In contrast to developed countries open-pollinated (OP) processing tomato cultivars still have a certain market value in Turkey. A total of 26 subpopulations of 6 different OP cultivars (9 of Rio Grande, 5 of Rio Fuego, and 3 of each of C-37, Interpeel, T2 Improved, and VF 6203) were evaluated in two experimental sites in Marmara Region and Aegean Region. A high degree of phenotypic variance for yield (kg/plant) was found for most subpopulations which revealed the variation for yield amongst individuals, and hence the possibility to select for superior plants. Eighteen populations were developed by two cycles of mass selection conducted within the initial populations in both regions. Most progeny populations significantly exceeded their source cultivars in yield. Heritability estimates occurred generally parallel to that of yield increases of the progenies, which were slightly higher in the Karacabey trial (Marmara Region) as compared to the Muradiye trial (Aegean Region). Results were discussed from the point of view of the resource-poor farmers conducting low-input agriculture.