Mohammad Sadat-Hosseini

Walnut has a large number of chromosomes (2n=32), and there have been very limited cytological studies in this species to date. Since haploid plants have half the number of the chromosomes of the parents, they will be useful to develop the karyotype. In our study, haploid plants of ‘Hartley’ obtained via parthenogenesis of irradiated pollen with 600 Gy were selected. Chromosome number was assessed in root tip cells of in vitro haploid plants, using the standard Feulgen technique. Micro Measure v3.3 software was used for chromosomal analyses. Length of the 16 chromosomes varied from 1.55 to 3.53 μm. Centromere position of chromosomes were measured according to Levan et al. (1964). The results showed that among the 16 chromosomes, 10 of them were metacentric, 5 submetacentric and 1 subtelocentric.