Morphological Leaf characteristics of Persian walnut (Juglans regia L.) in Iranian population

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, 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 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<0.001). After correction of variance coefficient (C.V.) of each genotype, based on deduction of corrected C.V. within genotype (C.V.G.) according toleaflet numbers (5, 7, 9 and 11 leaflets) from primary C.V., a high real value of C.V. was achieved. The Duncan method was used to compare the means and identify the less variable leaf characteristics, based on C.V.G. and correction of leaflet numbers. Correlation coefficient of leaf characteristics according toeach leaflet number groups (5, 7 and 9 leaflets) was investigated. Using cluster analysis (UPGMAmethod) to classify the 32 leaf morphological characteristics for the 243 trees, resulted in 19 clusterswhich seven clusters contained one individual members and four clusters contained double or triplemembers. The results showed that the most important, distinctive and reliable leaf morphologicalcharacteristics of J. regia were as follows: length of biggest leaflet, petiol length, leaflet marginal form,Arctangent of average leaflet length to average leaflet width, Arctangent of half leaf width to petiollength.