A study on the adaptive potential of new sterile cytoplasm of Beta patula and Beta maritima L. from wild beets of the genus Beta L.: cold resistance and traits of early sugar accumulation in introduced alloplasmic lines

Abstract

Purpose. Assessment of new sugar beet breeding genotypes by a set of economically valuable traits to determine their suitability for the efficiency of the process of managing the production of bioethanol with the study of the activity of photosynthesis according to the content of chlorophylls a and b, early accumulation of carbohydrates, tolerance to low temperatures, germination of apozygous seeds and using new plasma of the substituted lines of sugar beet with introduced sterile cytoplasms from wild species Beta patula and B. maritima L. and apozygous lines A9 with S vulgaris Owen's cytoplasm. Methods. Field methods were used (pollen-free regime for the reproduction of apozygotic seeds in conditions of isolation and seed monogermity of the seed plants), laboratory methods (selection of the best experimental genotypes for cold resistance, analysis of productivity and dynamics of carbohydrate accumulation). Results. Self-fertile pollen-sterile lines A9 Beta vulgaris Sxxzz rr with an apomictic method of seed reproduction of seeds (Yaltushkiv EBS) and commercial hybrids with early carbohydrate accumulation were selected for the recessive colour of the hypocotyl r-r- and gametophytic reduced parthenogenesis for hybridization according to the scheme: A9 Beta vulgaris Sxxzz rr × Beta vulgaris Mm Rr. The influence of cytoplasmic inheritance of B. maritima and B. patula on cold resistance indicators was studied and seed samples of the experimental genotypes No. 17225, 17221, 17222, 17220, 17226, 17223 were selected among substituted lines with seed germination rates at +4°C varying from 14.3 to 40.3%. Experimental genotypes of the substituted lines, grown in the conditions of pots were selected and examined by the indicators of early accumulation of sugars, which had values from 16.2 to 17.6% during four months of vegetation; photosynthetic activity with indicators of the content of chlorophyll varying from 2.06 to 1.32%, and chlorophyll b from 1.02 to 0.65%. Conclusions. Sugar beet hybrids, created with the use of cold-resistant substituted pollen-sterile lines of sugar beet, thanks to the natural evolution of the introduced cytoplasmic genome, ensure the extension of the growing season, high productivity, early accumulation of sugars and enrichment of the crop adaptation potential. The article contains the results of the study of the early carbohydrate accumulation, photosynthetic activity of selected experimental genotypes of the substituted sugar beet lines with high seed quality and 100% monogermity. Root crops of apomictic lines were selected based on R+r hypocotyl colour, generative reduced parthenogenesis, and studied for their specifics of seed set under the pollen-free regime.