Factors affecting rooting of Japanese persimmon hardwood cuttings

The factors influencing rooting of hardwood cuttings from two cvs. of Japan ese persimmon (Diospyros kaki Thunb.), Jiro and Nishimurawase, were studied . After the tops of micropropagated trees were removed, suckers sprouted fr om the roots. A quarter of the cuttings made from these basal suckers roote d. Half of the cuttings, whose basal part had been etiolated by mounding wi th rice husks, initiated roots. Some of the etiolated suckers which had alr eady rooted within the mounds were easily established in a bottom-heated me dium after being separated from the mother plants. Cuttings from the one-ye ar-old shoots of micropropagated or conventionally grafted trees did not ro ot. There was no significant difference in the rooting percentage between ' Jiro' and 'Nishimurawase' cuttings. In comparison with the control, soaking the base in 25 ppm IBA for 24 hr or dipping in 3000 ppm IBA for 5 sec did not improve the rooting percentage. Imbedding the cuttings in a looting mix ture from late-January to late-March had no effect on the rooting percentag e. Almost all rooted cuttings grew well and became established. Before the rooting treatment, adventitious root primordia at various differentiation s tages were found in the basal region of mounded suckers, in which a well-de veloped periderm and few sclerenchymatous cells were present. Root primordi a were not observed in the bases of unmounded suckers or their mid-sections . The unmounded suckers had a discontinuous sclerenchymatous ring and their cuttings rooted to some degree, whereas the mid-sections of suckers had a well-developed, continuous sclerenchymatous ring and their cuttings scarcel y rooted.