Evaluation of the cytogenetic diversity in exotic and domestic Persian walnut cultivars

To evaluate the cytogenetic diversity of six selected exotic and domestic Persian walnut cultivars\genotypes, relationships among the cultivars, Z63, Pedro, Z30, Serr, and the genotypes, B21 and K72 were studied using Karyotyping of cells obtained from their roots. The karyotyping was done using 10 samples at metaphase stage. The parameters measured were chromosome long arm, short arm, short/long arm and short/whole chromosome length ratios, and chromosome index. All samples were diploid with 32 chromosomes, 2n=32. The types of chromosomes identified were all with no satellites, mostly of metacentric and submetacentric kinds and rarely telocentric type was observed. The average size of chromosomes in the genotypes studied was 8 microns. In order to classify the cultivars/genotypes studied based on their karyotypes’ characteristics, cluster analysis using Ward method was applied and the cultivars/genotype were categorized into three distinct groups: Group I, (K72, Z30, Z63, Pedro); Group II, B21 and Group III, where Serr was classified into it alone.