Improving In Vitro Plant Regeneration from Leaf and Petiole Explants of `Marion' Blackberry

TLDR: Experiments focusing on plant growth regulators and combina- tions, mineral salt formulations, and TDZ pretreatment formations were conducted to optimize in vitro shoot regeneration from leaf and petiole explants of ʻMarionʼ black- berry.

Abstract: Additional index words. Rubus, tissue culture, thidiazuron Abstract. Experiments focusing on plant growth regulatorsʼconcentrations and combina- tions, mineral salt formulations, and TDZ pretreatment formations were conducted to optimize in vitro shoot regeneration from leaf and petiole explants of ʻMarionʼ black- berry. Optimum shoot formation was obtained when stock plants were incubated in TDZ pretreatment medium for 3 weeks before culturing leaf explants on regeneration medium (Woody Plant Medium with 5 µM BA and 0.5 µM IBA) in darkness for 1 week before transfer to light photoperiod (16-hour photoperiod at photosynthetic photon flux of ≈50 µmol·m-2 ·s -1 ) at 23 °C ± 2 °C for 4 weeks. Under these conditions, ≈70% of leaf explants formed ≈40 shoots per petri dish that could be harvested and rooted to form plantlets. Chemical names used: N6 -benzyladenine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); gibberellic acid (GA 3); indole-3-acetic acid (IAA); indole-3-butyric acid (IBA); α-naph- thaleneacetic acid (NAA); N-phenyl-Nʼ-1,2,3-thidiazol-5-ylurea (thidiazuron (TDZ)).