This research was carried out to reveal the phenological and genetic differences between the S-1/1 walnut genotype and 94 F1 genotypes obtained from this genotype with each other and with the maternal parent. In the phenological observations made, it was observed that bud burst in genotypes took 52 days, leafing 50 days, leaf yellowing 31 days, and defoliation date 27 days. When the maternal parent (S-1/1) and the genotypes were compared, it was found that there was a phenological variation of 75.54 % in budburst, 73.41 % in the leafing, 34.05 % in leaf yellowing, and 93.62 % in defoliation date, while the average variation was 69.15 %. In molecular genetic analyzes, 7 ISSR primers were used to determine genetic variations, as a result, 7 monomorphic and 45 polymorphic bands were obtained, and the rate of polymorphism was found to be 86.53 %. The average number of alleles was calculated to be 7.42. In genotypes, the polymorphism information content (PIC) value varied between 0.48 and 0.95, while the average PIC value was calculated to be 0.73. As a result of cluster analysis, it was seen that genotypes were divided into 2 main clusters and 2 subsets. At the end of the study, it was determined that the S-1/1 walnut genotype and F1 genotypes obtained from this genotype have a significant variation both phenologically and genetically.