Light intensity and fruit quality under hail protection nets.

摘要

The effect of hail netting on light penetration and fruit quality was evaluated from 1994-99 in 24 commercial and experimental apple orchards in Eastern Switzerland. Black nets reduced light levels (photosynthetically active radiation, PAR) by 18-25%, while netting by 8-12% and grey nets (black and white fibres) reduced PAR by 15-17%. No definite influence of black hail nets on maturity and fruit quality has been observed under good conditions (weather, site, small trees with loose canopies, optimum fruit load, etc.) and with cultivars for which fruit colour is mainly genetically determined. For Jonagold, the light intensity is decisive for fruit colour development. Reduced colour development under black nets may be observed on this cultivar. Theharvest time can be delayed by 8-10 days. Flesh firmness, soluble solid content and acidity were not affected. In general, external and internal fruit quality depends on several other factors which are more important than the effect of hail netting.