| Abstract: | This study is dedicated to the effect of the epimutagen 5-azacytidine on the structure of floral-stalk metameres in sugar beet Beta vulgaris L. Simple phytomeres consist of separate flowers (unianthous plants; UA phenotype), while complex metameres occur in synanthous plants (SA phenotype). Treatment of the synanthous line mcSOAN-5 dramatically reduced the number of flowers on phytomeres as early as in generation zero (A0Az0). For the first time, plants with simple phytomeres were found in this line. The proportion of plants with the SA phenotype in generation A0Az0 was 7.7%. In generation A1Az1, the tendency for reduction of the number of flowers on phytomeres persisted. The proportion of plants with simple phytomeres reached 77%; i.e., the frequency of SA phenotypes in the progeny (A1Az1) increased tenfold in comparison with the parents A0Az0. The high frequency of morphogenetic changes in the floral stalk structure under the influence of the epimutagen suggests that the variability of the UA--SA character in beet populations is of epigenetic rather than mutational nature. |
