PREVENTION OF SHOOT VITRIFICATION OF STRAWBERRY MICROPROPAGATED SHOOTS PROLIFERATED ON LIQUID-MEDIA BY NEW ANTIVITRIFYING AGENTS

Micropropagated strawberry (Fragaria x ananassa Duch. 'Kent.') cultured for 4 wk in liquid proliferation media supported on cellulose plugs (sorbarods) developed a high rate of vitrification. This high percentage of abnormal plantlets was significantly reduced by the inclusion of two antivitrifying agents, EM1 and EM2, to the liquid medium. Virtually no vitrification occurred at 5 g L-1 of EM1 or EM2. Shoots multiplied on liquid medium supplemented with 5 g L-1 of either EM1 or EM2 had significantly lower fresh weights and lower multiplication rates than on solidified agar medium (0.7%). EM2 produced better growth and proliferation than EM1 or liquid medium alone and was easier to use than EM1.