EFFECT OF CULTIVATION CONDITIONS ON THE GERMINATION/REGENERATION FREQUENCY OF MICROSPOROGENIC EMBRYOS BRASSICA OLERACEA L
Most genotypes of white cabbage (Brassica oleracea L.) have a low frequency of microspore-derived embryos germination and regeneration through adventitious shoots or secondary embryogenesis. Increasing the frequency of regeneration and the formation of seedlings can ensure the production of a large number of doubled haploids. This work studied the effects of gelling agents, such as agar (11 g/l), agargel (4.5 g/l), and phytagel (2 g/l), on the frequency of regeneration/germination of microspore-derived embryos of white cabbage (B. oleracea L.), as well as the effect of a cold incubation of kohlrabi cabbage embryos (B. oleracea var. gongylodes L. ) at 5°C for 3, 6, 9,12 and 15 days in complete darkness. The studies showed that when culturing embryos on regeneration medium B5 solidified with agar, the embryo germination and seedling regeneration were higher than those on media solidified with agargel and phytagel. No embryo germination but vitrification of embryo tissues was observed on media containing agargel and phytagel. Cold incubation of Kohlrabi cabbage embryos at 5°C for 3, 6 and 9 days in complete darkness twice increased the frequency of embryo germination compared to the control sample. More extended periods of cold incubation for 12 days in the dark, on the other hand, twice reduced the rate of direct embryo germination compared to the control sample, and for 15 days - 6 times.