Optimization of some conditions for production of cypress seedlings (Cupressus torulosa D. Don) using asexual propagation technique at Loang Lien National park, Lao Cai

Abstract

Himalayan or Bhutan cypress (Cupressus torulosa D. Don) is a medium-sized, green, beautiful tree that grows very slowly. Its parts (leaves, fruits, roots, bark) have many uses and are widely used in traditional medicine, modern medicine, and in industry. Due to overexploitation in the past 30 years, this cypress in the wild is almost extinct and has been listed in the Vietnam Red Book as critically endangered (CR). Therefore, the conservation and development of gene source of this cypress in Hoang Lien National Park, Lao Cai and in some northern mountainous provinces of Vietnam is extremely necessary. The present study aims to apply asexual propagation technique to reproduce Cupressus torulosa D. Don seedlings. In addition, investigation of factors affecting growth and rooting ability such as growth regulator (IBA), cutting type and cutting season would find the most suitable conditions for the rapid reproduction of this cypress seedlings to meet the goal. The results showed that using IBA concentration of 900 ppm, young cuttings, and cutting in summer indicated the best growth and rooting ability with callus rate of 76.85%, rooting rate of 69.44%, average number of roots per cutting (branch) of 4.17 roots, and average root length of 14.67 cm. These findings could be the scientific outcomes for the conservation and propagation of Cupressus torulosa D. Don in Hoang Lien National Park, Lao Cai in particular and for the northern mountainous provinces of Vietnam in general.