The interaction between various cultivar candidates were developed by breeding programs and different environmental conditions are important. This criterion that demonstrates the real performance ofgenotypes. It can be revealed that which genotypes are better to adapt good environmental conditions, where genotypes are better to adapt unsuitable environmental conditions or which genotypes are showing good or poor stability in all locations by means of genotype × environment interaction. In this study, it is aimed to determine the performances of some fruit quality characteristics and yield components of local promising winter squash cultivar candidates (55ÇA15, 55ÇA06and 57Sİ21) which are developed by selection breeding methods from Black Sea Region winter squash populations in three different ecological conditions (Bafra, Tekkeköy and Salýpazarý) of Samsun province. It was determined that there were significant differences wintersquash genotypes and locations in terms of fruit dimensions and fruit rind thickness values. However, fruit flesh color and total soluble solid content (TSS %) values were not statistically significant. In comparison with the yield values of the pumpkin cultivar candidates, 57Sİ21 (21 t ha-1) showed the best performance. This genotype was followed by 55ÇA15 (17 t ha-1) and 55BA03 (17 t ha-1). In terms of average fruit weight, 57Sİ21 genotype was found to be more stable than the other genotypes due to below 1 regression coefficient, positiveregression constant, Sd2 value close to 0 and 0.86 r2 value. Similarly, 57Sİ21 was found to be more stable than Arýcan-97 cultivar in fruit flesh hardness. As a consequence; 57Sý21 genotype compared toother genotypes; yield and fruit number values were higher and fruit weight, and fruit flesh firmness values were found to be more stable.It was determined the most promising genotype for Samsun ecological conditions.In the next years, cultivar registration procedure for this genotype will be initiated. Thus, a new winter squash cultivar will be released into production for Turkey.