EFFICIENT PLANT RETRIEVAL FROM ALGINATE-ENCAPSULATED VEGETATIVE BUDS OF MATURE MULBERRY TREES

Axillary vegetative buds of 3-year-old mature mulberry trees of three indigenous and two Japanese varieties from the open field were success fully encapsulated in calcium alginate beads. The best gel complexatio n was achieved using 4% sodium alginate with 75 mM CaCl2.2H(2)O. Use o f semi-solid MS medium resulted in 100% conversion of encapsulated sho ot buds into plantlets, especially when buds were pretreated with 1.0 mg l(-1) BA for 36 h. Although sprouting was faster on medium fortifie d with 1.0 mg l(-1) BA and 0.3 mg l(-1) GA(3), one-step germination, i .e. both shoot and root induction, was better on a MS basal medium wit hout added phytohormones. Among several plating substrates assessed fo r in vivo germination, the maximum response was elicited on artificial soil moistened with half-strength MS medium devoid of sucrose. A vari etal difference was evident with respect to germination potential betw een encapsulated meristems under in vitro and in vivo situations. The encapsulated buds could be stored for 60 days at 4 degrees C without l oss of viability only when the gel matrix contained MS nutrients, vita mins and sucrose. There was a negligible (< 10%) mortality of complete plants while they were being transferred from artificial soil to natu ral soil and finally to the open field.