INFLUENCE OF POTASSIC FERTILIZATION ON THE POSTHARVEST QUALITY OF TOMATO FRUITS
CHIESA, A.; MOCCIA, S.; FREZZA, D.; FILIPPINI DE DELFINO, S.
Abstract
Potassium is the nutrient "which most affects
the quality of the tomato fruit. Several physical-chemical and organoleptic
properties are related to the quantity of this nutrient in the fruit, due to
this fact it is of the upmost importance to consider potassic fertilization
as a preharvest factor that will modify the postharvest fruit. The aim of this
work was to study the evolution of the dry matter, soluble solids, titratable
acidity and pH during storage of tomato fruits cultivated with eigth different
levels of potassic fertilization in a greenhouse. The harvest was carried out
in two stages of ripeness: breaker and firm red. A randomized complete block
design was used with four replicates. An ANOVA and a multiple regression analysis
were carried out with comparisons between treatments according to Tukey test.
The results showed : a) a higher dry matter percentage and soluble solids content
in fruits with a higher potassium dose, b) no significant differences in pH
and titratable acidity were detected regarding potassic fertilization, although
the absolute values of pH are greater in fruits with the greatest potassium
dose and c) the acidity of the fruit changes with the degree of ripeness, decreasing
during storage.
Key words:
tomato, postharvest, storage, potassium.