“…Nevertheless, they are used as an outstanding source of germplasm and as a genetic basis underlying breeding activities, principally the development of new cultivars, clonal selection (Ogašanović et al, 1994;Milošević, 2000), the development of new plum, apricot and peach rootstocks (Paunović, 1988;Djurić et al, 1998), resistance to economically important diseases (Paunović and Paunović, 1994;Rodrigues et al, 2009) or intensive cultivation (Mratinić, 2000). Similar investigations with focus on identical or similar objectives were also conducted in the other countries of the former Yugoslavia -Serbia (Milošević, 2000), Bosnia and Herzegovina (Buljko, 1977;Jarebica and Muratović, 1977), Croatia (Jelačić et al, 2008) and Slovenia (Usenik et al, 2007). In situ investigations of cultivars derived from Prunus domestica L. and P. insititia L. in Serbia were conducted by a number of researchers (Paunović et al, 1985;Paunović, 1988;Paunović and Paunović, 1994;Petrović et al, 2002) who defined important biological, pomological and technological traits of both fruit and tree.…”