Efficiency of selection by ploidy in tetraploid populations of pollinator components of sugar beet MS hybrids

Abstract

Purpose. To identify the efficiency of tetraploid plants selection as affected by generations of polyploid populations of sugar beet and to create stable tetraploid pollinator components of MS triploid hybrids.Methods. Polyploid generations of sugar beet C3–C5 were used to stabilize pollinators. Cytological control of ploidity was used for selection of tetraploid plants.Results. The composition of tetraploid pollinator populations from the third to fifth polyploid generations of sugar beet of the Bila Tserkva Research Breeding Station was studied. In selection materials of various genotypes, different ratios of diploids, triploids and tetraploids occurred. The majority of the populations were tetraploids. In C3 generation, their share averaged 66.3% ranging from 52.5 to 80.0%. In C4 generation, the share of tetraploid plants increased by an average of 85.5% with a maximum of 90.0%. In the course of selection, 3rd and 4th generations of tetraploid population yielded in 12.7, and 3.0% of diploids, respectively, 21.0, and 11.5% of triploid biotypes. As a result of the cytotoxic analyses of each plant in the generation C5, a high level of genetic purity of tetraploid materials (97 to 100%) was recorded.Conclusions. In crossing tetraploid pollinators with pollen sterile component, it is necessary to pre-stabilize the ploidy of parent component. The ratio of diploid, triploid and tetraloid plants in the population of pollinator depends on the genotype. For the application of cytological control of ploidity during the selection of polyploid populations in combination with negative selection in C5 generation, practically complete stabilization of the ploidy was achieved (97 to 100% diploids). Two breeding numbers 1001 and 1003 were created, which were characterized by homogeneity of the ploidy (100% tetraploids).