Micropropagation of two apricot × plum inter specific hybrid rootstocks (HS405 and HS706)

Several new superior apricot × plum (Prunus armenica × P. domestica) inter specific hybrid rootstocks have been recently produced in Iran, but the propagation of these hybrids by conventional means has been shown to be very difficult. In vitro propagation could be a reliable method for mass clonal propagation of these new rootstocks. In this study, in vitro establishment, proliferation and rooting of two apricot × plum inter specific hybrid root stocks namely HS405 and HS706 were evaluated. For disinfection, different concentrations of ethanol, sodium hypochlorite and mercuric chloride were tested. The highest number of active buds was obtained from spring season nodal explants in hormone-free WPM medium. Addition of 200 mg/l Na-Cefotaxime or 100 mg/l nano silver had a positive effect on controlling indigenous contaminations. The greatest shoot proliferation was recorded by using 4 mg/l BAP + 0.5 mg/l GA3 supplemented in the WPM medium. Addition of 2 mg/l GA3 to the culture medium improved shoot elongation, significantly. The best results were obtained for rooting when micro shoots were dipped in a 1000 mg/l IBA solution for 20 seconds and cultured on hormone-free WPM.