In vitro culture of various genotypes of male sterile Japanese cedar (Cryptomeria japonica D. Don)

Abstract

The pollen allergy problem of Japanese cedar has been a nation-wide problem in spring time in Japan. It is said that about 20% of people suffer Japanese cedar pollinosis in urban areas. New projects substituting Japanese cedar forest stands with low-pollen or sterile male Japanese cedar trees started from 2008. The propagation of male sterile Japanese cedar genotypes is one of the most important steps in that project. We developed a micropropagation technique using an in vitro culture of male sterile Japanese cedar genotypes. Leafy shoot segments were used for explants. There was a genotypic difference in tissue culture response. Among the cytokinin tested, zeatin and 6-benzylaminopurine (BAP) were relatively effective for bud induction. More buds were induced in the medium containing zeatin than that containing BAP with the male sterile genotype Fukushima 5. Shoots developed from buds on the medium 1/2 LP containing 5 g l−1activated charcoal. Shoots produced roots on a medium containing 23.8 μM (5 mg l−1) 4-chloroindole-3-acetic acid and 0.044 μM (0.01 mg l−1) BAP. Rooted plantlets were successfully habituated and cultured in pots outside. The in vitro cultured materials will be used for the micropropagation of male sterile Japanese cedar in order to reduce the pollen in the air.