultivars, sugars, organic acids |
| Abstract:
The influence of black and white nets on cv. 'Elstar' and 'Jonagold' was studied at the Fruit Growing Centre Maribor – Gačnik in 1998. The orchard was planted in a single row system and trained as a slender spindle. Photosynthesis was measured in rosette leaves by a portable infrared photosynthesis measuring apparatus LCA-3. The contents of sugars and organic acids were determined by HPLC. The nets did not have any effect on the yield, but had a significant effect on fruit quality. Photosynthesis of individual leaves under the black net was significantly higher than under the white net in both cultivars. In both cultivars, the amount of red fruit colour was significantly higher on trees covered with white net than on uncovered trees as well as covered with black net. A higher content of soluble solids was found in fruit of covered trees in both cv. ‘Jonagold’ and cv. ‘Elstar’. In cv. ‘Elstar’ no significant differences among treatments were detected in the sucrose content. In cv. ‘Jonagold’ the sucrose content was significantly higher in fruits picked under the white net when compared to uncovered fruits, but the differences between fruits harvested under the black net and control and black net and the white one were not significant. The fructose content did not differ significantly among treatments in cv. ‘Jonagold’, whereas in cv. ‘Elstar’ significant differences were found between uncovered and covered trees. In cv. ‘Jonagold’ the significantly highest content of glucose was detected in fruit covered by the black net. No differences in the glucose content among treatments were observed in cv. ‘Elstar’. The contents of individual organic acids also varied among the treatments. | |
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