ปัจจัยที่มีผลต่อการเพาะเลี้ยงชื้นส่วนตาเขียวและ Longitudinally thin cell layer (LTCL) ของยางพาราพันธุ์ดั้งเดิมในหลอดทดลอง

Abstract

Early introduced clones of rubber tree are good sources of rootstock tolerated to root diseases. Recently, these clones have been gradually lost. The objective of this study was to investigate some factors affecting somatic embryogenesis for increase early introduced clones of rubber tree. In the present study, green bud from ex vitro grown plant were steriled and stored at 4°C for 24 hours then cultured on Murashige and Skoog (MS) supplemented with 2 mg/L 2,4- dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L 6-Benzyladenine (BA) for 6 months gave the highest callus formation at 100%, green compact callus at 72.45% and yellow friable callus at 27.55%. For adding silver nitrate (AgNO3), the concentration at 1.5 mg/L gave the highest fresh weight of callus at 950 mg and number of somatic embryos at 9.1 embryos/tube after 2 months of culture. The second times of subculture gave the highest somatic embryo induction at 81.33%, number of globular embryo (GE) at 11.61 embryos and cotyledonary embryo (CE) at 18.4 embryos. After subculture CE to PGR-free MS medium and cultured for one month the highest plant regeneration was obtained at 40%. The average number of complete plantlet at 0.24 plant/tube, average of shoot length and root length at 3.04 cm and 7.99 cm, respectively. For longitudinal thin cell layer (LTCL) culture, stem portion at 2 cm from shoot tip of seedling raised in vitro gave the best result in callus induction at 67.5% and earliest time required for callus formation at 17 days on MS medium supplemented with 2 mg/L 2,4-D and 0.5 mg/L BA under 14 h photoperiod. Application of wound by chopping the callus at frequency of 100 times gave the best result in proliferation of callus fresh weight at 471.08 mg after 1 month of culture. Addition of 1 mg/L AgNO3 to the culture medium gave the highest fresh weight of callus at 698.5 mg and average number of somatic embryos at 3.8 embryos/tube after 2 months of culture. So, this culture medium and protocol were suitable for rootstock propagation and breeding program of rubber tree in future.