Resistance of Sugar Beet Genotypes to Salt Stress

In this work, using biochemical and molecular genetic approaches, the genotypes of sugar beet were studied under conditions simulating salt stress to select stable samples for breeding. Sugar beet plants grown under 150-, 280-, and 500-mM salinity were used as materials for experiments. Under conditions of 150-mM salinity, RMS-127, O-type 2113, OP 021729, and MS 020026 samples showed an increase in catalase activity by 33.0, 14.1, 81.4, 5.1%, accordingly, in comparison with control samples. In these genotypes, with an increase in NaCl concentration to 280 mM, an increase in superoxide dismutase activity was noted, by 28.9% in RMS-127, 78.7% in MS 020022, 54.3% in O-type 09001, 65.5% in OP 021722, and 67.3% in OP 021729 relative to the control. As a result of quantitative real-time RT-PCR, the expression of the SOD and CAT genes was detected in the studied sugar beet genotypes under conditions of 150- and 280-mM salinity. An increase in the expression of the SOD gene was shown in samples MS 020026, O-type 2113, and OP 021729 at 150-mM salinity by 2.5 times on average relative to the control. The maximum expression level of the SOD gene was established in the MS 020022 and RMS-127 genotypes at 280-mM salinity (1.5 times higher than the control). In MS 020026, MS 020022, and O-type 09001, the maximum gene expression was recorded at 150 and 280 mM of salt by more than five times compared to the control and by three times in O-type 2113 at 150 mM compared with the control. According to the results of the study, all the studied genotypes were selected as salinization-resistant starting material for breeding.