Development of in vitro shoot cultures of strawberry (Fragaria × ananassa Duch.) ‘Senga Sengana’ and ‘Elsanta’ under the influence of high doses of gibberellic acid

In this study, the influence of gibberellic acid (GA₃) on strawberry in vitro shoot culture growth and development was investigated. ‘Senga Sengana’ and ‘Elsanta’ clones were grown on the medium recommended by Boxus (1999), supplemented with BA (0.5 mg dm^-3), IBA (0.1 mg dm^-3), glucose (40.0 g dm^-3) and GA₃ (0.1 - control, 1.0, 2.0, 5.0, 10.0 mg dm^-3). In general, gibberellic acid improved axillary shoot elongation and reduced the growth of callus as well as the formation of roots and the development of adventitious shoots. GA₃ applied at a concentration of 1.0-2.0 mg dm^-3 significantly increased the number of axillary shoots (mainly crown shoots), whereas under higher (5.0-10.0 mg dm^-3) doses it stimulated the development of runners. It seems that a new method of strawberry micropropagation based on the multiplication of axillary crowns and runners, which could also reduce the risk of domination of in vitro cultures with adventitious shoots, might be elaborated