Urgent propagation of the endemic and possibly extinct in the wild tree Cassine koordersii (Celastraceae)

Abstract

Abstract Cassine koordersii Kosterm. (Celastraceae) is a narrow endemic tree species known only to Mt. Puger, Jember, Indonesia. The IUCN Red List classifies it as Critically Endangered (CR) possibly extinct in the wild. Currently, there are only two living collections at the Bogor Botanic Gardens. As an urgent measure to anticipate extinction, vegetative propagation through shoot cuttings was conducted. This study aimed to determine the effects of rooting media and Rootone-F hormone on the successfulness of shoot cuttings of C. koordersii. It was carried out at the glass house in April 2022 with a 3-months observations period. The Komatsu-FORDA Fog Cooling (KOFFCO) system was adopted. The research used a completely randomized factorial design with rooting media and Rootone-F hormone as treatments. The media were sand (M1), cocopeat+burnt husk 2:1 (M2), and perlite+vermiculite 1:1 (M3). The Rootone-F hormone treatments included control (R1) and the addition of Rootone-F (R2). Six treatment combinations and four replications by 12 units obtained a total of 288 cuttings. The results indicate that in general, M2 and R2 have the best average yield: percentage of rooted cuttings (14.58%), number of primary roots (1.7), primary root length (1.58 cm), and percentage of survival cuttings (78.12%). The interaction between rooting media and Rootone-F hormone was not significant for all parameters. Despite only few new individuals are generated, they are valuable material for ex-situ collection backup. In addition, new juvenile seedlings are designed as mother trees for clonal orchards. Their high percentage rooting is expected to support the reintroduction program to their natural habitats.