Objective  To improve the fertility purity of beet monogerm cytoplasmic male sterile lines and maintainers.

  Method  Forty pairs of molecular markers from a collection of 620 monogerm cytoplasmic male sterile and maintainer sugar beet germplasms were identified.All genetically mixed markers in the sterile and maintainer plants were given specific codes and recorded.Subsequently, a morphological observation was carried out in the field to exclude genetically impure plants.

  Result   The verification of heredity purity by molecular markers revealed 92 DNA including 73 in the maintainers mixed with that of the sterile plant and 19 in the sterile lines contaminated with that belonged to the maintainer.The field examination on pollens and grains identified 122 plants (as compared to 92 isolated by the molecular marker verification) with 73 maintainers and 49 sterile lines to be promiscuous.In addition, polygerm plants were unexpectedly found in the lot that could have grown from the accidentally included seeds.

  Conclusion   By excluding adulterated plants in the field, the purity on heredity of sterile and maintainer lines could be assured.The procedure would provide the prerequisite essential for accurate genetic diversity determination and successful preparation of binary sterile sugar beet lines.