Somaclonal variation in regenerated plants derived from callus of peach rootstocks

摘要

This research aimed to investigate a reliable protocol for callus induction and regeneration of peach {Prunus persica L.) rootstocks; 'Montclair', 'Nemaguard' and 'Okinawa', using mature seeds as in vitro establishment material. Seeds recorded the highest germination percentage when disinfested using 20% Clorox for 30 min prior to culture on Woody Plant Medium (WPM). Each seed was cultured separately and tagged with a serial code. The combination of 1.5 mg L' benzyladenine (BA) + 0.2 mg L1 gibberellic acid (GA:i) produced sufficient number of shoots with suitable medium height for all tested rootstocks during multiplication stage. After three consecutive subcultures, all the three tested rootstocks succeeded in callus formation with highest mass byadding 1.0 mg L 1 indolebutyric acid (IBA) + 1.0 mg L1 naphthaleneacetic acid (NAA) to half-strength Murashige and Skoog (MS) culture medium in the presence of 1.0 g L1 polyvinyl alcohol (PVA). Callus clusters of 'Montclair' rootstock, which recorded thehighest callus induction frequency on different auxin treatments, were differentiated when transferred to MS medium free of PVA and growth regulators. The highest concentration of NAA (2.0 mg L1) was more effective regarding root formation, especially when combined with the highest IBA concentration (2.0 mg L1). Inter Simple Sequence Repeat-Polymerase Chain Reaction (ISSR-PCR) results confirmed the role of fragments polymorphism of 'Montclair' rootstock regenerants identification and discrimination ascompared to directly regenerated one from the original individual.