1 玉米亲本种子质量现状 1.1 亲本种子混杂严重。经国家三年抽检,玉米自交系种子合格率平均为39%,主要问题是纯度太低,普遍表现在自交系混杂严重。一是混入其它品种的自交系,主要是由机械混杂造成;二是混入杂交种子,原因是在亲本繁殖过程中,未能严格按照制种规程操作,隔离或错期不当,去杂去劣不彻底,造成亲本种子的生物学混杂。当然,也不排除机械混杂因素;三是出现可疑植株,主要是由于自交系经过长期混合繁殖,本身发生变异,使植株间差异逐渐扩大,由纯向杂转化,出现非典型植株,亲本种子的混 1 Maize seed quality status 1.1 The parent seed mixed serious. The national three-year sampling, maize inbreds pass rate of 39% on average, the main problem is the purity is too low, generally manifested in the inbred mixed serious. One is mixed with other varieties of inbred lines, mainly caused by mechanical mixing; the second is the hybrid seed mixed because the parent reproduction process, failed to strictly follow the rules of seed production, isolation or improper distribution, miscellaneous and bad Incomplete, resulting in the biological hybrid of the parental seed. Of course, it does not rule out the confounding factors of machinery. Third, there are suspicious plants, mainly due to long-term inbred lines after inbreeding and mutation itself, so that the differences between plants are gradually widened, transformed from pure to heterotic plants, and atypical plants Mixed