The analysis of the existing relations between characters is of great importance because it allows the selection of genotypes that possess simultaneously a combination of several useful characters. Values close to +1 indicates a strong positive correlation; those who are closed to -1 indicates a strong negative correlation and values close to zero indicates that between those two characters does’n exist any correlation. Between the analysed characters used for experience, there are positive and negative connections, some of them closer, statistically ensured. Experience was conducted from 2012 to 2014. The study took place in fruit-growing ecosystems Călacea, were analyzed 4 varieties of plum. Determinations regarding the influence of thinning have been made for these varieties on: fruit firmness (Kgf/cm2), fruit weight (g), dry substance (% SU) and total acidity (% malic acid). There is a positive correlation between firmness (Kgf/cm2) and fruit weight (g), the coefficient of correlation being significant (r = 0,438). The correlation between solids content (% SC) and fruit weight (g) shows a strong dependence between the two characters, the coefficient of correlation being very significant (r = 0.706). Between the total acidity (% malic acid) and fruit weight (g), there is a strong dependency, the coefficient of correlation being significantly negative (r = - 0.652).