Biotechnological approaches to the reproduction of remontant forms of red raspberry

Rubus idaeus L. is one of the oldest and most widespread berry crops, which is cultivated for the excellent taste as well as for medical and dietary properties of berries. Rubus fruits contain a significant amount of vitamins A and C, anthocyanins, polyphenolic substances, which determines their high antioxidant activity. Remontant red raspberry forms are able to berry on annual shoots in the second half of summer, which extends the term of consumption of fresh berries by 1.5-2 months. However, many forms of remontant raspberry have a low potential for vegetative propagation compared to summer varieties, which makes them difficult to reproduce and to use in the breeding process. We investigated the possibility of increasing the efficiency of in vitro micropropagation of a remontant raspberry variety ʻBiryulevskaya’. The effects of 6-benzylaminopurine (6-BAP) at concentrations of 0.5–3 mg l and thidiazuron (TDZ) at concentrations of 0.05–0.2 mg l as well as doubled and tripled iron chelate Fe-EDTA (Ferric ethylenediamine-tetraacetic acid) doses were studied. We found the adding 1.0 mg l 6-BAP to the MS medium containing a triple dose of iron chelate, provided intensive proliferation of high quality adventitious shoots.