E-mail: ab.ehteshamnia@gmail.com Efficient plant regeneration through immature embryos was achieved from immature cotyledons explants of walnut (Juglans regia L.). The present studies were conducted to investigate immature cotyledons of open-pollinated fruits from four walnut (Juglans regia L.) cultivars (and genotypes). Immature cotyledons were aseptically excised from nine weeks after full pistillate bloom and cultured on Driver and Kuniyuki Walnut (DKW) medium supplemented with different combinations of Indol butyric acid (IBA) and Benzyl amino purine (BAP) hormones. Result indicated that significant differences were among different concentration of plant growth regulators and different cultivars. Best results were obtained on the medium supplemented with 0.5 and 1 mg L-1 BAP in conjunction with 0.2 mg L-1 IBA, where percentage of germination of excised embryos was varies between 50.73% and 71.27%. B21 Genotype was found to be the best responding cultivar (genotypes), which had a range of 59.1–74.6% embryo germination under various combinations of IBA and BAP were simultaneously applied.
