INFLUENCE OF LIGHT ON SHAPE AND QUALITY OF GOLDEN DELICIOUS APPLES
Shape and quality of apple fruit are greatly influenced by environmental factors: apples grown on hills are more elongated and less russeted than those grown in low valleys; (differences also exist in other quality parameters such as sugar and acid content, texture, color and storeability); treatments with exogenous GAs produce the same effects on russet and elongation of apples as high altitude, while the opposite occurs treating apple trees with GA inhibitors. A higher endogenous gibberellin content was found in apple fruitlets grown at higher altitudes (Eccher T., 1986); besides, relative proportion of irradiance in violet-UV and in red-IR wavebands were found to be higher at higher altitude (Eccher T., 1990). Supposing therefore that light quality could play a role in the synthesis or in the activation of endogenous GAs, a research was carried out by modifying natural light spectrum. The canopy of potted apple trees was therefore either lighted with additional lamps or covered with photoselective materials. The aim of the research was to verify whether variations of light spectrum would affect shape and quality of the fruit.
Eccher, T. and Noe, N. (1993). INFLUENCE OF LIGHT ON SHAPE AND QUALITY OF GOLDEN DELICIOUS APPLES. Acta Hortic. 329, 156-158