IN VITRO SOMACLONAL VARIATION AS INITIAL MATERIAL FOR BREAD WHEAT BREEDING

Somaclonal variation is an effective tool for creating genetic diversity of plants, an alternative method to classical ones based on crossing and using mutagens. The article presents the evaluation of quantitative and qualitative characteristics of the first generation somaclones (SC1) derived from immature embryo culture of 11 spring bread wheat varieties of different geographical origin. Phenotypic differences in 28.7 percent of regenerants compared with their donor parents were found. Among them, more than 46% of the plants have formed sterile ears or very frail grain, 17 percent of somaclones have increased tillering (up to 8-17 shoots) which led to the formation of a large number of productive stems. About 10% of the studied plants have changed ear color. Dwarfs, awnless forms and plants with short spikes containing reduced spikelets were discovered approximately equal amount (6.0–7.8 percent). Phenotypes with a curved stem, the changed stem color and a square-headed ear with the compressed apical part have segregated with a minimum frequency not exceeding 2.8 percent. The frequency of changed forms and spectrum of variation were specific to each cultivar. The variation ranged from 20.0 (Tselinnaya 20) to 56.6 percent (Botanicheskaya 2). A number of variable traits ranged from 2 to 8 depending on a donor. The genotypes with a wide spectrum of variable features which could be of great interest for producing new forms were revealed. It is noted that the display of traits affected not only a genotype, but changes occurring at the cellular level during in vitro cultivation. Significant differences among somaclones derived from a callus were stated. Key words: bread wheat, immature embryos, somaclonal variation, regenerant, agronomic and biological traits, variation frequency, variation spectrum.