Abstract

Abstract: Pinus parviflora is naturally distributed in cool temperate zones from the southern Tohoku region to the mountainous area on the Kyushu Island in Japan. However, in the Boso Hills, it is distributed in the warm temperate hilly zone, present at regions lower than 350 m above sea level, and regarded to be genetically valuable. Since the 1970s, the population has rapidly decreased due to pine wilt disease and other causes. Therefore, in the Chiba Prefectural Government Office, clonal propagation by grafting was carried out as a method of conservation of gene resources. However, many grafted trees died several years after grafting, thereby leading to difficulties in long-term gene conservation. Therefore, we hypothesized that clonal propagation with cuttings of natural tr es was the most effective method for long-term gene conservation and examined this possibility by cutting and grafting from natural trees and their grafted clones. Our results indicated that the rooting rate of the cuttings was relatively high when the 2-year-old plants grafted from the grafted clones of natural trees were used as scions. Based on our results, we discussed a procedure to produce cutting clones from aged natural trees.