Genetic resources are the most valuable national treasure of a country and it is vital to identify, conserve and use them.The Persian walnut (Juglans regia L.) is one of the most valuable genetic resource in Iran due to its multi benefits (nutrition, wood, Sta-Rite Max-E-Pro Parts environment conservation, genetics and medicine).For this reason, 32 leaf morphological characteristics of J.
regia were studied on nine populations (four native and five cultivated) and Hats 243 individual trees.Leaf sampling was made two years for the native populations and one year for the cultivated populations.The effects of year variation on leaf characteristics and the effects of leaflet numbers on wealth variation of the characteristics within each genotype were studied.The ANOVA analysis showed that there were significant differences between the walnut genotypes in respect to their leaf characteristics (P.