Oh, S.I.; Park, E.H.; Koh, H.M.; Gil, M.; Yoon, M.J.; Bae, J.K.; Ko, C.H. Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.. Horticulturae2023, 9, 101.
Oh, S.I.; Park, E.H.; Koh, H.M.; Gil, M.; Yoon, M.J.; Bae, J.K.; Ko, C.H. Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.. Horticulturae 2023, 9, 101.
Oh, S.I.; Park, E.H.; Koh, H.M.; Gil, M.; Yoon, M.J.; Bae, J.K.; Ko, C.H. Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.. Horticulturae2023, 9, 101.
Oh, S.I.; Park, E.H.; Koh, H.M.; Gil, M.; Yoon, M.J.; Bae, J.K.; Ko, C.H. Propagation Characteristics of the Rare Endemic Rhododenderon micranthum Turcz.. Horticulturae 2023, 9, 101.
Abstract
Studies on the cutting propagation of plants belonging to the genus Rhododendron are limited to R. mucronulatum and R. yedoense, which are mainly used as ornamental flowering trees, and additional studies on a greater variety of species are required. This study examined the characterisitics of cutting propagation according to treatment with growth regulators indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA) to generate basic data on the methods of reproducing R. micarnthum Turcz.. The number of roots (r=0.740**), length of root (r=0.844**), and number of leaves (r=0.649**) affected the rooting rate of R. micarnthum Turcz., and the number of roots (r=0.646**), length of roots (r=0.673**), number of leaves (r=0.738**), and chlorophyll content (r=0.710**) affected the survival rate. Further, the rooting and survival rates were highly correlated (r=0.794**). The growth characteristics of underground sections after growth regulator treatment were as follows: the number of formed roots was 7.0 and 7.2, and the length of roots was 6.2 cm and 5.3 cm in 150 mg·L-1 and 250 mg·L-1 NAA treatment groups, respectively. The rooting rate was 60% or above in the growth regulator treatment groups compared to that in the control group. Particularly, the rooting rates of 150 mg·L-1 and 250 mg·L-1 NAA treatment groups were 90% or above, and the latent period before rooting was shorter than other treatment groups at approximately 14 days, which was considered to be effective for root growth. The aboveground growth characteristics after propagating the cuttings showed that groups treated with 150 mg·L-1 and 250 mg·L-1 NAA showed a significantly higher plant length (5.2-5.8 cm), number of leaves (6.2 and 6.9), and leaf-length and leaf-width as compared to other treatment groups. Moreover, the survival rates of 150 mg·L-1 and 250 mg·L-1 NAA treatment groups were 80% or above, and the sound root growth manifested in the tendency of good aboveground growth. Additionally, IBA and NAA were highly correlated to the rooting and survival rates during cutting propagation of R. micarnthum Turcz.. The rooting and survival rates increased with the increase in growth regulator concentration. Particularly, NAA had a higher correlation to the rooting and survival rates than IBA (r=0.7316**, 0.7013**). Thus, R. micarnthum Turcz. could be propagated through cutting. Growth regulator treatment with 150 mg·L-1 and 250 mg·L-1 of NAA was effective for rooting and root growth of cutting, and these treatments were considered appropriate because the effects of aboveground growth were positive.
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