Identification And Genetic Diversity Analysis Of Mesoembryonic Sterile Lines And Maintainer Lines In Sugar Beet

Sugar beet is one of the main sugar crops in China.The breeding results is great significance to promote the development of local economy and ensure the safety of sugar in China.At present,the sugar beet varieties are mainly monogerm trihybrids,so it is very important for sugar beet breeding to use monogerm cytoplasmic male sterile line and heteromorphic maintainer line to prepare binary male sterile line.40 pairs of single embryo cytoplasmic male sterile lines and maintainers of sugar beet（a total of 620 individual plants）were used in this study.Using molecular markers to sterility hybrid identification of sterile line and maintainer line,the fertility was verified by field morphological observation and the grain size of plants was observed,the hybrid plants and polygerm plants were removed,then,choose better agronomic traits of sugar beet plant DNA,using SSR molecular marker technology analysis of 40 to single embryo cytoplasmic male sterile line and maintainer of genetic diversity,The aim of this study was to provide basis for the preparation of binary male sterile line.The test results are as follows:1.The results of molecular marker fertility identification showed that 92 of the 620 individual plant DNA had mixed DNA fertility（N type cytoplasm in 19 sterile lines and S type cytoplasm in 73 maintainer lines）,the numbers of corresponding hybrid plants were recorded and morphological verification was carried out in the field.Morphological verification in the field showed that 122 plants were mixed（including 92 plants with molecular markers for fertility identification）.Through pollen observation,118 plants were found to have mixed fertility（49 fertile plants in sterile lines and 69 sterile plants in maintainers）,and 4 maintainers had different fertility identification results from molecular markers.There were 30 sterile plants（12 polygerm plants,18 monogerm plants）and 4 maintainer plants with different morphological and molecular marker identification results.All hybrid plants were removed in the field,which not only ensured the fertility and grain purity of sterile lines and maintainers,but also provided preconditions for genetic diversity analysis of these 40 pairs of sugar beet monogerm cytoplasmic male sterile lines and maintainers.2.35 pairs of SSR core primers were used to analyze the genetic diversity of 40 pairs of monogerm cytoplasmic male sterile lines and maintainers in sugar beet.Cluster analysis showed that tested material 22 had a far genetic distance from other materials and formed a separate group,while other materials were divided into four groups.There were 14 pairs of sterile lines and maintainers in the original group,and 26 pairs of sterile lines were not.To observe the genetic distance of male sterile lines in 14 pairs of original combinations,the male sterile lines with larger genetic distance between 14 primary groups and their heteromorphic maintainers were selected as the parents of binary male sterile lines for cross breeding.3.The nuclei of the 26 unpolymerized male sterile lines and their maintainers were still significantly different,so backcrossing and selfcrossing should be continued to achieve the purpose of nuclear homonucleation,and further tests should be conducted in the future.Through genetic diversity analysis,the possibility of breeding new varieties of sugar beet was increased,the blindness in breeding was reduced,the breeding efficiency of sugar beet was improved effectively,and the foundation for the preparation of binary sterile lines was laid.