Some technological aspects in vitro impact on spring rapeseed (Brassica napus L.) unfertilized ovules differentiation

The aim of research is to study the influence of the stage of development (size), the time of treatment of the buds with low positive temperatures and the genotype of the donor sample on the dedifferentiation of callus from unpollinated ovules of spring rape. Research objectives: to introduce isolated ovules into in vitro crop and determine the frequency of explants dedifferentiation on Murashige-Skoog (MS) agar nutrient medium with the addition of growth regulators 2,4-D (2-4 dichlorophenoxyacetic acid) and kinetin at 5.0 mg / l. The objects of the study were non-pollinated ovules of eight hybrid samples of spring rape. Samples 1 and 2 formed callus tissue with a frequency of 2.6 and 2.5 %, respectively. Ovules isolated from buds of the studied sizes (2.0; 4.0; 6.0 mm) differed in the frequency of callus dedifferentiation from 11.59 to 16.95 %. The ovules isolated from the 6.0 mm buds were the most competent for callus formation and formed callus with a maximum frequency of 16.95 %. Treatment of inflorescences for 24, 36 and 60 hours at low temperatures of 4 ± 1 ° C does not have a positive effect on the formation of callus tissue from ovules. The frequency of dedifferentiation decreases from 7.29 % without treatment of buds to 1.24 % - with 60 hours of treatment. The results of the cultivation of ovules on the initial nutrient medium showed that the frequency of dedifferentiation in the studied genotypes of spring rape varied from 0.2 (sample 188) to 2.6 % (sample 1). Ovules isolated from donor plants obtained using tissue culture induced callus tissue at a frequency of 15.57 %. Secondary structures and seedlings were obtained on MS medium supplemented with 6-BAP (6-benzylaminopurine) - 0.5 mg / L and kinetin - 3.0 mg / L. The results obtained indicate the effect of preprocessing, the size of the buds and the genotype of the donor plant on the frequency of dedifferentiation of ovules of spring rape.