Plant Regeneration and In Vitro Growth Performance of Male-Sterile Somatic Plantlets of Sugi (Japanese Cedar, Cryptomeria japonica) Derived from Different Embryogenic Cell Lines

Abstract

With the spread of pollinosis caused by sugi (Japanese cedar, Cryptomeria japonica) pollen, the use of pollen-free somatic seedlings of sugi is expected in Japan. However, there is a lack of knowledge on the relationship between the abilities during somatic embryogenesis, initial in vitro growth traits, and subsequent growth of somatic seedlings. In the present study, we provide the first basic information on somatic embryo maturation efficiency, somatic embryo germination, and plantlet conversion frequencies, as well as on in vitro growth performance of pollen-free somatic plantlets derived from different embryogenic cell lines (ECLs). Somatic embryo maturation efficiency varied from 34 to 514 cotyledonary embryos per plate and the average for the 19 ECLs tested was 244 embryos per plate. Subsequently, the overall average rates of somatic embryo germination and conversion among ECLs were 87.8% and 85.3%, respectively. The results of in vitro growth performance of pollen-free somatic plantlets showed significant differences in growth rate among ECLs.

An Improved and Simplified Propagation System for Pollen-Free Sugi (Cryptomeria japonica) via Somatic Embryogenesis

“…The development of this novel technique for the efficient production of sugi MSPs was first reported by our research group ( Maruyama et al, 2020 ). Then, we released improved methodologies for SE initiation ( Maruyama et al, 2021a ), somatic embryo production, and somatic plant regeneration ( Maruyama et al, 2021b ; Tsuruta et al, 2021b ), as well as for the early effective selection of male-sterile ECLs ( Hasegawa et al, 2021 ; Tsuruta et al, 2021a ).…”