Abstract:

35 pairs of SSR primers were used to analyze the genetic diversity of 40 pairs of monogerm cytoplasmic male sterile lines and maintainer lines of sugar beet. The results showed that: the number of bands amplified by each pair of primers ranged from 2 and 12, and the average value of effective number of alleles (Ne), Shannon’s information index (I) and Nei’s gene diversity index (H) was 2.306, 0.891 and 0.519 respectively. The UPGMA method was used for cluster analysis and genetic distance calculation. The cluster analysis results showed that tested material 22 had a far genetic distance from other materials, which indicated a distant genetic relationship, and the material belonged to a separate group. The rest of the tested sugar beet lines could be divided into four groups. A total of 14 pairs of monogerm cytoplasmic male sterile lines and maintainer lines of sugar beet were completely polymerized together, indicating that after backcrossing, the nuclear genomes of male sterile lines and maintainer lines were almost identical with high purity, which could be directly used in sugar beet breeding in the future. The other 26 pairs of low purity, large genetic distance, still need to continue to backcross to homozygous. The maximum genetic distance of the 80 tested materials was 0.462 and the minimum was 0.120. The genetic distances of the sterile lines in the 14 pairs of primary mating groups were different. In the future, sugar beet cytoplasmic male sterile lines with large genetic distance from the 14 pairs could be selected with their heterogeneous maintainer lines to prepare binary male sterile lines for female parents in hybrids. The study can promote new sugar beet variety breeding and effectively improve the breeding efficiency.

Key words: sugar beet, SSR molecular marker, cytoplasmic male sterile line, genetic diversity