In efforts to combat cedar pollen allergy, the Toyama Prefectural Forestry Research Institute initially discovered a variety of Japanese cedar (Cryptomeria japonica D. Don) which tended to be pollen-free (expressing male sterility). This characteristic was revealed to be attributed to a pair of recessive genes (aa). We then developed and registered a male-sterile cultivar of Japanese cedar named “Haruyokoi,” which shows excellent early growth and rooting of cuttings. Furthermore, we discovered multiple Japanese cedar elite trees with heterozygous male sterility genes (Aa). We used these specimens as a mating parent to develop an elite, male-sterile Japanese cedar cultivar named “Tateyama Mori no Kagayaki.” To collect seeds of this variety efficiently, we constructed indoor miniature seed orchards and established a mass propagation method. We also characterized 11 male-sterile Japanese cedar trees newly discovered in various regions and created and unveiled the “Male-sterile Japanese Cedar Database.” These achievements are expected to contribute to reduction of airborne cedar pollen levels and activation of the forestry industry.
