Plant growth regulators and rooting substrates affect growth and development of Salix koriyanagi cuttings

Abstract Salix koriyanagi is an endemic species with high conservation priority in Korea because of its isolated distribution. We evaluated the effects of plant growth regulators (PGRs), including 500 mg L-1 or 1000 mg L-1 IBA, 1000 mg L-1 or 2000 mg L-1 NAA and rootone, and rooting substrates such as phenolic foam, bonded medium, and perlite on the growth and development of S. koriyanagi cuttings. The highest percent rooting was observed in the cuttings treated with 500 mg L-1 IBA in phenolic foam. PGR treatment increased the number of roots on the cuttings, and the highest root fresh and dry weights were observed in the cuttings treated with 500 mg L-1 IBA in phenolic foam. These results suggest that treatment with 500 mg L-1 IBA in phenolic foam was the most effective for root initiation in this species and can be used for the mass production of Korean endemic S. koriyanagi through cuttings.