Development of an improved cutting-based propagation method for hybrid larch

Abstract

Abstract: Clean Larch, which is a superior progeny of the F1 hybrid larch, is propagated by cuttings because seed production is inadequate. The original cutting method, whereby the stock plants are grown in the field and a paper pot is used as a growing tray for the cuttings, has two problems: a shortage of shoots for cuttings and an increased risk of root girdling. In this study, we investigated the effect of using a container, which doubled as a growing tray, for both the stock plant （ortet） and the cuttings. The number of rooted cuttings increased from 10.2 ± 4.4/ortet for the original method to 18.0 ± 3.8/ortet for the improved method. The mean root dry weight of a cutting incubated in a greenhouse until late October was 3.3 times the dry weight of the mean value of cuttings produced by the original method. The survival rate of rooted cuttings from the improved method was 12.8% higher than that from the original method in the year after the cuttings were taken. High plant density in the container in the improved method reduced the diameter of rooted cuttings.