Introduction. The aim of our
study was to analyze the effect of various levels of light availability
in the fruit microenvironment (induced by summer pruning) on some
fruit quality traits. Materials and methods. Two levels
of summer pruning were set: removal of either 30% or 60% of the
canopy leaf area. These treatments were compared with the control
(unpruned vines). Two canopy layers (upper and lower) were identified
in each treatment and in the control vines. At harvest, yield per
cane and per shoot was recorded in the two canopy layers; fruit
fresh weight, flesh firmness, total soluble solid content and total
titratable acidity were measured. Fruit Total Antioxidant Capacity (TAC)
and Total Polyphenols (TPH) were determined at kiwifruit harvest
and post-harvest (60 days after storage at 1 °C) in relation to
their position within the canopy (layer) and to the pruning treatment
applied. Results. Removing 60% of the canopy leaf area
induced higher titratable acidity and flesh firmness of kiwifruits
at harvest; it reduced fruit weight and crop yield, but increased
TAC and TPH compared with kiwifruits of control. Removing 30% leaf area
did not reduce mean fruit weight and crop yield; it increased TAC
and TPH at harvest by 20%. Post-harvest TAC and TPH evolution did
not differ among treatments. Discussion and conclusion.
Pergola-trained kiwifruit vines showed good performances in terms
of crop yield and fruit quality when summer pruning reduced the Leaf
Area Index (LAI) to 3. More intense pruning resulted in a significant
increase in fruit TAC, but reduced fruit weight and crop yield,
and delayed softening of pulp.