Fruit weight, firmness and soluble solids content during ripening of Karešova cv. sweet cherry

Changes in fruit weight, firmness and soluble solids content during the ripening period of Karešova cv. Including relationships between these characteristics were studied in 1998-2001. These years differed from each other in the amount and distribution of rainfall and in the course of temperatures. The length of ripening period fluctuated from 14 to 21 days. An increase in average fruit weight during the ripening period was 0.1 g per day. The actual increase in fruit weight was in a close correlation with the amount of rainfall in a few previous days. After heavy rainfalls, above 40 mm, fruit weight increased by nearly 1 g within in a few days. In the course of the ripening period fruit firmness decreased from about 2.5 N at the beginning of the period to about 1.5 N at its end. This decrease seems to be mainly the function of time during ripening. However, a low correlation between the amount of rainfall in the previous days and the decrease in firmness was also found. This correlation could be connected with negative regression of fruit firmness on the weight of the fruit. In the more rainy years 1998 and 1999 these decreases in firmness were more significant than in the other two years. Soluble solids content (SSC) increased from about 12% Brix at the beginning of the period to about 16% at its end. There were also found positive correlations between the weight of fruits and SSC. Taking into account contributions of all studied factors and their changes a conclusion was drawn that Karešova cv. should be harvested within one week from the beginning of its ripening period.