NEW PROTOCOL FOR IN VITRO PROPAGATION OF BERRY PLANTS BY TIS BIOREACTOR

M. Georgieva, L. Georgieva, V. Kondakova, I. Tsvetkov

Abstract: The purpose of this study is to explore the possibility of optimizing the standard protocols for in vitro propagation of important berry crops: raspberry, cv. Polka and strawberry, cv. Tudla, using bioreactor system. The effectiveness of the two systems (solid media and liquid in TIS bioreactor, RITA® type) are evaluated in 2 stages – propagation (on MS based media supplement with 0.5 mg.l–1 BAP, 0.05 mg.l–1 IBA, 0.03 mg.l–1 GA3 and 30 g.l–1 sucrose) and rooting (MS without hormones supplement with 30 g.l–1 sucrose). At each stage are measured fresh and dry weights of the explants, while the rest continued their development. In solid medium strawberry plants multiplication ratio for 4 weeks was 1.9 while in liquid – 4.1. Respectively for raspberry this ratio was 3.2 and 6.7. Fresh mass of TIS plants were increased for both species, whereas in plants grown on solid medium was observed a much higher percentage of dry matter. This means that the high fresh weight of the plants in a liquid medium is primarily due to water accumulation. Root initiation of strawberry began about 3rd week and after 5th week all plants was rooted successfully in both liquid and in the solid medium. For the same time only few raspberry plants formed roots in the same condition. That is the reason we tested another 3 variants of rooting systems. All plants of the three variants are rooted successful within 4 weeks. Highest percent dry weight, where the plants transferred on solid medium from liquid one (variant 2). Rooted plants were successfully adapted in soil in a greenhouse. TIS is a promising alternative system of mass propagation for strawberries and raspberries. The different purposes of application of the bioreactor system requires further optimization of the growing medium and precise conditions of cultivation of each species and variety. Micropropagation for strawberry could be entirely in liquid medium. For raspberry there is a problem with hyperhydration when the plants stay more time in liquid medium. We suggest an optimized protocol for mass propagation of raspberries, which includes plant propagation in a liquid medium (TIS bioreactor) and rooting them in solid medium.

Keywords: in vitro propagation; raspberry; strawberry; TIS bioreactor

Date published: 2017-08-28