<i>Hibiscus</i> 属植物に関する研究 (第10報)

Abstract

Grafting experiments were made with 12 species in Hibiscus (Table 1) to examine the affinity between species and the possibility of using grafting for breeding and cultural practice. The materials included annual and perennial or herbaceous and arboreal species.1. When annual species were grafted on to perennial herbaceous species and an arboreal species (H. mutabilis), all the combinations resulted in good union. In some cases, grafted scions grew better on stocks of different species than on the stock of own species (control). The number of flowers was, however, reduced by inter-specific grafting (Table 2, 6 and 7).2. Mutual graftings between the three herbaceous perennials of North American origin resulted in good flowering and vegetative growth not inferior to those of the control plants. Grafting them on to H. mutabilis stock caused a fairly decrease in the percentage of flowering to control in the second year (Table 3, 6 and 7, Fig. 1).3. The scions of two tropical woody species united well with the stocks of three hardy arboreal species and H. moscheutos (a herbaceous perennial). Their vegetative growth was, however, inhibited and no flowering was observed except in control plants. A dwarf tropical woody species, H. pedunculatus, grew vigorously on any of the stocks, but the flowering of the scions was very poor, especially when grafted on to H. syriacus and H. moscheutos (Table 4, 6 and 7, Fig. 1).4. Relatively good growth but fairly reduced flowering resulted from the mutual graftings between the three hardy arboreal species, H. mutabilis, H. syriacus and H. hamabo. H. mutabilis showed excellent growth and flowering when grafted on to perennial herbaceous species, but other two species on to the same stocks showed an inferior performance especially in their flowering (Table 5, 6 and 7, Fig, 1).5. H. rosa-sinensis a popular tropical shrub, did not grow well and flower on the stocks of any species. Its use as stock also brought the same results for all scions tested (Table 4).6. The results of all graft combinations suggested that the three species, H. coccineus, H. militaris and H. moscheutos, were, as compared with the other species, closely related to each other as shown by their excellent mutual grafting affinity (Table 3).7. As far as the graft union is concerned, all the combinations of the species tested proved to be successful, but none of them was found practically useful for the purpose of promoting scion′s growth and of dwarfing.