Development of an Efficient Micropropagation Protocol for Hemerocallis ‘Betty Woods’

Conventional division of newly developed daylily cultivars is constrained by a low multiplication rate, limiting the rapid production of uniform planting material. In this study, young rhizome and scape explants of Hemerocallis ‘Betty Woods’ were used to develop an efficient micropropagation protocol and evaluate the effects of thidiazuron (TDZ) on in vitro induction and proliferation. Surface disinfection, shoot induction and multiplication, rooting, and acclimatization were systematically evaluated. A suitable rhizome disinfection treatment used 75% ethanol for 30 s followed by 2% sodium hypochlorite for 10 min, whereas a suitable scape treatment used the same ethanol treatment followed by 2% sodium hypochlorite for 5 min. The selected rhizome induction medium was MS supplemented with 2.0 mg L−1 6-benzyladenine (6-BA), 0.2 mg L−1 α-naphthaleneacetic acid (NAA), and 0.1 mg L−1 TDZ, resulting in 83.3% adventitious shoot induction and 4.62 shoots per explant. For scapes, MS supplemented with 1.0 mg L−1 6-BA, 0.2 mg L−1 NAA, and 0.05 mg L−1 TDZ produced callus induction and shoot differentiation rates exceeding 80%. The selected multiplication and rooting media were MS + 1.0 mg L−1 6-BA + 0.1 mg L−1 NAA + 0.005 mg L−1 TDZ and half-strength MS + 0.3 mg L−1 NAA, respectively. A peat: vermiculite: perlite mixture (3:1:1, v/v/v) was selected for acclimatization. Overall, low TDZ concentrations enhanced induction, differentiation, and proliferation, and the optimized protocol provides a practical approach for rapid clonal propagation and large-scale production of Hemerocallis ‘Betty Woods’.