从行业标准中筛选出8对适用于玉米品种纯度鉴定的引物组合，能区分90%以上的审定品种。96%的审定品种在8个引物组合中有4个以上的杂合位点，具有较高的杂合率和品种区分能力。38份来自全国种子市场的样品同时进行田间种植和SSR纯度鉴定，8对SSR引物组合检测出自交苗平均值为0.6%，异型株为1.8%，纯度为97.7%；田间种植鉴定检测出的自交苗平均值为1.4%，异型株为0.6%，纯度为97.9%，两种方法检测的纯度值具有良好的相关性。对田间鉴定出的自交苗、弱苗、异型株和典型株进行SSR鉴定，结果表明，自交苗、异型株与典型株两种方法检测结果一致，SSR能准确区分田间难以鉴定的弱苗和病株。7份SSR检测一致性为3～5级的样品，SSR基因型和田间表型均表现出明显的分离，样品一致性差引起的非典型株界于典型株和异型株之间，是品种纯度鉴定的难点。

A combination of eight pairs of primer was selected from the industry standards suitable for purity assessment which had high heterozygosity and variety discrimination ability could identify more than 90% of approved varieties, and 96% of approved varieties have more than four heterozygous loci. SSRs and plant inspection were used to compare their ability to assess seed purity, 38 maize samples collected from national seed market were both tested by field planting and SSR purity. An average rate of 0.6% of inbred seedlings and 1.8% of off-types was detected by 8 SSR markers combination, and compared with the average rate of 1.4% for inbred seedlings and 0.6% for off-types in field planting identification. The purity values detected by the two methods had good correlation. The result of field inspection was consistent with SSR for identifying off-types and typical individuals, and SSR could accurately distinguish weak seedlings and diseased plants that were difficult to identify in the field. Significant separation of genotypes and phenotypes was observed in 7 samples with grade 3-5 of uniformity detected by SSR markers. Atypical seedlings caused by poor uniformity are difficult to identify in a variety purity assessment both for SSR and field inspection.

北京市农林科学院科技创新能力建设项目（KJCX20200305）