Plant regeneration from young leaves in loquat (Eriobotrya japonica L.) using young grafted seedlings as mother plants

Abstract

A plant regeneration technique was successfully developed for the first time using young leaves harvested from two-y-old grafted seedlings in loquat (Eriobotrya japonica L.) cv. Dawuxing. Callus cultures were induced from the cut edge of the leaf explants after 2 wk of culture on Murashige and Skoog (MS) medium supplemented with 0.5 mg L⁻¹ 6-benzyladenine (BA) and 0.5 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), in which callus cultures were induced at a frequency of 89.2%. White-greenish adventitious buds occurred after 3 wk of culture on MS medium supplemented with 0.8 mg L⁻¹ thidiazuron (TDZ), 0.3 mg L⁻¹ α-naphthaleneacetic acid (NAA), and 0.2 mg L⁻¹ AgNO₃, the adventitious buds developed to shoots after 5 wk of culture, with 30.6% of shoot induction rate. The shoots (about 5 cm in length with expanded leaves) rooted at a rate of 68.9% on the rooting medium consisting of ½ MS medium containing 1.0 mg L⁻¹ NAA and 1.0 mg L⁻¹ indolebutyric acid (IBA). The rooted plantlets, after hardening, survived satisfactorily in the transplantation matrix of peat and humus under optimum temperature, light, and water management. The morphology and inter simple sequence repeat (ISSR) marker banding patterns of the regenerated plants were all identical and similar to that of the mother plant. The plant regeneration technique developed in this study could be useful for Agrobacterium-mediated genetic transformation in loquat.