Micropropagation of Two Australian Native Fruit Species,Davidsonia pruriens and Davidsonia jerseyana G. Harden & J.B. Williams

Nodal explants from in vitro grown seedlings of Davidsonia pruriens and D. jerseyana, established on MS media were treated with various concentrations of three cytokinins. D. pruriens developed optimum shoot growth in terms of shoot height and number of leaves per shoot when 1.0 µM BA was added to basal MS medium while optimum shoot growth for D. jerseyana was obtained when 0.01 µM 2iP was added to the medium. Optimum root initiation and development was obtained when actively growing axillary shoots were cultured on 1/2MS medium plus 32.2 µM IBA for 3–5 days for D. pruriens and 2–3 days for D. jerseyana before transfer to PGR-free medium containing 10 µM riboflavin. Root initiation of more than 80% was achieved with multiple genotypes of D. pruriens and three genotypes of D. jerseyana using juvenile material. The plantlets were transferred to pots and grown in the greenhouse with a success rate of 60% for D. pruriens and 75% for D. jerseyana. Adult D. jerseyana stem explants produced 2–5 shoots per nodal explant upon treatment with 0.1 µM BA. Side shoots from adult D. jerseyana produced similar results for shoot multiplication as for juvenile material. Protocol for multiplication of adult D. pruriens was achieved with much greater difficulty by using material from the green house. Axillary shoots were initiated when 100 µM TDZ was applied to the stem of an adult pot plant and the resultant side shoots were cultured on MS medium containing 1.0 µM BA and 1.0 µM GA₃.